feat(gui): step1 skeleton — dsc web serves built web UI over booted harness host

Five new modules: apps/dsc (bin: parseArgs + node:http static server +
signal shutdown), packages/host/apiproxy (programmatic harness core
composition, agents:[]), packages/client/web-runtime (React-free browser
runtime), packages/client/web-ui (React mount), apps/web (vite build
entry producing dist consumed by apps/dsc via package exports).

Root wiring: apps/* workspace glob, dsh-* paths for host/client groups,
demo:web script, apps/web/dist gitignore. No protocol/API routes yet —
contract lands in step2 (see missions/tasks/20260719-1902-apiproxy-api-design).

Includes the design + implementation archives (spec v2.1, deepseekchat
baseline and harness boot research, implementation run log).

Acceptance: 12/12 passed incl. real-key llm.stream smoke (51 chunks).

feat(gui): apiproxy — four-quadrant RPC contract + fetch carriers, live end to end

Contract layer (src/api/, 14 files): four named wire message types
(ClientRequest / ServerResponse / ServerRequest / ClientResponse) as a
discriminated union over strict bidirectional rpcId (initiator mints,
responder echoes; channel and message fully decoupled — HTTP is the
client->server pipe, SSE the reverse); narrow RpcRequest<P>/
RpcResponse<T> signature forms; RpcMethodMap with RequestPayload<K>/
ResponseValue<K> derivation; typed RpcError details map; approval/
question responses modeled as ClientResponse via a single /api/respond
endpoint (RpcReceipt carrier ack); zod schemas anchored per Wire<T>
against exactOptionalPropertyTypes.

impl/api-proxy.ts: describe/list/create, both SSE streams (frame queue
pump, subscribed baseline, lifecycle frames, signal cleanup); history
pages on message boundaries (tail-back scan, partial included in the
tail page); prompt dispatches queue->agent.send / steer->agent.steer
with rpcId carried through MessageSource; cancel for attached sessions;
cold-session resume deduped via a per-id promise map; host-level
provider/model defaults injected at create/resume.

fetch/: mechanical UNARY_ROUTES table, two-level parse with
path==method check, SSE frames completed to ServerRequest full form;
client mints -> narrows -> envelopes outbound, verifies rpcId echo
inbound, streams SSE frames, four-quadrant onEnvelope tap (debug panel
choke point). Real-browser fixes: URL base resolves to location.origin
(hardcoded internal base broke real pages), browser-safe export paths.

Design archives: contract design.md v2.0 with decision log,
core-coverage audit, comparative studies, step2 impl run log. Probed
end to end over real HTTP: prompt -> live model stream -> history
returns the finished reply.

feat(gui): RpcLog debug panel — fixture-driven milestone, playwright-verified 10/10

web-runtime: rpcLog + ui slices (zustand), four-quadrant RpcLogEntry
(client-request / server-response / server-request / client-response),
onEnvelope tap -> microtask-batched pump with 500-entry ring buffer,
ConnectionController (private state, backoff reconnect), fixture API
with fake envelopes (?fixture switch), bootWebRuntime; contract types
via temporary local copies (api-types.ts, swapped for real imports when
W3 client lands).

web-ui: components/panels/RpcLog five-piece set (badge with unread
count, floating panel, direction glyphs per quadrant, same-rpcId
pair highlighting in two families, JSON payload expand, follow/pause,
clear), App shell, utils/formatRelative, light-theme CSS variables with
dark placeholders.

dsc bin: mime lookup fixed to use the actually-served file (naked
'/?query' no longer falls through to octet-stream download); shutdown
closes SSE keep-alive connections so SIGTERM actually exits.

Acceptance: scripts/verify-rpclog-panel.mjs (chromium headless) ALL
PASS 10/10 over design.md §D 1-6.

pkg: add web scripts for building

feat(gui): session milestone — list + conversation over Session OOP, styled RpcLog v2.1

web-runtime: Session/SessionManager object layer (resident instances,
mux frame routing, lineage flattening), foldSurface adapter with padding
sentinels for paged windows, chunk accumulator for streaming partials,
batched change notification (useSyncExternalStore contract), connection
sinks + reconnect fix (the 300ms self-abort reconnect storm that made
the session list flap is gone), fixture rewritten as a scripted host
(60-turn history, typewriter replay, resident pending approval, child
session); temporary contract copies deleted in favor of real apiproxy
imports.

web-ui: sessions screen (list with lineage indent + selection as
container-local state), conversation view (turn grouping, reasoning
fold, tool cards, steering, pending interaction cards, upward paging
with scroll anchoring), input bar with queue/steer/stop; RpcLog panel
restyled per docs/web-styling.md (tokenized palette, quadrant badge
glyphs now vertical ↑↓⇟⇞, pair highlighting, floating shadow).

docs/web-styling.md: living style guide (tokens, visual baseline,
coding rules, evolution log).

Acceptance: verify-session.mjs 31/31, verify-session-real.mjs 5/5
(real model streaming), verify-rpclog-panel.mjs 10/10.

feat(gui): hostruntime split + repo-wide package prefix rename

Package split (design: 20260720-0101-hostruntime-split-design):
dsh-host-runtime carries bootHost + createApiProxy + startHost()
(RunningHost {api, handler, defaults, ctx, dispose} — the seam Electron
and any future shell reuses; ctx is the official front-door mount
point); dsh-host-webserver carries the node:http static+API bridge
(fixed: abort now keys on res 'close' + writableEnded — req 'close'
fires on body end since Node 16 and was killing every SSE stream
instantly, the reconnect-storm root cause); apps/dsc is now a thin
assembly with web/-p subcommands. dsc -p runs the full isomorphic
carrier chain in process (second real protocol consumer; probed
end-to-end against the live model).

Naming rule (user decree): packages under host/ and client/ carry the
directory prefix in their npm name — dsh-host-apiproxy,
dsh-client-web-runtime, dsh-client-web-ui renamed repo-wide in one
frozen batch; explicit tsconfig paths entries added where the wildcard
no longer matches.

Acceptance: verify-session 31/31, verify-rpclog-panel 10/10,
verify-session-real 7/7 (incl. new 12s connection-stability sentinels),
tsc green, dsc web + dsc -p smoke both pass.

refactor(gui): AbstractApiClient class hierarchy — OO client with inheritable seams

AbstractApiClient (apiproxy) carries every protocol invariant: rpcId
minting, four-quadrant envelope wrap/unwrap, zod parsing, SSE frame
parsing, the payload-direct IApiClient surface (callers no longer mint
rpcIds — the carrier does), and the instance-level envelope observation
pump (batched via microtask; moved off module-level globals in
rpc-log.ts, which is now a pure subscriber mapping envelopes into store
entries — the debug panel observes the connection, it is not part of
it).

Platform subclasses own two abstract seams (doFetch, onEnvelope) plus
three protocol-level virtuals for transportless overrides:
InProcessApiClient (apiproxy; dsc -p uses new InProcessApiClient(
host.handler)), WebApiClient (web-runtime), FixtureApiClient (fixture
now subclasses instead of wrapping). Naming per decree: AbstractApiClient
/ IApiClient; ApiProxy stays the impl-side narrow-form contract.

headless.ts call sites drop rpcRequest wrappers (payload-direct);
split-design archive updated with the naming-rule ledger.

tsc green; verify-session 31/31, verify-rpclog-panel 10/10,
verify-session-real 7/7 (12s connection sentinel count=4); dsc -p smoke
CALLER-OK.

feat(gui): InputBar final form — bug batch, deepseekchat layout, single primary button, running locks input

Squashes the whole InputBar iteration batch: IME/caret/auto-grow/focus/dedup
bug fixes, layout aligned to the deepseekchat baseline, single primary button
with hover flyout, finalized button semantics with the Codex-style icon
circle, and running-state locking where stop is the only mid-turn action.
The same batch carried the Chinese-to-English code comment sweep
(density pruned), folded in here.

docs(gui): purge work-log references from code comments

76 design-doc references cleared across the GUI packages: section
pointers inlined as self-contained constraint statements, pure pointer
comments dropped, milestone codenames and ruling tags out, and the 14
contract file headers switched to the formal RFC (the only sanctioned
external reference). web-styling.md now cites the styling RFC instead
of the disposable research archive. grep for work-log reference
variants is clean across the GUI packages.

docs(gui): file-header comments self-contained — drop RFC filename references

RFC renames/reorgs must not require a source sweep (the 2026-07-20
two-way merge proved it). 11 headers lose only the '(RFC …)' tail and
stay self-contained; api-proxy.ts keeps its minimal-first note.

fix(gui): session streaming — freeze interrupted partials, sweep stale running calls, send force-scrolls

Aborted turns never emit the finalizing assistant/message, so the
accumulated partial and its running tool cards kept rendering below
later messages — the "new message lands above the stopped reply"
illusion. turn/end side effects now freeze content-bearing partials
into interrupted terminal nodes (fractional seq keeps flow order; the
live freeze and history replay converge through applyEventSideEffects,
so a refresh reconstructs identical frozen nodes) and turn running tool
cards into interrupted terminal cards; only content-free partials are
swept outright. ConversationView gains the send-force-scroll rule (own
words must be visible) alongside the pre-update atBottom follow flag.
Regressions pinned as E2-4a–c (real host) and §E1-11h (fixture).

feat(gui): webserver hardening verify script

feat(gui): dark-mode toggle pinned to the sidebar bottom

Interim home before the Settings page exists (the button re-homes with
zero logic change — mechanics live in utils/theme.ts): html[data-theme]
flip + dsc.theme localStorage, stored choice wins over the OS
prefers-color-scheme default, applied in mount() before first paint so
a dark reload never flashes light. Moon/sun inline SVG icon button at
the sidebar's pinned bottom row. Pure front-end local concern: no RPC,
no Session/store involvement. Dark sweep of list/conversation/input
card/RPC panel found no unreadable pairs — no token changes needed.

docs(gui): GUI RFCs and web styling handbook

Layering+RPC protocol and web client architecture RFCs (post-reorg,
developer-facing polish folded in) plus the styling engineering
handbook. Mission work logs live in the commit above; PRs can be cut
from this commit to include formal docs only.

fix(gui): client object-layer hardening — audit timing/reference/resilience batches (S3-S5,C1-C3,C5-C8)

fix(gui): carrier error channel + webserver backpressure (audit A1-A5,A7-A10,R2,R5)

feat(gui): session persistence surface — cold list, project cwd, legacy no-cwd retirement

refactor: rename dsc CLI to dsh — apps/cli, bin name, package scope

Includes the root tsconfig project-references fix for host/* and
client/web-runtime (originally a separate build fix commit).

test(gui): three-tier suite — protocol/object/browser lanes, tier-a fill to per-file 100%

test(gui): jsdom lane for web-ui + web-runtime coverage gate entry

docs(gui): GUI testing system RFC (zh)

feat(gui): tool-card views — contract slot, host-computed delivery, three-level card fallback

fix(gui): lint clean across GUI packages — wrap long doc comments, drop dead type args, sync-return methods without awaits

docs(gui): doc-sync mechanical fixes — JSDoc on apiproxy/host exports, RFC sketch fences ignore-check, md-wrap paragraphs, drop missions links, web-ui plain-ts entry

chore(gui): module-graph regen + knip clean — drop dead re-exports, internalize createFixtureApi, scan web-ui tsx and verify mjs scripts

build(gui): wire client/host packages into the lib build shape — tsc references + tsdown (web-ui css-external), lib manifests, cordis peer, apiproxy typed subpaths, vite src aliases

test(gui): host-side per-file 100% coverage — apiproxy schema/carrier suites, webserver http-bridge suite, host-runtime composition suite; client/* coverage excluded pending the browser-side testing work item

docs(gui): package READMEs for the five GUI packages — model-experience audit entries, limitations sections

docs(gui): bilingual RFC pairs + client JSDoc completion — translate the three GUI RFCs to English with i18n records and manifest ratchet, Consequences sections both sides, full client/* export JSDoc, regen doc graphs and RFC index

fix(scripts): doc-typecheck built-declarations mode maps /src/* subpath wildcards (apiproxy browser-safe channels)

docs(gui): apply dsh rename across pr-gates docs — READMEs, layering RFC en, web-ui entry comment, i18n re-record

fix(gui): post-rebase lint reconciliation — wrap main-tree long doc comments, read-through narrowing guards, abortError Error normalization, handleUnary generic justification

fix(gui): post-rebase doc/test reconciliation — align host specs with evolved carrier contracts (sentinel rpcId, stream/error surfacing, url-path transport messages, defaults.cwd), Agent Note titles and relocated links, KV Cache effect sections, JSDoc on evolved exports

fix(gui): second-rebase reconciliation to 509db0cb3 — restore api panel exports the baseline suites consume, knip workspace entries for jsdom lane and apps/web smokes, hoist result narrowing, align testing.md to the narrowed web-ui exclusion

fix(test): vitest-scoped tsconfig maps bare imports for tsx specs — with GUI manifests now pointing at lib, an unmapped importer loaded a second copy of the web-runtime singletons

fix(gui): typecheck + lint clean over the tool-card batch — brand callIds and object-form turn/end reason in the view spec, narrow fixture arg stringification, wrap long v8-ignore comments

docs(gui): export JSDoc for tool-card surfaces + testing-note pairing header

docs: rfc for web testing

feat: add tools to host-runtime

fix(gui): dispatch agent/error via agentEvents in host-runtime spec — mounted invariants plugin rejects raw ctx.emit without the scope carrier

fix(gui): restore GUI knip workspaces + scripts/mjs entries and regenerate lockfile after master rebase

fix(gui): post-rebase gate repairs — drop context-node envelope (master unwrapped injected content envelopes), regen event matrix, condense testing.md web-ui exclusion within budget

fix(session): browser-safe deep-equal in surface — node:util import broke the vite bundle

ci(gates): frontend vite build joins pre-push — node: imports in the client closure pass tsc but break the browser bundle

test(tui): drop the checkout-dependent process.cwd() harness default — a long worktree path pushes the footer token counters past the 88-column fake terminal

test(gui): jsdom behavior E2E — conversation main path over fixture runtime, reconnect banner lifecycle

test(gui): jsdom RPC panel behavior — ledger rows, expand, pairing, pause/clear, follow-pause, payload truncation

test(gui): jsdom tier-2 — InputBar guards, reasoning fold, JSON blocks, message variants, theme, create-then-select; act-harden banner case

test(gui): jsdom tier-3 — ConversationView states/paging/force-bottom, ToolCallCard arms, PendingCard, list rows

test(gui): jsdom tails — view-card variants, LogRow directions, registry hygiene, badge overflow, hook ops, mount glue

test(gui): jsdom tails round 2 — call-ref blocks, resume follow, view precedence, failed create, empty-diff arm

test(gui): jsdom final arms — anchor compensation, follow-off, interval ticks, view halves, node-over-running precedence

test(gui): web-ui joins the per-file 100% coverage gate

Annotation-only src changes plus the config swap. The web-ui exclusion is
replaced by a single index.tsx entry (stale byte-identical duplicate of
mount.tsx, nothing imports it; same entry-glue treatment as bin.ts) and the
coverage include gains .tsx.

v8-ignore sites (each with its reason inline):
- ConversationView 3x ref-null guards; InputBar disabled-click guard
- ToolCallCard both-null arms + windowless-custom argsRaw arm
- LogRow css-module key fallbacks (start/stop block); RpcLogBody 3x ref-null guards
- web-runtime drift from the tool-card batch: fixture presenter catch/str
  typo-guards, dense-array guards (fold-adapter reset, session rebuild,
  fixture backscan), live view-present arm (fixture replays are text-only;
  view vocabulary is covered by the history samples)

test(gui): close the PR #443 host-side coverage gaps — apiproxy client abort arms, api-proxy cold/view paths, webserver drain

- apiproxy fetch/client.ts: 3 new cases (pre-aborted signal short-circuits
  before transport + string reason mapping, non-Error/string reason falls to
  the default AbortError message, signal-less doFetch passthrough)
- runtime/api-proxy.ts: one v8-ignore (summarizeCold cwd arm — list()
  filters cwd-less legacy metas) + api-proxy-cold.spec.ts (cold list merge:
  mtime source, locate-undefined and vanished-log fallbacks, lineage;
  no-persistence/no-factory resume → internal) + 2 view cases (history views
  with meta passthrough and orphan/bad-args/presenterless soft-falls,
  session/disposed open-call cleanup on the mux stream)
- webserver/index.ts: /api/big fixture drives both drain-wait legs (full
  8MiB readback after drain, mid-chunk disconnect wakes via 'close')

feat: app shell

fix: rebase conflicts

fix: coverage

fix(gui): lint clean after rebase — wrap long v8-ignore comments, unconditional v1 detail-block claim

chore(gui): remove browser/probe verify scripts from scripts/

The six GUI acceptance/probe scripts (carrier-errors, rpclog-panel,
session, session-real, webserver-backpressure, webserver-hardening)
leave the repo's scripts/ tree; the three code comments that pointed at
them now describe the coverage lane without naming a script path.

fix(webserver): guard the request callback — one malformed request must not kill the process

The async handle() had no top-level catch, so any throw inside it (a bad
%-escape reaching decodeURIComponent, a client dropping mid-body, a
response stream erroring) became an unhandled rejection and took the whole
process down (audit R1 must-fix). The guard answers 400 when headers are
not out yet, destroys the socket when they are, and reports the failure to
onError (the package never prints). Spec covers all three legs: %-escape
barrage → 400 + server stays alive, non-Error throw wrapped for onError,
mid-stream explosion → socket teardown.

feat: client AGENTS.md

fix: client/AGENTS.md

fix: rebase

feat(gui): T0 cut 1 — 12 client package skeletons with contract stubs, dshClient declarations, tsdown client preset, theme token sheets

feat(gui): T0 cut 2 — pure git mv migration per v3 §11 (connection six, runtime sessions/kernel, ui-conversation chat, ui-primitives markdown family, web shell + e2e)

feat(gui): T0 cuts 3+4 — import rewiring to new package names, .legacy demotion of owner-rewrite files, legacy web-runtime/web-ui/apps-web retired to attic

feat(gui): connection 对账刀——index.ts 精确导出清单替换 export *，intents.legacy 溶解删除

feat(client/ui-slots): SlotCore real implementation — kind semantics, sync version + microtask-batched notify, onMutate bridge

feat(gui): web shell vite alias — retarget to new client packages, shell static surface only

feat(gui): host 侧刀属地半——HostWebPluginRegistry（entries 扫描+internal/plugin 去抖重扫+dshClient 校验+exports./client 解析）、GET /plugins/<id>/client.js 分发端点、GET / 与 SPA fallback 注入 __DSH_BOOT__（webPlugins 可选注入，不传行为不变）

feat(web-react): add use-sync-external-store dep + local shim typings

feat(web-react): bindSnapshotSelector via uSES with-selector shim

feat(gui): ui-layout concession-chain solver — pure computeColumns with contract geometry

feat(gui): ui-layout LayoutService — four persisted stores, clamped actions, list-driven prune

feat(gui): ui-layout AppFrame styles — grid columns, collapse-safe borders, edge drag handles

test(gui): 存量 spec 平移——connection 三件+runtime 六件自 attic 捞回改包名路径全绿；api-helpers 按归属拆分（wire 半留 connection、classifier 半随 conversation.ts 入 runtime）；boot-intents/preinit/rpc-log 随 intents/rpc-log 退役不迁（记 v3 §3.2 溶解项）

feat(client/ui-primitives): StateDot/Button/Pill/Input/Menu atoms, ConnectionBanner de-legacied to pure props, JsonBlock CSS on --dsw tokens

feat(web-react): createSnapshotStore engine (rafFlush batch, persist opt-in, dev freeze) + spec

feat(gui): ui-layout AppFrame — grid tracks, pointer-capture drag handles with rAF throttle, frame ResizeObserver

feat(web-react): useInvoke (external pending store, stable invoke, concurrency count) + spec

test(web-react): bind spec — equality bail, custom eq, zero resubscribe, StrictMode, method sources

feat(gui): ui-layout index rewiring — real exports, client apply provides ctx.layout and defines three slots

feat(web-react): SessionProvider (renderBody deps) + RootBindingProvider + binding contexts + spec

feat(gui): web shell AppRoot boot-page styles — self-contained with neutral token fallbacks

feat(gui): web shell AppRoot — boot gate over loader status, fail-loud plugin failure list

fix(gui): AppRoot gates on explicit settled signal — status-derived readiness races the incrementally filled table

feat(client/ui-theme): ThemeService real implementation — registry with built-in light/dark, apply toggles body[data-ds-dark-theme], third-party token overrides as body inline vars

feat(web-react): scopedSlots outlet (kind matrix, inject WeakMap caches, per-entry error boundary) + spec

feat(gui): web shell module-table seed — pure-library entities for the loader require surface

feat(client/i18n): I18nService real implementation — ns×locale registry, stable bind(ns) reference, zh fallback chain, zh/en skeleton dictionaries

feat(gui): web shell assembly closure — layout exports via module table, SessionProvider + scopedSlots + RootBindingProvider

feat: client/ui-conversation

feat: code

codedoc

build(gui): root bundle green — web shell excluded from the lib workspace (vite app), ui-primitives lib externalizes css side-effect imports (web-ui precedent)

gates(gui): verify-cordis-config follows aggregate tsconfig references (root is a shell over host/client programs); module graph regenerated for the twelve client packages

chore(gui): retire legacy migration sources — every owner rewrite landed (t0-checklist §7 ledger honored); orphan css of retired components removed

gates(gui): knip green groundwork — e2e/tsx entries for the new packages, loader-runtime deps ignored where loading is by specifier string, fake plugin ids un-bare-named, dead test export dropped

chore(client): manifest shape batch A — ui-slots/web-react/ui-primitives invariant companions, files whitelist, cordis+invariants peer/dev, tsconfig refs

chore(client): manifest shape batch B — connection/runtime/ui-conversation/ui-trajectory files whitelist, cordis peer+dev, explicit invariant lib entries (clientBundle signature)

chore(client): manifest shape batch C — i18n/ui-layout/ui-sidebar/ui-theme invariant companions, files whitelist, invariants peer/dev, tsconfig refs

chore(client): manifest shape batch D — web shell gains node-half lib entry + invariant companion + uniform files whitelist

chore(client): drop verified-unused deps — dsh-tools from runtime/ui-conversation (types ride /presentation), ui-primitives+clsx from ui-layout

gates(gui): doc-gate fixes — theme JSDoc prose, three client type-link exemptions, agent-note paths follow the migration, config catalog regenerated

gates(gui): type-equiv manifest follows the types.ts extraction, approval JSDoc keeps its link form, persistence catalog regenerated

docs(gui): per-constant JSDoc on the contract geometry exports (export-jsdoc gate)

test(gates): loader-composition budget covers cold tsx resolution after the program split (was flaking at the default 5s)

docs(gui): README substantiation batch 1 — ui-slots/ui-primitives/web-react/connection: Model Experience short form, real deferred-work ledgers, description accuracy pass

fix(client): theme/i18n dual-entry split — service classes + cordis merges move to src/client (host catalog scanner no longer misclassifies client services), node halves keep types + empty apply; catalogs regenerated

docs(gui): README substantiation batch 2 — runtime/ui-layout/ui-sidebar/ui-conversation: Model Experience short form, package-owned deferred-work ledgers (unload stub, watch approximation, /client value-import rule, global details state, two-state dots, stats duration gap, single-bundle caches)

docs(gui): README substantiation batch 3 — ui-trajectory/ui-theme/i18n/web: Model Experience short form, deferred-work ledgers (placeholder charter, no theme toggle owner, empty locale dictionaries, one-shot rendering); both README gates green

test(scripts): purity spec adopts clientBundle two-arg signature (explicit libEntry, no default)

gates(gui): knip green — declaration-merge dep ignored, fake plugin id assembled at runtime, invariants dep de-duplicated to peer+dev, stale apps/web section dropped

feat(gui): 门禁波次 host 三包 invariant 形状——apiproxy explained-empty 伴生（wire 契约层零事件面）、webserver 真关系伴生（manifest 行必解析出 clientPath，防 __DSH_BOOT__ 广告 404 bundle；apps/cli 发布 webPlugins 键供审计）、runtime 补 files 白名单；三包 exports/files/peer+dev/tsconfig refs 齐 fw-react 形状；constraints+invariants 双 gate 零违规

build(client): ui-layout/ui-sidebar tsdown configs adopt the explicit two-arg clientBundle signature (orphaned follow-up of the manifest shape batch)

refactor(gui): shell boot becomes a library face — bootWebShell(el) exported for the apps/web entry; main.ts retired

refactor(gui): exports 纪律刀1——ui-theme/i18n node index 收敛为只空 apply（Translate/LocaleDict/ThemeTokens 类型下沉 src/client/），ui-conversation 的 I18nService import 改 /client 子路径

build(typecheck): converge to root host aggregate + tsconfig.client.json — delete tsconfig.host.json, verify-cordis-config seeds both aggregates

feat(gui): apps/web restored as the vite application — thin main over bootWebShell; dsh-client-web becomes a plain lib (index exports shell surface, vite files and e2e moved out)

chore(gates): knip.json rewritten on the master base — same semantics, minimal diff (formatting churn dropped)

docs(gui): 时效清扫②——testing.md 删 web-ui 覆盖豁免残句；web-styling.md 加 token 换代头注（--dsw-* 现行、工程约束条款仍有效并注明收编处）

docs(gui): 时效清扫③——四对 GUI Agent Note 加路径更新头注（web-runtime/web-ui/dsh-frontend→现行 12 包结构；设计结论存续声明；双语对同步）

docs(gui): 时效清扫③b——四对 note 头注的 i18n 配对哈希重录

build(typecheck): minimal-diff tsconfig shape — drop root files entry (purity spec + preset move to client program), compress comments, drop redundant util/home root ref

feat(gui): apps/web restoration follow-through — dsh-frontend package name, cli dist resolve, root build:web filter, tsdown exemption dropped, vitest web lane + knip + client aggregate retargeted, e2e paths rebased

refactor(gui): exports 纪律刀2——connection wire 六件 git mv 进 src/client/（wire 即该 dshClient 插件的 client 半），node index=只空 apply，/client 半边整面导出（v3 §3.2 清单原样），包内 tests 改 src/client 直取

refactor(gui): exports 纪律刀3——runtime 实现整体下沉 src/client/（sessions/slots/loader；契约类型与 cordis merge 随迁 client/index），node index=只空 apply；./loader exports 指 client/loader；全消费面（web 壳/ui-sidebar/ui-trajectory/tests）bare→/client 机械跟改；vitest.e2e 换 tsconfig.vitest paths（root tsconfig 排除 client 会把 /client import 掉到 exports 的浏览器 dist bundle）

refactor(gui): exports 纪律刀3 补遗——ui-layout 三处 bare runtime import 改 /client（刀3 消费面机械跟改漏提交件；跨属地机械一行×3 报备 ui-shell）

test(gui): drop the getSessionManager singleton case — the init/get pair is a dead legacy-boot surface with zero live consumers (SessionsService constructs and holds the manager under the plugin architecture); source removal tracked with rt-core

refactor(gui): 删 manager.ts 尾部 initSessionManager/getSessionManager 单例对——旧 boot 直连遗物，插件化下 SessionsService 构造持有 manager，全仓零活消费者（convo-b 测试清扫对表，其测试用例已先行退役 7e2c51898）；头注释同步去单例措辞

code

refactor

packages/client/AGENTS.md

@@ -0,0 +1,71 @@
+# AGENTS.md — Web client stack
+
+Rules for `packages/client/*` (the browser side of the dsh web GUI) plus its build entry `apps/web`. They supplement the repo-wide [conventions](../../AGENTS.md#conventions) and the [package rules](../README.md); read the two architecture notes linked below before structural changes.
+
+Packages here are named with the directory prefix: `@deepseek-ai/dsh-client-<name>`.
+
+## Layering red lines
+
+The stack is three layers with one-way knowledge, settled in the [web client architecture note](../../.agents/notes/implemented/architecture/2026-07-19-gui-web-client-architecture.md):
+
+1. **Data object layer** (`web-runtime`, React-free): `ConnectionController` → `SessionManager` → `Session` own all business state (event windows, streaming accumulation, reconnect machine). Zero React imports — grep-assertable.
+2. **Hooks layer** (`web-ui/src/hooks`, pure data): subscribes to object snapshots via `useSyncExternalStore`, exposes plain-data handles. No JSX, no DOM.
+3. **Presentation components** (`web-ui`, pure props): consumables, expected to be rewritten wholesale. Business logic must not leak into them; they receive data and callbacks through props only.
+
+Non-negotiables across the layers:
+
+- **No business objects in the store.** zustand carries cross-view presentation state only (`rpcLog`, `ui`, `connection` slices). Sessions, frames, and connections live in the object layer. View-local facts (selection, expansion) stay in component state, not the store.
+- **rpcId is strictly bidirectional**: the initiator mints, the responder echoes; business signatures see only `RpcRequest<P>`, minting stays in the carrier layer ([layering and RPC protocol note](../../.agents/notes/implemented/architecture/2026-07-19-gui-layering-and-rpc-protocol.md)).
+- **Notifier dual-channel discipline**: `notifyNow` only as the direct echo of a user gesture; frame-driven updates always go through `markDirty` (microtask-batched). See `web-runtime/src/session/notifier.ts`.
+- **The web layer is pure presentation.** Nothing that is "how to draw" (tool-card views, queue states) enters the session log; the host computes such data per frame or pushes it live, and replay recomputes it — falling back to the generic form when it can't. A new *model-visible* input still requires a session event (repo-wide rule).
+
+## Directory regime (`web-ui/src`)
+
+> Shell restructure in progress: the tree is converging to this layout (today's `components/{conversation,sessions,panels}` migrate into it); the regime below is the target every new feature follows now.
+
+Two-level feature directories, one contributor per directory — physical conflict avoidance:
+
+```
+web-ui/src/
+  shell/                  # AppShell + the three slot registries + builtins
+  leftmenu/<bar>/         # one directory per left-nav bar (sessions, rpclog, …)
+  sessiontabs/<tab>/      # one directory per session tab (conversation, gantt, …)
+  components/             # shared leaves (MessageText, JsonBlock, …)
+  hooks/ utils/ style/    # cross-cutting; not feature-owned
+```
+
+- `leftmenu/<a>` must not import `leftmenu/<b>` or `sessiontabs/*` (and vice versa). Anything two features need sinks into `components/`.
+- Bars, tabs, and detail blocks register through the `shell/` registries (module-level map, `register*()` returns the disposer — same shape as `toolCardRegistry`). v1 registration is static in `shell/builtins.ts`; plugin-driven registration later calls the same functions.
+- **Claiming a placeholder slot**: pick a `placeholder: true` tab (or add a bar) in `shell/builtins.ts`, create your feature directory, and replace the placeholder component with your container. Don't build features outside this regime.
+
+## Styling
+
+[docs/web-styling.md](../../docs/web-styling.md) is authoritative. In short: design tokens live in `web-ui/src/style/global.css` (`:root` light values, `[data-theme='dark']` overrides); component CSS references tokens only — no literal color values. CSS Modules + `clsx`; no component library, no tailwind ([framework ruling](../../.agents/notes/implemented/process/2026-07-19-web-styling-system.md)). Product copy is Chinese; code comments are English.
+
+## Testing and coverage
+
+The GUI test structure (three tiers, lane map) is settled in the [GUI testing system note](../../.agents/notes/implemented/process/2026-07-20-gui-testing-system.md); repo-wide policy in [docs/testing.md](../../docs/testing.md).
+
+- **Both client packages are inside the per-file 100% coverage gate** (`pnpm run test:coverage`). `web-runtime` is covered by node-env object/protocol suites; `web-ui` rides the jsdom lane. Genuinely unreachable defensive arms take a `/* v8 ignore -- <reason> */` comment with a real reason, never a bare ignore.
+- **web-ui specs are end-to-end behavior checks, not unit tests.** A jsdom spec renders the component with realistic props (or a driven fixture runtime) and asserts what the user would see — never class names, hook internals, or render counts. Components are consumables: behavior-shaped specs survive a rewrite, implementation-shaped specs don't.
+- The jsdom environment comes from a per-file `// @vitest-environment jsdom` pragma on the spec's first line — the shared config stays node-env. Start a new spec from an existing one (`web-ui/tests/tool-card.spec.tsx` is a good template).
+- **Each tier asserts its own layer.** Data-layer semantics (state machines, wire shapes, reference stability) belong to the `web-runtime` and `apiproxy` suites — don't re-assert them from component specs.
+
+## Before you push: the local check ladder
+
+Run the narrowest rung that covers what you touched; escalate only when the change surface demands it.
+
+1. **Every GUI code change** — `pnpm run test:gui` (seconds; no browser, no server): the client suites plus the host-side GUI packages. This is the inner loop; run it as freely as a typecheck.
+2. **Changes to the build surface, boot wiring, or static serving** (`apps/web`, vite config, `dsh-host-webserver`) — additionally `pnpm run test:web`: rebuilds the frontend dist, then runs the browser smoke pair (the real-host case self-skips without `DEEPSEEK_API_KEY`).
+3. **Before a PR** — `pnpm run check:pre-push` (the repo-wide gate ladder). Between PR windows this rung is not expected on every commit.
+
+If `test:gui` is red on code you did not touch, neither silently fix nor ignore it: note it in your handoff so it lands in the next PR window's sweep.
+
+## New component checklist
+
+1. Claim the slot (see the directory regime above): one feature, one directory.
+2. Build the container in your feature directory; keep leaves pure-props. Wire data through the hooks layer, not by importing business objects into components.
+3. Copy a neighbouring jsdom spec into `web-ui/tests/`, keep it behavior-shaped: start from the happy path and the edge states, then widen until the component's branches are covered — the coverage gate applies; only the assertion style stays behavior-level.
+4. Tokens only in CSS; Chinese product copy; English comments.
+5. `pnpm run test:gui` green (plus `test:web` if you touched the build surface).
+6. Non-trivial change? It needs an Agent Note in the same PR (repo-wide rule) — the three GUI notes above are the precedents to extend.

packages/client/connection/README.md

@@ -0,0 +1,16 @@
+# @deepseek-ai/dsh-client-connection
+
+Wire consumer layer (moved verbatim from web-runtime): IApiClient family (WebApiClient/FixtureApiClient), ConnectionController (SSE dual-stream + backoff reconnect), WEB_EVENTS. Contract: api-contracts v3 §3, export inventory in §3.2.
+
+## Model Experience
+
+None, as the wire consumer layer moves already-composed messages between browser and host; nothing here reaches a model request.
+
+#### KV Cache effect
+
+None; this package neither assembles nor sends a provider request.
+
+## Known Limitations and Deferred Work
+
+- **history's implicit resume is arguable** — opening history on an unattached session pulls an agent up host-side; the pure-persistence-read alternative is recorded in the rt-core reconciliation ledger, unchanged in P-I. This package's consumers see it as latency on first open.
+- **`ToolEventView`/`ToolCallView`/`ToolResultView` re-exports are scheduled for removal** — they fall when the toolview migration deletes the host `viewFor` line (presentation belongs to the client); the fixture keeps a local `viewFor` mirror until then.

packages/client/connection/package.json

@@ -0,0 +1,53 @@
+{
+  "name": "@deepseek-ai/dsh-client-connection",
+  "description": "Wire consumer layer: IApiClient subclasses, ConnectionController (SSE dual-stream + reconnect), fixture api (no cordis)",
+  "version": "0.0.1",
+  "private": true,
+  "type": "module",
+  "main": "lib/index.js",
+  "types": "lib/types/index.d.ts",
+  "exports": {
+    ".": {
+      "types": "./lib/types/index.d.ts",
+      "default": "./lib/index.js"
+    },
+    "./invariant": {
+      "types": "./lib/types/invariant.d.ts",
+      "default": "./lib/invariant.js"
+    },
+    "./client": {
+      "types": "./lib/types/client/index.d.ts",
+      "default": "./lib/client.js"
+    },
+    "./src/*": "./src/*",
+    "./package.json": "./package.json"
+  },
+  "dshClient": {
+    "inject": [],
+    "platform": "web",
+    "immediately": true
+  },
+  "license": "BSD-3-Clause",
+  "dependencies": {
+    "@deepseek-ai/dsh-host-apiproxy": "workspace:^",
+    "@deepseek-ai/dsh-llm": "workspace:^",
+    "@deepseek-ai/dsh-session": "workspace:^",
+    "@deepseek-ai/dsh-tools": "workspace:^"
+  },
+  "files": [
+    "lib/index.js",
+    "lib/invariant.js",
+    "lib/client.js",
+    "lib/types/**/*.d.ts",
+    "lib/types/**/*.d.ts.map",
+    "src"
+  ],
+  "peerDependencies": {
+    "@deepseek-ai/dsh-invariants": "^0.0.1",
+    "cordis": "^4.0.0-rc.7"
+  },
+  "devDependencies": {
+    "@deepseek-ai/dsh-invariants": "workspace:^",
+    "cordis": "^4.0.0-rc.7"
+  }
+}

packages/client/connection/src/client/api.ts

@@ -0,0 +1,47 @@
+// Central contract re-export point: every contract import inside
+// web-runtime goes through this single file.
+// Types are type-only imports from the apiproxy api/ layer (zero Node deps, browser-safe);
+// the only runtime values are the RpcId constructor and the AbstractApiClient seam.
+// NEVER import the package root: it drags bootHost/cordis into the browser bundle.
+// The ./api and ./client subpath exports are the browser-safe channels added for this.
+
+export type {
+  ApiProxy, SessionsApi, SessionSummary, HostApi, EventsApi, MuxFrame, HostFrame,
+  ApprovalResponsePayload, QuestionResponsePayload, HistoryEntry, ToolEventView,
+} from '@deepseek-ai/dsh-host-apiproxy/api'
+export type { ToolCallView, ToolResultView } from '@deepseek-ai/dsh-tools/presentation'
+export type {
+  RpcRequest, RpcResponse, RpcResult, RpcError, RpcErrorCode,
+  ClientRequest, ServerResponse, ServerRequest, ClientResponse, RpcMessage, RpcReceipt,
+} from '@deepseek-ai/dsh-host-apiproxy/api'
+export { RpcId } from '@deepseek-ai/dsh-host-apiproxy/api'
+export { AbstractApiClient } from '@deepseek-ai/dsh-host-apiproxy/client'
+export type { IApiClient } from '@deepseek-ai/dsh-host-apiproxy/client'
+export type { SessionId, SessionEvent } from '@deepseek-ai/dsh-session/types'
+export type { ContentBlock, StreamChunk } from '@deepseek-ai/dsh-llm/types'
+
+import type { RpcResponse, RpcResult } from '@deepseek-ai/dsh-host-apiproxy/api'
+
+/**
+ * Unwrap a unary response: RpcResponse<T> -> RpcResult<T> (business code only
+ * cares about the result slot).
+ * @param response - the unary response.
+ * @returns its result slot.
+ */
+export function resultOf<T>(response: RpcResponse<T>): RpcResult<T> {
+  return response.result
+}
+
+/**
+ * Fold a transport exception into the RpcResult error branch (unified error
+ * surface; 'internal' as the catch-all code).
+ * @param error - the thrown value from the carrier.
+ * @returns the error branch of an RpcResult.
+ */
+export function transportError<T>(error: unknown): RpcResult<T> {
+  return {
+    ok: false,
+    error: { code: 'internal', message: error instanceof Error ? error.message : String(error), details: {} },
+  }
+}
+

packages/client/connection/src/client/connection.ts

@@ -0,0 +1,190 @@
+import type { IApiClient, HostFrame, MuxFrame, RpcRequest } from './api.ts'
+
+/** Reconnect/backoff tunables (deployment-varying — no hardcoded tunables; web-cordis §B.1 lists
+ *  these as the future `ctx.connection` plugin Config). All fields optional; defaults below. */
+export interface ConnectionConfig {
+  /** First-retry backoff cap in ms (jittered: actual delay is cap/2..cap). */
+  backoffBaseMs?: number
+  /** Exponential growth factor per consecutive failed attempt. */
+  backoffFactor?: number
+  /** Upper bound for the backoff cap in ms. */
+  backoffMaxMs?: number
+  /** Cap on waiting for both streams' onOpen before onConnected, in ms. The strict handshake
+   *  (audit C2) waits for mux+host stream establishment plus describe; a carrier that never
+   *  fires onOpen (misbehaving proxy) must not wedge the connection forever — on timeout the
+   *  generation proceeds as connected and the live-gap repair path (audit S3) covers stragglers. */
+  streamOpenTimeoutMs?: number
+}
+
+const CONNECTION_DEFAULTS: Required<ConnectionConfig> = {
+  backoffBaseMs: 500,
+  backoffFactor: 2,
+  backoffMaxMs: 10_000,
+  streamOpenTimeoutMs: 3_000,
+}
+
+function sleep(ms: number, signal: AbortSignal): Promise<void> {
+  return new Promise((resolve) => {
+    const t = setTimeout(done, ms)
+    signal.addEventListener('abort', done, { once: true })
+    function done(): void {
+      clearTimeout(t)
+      signal.removeEventListener('abort', done)
+      resolve()
+    }
+  })
+}
+
+/** Coarse connection state for the UI (audit C1): 'connected' after each generation's handshake,
+ *  'reconnecting' the moment the generation fails (covers the whole backoff+retry span). */
+export type ConnectionState = 'connected' | 'reconnecting'
+
+/** Frame sink callbacks: the Controller owns the physical streams; business dispatch belongs to
+ *  SessionManager. */
+export interface ConnectionSinks {
+  onMuxEnvelope?: (envelope: RpcRequest<MuxFrame>) => void
+  onHostEnvelope?: (envelope: RpcRequest<HostFrame>) => void
+  /** After each connection generation is established (both streams open + describe succeeded), first connect included. */
+  onConnected?: () => void
+  /** Coarse state transitions (deduplicated: fires only on change). The initial pre-connect
+   *  span reports nothing — the UI treats "no state yet" as connecting, not as an outage. */
+  onStateChange?: (state: ConnectionState) => void
+}
+
+/**
+ * Opens both streams and keeps iterating (pull mode: nothing reads the socket and the tap
+ * never fires unless someone for-awaits), reconnecting with exponential backoff on loss.
+ * State (generation/attempt) is instance-private, never in the store.
+ * The pump body feeds each frame to a sink (sink exceptions must
+ * not kill the pump — a broken business layer must not drag down the connection layer).
+ */
+export class ConnectionController {
+  private generation = 0
+  private attempt = 0
+  private current: AbortController | null = null
+  private running = false
+  private lastState: ConnectionState | null = null
+  private readonly config: Required<ConnectionConfig>
+
+  constructor(
+    private readonly api: IApiClient,
+    private readonly sinks: ConnectionSinks = {},
+    config: ConnectionConfig = {},
+  ) {
+    this.config = { ...CONNECTION_DEFAULTS, ...config }
+  }
+
+  /** Idempotent: begin the connect/pump/reconnect loop. */
+  start(): void {
+    if (this.running) return
+    this.running = true
+    void this.loop()
+  }
+
+  /** Stop the loop and abort the current generation's streams. */
+  stop(): void {
+    this.running = false
+    this.current?.abort()
+    this.current = null
+  }
+
+  private backoffDelay(attempt: number): number {
+    const { backoffBaseMs, backoffFactor, backoffMaxMs } = this.config
+    const cap = Math.min(backoffMaxMs, backoffBaseMs * backoffFactor ** Math.max(0, attempt - 1))
+    return cap / 2 + Math.random() * (cap / 2)
+  }
+
+  /** Read through a method: stop() flips the flag across awaits, so narrowing from the loop condition must not stick. */
+  private isRunning(): boolean {
+    return this.running
+  }
+
+  private async loop(): Promise<void> {
+    while (this.running) {
+      const gen = ++this.generation
+      const ac = new AbortController()
+      this.current = ac
+
+      /* v8 ignore next -- initializer placeholder: the Promise executor
+       * below runs synchronously and replaces it before anyone can call it. */
+      let muxOpened = (): void => {}
+      /* v8 ignore next -- same placeholder pattern as muxOpened. */
+      let hostOpened = (): void => {}
+      const streamsOpen = Promise.all([
+        new Promise<void>((resolve) => { muxOpened = resolve }),
+        new Promise<void>((resolve) => { hostOpened = resolve }),
+      ])
+
+      const failed = new Promise<void>((resolve) => {
+        const settle = (): void => {
+          if (gen === this.generation && !ac.signal.aborted) ac.abort()
+          resolve()
+        }
+        void this.pumpStream(this.api.events.mux({}, ac.signal, muxOpened), this.sinks.onMuxEnvelope, settle)
+        void this.pumpStream(this.api.events.host({}, ac.signal, hostOpened), this.sinks.onHostEnvelope, settle)
+      })
+
+      try {
+        // Strict readiness handshake (audit C2): describe proves unary reachability, onOpen
+        // proves each SSE transport is established (response headers in, before any frame) —
+        // only then may onConnected fire, so the resync it triggers cannot outrun the
+        // subscribed baseline. The timeout guards against a carrier that never fires onOpen
+        // (see ConnectionConfig.streamOpenTimeoutMs).
+        const timeout = new AbortController()
+        await Promise.all([
+          this.api.host.describe({}),
+          Promise.race([streamsOpen, sleep(this.config.streamOpenTimeoutMs, timeout.signal)]),
+        ])
+        timeout.abort()
+        if (ac.signal.aborted) throw new Error('generation aborted during readiness handshake')
+        this.attempt = 0
+        this.emitState('connected')
+        this.callSink(this.sinks.onConnected)
+      } catch {
+        // Transport failure: treat as generation failure, fall through to the shared backoff.
+        if (!ac.signal.aborted) ac.abort()
+      }
+
+      await failed
+      if (!this.isRunning()) return
+      this.emitState('reconnecting')
+      this.attempt += 1
+      console.warn(`[web-runtime] connection lost, retry #${this.attempt}`)
+      const idle = new AbortController()
+      await sleep(this.backoffDelay(this.attempt), idle.signal)
+    }
+  }
+
+  /** Deduplicated state emission (sink isolation applies). */
+  private emitState(state: ConnectionState): void {
+    if (this.lastState === state) return
+    this.lastState = state
+    this.callSink(() => this.sinks.onStateChange?.(state))
+  }
+
+  private async pumpStream<F extends { type: string }>(
+    stream: AsyncIterable<RpcRequest<F>>,
+    sink: ((envelope: RpcRequest<F>) => void) | undefined,
+    onEnd: () => void,
+  ): Promise<void> {
+    try {
+      for await (const envelope of stream) {
+        if (envelope.payload.type === 'stream/error') break
+        if (sink !== undefined) this.callSink(() => { sink(envelope) })
+      }
+    } catch {
+      // Stream loss: converge on onEnd, which triggers the shared reconnect.
+    }
+    onEnd()
+  }
+
+  /** Sink exception isolation: a business-layer throw is logged only, never affecting pump or reconnect semantics. */
+  private callSink(fn: (() => void) | undefined): void {
+    if (fn === undefined) return
+    try {
+      fn()
+    } catch (error) {
+      console.error('[web-runtime] connection sink threw:', error)
+    }
+  }
+}

packages/client/connection/src/client/fixture.ts

@@ -0,0 +1,554 @@
+// FixtureApi: standalone UI development without a server. Real contract shape: unary takes
+// RpcRequest<P> and returns RpcResponse<T> (echoing the rpcId); streams yield RpcRequest<frame>
+// (the fixture IS the fake server, so it mints frame rpcIds); root respond takes ClientResponse
+// and returns RpcReceipt. fx-alpha carries a hand-built history script (60 turns, pageable);
+// prompt triggers a chunked streaming replay; cancel stops the replay; one resident pending
+// approval (placeholder-card material, subscribed-baseline-replay semantics: stable rpcId reuse).
+
+import type { ContentBlock } from '@deepseek-ai/dsh-llm/types'
+import type { SessionEvent, SessionId } from '@deepseek-ai/dsh-session/types'
+import type {
+  ApiProxy, ClientRequest, ClientResponse, HistoryEntry, HostFrame, MuxFrame, RpcReceipt,
+  RpcRequest, RpcResponse, RpcResult, ServerRequest, ServerResponse, SessionSummary,
+  ToolCallView, ToolEventView, ToolResultView,
+} from './api.ts'
+import type { RequestPayload, ResponseValue, RpcMethodMap } from '@deepseek-ai/dsh-host-apiproxy/api'
+import { AbstractApiClient, RpcId } from './api.ts'
+
+/** The fake carrier mints like a real one (business code never mints). */
+function rpcRequest<P>(payload: P): RpcRequest<P> {
+  return { rpcId: RpcId(crypto.randomUUID()), payload }
+}
+
+function text(t: string): ContentBlock[] {
+  return [{ type: 'text', text: t }]
+}
+
+function sid(id: string): SessionId {
+  return id as SessionId
+}
+
+/** fx-alpha history script: 60 turns (~130+ messages -> 3 pages at PAGE_MESSAGES=50),
+ *  mixing reasoning blocks / tool call+result / steering / context. */
+function buildAlphaLog(): SessionEvent[] {
+  const events: Record<string, unknown>[] = []
+  let time = Date.now() - 3_600_000
+  const push = (e: Record<string, unknown>): number => {
+    const seq = events.length
+    events.push({ seq, time: (time += 800), ...e })
+    return seq
+  }
+  for (let turn = 0; turn < 60; turn++) {
+    push({ type: 'turn/start', data: { turn, trigger: { kind: 'message', source: { kind: 'user' } } } })
+    push({ type: 'user/message', surfaceOp: 'append', data: { content: text(`问题 ${turn}：fixture 历史消息，用于翻页与渲染验收。`), source: { kind: 'user' } } })
+    if (turn % 9 === 4) {
+      push({ type: 'context/message', surfaceOp: 'append', data: { content: text(`[fixture] 上下文注入（turn ${turn}）`), source: { kind: 'plugin', plugin: 'fixture' } } })
+    }
+    push({ type: 'step/start', data: { turn, step: 0 } })
+    const withTool = turn % 5 === 2
+    const withReasoning = turn % 3 === 1
+    const blocks: ContentBlock[] = []
+    if (withReasoning) blocks.push({ type: 'reasoning', text: `思考过程 ${turn}：这是一段可折叠的 reasoning 内容。` })
+    blocks.push({ type: 'text', text: `回答 ${turn}：这是 fixture 生成的历史回复正文。` })
+    if (withTool) {
+      const callId = `fx-call-${turn}`
+      blocks.push({ type: 'tool-call', id: callId, name: 'echo', arguments: `{"text":"turn ${turn}"}` } as ContentBlock)
+      push({ type: 'assistant/message', surfaceOp: 'append', data: { turn, step: 0, content: blocks, provenance: { provider: 'fixture', model: 'fx-1' } } })
+      push({ type: 'tool/call', data: { turn, step: 0, callId, name: 'echo', arguments: `{"text":"turn ${turn}"}` } })
+      push({ type: 'tool/result', surfaceOp: 'append', data: { turn, step: 0, callId, content: text(`ECHO: TURN ${turn}`), isError: turn % 25 === 12 } })
+      push({ type: 'step/end', data: { turn, step: 0 } })
+      push({ type: 'step/start', data: { turn, step: 1 } })
+      push({ type: 'assistant/message', surfaceOp: 'append', data: { turn, step: 1, content: text(`工具结果已消化（turn ${turn}）。`), provenance: { provider: 'fixture', model: 'fx-1' } } })
+      push({ type: 'step/end', data: { turn, step: 1 } })
+    } else {
+      push({ type: 'assistant/message', surfaceOp: 'append', data: { turn, step: 0, content: blocks, provenance: { provider: 'fixture', model: 'fx-1' } } })
+      push({ type: 'step/end', data: { turn, step: 0 } })
+    }
+    if (turn % 13 === 6) {
+      push({ type: 'steering/message', surfaceOp: 'append', data: { turn, content: text(`插话 ${turn}：fixture steering 消息。`), source: { kind: 'user' } } })
+    }
+    push({ type: 'turn/end', data: { turn, reason: { kind: 'completed' } } })
+  }
+  // Three view-sample turns (60-62) for the tool-card wire acceptance: one per built-in card
+  // type. `echo` above stays presenter-less on purpose — it is the no-view fallback sample.
+  const toolTurn = (turn: number, name: string, args: string, resultText: string): void => {
+    const callId = `fx-call-${turn}`
+    push({ type: 'turn/start', data: { turn, trigger: { kind: 'message', source: { kind: 'user' } } } })
+    push({ type: 'user/message', surfaceOp: 'append', data: { content: text(`问题 ${turn}：${name} 样本。`), source: { kind: 'user' } } })
+    push({ type: 'step/start', data: { turn, step: 0 } })
+    push({
+      type: 'assistant/message', surfaceOp: 'append',
+      data: { turn, step: 0, content: [{ type: 'tool-call', id: callId, name, arguments: args } as ContentBlock], provenance: { provider: 'fixture', model: 'fx-1' } },
+    })
+    push({ type: 'tool/call', data: { turn, step: 0, callId, name, arguments: args } })
+    push({ type: 'tool/result', surfaceOp: 'append', data: { turn, step: 0, callId, content: text(resultText), isError: false } })
+    push({ type: 'step/end', data: { turn, step: 0 } })
+    push({ type: 'turn/end', data: { turn, reason: { kind: 'completed' } } })
+  }
+  toolTurn(60, 'fx-bash', '{"command":"ls -la","cwd":"/tmp/fixture"}', 'total 2\ndrwxr-xr-x fixture\n-rw-r--r-- demo.txt')
+  toolTurn(61, 'fx-write', '{"path":"notes/demo.txt","content":"hello fixture\\n"}', 'wrote notes/demo.txt')
+  toolTurn(62, 'fx-note', '{"note":"三型卡验收样本"}', '已记录')
+  return events as unknown as SessionEvent[]
+}
+
+/** Narrows a parsed-JSON field to string; fixture args are authored in-file, so non-strings only mean a typo here. */
+/* v8 ignore next -- the fallback arm is the same in-file-typo guard as the JSON.parse catch above. */
+const str = (value: unknown, fallback = ''): string => typeof value === 'string' ? value : fallback
+
+/** Fixture presenter registry (mirrors host viewFor): pure derivation, undefined = no view. */
+function presentCall(name: string, argsRaw: string): ToolCallView | undefined {
+  let args: Record<string, unknown>
+  try {
+    args = JSON.parse(argsRaw) as Record<string, unknown>
+  } catch {
+    /* v8 ignore next 2 -- defensive: fixture args are authored in-file as valid JSON; only an in-file typo could reach the catch. */
+    return undefined
+  }
+  switch (name) {
+    case 'fx-bash':
+      return { card: 'terminal', title: str(args.command), cwd: str(args.cwd, '/tmp/fixture'), description: 'fixture 终端样本' }
+    case 'fx-write':
+      return {
+        card: 'diff', title: `Write ${str(args.path)}`,
+        diffs: [{ path: str(args.path), oldText: null, newText: str(args.content) }],
+      }
+    case 'fx-note':
+      return { card: 'generic', title: '记录笔记', kind: 'edit', rawInput: args }
+    default:
+      return undefined // echo et al: the documented no-view fallback path
+  }
+}
+
+function presentResult(name: string, argsRaw: string, resultText: string): ToolResultView | undefined {
+  const call = presentCall(name, argsRaw)
+  if (call === undefined) return undefined
+  switch (call.card) {
+    case 'terminal':
+      return { card: 'terminal', output: resultText, exitCode: 0 }
+    case 'diff':
+      return { card: 'diff', diffs: call.diffs }
+    case 'generic':
+      return { card: 'generic', content: text(resultText) }
+  }
+}
+
+/** Host-side viewFor mirror: tool/call presents from its own args; tool/result back-scans the log for the paired call. */
+function viewFor(event: SessionEvent, log: readonly SessionEvent[]): ToolEventView | undefined {
+  if (event.type === 'tool/call') {
+    const view = presentCall(event.data.name, event.data.arguments)
+    return view === undefined ? undefined : { for: 'call', view }
+  }
+  if (event.type === 'tool/result') {
+    const callId = String(event.data.callId)
+    for (let i = log.length - 1; i >= 0; i--) {
+      const candidate = log[i]
+      /* v8 ignore next -- dense-array guard: i stays within [0, log.length),
+      so the undefined arm needs a sparse log no code path builds. */
+      if (candidate !== undefined && candidate.type === 'tool/call' && String(candidate.data.callId) === callId) {
+        const resultText = event.data.content.map(b => (b.type === 'text' ? b.text : '')).join('')
+        const view = presentResult(candidate.data.name, candidate.data.arguments, resultText)
+        return view === undefined ? undefined : { for: 'result', view }
+      }
+    }
+    return undefined // cross-page unpaired: documented default
+  }
+  return undefined
+}
+
+/**
+ * Message-boundary paging (mirrors the host's paging contract): count
+ * maxMessages messages
+ *  backwards from end, cut at a turn/start boundary.
+ Entries carry pagination-time views
+ *  (the host analogue computes viewFor per entry at page time). */
+function pageOf(
+  log: readonly SessionEvent[],
+  beforeSeq: number | undefined,
+  maxMessages: number,
+): { events: HistoryEntry[]; hasMore: boolean } {
+  const end = beforeSeq === undefined ? log.length : Math.max(0, Math.min(beforeSeq, log.length))
+  let start = 0
+  let messages = 0
+  for (let i = end - 1; i >= 0; i--) {
+    const event = log[i]
+    /* v8 ignore next -- dense-array guard: log seqs are array indexes, i stays within [0, end). */
+    if (event === undefined) break
+    if (event.type === 'user/message' || event.type === 'assistant/message' || event.type === 'steering/message') messages++
+    if (event.type === 'turn/start' && messages >= maxMessages) {
+      start = i
+      break
+    }
+  }
+  const events = log.slice(start, end).map((event): HistoryEntry => {
+    const view = viewFor(event, log)
+    return view === undefined ? { event } : { event, view }
+  })
+  return { events, hasMore: start > 0 }
+}
+
+interface StreamConn<F> {
+  push(envelope: RpcRequest<F>): void
+}
+
+/** Inbox pump shared by both stream generators (FrameQueue pattern: ONE abort listener hung
+ *  outside the loop — a per-iteration {once:true} listener never fires for non-final rounds and
+ *  piles up for the stream's lifetime, audit C5). breakNow force-ends the stream without the
+ *  client's signal (timing hook: simulated connection loss). */
+class FxInbox<F> implements StreamConn<F> {
+  private readonly inbox: RpcRequest<F>[] = []
+  private wake: (() => void) | null = null
+  private broken = false
+
+  push(envelope: RpcRequest<F>): void {
+    this.inbox.push(envelope)
+    this.wake?.()
+  }
+
+  breakNow(): void {
+    this.broken = true
+    this.wake?.()
+  }
+
+  /** Read through a method: breakNow()/abort flip state across yields, so narrowing from the loop condition must not stick. */
+  private isLive(signal: AbortSignal): boolean {
+    return !signal.aborted && !this.broken
+  }
+
+  async *drain(signal: AbortSignal): AsyncGenerator<RpcRequest<F>> {
+    const onAbort = (): void => this.wake?.()
+    signal.addEventListener('abort', onAbort)
+    try {
+      while (this.isLive(signal)) {
+        while (this.inbox.length > 0) yield this.inbox.shift() as RpcRequest<F>
+        if (!this.isLive(signal)) break
+        await new Promise<void>((resolve) => {
+          this.wake = resolve
+        })
+        this.wake = null
+      }
+    } finally {
+      signal.removeEventListener('abort', onAbort)
+    }
+  }
+}
+
+/**
+ * In-memory fake host: fx-alpha carries history and replay scripts; fx-beta is fx-alpha's child session (lineage indent material).
+ * @returns an ApiProxy backed entirely by in-memory state — no host process, no network.
+ */
+export function createFixtureApi(): ApiProxy {
+  const sessions: SessionSummary[] = [
+    { sessionId: sid('fx-alpha'), updatedAt: Date.now(), running: true, cwd: '/tmp/fixture' },
+    { sessionId: sid('fx-beta'), updatedAt: Date.now() - 60_000, running: false, parentSessionId: sid('fx-alpha'), cwd: '/tmp/fixture' },
+    { sessionId: sid('fx-gamma'), updatedAt: Date.now() - 120_000, running: false, cwd: '/tmp/fixture' },
+  ]
+  const logs = new Map<SessionId, SessionEvent[]>([[sid('fx-alpha'), buildAlphaLog()]])
+  const nextTurn = new Map<SessionId, number>([[sid('fx-alpha'), 60]])
+  let nextSession = 1
+  let nextRpc = 1
+  const mint = (): ReturnType<typeof RpcId> => RpcId(`fx-rpc-${nextRpc++}`)
+  /** Resident pending approval (stable rpcId: every mux open replays the same id, matching host replay semantics). */
+  const pendingApprovalRpcId = mint()
+
+  const muxConns = new Set<StreamConn<MuxFrame>>()
+  const hostConns = new Set<StreamConn<HostFrame>>()
+  const emitMux = (frame: MuxFrame): void => {
+    for (const conn of muxConns) conn.push({ rpcId: mint(), payload: frame })
+  }
+  const emitHost = (frame: HostFrame): void => {
+    for (const conn of hostConns) conn.push({ rpcId: mint(), payload: frame })
+  }
+
+  /** OK response echoing the caller's rpcId (contract: responses always backfill, never mint). */
+  function ok<P, T>(request: RpcRequest<P>, value: T): Promise<RpcResponse<T>> {
+    return Promise.resolve({ rpcId: request.rpcId, result: { ok: true, value } })
+  }
+  function err<P, T>(request: RpcRequest<P>, error: Extract<RpcResult<T>, { ok: false }>['error']): Promise<RpcResponse<T>> {
+    return Promise.resolve({ rpcId: request.rpcId, result: { ok: false, error } })
+  }
+
+  const summaryOf = (id: SessionId): SessionSummary | undefined => sessions.find(s => s.sessionId === id)
+  const setRunning = (id: SessionId, running: boolean): void => {
+    const summary = summaryOf(id)
+    if (summary === undefined || summary.running === running) return
+    summary.running = running
+    emitHost({ type: 'host/session-status', sessionId: id, running })
+  }
+  const logOf = (id: SessionId): SessionEvent[] => {
+    let log = logs.get(id)
+    if (log === undefined) {
+      log = []
+      logs.set(id, log)
+    }
+    return log
+  }
+  const append = (id: SessionId, e: Record<string, unknown>): void => {
+    const log = logOf(id)
+    const event = { seq: log.length, time: Date.now(), ...e } as unknown as SessionEvent
+    log.push(event)
+    // Emission-time view derivation (mirrors the host's live path).
+    const view = viewFor(event, log)
+    /* v8 ignore next 3 -- the view-present arm needs a live tool/call emission,
+    but the fixture replay produces text-only turns; view vocabulary is
+    exercised through the history samples (turns 60-62). */
+    emitMux(view === undefined
+      ? { type: 'session/event', sessionId: id, event }
+      : { type: 'session/event', sessionId: id, event, view })
+  }
+
+  /** At most one in-flight replay per session; cancel clears it. */
+  const replays = new Map<SessionId, { timer: ReturnType<typeof setTimeout>; finish(aborted: boolean): void }>()
+
+  /** history transit delay (timing hooks below); the page snapshot is taken at request time, like a real host. */
+  let historyDelayMs = 0
+  /** One-shot history failure (timing hook: the doomed in-flight request of the S4 reconnect scenario). */
+  let failNextHistory = false
+  /** Force-enders for currently open stream generators (timing hook: simulated connection loss). */
+  const streamBreakers = new Set<() => void>()
+
+  // Timing-acceptance hooks (browser test backdoor): the in-memory fixture is ideally timed, which
+  // is exactly what masked the open-window and reconnect-gap bugs (audit S1/S3). These let
+  // browser acceptance runs create slow-history, lost-frame, and reconnect
+  // windows a real host produces naturally.
+  const timingHooks = {
+    setHistoryDelay(ms: number): void {
+      historyDelayMs = ms
+    },
+    /** Fail the NEXT history call (after its transit delay) with a transport-level throw. */
+    failNextHistory(): void {
+      failNextHistory = true
+    },
+    /** Log append + mux emit (the normal live path). */
+    appendUser(id: string, msg: string): void {
+      append(sid(id), { type: 'user/message', surfaceOp: 'append', data: { content: text(msg), source: { kind: 'user' } } })
+    },
+    /** Log append WITHOUT the mux emit: a frame lost in transit — history still serves it, the client must repull. */
+    appendSilent(id: string, msg: string): void {
+      const log = logOf(sid(id))
+      log.push({ type: 'user/message', surfaceOp: 'append', seq: log.length, time: Date.now(), data: { content: text(msg), source: { kind: 'user' } } } as unknown as SessionEvent)
+    },
+    /** End every open stream generator (client sees both streams close -> reconnect + resync path). */
+    breakStreams(): void {
+      for (const breakNow of [...streamBreakers]) breakNow()
+    },
+  }
+  ;(globalThis as Record<string, unknown>).__fxTiming = timingHooks
+
+  /** Prompt replay: chunk typewriter (80ms/frame) -> assistant/message finalize -> turn/end + running flip. */
+  const startReply = (id: SessionId, turn: number, replyText: string): void => {
+    const step = 0
+    append(id, { type: 'step/start', data: { turn, step } })
+    append(id, { type: 'assistant/chunk', data: { turn, step, chunk: { type: 'block-start', index: 0, blockType: 'text' } } })
+    /* v8 ignore next -- the ?? arm needs a null match, but replyText is never empty (prompt always prefixes 回声). */
+    const pieces = replyText.match(/.{1,6}/gu) ?? [replyText]
+    let i = 0
+    const finish = (aborted: boolean): void => {
+      replays.delete(id)
+      const done = pieces.slice(0, i).join('')
+      append(id, { type: 'assistant/chunk', data: { turn, step, chunk: { type: 'block-end', index: 0, block: { type: 'text', text: done } } } })
+      append(id, { type: 'assistant/message', surfaceOp: 'append', data: { turn, step, content: text(aborted ? `${done}（已中断）` : done), provenance: { provider: 'fixture', model: 'fx-1' } } })
+      append(id, { type: 'step/end', data: { turn, step } })
+      append(id, { type: 'turn/end', data: { turn, reason: { kind: aborted ? 'cancelled' : 'completed' } } })
+      setRunning(id, false)
+    }
+    const tick = (): void => {
+      const piece = pieces[i]
+      if (piece === undefined) {
+        finish(false)
+        return
+      }
+      i++
+      append(id, { type: 'assistant/chunk', data: { turn, step, chunk: { type: 'text-delta', index: 0, text: piece } } })
+      replays.set(id, { timer: setTimeout(tick, 80), finish })
+    }
+    replays.set(id, { timer: setTimeout(tick, 80), finish })
+  }
+
+  return {
+    sessions: {
+      list: request => ok(request, { items: [...sessions].sort((a, b) => b.updatedAt - a.updatedAt) }),
+      create: (request) => {
+        const created: SessionSummary = {
+          sessionId: sid(`fx-${nextSession++}`), updatedAt: Date.now(), running: false, cwd: '/tmp/fixture',
+        }
+        sessions.push(created)
+        emitHost({ type: 'host/session-added', sessionId: created.sessionId })
+        return ok(request, { sessionId: created.sessionId })
+      },
+      history: async (request) => {
+        const log = logs.get(request.payload.sessionId) ?? []
+        // Snapshot at request time, deliver after the transit delay (mirrors a real host under latency).
+        const page = pageOf(log, request.payload.beforeSeq, request.payload.maxMessages ?? 50)
+        const doomed = failNextHistory
+        failNextHistory = false
+        const delay = historyDelayMs
+        if (delay > 0) await new Promise(resolve => setTimeout(resolve, delay))
+        if (doomed) throw new Error('fixture: simulated history transport failure')
+        return ok(request, page)
+      },
+      prompt: (request) => {
+        const { sessionId: id, mode, content } = request.payload
+        const summary = summaryOf(id)
+        if (summary === undefined) {
+          return err(request, { code: 'session-not-found', message: `no session ${id}`, details: { sessionId: id } })
+        }
+        summary.updatedAt = Date.now()
+        const userText = content.map(b => (b.type === 'text' ? b.text : '')).join('')
+        if (mode === 'steer' && replays.has(id)) {
+          // Steering: insert a steering message into the current turn; the replay continues.
+          /* v8 ignore next -- the ?? arm needs a missing counter, but a live replay implies a prior prompt already set it. */
+          const turn = (nextTurn.get(id) ?? 1) - 1
+          append(id, { type: 'steering/message', surfaceOp: 'append', data: { turn, content, source: { kind: 'user' } } })
+          return ok(request, { accepted: true as const })
+        }
+        const turn = nextTurn.get(id) ?? 0
+        nextTurn.set(id, turn + 1)
+        setRunning(id, true)
+        append(id, { type: 'turn/start', data: { turn, trigger: { kind: 'message', source: { kind: 'user' } } } })
+        append(id, { type: 'user/message', surfaceOp: 'append', data: { content, source: { kind: 'user' } } })
+        startReply(id, turn, `回声：${userText}。这是 fixture 的流式回复，用于验证打字机增长与定稿切换。`)
+        return ok(request, { accepted: true as const })
+      },
+      cancel: (request) => {
+        const replay = replays.get(request.payload.sessionId)
+        if (replay !== undefined) {
+          clearTimeout(replay.timer)
+          replay.finish(true)
+        } else {
+          setRunning(request.payload.sessionId, false)
+        }
+        return ok(request, { accepted: true as const })
+      },
+    },
+    host: {
+      describe: request => ok(request, { version: '0.0.0-fixture', cwd: '/tmp/fixture', attachedSessions: 1 }),
+    },
+    events: {
+      async *mux(_request, signal) {
+        const conn = new FxInbox<MuxFrame>()
+        muxConns.add(conn)
+        const breakNow = (): void => { conn.breakNow() }
+        streamBreakers.add(breakNow)
+        // Open baseline: subscribed for attached (running) sessions + pending approval replay (stable rpcId).
+        for (const s of sessions) {
+          if (!s.running) continue
+          conn.push({ rpcId: mint(), payload: { type: 'session/subscribed', sessionId: s.sessionId, lastSeq: (logs.get(s.sessionId)?.length ?? 0) - 1 } })
+        }
+        conn.push({
+          rpcId: pendingApprovalRpcId,
+          payload: {
+            type: 'approval/requested', sessionId: sid('fx-alpha'),
+            approvalId: 'fx-approval-1' as MuxFrame extends never ? never : Extract<MuxFrame, { type: 'approval/requested' }>['approvalId'],
+            toolName: 'dangerous_tool', reason: 'fixture 常驻占位审批（可见不可答）',
+          },
+        })
+        try {
+          yield* conn.drain(signal)
+        } finally {
+          streamBreakers.delete(breakNow)
+          muxConns.delete(conn)
+        }
+      },
+      async *host(_request, signal) {
+        const conn = new FxInbox<HostFrame>()
+        hostConns.add(conn)
+        const breakNow = (): void => { conn.breakNow() }
+        streamBreakers.add(breakNow)
+        // Periodic material (the RPC-panel acceptance's clear-then-new-frames step depends on it): flip fx-gamma every 5s.
+        // fx-gamma only: never touch fx-alpha's running semantics (the conversation replay drives that).
+        const timer = setInterval(() => {
+          const gamma = summaryOf(sid('fx-gamma'))
+          /* v8 ignore next -- the undefined arm needs fx-gamma deleted, but the fixture never removes sessions. */
+          if (gamma !== undefined) setRunning(gamma.sessionId, !gamma.running)
+        }, 5000)
+        try {
+          yield* conn.drain(signal)
+        } finally {
+          clearInterval(timer)
+          streamBreakers.delete(breakNow)
+          hostConns.delete(conn)
+        }
+      },
+    },
+    respond(message: ClientResponse): Promise<RpcReceipt> {
+      // The v1 UI never answers (PendingCard is visible but not answerable); implemented for type completeness, always not-pending.
+      void message
+      return Promise.resolve({ accepted: false, reason: 'not-pending' })
+    },
+  }
+}
+
+/**
+ * Fixture platform subclass: there is no HTTP at all, so instead of a doFetch transport it
+ * overrides the protocol-level virtuals (callUnary/openMux/openHost/respond) to dispatch
+ * straight into the in-memory ApiProxy — while still minting rpcIds, fabricating the four
+ * named full forms, and feeding the same tap as a real carrier. Delete when the fixture moves
+ * to the isomorphic pipeline (InProcessApiClient over toFetchHandler(fixtureImpl)).
+ */
+export class FixtureApiClient extends AbstractApiClient {
+  private readonly api = createFixtureApi()
+
+  protected doFetch(): Promise<Response> {
+    throw new Error('FixtureApiClient overrides all protocol paths; doFetch must be unreachable')
+  }
+
+  protected override async callUnary<K extends keyof RpcMethodMap>(
+    method: K,
+    payload: RequestPayload<K>,
+  ): Promise<RpcResponse<ResponseValue<K>>> {
+    const request = rpcRequest(payload)
+    const full: ClientRequest = { type: 'client-request', rpcId: request.rpcId, method, payload }
+    this.onEnvelope(full)
+    const response = await this.dispatch(method, request as RpcRequest<never>) as RpcResponse<ResponseValue<K>>
+    const fullResponse: ServerResponse = { type: 'server-response', rpcId: response.rpcId, result: response.result }
+    this.onEnvelope(fullResponse)
+    return response
+  }
+
+  /** Method-key dispatch into the in-memory contract impl (a real carrier routes by URL path instead). */
+  private dispatch(method: keyof RpcMethodMap, request: RpcRequest<never>): Promise<RpcResponse<unknown>> {
+    switch (method) {
+      case 'session.list': return this.api.sessions.list(request)
+      case 'session.create': return this.api.sessions.create(request)
+      case 'session.history': return this.api.sessions.history(request)
+      case 'session.prompt': return this.api.sessions.prompt(request)
+      case 'session.cancel': return this.api.sessions.cancel(request)
+      case 'host.describe': return this.api.host.describe(request)
+    }
+  }
+
+  protected override openMux(
+    payload: { since?: Record<SessionId, number> },
+    signal: AbortSignal,
+    onOpen?: () => void,
+  ): AsyncIterable<RpcRequest<MuxFrame>> {
+    return this.tapStream(this.api.events.mux(rpcRequest(payload), signal), onOpen)
+  }
+
+  protected override openHost(
+    payload: Record<never, never>,
+    signal: AbortSignal,
+    onOpen?: () => void,
+  ): AsyncIterable<RpcRequest<HostFrame>> {
+    return this.tapStream(this.api.events.host(rpcRequest(payload), signal), onOpen)
+  }
+
+  private async *tapStream<F extends MuxFrame | HostFrame>(
+    stream: AsyncIterable<RpcRequest<F>>,
+    onOpen?: () => void,
+  ): AsyncGenerator<RpcRequest<F>> {
+    // No HTTP here: the in-memory stream is established the moment iteration starts (mirrors
+    // readSse firing onOpen after response headers, before any frame).
+    onOpen?.()
+    for await (const envelope of stream) {
+      const full: ServerRequest = { type: 'server-request', rpcId: envelope.rpcId, method: envelope.payload.type, payload: envelope.payload }
+      this.onEnvelope(full)
+      yield envelope
+    }
+  }
+
+  override async respond(message: ClientResponse): Promise<RpcReceipt> {
+    this.onEnvelope(message)
+    return this.api.respond(message)
+  }
+}

packages/client/connection/src/client/index.ts

@@ -0,0 +1,76 @@
+/**
+ * Browser half of the wire consumer layer (contract: api-contracts v3
+ * section 3; export inventory = v3 §3.2). The wire is this package's client
+ * half in its entirety — apply mounts ctx.connection: the shared api client
+ * plus the connection controller handle. Mode selection (?fixture) happens
+ * here so the rest of the client tree is mode-blind; the controller's sinks
+ * are wired by the runtime plugin (object layer), which injects this service.
+ */
+import type { Context } from 'cordis'
+import type { IApiClient } from './api.ts'
+import { ConnectionController, type ConnectionConfig, type ConnectionSinks, type ConnectionState } from './connection.ts'
+import { FixtureApiClient } from './fixture.ts'
+import { WebApiClient } from './web-api-client.ts'
+
+// ---- Contract re-exports (browser-safe apiproxy channels + core types) ----
+export type {
+  ApiProxy, SessionsApi, SessionSummary, HostApi, EventsApi, MuxFrame, HostFrame,
+  ApprovalResponsePayload, QuestionResponsePayload, HistoryEntry, ToolEventView,
+  ToolCallView, ToolResultView,
+  RpcRequest, RpcResponse, RpcResult, RpcError, RpcErrorCode,
+  ClientRequest, ServerResponse, ServerRequest, ClientResponse, RpcMessage, RpcReceipt,
+  IApiClient, SessionId, SessionEvent, ContentBlock, StreamChunk,
+} from './api.ts'
+export { RpcId, AbstractApiClient, resultOf, transportError } from './api.ts'
+
+// ---- Connection loop ----
+export { ConnectionController } from './connection.ts'
+export type { ConnectionConfig, ConnectionSinks, ConnectionState }
+
+// ---- Platform client subclasses ----
+export { WebApiClient } from './web-api-client.ts'
+export { FixtureApiClient, createFixtureApi } from './fixture.ts'
+
+
+/** Required services (none — this is the wire root). */
+export const inject: string[] = []
+
+/**
+ * The ctx.connection service surface: the api client plus a one-shot
+ * controller starter (the runtime plugin supplies sinks when its object layer
+ * is ready — connection stays consumer-agnostic).
+ */
+export interface ConnectionHandle {
+  /** Shared api client (fixture or real, decided at boot from the page URL). */
+  readonly api: IApiClient
+  /**
+   * Start the connect/pump/reconnect loop with the consumer's frame sinks.
+   * One consumer owns the streams (the runtime object layer); a second call
+   * throws.
+   * @param sinks - frame/state callbacks.
+   * @param config - reconnect/backoff tunables.
+   * @returns stop handle for the loop.
+   */
+  start(sinks: ConnectionSinks, config?: ConnectionConfig): { stop(): void }
+}
+
+/**
+ * Client plugin body: pick the api by page mode and provide ctx.connection.
+ * @param ctx - client cordis context.
+ */
+export function apply(ctx: Context): void {
+  const fixture = typeof location !== 'undefined' && new URLSearchParams(location.search).has('fixture')
+  const api: IApiClient = fixture ? new FixtureApiClient() : new WebApiClient()
+  let started = false
+  const handle: ConnectionHandle = {
+    api,
+    start(sinks, config) {
+      if (started) throw new Error('connection: the stream loop is already owned by another consumer')
+      started = true
+      const controller = new ConnectionController(api, sinks, config ?? {})
+      controller.start()
+      return { stop: () => { controller.stop() } }
+    },
+  }
+  ctx.provide('connection', handle)
+}

packages/client/connection/src/client/web-api-client.ts

@@ -0,0 +1,12 @@
+// WebApiClient: the browser platform subclass — transport = global fetch over same-origin
+// /api/* (base resolution handled by AbstractApiClient). Envelope observation comes from the
+// base batching aspect; subscribers attach via subscribeEnvelopes (see boot).
+
+import { AbstractApiClient } from './api.ts'
+
+/** Browser platform subclass: transport = global fetch over same-origin /api/*. */
+export class WebApiClient extends AbstractApiClient {
+  protected doFetch(input: URL, init?: RequestInit): Promise<Response> {
+    return globalThis.fetch(input, init)
+  }
+}

packages/client/connection/src/index.ts

@@ -0,0 +1,10 @@
+/**
+ * Connection plugin, node half. The package IS a dshClient plugin: the wire
+ * consumer layer lives in its client half in full (src/client/ — contract:
+ * api-contracts v3 section 3, inventory §3.2); consumers import the /client
+ * subpath. The empty apply exists so the plugin appears in the host Loader
+ * (lifecycle governance + dshClient discovery).
+ */
+
+/** Host plugin body — no host-side behavior for the connection plugin. */
+export function apply(_ctx: unknown): void {}

packages/client/connection/src/invariant.ts

@@ -0,0 +1,32 @@
+/**
+ * Package-owned invariant companion for `@deepseek-ai/dsh-client-connection`.
+ * @module @deepseek-ai/dsh-client-connection/invariant
+ */
+
+/* jscpd:ignore-start */
+import type { Context } from 'cordis'
+import type { InvariantInstaller } from '@deepseek-ai/dsh-invariants'
+
+const PACKAGE_NAME = '@deepseek-ai/dsh-client-connection'
+
+/** Cordis companion plugin name. */
+export const name = 'client-connection-invariant'
+/** Service required before the companion can reserve package ownership. */
+export const inject = ['invariants']
+
+/**
+ * No runtime invariant: the pure wire layer emits no cordis events and owns no
+ * mutable cross-plugin relation — stream/reconnect sequencing is exercised
+ * directly by its behavior specs, and rpcId round-trip discipline is owned by
+ * the apiproxy contract layer.
+ */
+const install: InvariantInstaller = () => {}
+
+/**
+ * Register this package's invariant companion.
+ * @param ctx - Cordis context carrying the invariant service.
+ * @returns the installed registration's disposer after setup succeeds.
+ */
+export const apply = (ctx: Context): Promise<() => void> =>
+  Promise.resolve(ctx.invariants.register(PACKAGE_NAME, install))
+/* jscpd:ignore-end */

packages/client/connection/tests/api-helpers.spec.ts

@@ -0,0 +1,21 @@
+/**
+ * Contract-layer helpers: transport-error folding and response unwrapping.
+ * (The assistant block classifier half of the legacy spec lives in
+ * runtime/tests — the classifier moved there.)
+ */
+
+import { describe, expect, it } from 'vitest'
+import { RpcId, resultOf, transportError } from '../src/client/api.ts'
+
+describe('transportError', () => {
+  it('folds an Error to internal keeping the message, and stringifies non-Errors', () => {
+    expect(transportError(new Error('线断了'))).toEqual({ ok: false, error: { code: 'internal', message: '线断了', details: {} } })
+    expect(transportError('raw string')).toMatchObject({ ok: false, error: { message: 'raw string' } })
+  })
+})
+
+describe('resultOf', () => {
+  it('unwraps the result slot', () => {
+    expect(resultOf({ rpcId: RpcId('r'), result: { ok: true, value: 7 } })).toEqual({ ok: true, value: 7 })
+  })
+})

packages/client/connection/tests/connection.spec.ts

@@ -0,0 +1,238 @@
+/**
+ * ConnectionController: stream pumping into sinks, the strict readiness
+ * handshake (describe + both streams' onOpen, timeout-guarded), generation
+ * abort on loss, backoff reconnection, state transitions, and sink-exception
+ * isolation. Real (short) timers — the timeout and backoff are configurable,
+ * so tests run them at millisecond scale.
+ */
+
+import { describe, expect, it, vi } from 'vitest'
+import type { SessionId } from '../src/client/api.ts'
+import type { ConnectionState } from '../src/client/connection.ts'
+import { ConnectionController } from '../src/client/connection.ts'
+import { FakeApiClient, deferred, ok } from './fake-api.ts'
+
+const SID = 'fk-c1' as SessionId
+const FAST = { backoffBaseMs: 10, backoffFactor: 1, backoffMaxMs: 10, streamOpenTimeoutMs: 500 }
+
+function subscribedFrame(lastSeq = 0) {
+  return { type: 'session/subscribed', sessionId: SID, lastSeq } as const
+}
+
+describe('connection lifecycle', () => {
+  it('announces connected after describe + both streams open, then pumps frames to sinks', async () => {
+    const api = new FakeApiClient()
+    const muxSeen: string[] = []
+    let connected = 0
+    const controller = new ConnectionController(api, {
+      onMuxEnvelope: envelope => muxSeen.push(envelope.payload.type),
+      onConnected: () => { connected++ },
+    }, FAST)
+    controller.start()
+    try {
+      await vi.waitFor(() => { expect(connected).toBe(1) })
+      api.pushMux(subscribedFrame())
+      await vi.waitFor(() => { expect(muxSeen).toEqual(['session/subscribed']) })
+      expect(api.callsOf('host.describe')).toHaveLength(1)
+    } finally {
+      controller.stop()
+    }
+  })
+
+  it('reconnects with a fresh generation when a stream fails, and stop() ends the loop', async () => {
+    const api = new FakeApiClient()
+    let connected = 0
+    const warnSpy = vi.spyOn(console, 'warn').mockImplementation(() => undefined)
+    const controller = new ConnectionController(api, { onConnected: () => { connected++ } }, FAST)
+    controller.start()
+    try {
+      await vi.waitFor(() => { expect(connected).toBe(1) })
+      api.failStreams(new Error('stream torn'))
+      await vi.waitFor(() => { expect(connected).toBe(2) }) // new generation after backoff
+      expect(api.openMuxCount).toBe(1) // the dead generation's stream is gone, exactly one live
+    } finally {
+      controller.stop()
+      warnSpy.mockRestore()
+    }
+    // stop() aborts the live generation (streams tear down) and no reconnect follows.
+    await vi.waitFor(() => { expect(api.openMuxCount).toBe(0) })
+    await new Promise(resolve => setTimeout(resolve, 40))
+    expect(api.openMuxCount).toBe(0)
+  })
+
+  it('treats describe failure as generation failure and retries', async () => {
+    const api = new FakeApiClient()
+    const gate = deferred<Awaited<ReturnType<FakeApiClient['onDescribe']>>>()
+    let describeCalls = 0
+    api.onDescribe = () => {
+      describeCalls++
+      return describeCalls === 1 ? Promise.reject(new Error('host down')) : gate.promise
+    }
+    let connected = 0
+    const warnSpy = vi.spyOn(console, 'warn').mockImplementation(() => undefined)
+    const controller = new ConnectionController(api, { onConnected: () => { connected++ } }, FAST)
+    controller.start()
+    try {
+      await vi.waitFor(() => { expect(describeCalls).toBe(2) }) // retried after backoff
+      expect(connected).toBe(0) // never announced during the failed generation
+      gate.resolve(ok({ version: '0', cwd: '/f', attachedSessions: 0 }))
+      await vi.waitFor(() => { expect(connected).toBe(1) })
+    } finally {
+      controller.stop()
+      warnSpy.mockRestore()
+    }
+  })
+
+  it('converges stream/error frames into reconnect instead of dispatching them', async () => {
+    const api = new FakeApiClient()
+    const muxSeen: string[] = []
+    let connected = 0
+    const warnSpy = vi.spyOn(console, 'warn').mockImplementation(() => undefined)
+    const controller = new ConnectionController(api, {
+      onMuxEnvelope: envelope => muxSeen.push(envelope.payload.type),
+      onConnected: () => { connected++ },
+    }, FAST)
+    controller.start()
+    try {
+      await vi.waitFor(() => { expect(connected).toBe(1) })
+      api.pushMux({ type: 'stream/error', error: { code: 'internal', message: 'impl broke', details: {} } })
+      await vi.waitFor(() => { expect(connected).toBe(2) }) // treated as loss → reconnect
+      expect(muxSeen).toEqual([]) // never forwarded to the business sink
+    } finally {
+      controller.stop()
+      warnSpy.mockRestore()
+    }
+  })
+
+  it('isolates sink exceptions from the pump', async () => {
+    const api = new FakeApiClient()
+    const seen: string[] = []
+    let connected = 0
+    const errorSpy = vi.spyOn(console, 'error').mockImplementation(() => undefined)
+    const controller = new ConnectionController(api, {
+      onMuxEnvelope: (envelope) => {
+        seen.push(envelope.payload.type)
+        throw new Error('business layer bug')
+      },
+      onConnected: () => { connected++ },
+    }, FAST)
+    controller.start()
+    try {
+      await vi.waitFor(() => { expect(connected).toBe(1) })
+      api.pushMux(subscribedFrame(1))
+      api.pushMux(subscribedFrame(2))
+      await vi.waitFor(() => { expect(seen).toHaveLength(2) }) // second frame still pumped
+      expect(connected).toBe(1) // no reconnect triggered by the sink throw
+    } finally {
+      controller.stop()
+      errorSpy.mockRestore()
+    }
+  })
+
+  it('holds onConnected until both streams establish even after describe succeeds', async () => {
+    const api = new FakeApiClient()
+    api.holdStreamOpen = true // describe resolves immediately; stream establishment is in the case's hand
+    let connected = 0
+    const controller = new ConnectionController(api, { onConnected: () => { connected++ } }, FAST)
+    controller.start()
+    try {
+      await vi.waitFor(() => { expect(api.callsOf('host.describe')).toHaveLength(1) })
+      await new Promise(resolve => setTimeout(resolve, 30))
+      expect(connected).toBe(0) // describe alone must not announce
+      api.releaseStreamOpens()
+      await vi.waitFor(() => { expect(connected).toBe(1) })
+    } finally {
+      controller.stop()
+    }
+  })
+
+  it('proceeds as connected via the timeout guard when a carrier never fires onOpen', async () => {
+    const api = new FakeApiClient()
+    api.suppressStreamOpen = true // misbehaving carrier: streams open but onOpen never fires
+    let connected = 0
+    const controller = new ConnectionController(api, { onConnected: () => { connected++ } }, { ...FAST, streamOpenTimeoutMs: 20 })
+    controller.start()
+    try {
+      await vi.waitFor(() => { expect(connected).toBe(1) }) // handshake resolved by the guard, not wedged
+    } finally {
+      controller.stop()
+    }
+  })
+
+  it('emits deduplicated connected/reconnecting state transitions', async () => {
+    const api = new FakeApiClient()
+    const states: ConnectionState[] = []
+    let connected = 0
+    const warnSpy = vi.spyOn(console, 'warn').mockImplementation(() => undefined)
+    const controller = new ConnectionController(api, {
+      onConnected: () => { connected++ },
+      onStateChange: state => states.push(state),
+    }, FAST)
+    controller.start()
+    try {
+      await vi.waitFor(() => { expect(connected).toBe(1) })
+      expect(states).toEqual(['connected'])
+      api.failStreams(new Error('torn'))
+      await vi.waitFor(() => { expect(connected).toBe(2) })
+      expect(states).toEqual(['connected', 'reconnecting', 'connected'])
+    } finally {
+      controller.stop()
+      warnSpy.mockRestore()
+    }
+  })
+
+  it('deduplicates consecutive reconnecting emissions across two straight failures', async () => {
+    const api = new FakeApiClient()
+    const gate = deferred<Awaited<ReturnType<FakeApiClient['onDescribe']>>>()
+    let describeCalls = 0
+    api.onDescribe = () => {
+      describeCalls++
+      return describeCalls <= 2 ? Promise.reject(new Error('down')) : gate.promise
+    }
+    const states: ConnectionState[] = []
+    let connected = 0
+    const warnSpy = vi.spyOn(console, 'warn').mockImplementation(() => undefined)
+    const controller = new ConnectionController(api, {
+      onConnected: () => { connected++ },
+      onStateChange: state => states.push(state),
+    }, FAST)
+    controller.start()
+    try {
+      await vi.waitFor(() => { expect(describeCalls).toBe(3) })
+      gate.resolve(ok({ version: '0', cwd: '/f', attachedSessions: 0 }))
+      await vi.waitFor(() => { expect(connected).toBe(1) })
+      expect(states).toEqual(['reconnecting', 'connected']) // two failures, one reconnecting emission
+    } finally {
+      controller.stop()
+      warnSpy.mockRestore()
+    }
+  })
+
+  it('runs with no sinks at all (every callback slot optional)', async () => {
+    const api = new FakeApiClient()
+    const controller = new ConnectionController(api, {}, FAST)
+    controller.start()
+    try {
+      await vi.waitFor(() => { expect(api.callsOf('host.describe')).toHaveLength(1) })
+      api.pushMux(subscribedFrame()) // pumped with sink undefined: dropped silently
+      await new Promise(resolve => setTimeout(resolve, 20))
+    } finally {
+      controller.stop()
+    }
+  })
+
+  it('start() is idempotent (one loop, one stream set)', async () => {
+    const api = new FakeApiClient()
+    let connected = 0
+    const controller = new ConnectionController(api, { onConnected: () => { connected++ } }, FAST)
+    controller.start()
+    controller.start()
+    try {
+      await vi.waitFor(() => { expect(connected).toBe(1) })
+      expect(api.openMuxCount).toBe(1)
+      expect(api.callsOf('host.describe')).toHaveLength(1)
+    } finally {
+      controller.stop()
+    }
+  })
+})

packages/client/connection/tests/fake-api.ts

@@ -0,0 +1,154 @@
+// Test-local programmable IApiClient fake (NOT the fixture: fixture is a demo
+// data source on a real clock; behavior tests need per-case responses and
+// deferred-controlled timing). Streams are hand pumps: pushMux/pushHost.
+import type {
+  HostFrame, IApiClient, MuxFrame, RpcRequest, RpcResponse, SessionId,
+} from '../src/client/api.ts'
+import { RpcId } from '../src/client/api.ts'
+
+export interface Deferred<T> {
+  promise: Promise<T>
+  resolve(value: T): void
+  reject(error: unknown): void
+}
+
+/** Test-held settlement: the case decides when an RPC lands (history-pending injections etc.). */
+export function deferred<T>(): Deferred<T> {
+  let resolve!: (value: T) => void
+  let reject!: (error: unknown) => void
+  const promise = new Promise<T>((res, rej) => {
+    resolve = res
+    reject = rej
+  })
+  return { promise, resolve, reject }
+}
+
+let nextRpc = 0
+
+export function ok<T>(value: T): RpcResponse<T> {
+  return { rpcId: RpcId(`fake-${nextRpc++}`), result: { ok: true, value } }
+}
+
+
+type StreamItem<F> = { kind: 'frame'; envelope: RpcRequest<F> } | { kind: 'end' } | { kind: 'fail'; error: unknown }
+
+interface StreamConn<F> {
+  feed(item: StreamItem<F>): void
+}
+
+export class FakeApiClient implements IApiClient {
+  /** Chronological call record: [method, payload]. */
+  readonly calls: { method: string; payload: unknown }[] = []
+
+  // Programmable slots (defaults answer OK-empty); reassign per case.
+  onList: (payload: unknown) => Promise<RpcResponse<{ items: never[] }>> = () => Promise.resolve(ok({ items: [] }))
+  onCreate: (payload: unknown) => Promise<RpcResponse<{ sessionId: SessionId }>> = () => Promise.resolve(ok({ sessionId: 'fk-new' as SessionId }))
+  onHistory: (payload: { sessionId: SessionId; beforeSeq?: number; maxMessages?: number })
+  => Promise<RpcResponse<{ events: never[]; hasMore: boolean }>> =
+    () => Promise.resolve(ok({ events: [], hasMore: false }))
+
+  onPrompt: (payload: unknown) => Promise<RpcResponse<{ accepted: true }>> = () => Promise.resolve(ok({ accepted: true as const }))
+  onCancel: (payload: unknown) => Promise<RpcResponse<{ accepted: true }>> = () => Promise.resolve(ok({ accepted: true as const }))
+  onDescribe: (payload: unknown) => Promise<RpcResponse<{ version: string; cwd: string; attachedSessions: number }>> =
+    () => Promise.resolve(ok({ version: '0-fake', cwd: '/f', attachedSessions: 0 }))
+
+  private readonly muxConns: StreamConn<MuxFrame>[] = []
+  private readonly hostConns: StreamConn<HostFrame>[] = []
+
+  readonly sessions: IApiClient['sessions'] = {
+    list: payload => this.record('session.list', payload, this.onList(payload)),
+    create: payload => this.record('session.create', payload, this.onCreate(payload)),
+    history: payload => this.record('session.history', payload, this.onHistory(payload)),
+    prompt: payload => this.record('session.prompt', payload, this.onPrompt(payload)),
+    cancel: payload => this.record('session.cancel', payload, this.onCancel(payload)),
+  }
+
+  readonly host: IApiClient['host'] = {
+    describe: payload => this.record('host.describe', payload, this.onDescribe(payload)),
+  }
+
+  /** When true, streams never fire onOpen (misbehaving-carrier material for the handshake timeout guard). */
+  suppressStreamOpen = false
+
+  /** When true, onOpen callbacks are parked instead of fired; releaseStreamOpens() fires them.
+   *  Lets a case hold the readiness handshake open (describe done, streams not yet "established"). */
+  holdStreamOpen = false
+  private heldOpens: (() => void)[] = []
+
+  releaseStreamOpens(): void {
+    const held = this.heldOpens
+    this.heldOpens = []
+    for (const fire of held) fire()
+  }
+
+  readonly events: IApiClient['events'] = {
+    mux: (_payload, signal, onOpen) => this.openStream(this.muxConns, signal, onOpen),
+    host: (_payload, signal, onOpen) => this.openStream(this.hostConns, signal, onOpen),
+  }
+
+  respond(): Promise<{ accepted: false; reason: 'not-pending' }> {
+    return Promise.resolve({ accepted: false, reason: 'not-pending' })
+  }
+
+  /** Push one mux frame to every open mux stream (rpcId minted unless pinned by the case). */
+  pushMux(frame: MuxFrame, rpcId?: string): void {
+    for (const conn of [...this.muxConns]) conn.feed({ kind: 'frame', envelope: { rpcId: RpcId(rpcId ?? `push-${nextRpc++}`), payload: frame } })
+  }
+
+  pushHost(frame: HostFrame, rpcId?: string): void {
+    for (const conn of [...this.hostConns]) conn.feed({ kind: 'frame', envelope: { rpcId: RpcId(rpcId ?? `push-${nextRpc++}`), payload: frame } })
+  }
+
+  /** End (clean close) or fail (throw) every open stream — reconnect-path material. */
+  endStreams(): void {
+    for (const conn of [...this.muxConns, ...this.hostConns]) conn.feed({ kind: 'end' })
+  }
+
+  failStreams(error: unknown): void {
+    for (const conn of [...this.muxConns, ...this.hostConns]) conn.feed({ kind: 'fail', error })
+  }
+
+  get openMuxCount(): number {
+    return this.muxConns.length
+  }
+
+  callsOf(method: string): unknown[] {
+    return this.calls.filter(c => c.method === method).map(c => c.payload)
+  }
+
+  private record<T>(method: string, payload: unknown, response: Promise<T>): Promise<T> {
+    this.calls.push({ method, payload })
+    return response
+  }
+
+  private async *openStream<F>(registry: StreamConn<F>[], signal: AbortSignal, onOpen?: () => void): AsyncGenerator<RpcRequest<F>> {
+    const inbox: StreamItem<F>[] = []
+    let wake: (() => void) | null = null
+    const conn: StreamConn<F> = {
+      feed: (item) => {
+        inbox.push(item)
+        wake?.()
+      },
+    }
+    registry.push(conn)
+    if (this.holdStreamOpen && onOpen !== undefined) this.heldOpens.push(onOpen)
+    else if (!this.suppressStreamOpen) onOpen?.()
+    try {
+      while (!signal.aborted) {
+        while (inbox.length > 0) {
+          const item = inbox.shift() as StreamItem<F>
+          if (item.kind === 'end') return
+          if (item.kind === 'fail') throw item.error
+          yield item.envelope
+        }
+        await new Promise<void>((resolve) => {
+          wake = resolve
+          signal.addEventListener('abort', () => { resolve() }, { once: true })
+        })
+        wake = null
+      }
+    } finally {
+      registry.splice(registry.indexOf(conn), 1)
+    }
+  }
+}

packages/client/connection/tests/fixture.spec.ts

@@ -0,0 +1,338 @@
+/**
+ * Fixture impl semantics: the demo data source must honor the same contract
+ * shapes as the real host (paging boundaries, rpcId echo, replay lifecycle,
+ * baseline replay, timing hooks) — this is the vitest-side drift detector for
+ * the hand-written fixture/host parallel implementations.
+ */
+
+import { afterEach, describe, expect, it, vi } from 'vitest'
+import type { SessionId } from '../src/client/api.ts'
+import { RpcId } from '../src/client/api.ts'
+import type { HostFrame, MuxFrame, RpcMessage, RpcRequest } from '../src/client/api.ts'
+import { FixtureApiClient, createFixtureApi } from '../src/client/fixture.ts'
+
+const sid = (id: string): SessionId => id as SessionId
+const req = <P>(payload: P): RpcRequest<P> => ({ rpcId: RpcId(`t-${Math.abs(Math.sin(reqCount++)).toString(36).slice(2, 10)}`), payload })
+let reqCount = 0
+
+interface TimingHooks {
+  setHistoryDelay(ms: number): void
+  failNextHistory(): void
+  appendUser(id: string, msg: string): void
+  appendSilent(id: string, msg: string): void
+  breakStreams(): void
+}
+const timing = (): TimingHooks => (globalThis as Record<string, unknown>).__fxTiming as TimingHooks
+
+/** Collect stream frames until the predicate or a soft cap; abort ends the stream. */
+async function collect<F>(stream: AsyncIterable<RpcRequest<F>>, abort: AbortController, done: (frames: F[]) => boolean): Promise<F[]> {
+  const frames: F[] = []
+  for await (const envelope of stream) {
+    frames.push(envelope.payload)
+    if (done(frames) || frames.length > 500) {
+      abort.abort()
+      break
+    }
+  }
+  return frames
+}
+
+describe('createFixtureApi', () => {
+  it('serves the session list sorted by updatedAt desc and echoes rpcIds on every unary', async () => {
+    const api = createFixtureApi()
+    const request = req({})
+    const response = await api.sessions.list(request)
+    expect(response.rpcId).toBe(request.rpcId)
+    if (!response.result.ok) throw new Error('list failed')
+    expect(response.result.value.items.map(s => s.sessionId)).toEqual(['fx-alpha', 'fx-beta', 'fx-gamma'])
+    expect(response.result.value.items[1]?.parentSessionId).toBe('fx-alpha') // lineage material
+  })
+
+  it('pages history backwards on message-boundary cuts with seq-contiguous stitching', async () => {
+    const api = createFixtureApi()
+    const tail = await api.sessions.history(req({ sessionId: sid('fx-alpha'), maxMessages: 10 }))
+    if (!tail.result.ok) throw new Error('history failed')
+    const tailPage = tail.result.value
+    expect(tailPage.hasMore).toBe(true)
+    expect(tailPage.events[0]?.event.type).toBe('turn/start') // cut lands on a turn boundary
+    const boundary = tailPage.events[0]?.event.seq ?? 0
+    expect(boundary).toBeGreaterThan(0)
+    const older = await api.sessions.history(req({ sessionId: sid('fx-alpha'), beforeSeq: boundary, maxMessages: 10 }))
+    if (!older.result.ok) throw new Error('older failed')
+    const olderTail = older.result.value.events.at(-1)?.event
+    expect((olderTail?.seq ?? -1) + 1).toBe(boundary) // pages stitch with no hole/overlap
+    // Out-of-range beforeSeq clamps instead of exploding.
+    const clamped = await api.sessions.history(req({ sessionId: sid('fx-alpha'), beforeSeq: -5, maxMessages: 10 }))
+    if (!clamped.result.ok) throw new Error('clamped failed')
+    expect(clamped.result.value.events).toEqual([])
+    // Unknown session: empty page, not an error (history of a bare id).
+    const empty = await api.sessions.history(req({ sessionId: sid('no-such'), maxMessages: 10 }))
+    if (!empty.result.ok) throw new Error('empty failed')
+    expect(empty.result.value).toEqual({ events: [], hasMore: false })
+  })
+
+  it('create adds a session and pushes host/session-added to open host streams', async () => {
+    const api = createFixtureApi()
+    const abort = new AbortController()
+    const seen: HostFrame[] = []
+    const consuming = (async () => {
+      for await (const envelope of api.events.host(req({}), abort.signal)) {
+        seen.push(envelope.payload)
+        if (seen.length >= 1) abort.abort()
+      }
+    })()
+    await new Promise(resolve => setTimeout(resolve, 10)) // let the stream register
+    const created = await api.sessions.create(req({}))
+    if (!created.result.ok) throw new Error('create failed')
+    await consuming
+    if (!created.result.ok) throw new Error('create failed')
+    const createdId = created.result.value.sessionId
+    expect(seen).toEqual([{ type: 'host/session-added', sessionId: createdId }])
+    const list = await api.sessions.list(req({}))
+    if (!list.result.ok) throw new Error('list failed')
+    expect(list.result.value.items.some(s => s.sessionId === createdId)).toBe(true)
+  })
+
+  it('prompt replays a full streamed turn and cancel mid-replay freezes with (已中断)', async () => {
+    const api = createFixtureApi()
+    const created = await api.sessions.create(req({}))
+    if (!created.result.ok) throw new Error('create failed')
+    const id = created.result.value.sessionId
+    const abort = new AbortController()
+    const frames: MuxFrame[] = []
+    const consuming = (async () => {
+      for await (const envelope of api.events.mux(req({}), abort.signal)) {
+        frames.push(envelope.payload)
+        const last = envelope.payload
+        if (last.type === 'session/event' && last.event.type === 'turn/end') {
+          abort.abort()
+        }
+      }
+    })()
+    await new Promise(resolve => setTimeout(resolve, 10))
+    // Unknown session → session-not-found with the id echoed in details.
+    const missing = await api.sessions.prompt(req({ sessionId: sid('ghost'), mode: 'queue' as const, content: [{ type: 'text' as const, text: 'x' }] }))
+    expect(missing.result).toMatchObject({ ok: false, error: { code: 'session-not-found', details: { sessionId: 'ghost' } } })
+    // Real prompt: replay starts (running flips true), cancel freezes it.
+    const accepted = await api.sessions.prompt(req({ sessionId: id, mode: 'queue' as const, content: [{ type: 'text' as const, text: '取消我' }] }))
+    expect(accepted.result).toMatchObject({ ok: true, value: { accepted: true } })
+    await new Promise(resolve => setTimeout(resolve, 120)) // a couple of typewriter ticks
+    await api.sessions.cancel(req({ sessionId: id }))
+    await consuming
+    const types = frames.filter((f): f is Extract<MuxFrame, { type: 'session/event' }> => f.type === 'session/event').map(f => f.event.type)
+    expect(types).toContain('turn/start')
+    expect(types).toContain('user/message')
+    expect(types).toContain('assistant/chunk')
+    expect(types).toContain('assistant/message')
+    expect(types.at(-1)).toBe('turn/end')
+    const finalize = frames.find((f): f is Extract<MuxFrame, { type: 'session/event' }> => f.type === 'session/event' && f.event.type === 'assistant/message')
+    expect(JSON.stringify(finalize?.event.data)).toContain('（已中断）')
+    // Idle cancel: no replay in flight, must not explode; running flips false.
+    const idleCancel = await api.sessions.cancel(req({ sessionId: id }))
+    expect(idleCancel.result).toMatchObject({ ok: true })
+  })
+
+  it('steer during a replay inserts a steering message and the replay continues to completion', async () => {
+    const api = createFixtureApi()
+    const created = await api.sessions.create(req({}))
+    if (!created.result.ok) throw new Error('create failed')
+    const id = created.result.value.sessionId
+    const abort = new AbortController()
+    const framesPromise = collect<MuxFrame>(api.events.mux(req({}), abort.signal), abort,
+      frames => frames.some(f => f.type === 'session/event' && f.event.type === 'turn/end'))
+    await new Promise(resolve => setTimeout(resolve, 10))
+    await api.sessions.prompt(req({ sessionId: id, mode: 'queue' as const, content: [{ type: 'text' as const, text: '短' }] }))
+    await api.sessions.prompt(req({ sessionId: id, mode: 'steer' as const, content: [{ type: 'text' as const, text: '插话' }] }))
+    const frames = await framesPromise
+    const types = frames.filter((f): f is Extract<MuxFrame, { type: 'session/event' }> => f.type === 'session/event').map(f => f.event.type)
+    expect(types).toContain('steering/message')
+    expect(types.at(-1)).toBe('turn/end') // steer did not restart the turn
+  })
+
+  it('mux open replays the baseline: subscribed for running sessions + the resident approval with a stable rpcId', async () => {
+    const api = createFixtureApi()
+    const openOnce = async (): Promise<RpcRequest<MuxFrame>[]> => {
+      const abort = new AbortController()
+      const envelopes: RpcRequest<MuxFrame>[] = []
+      for await (const envelope of api.events.mux(req({}), abort.signal)) {
+        envelopes.push(envelope)
+        if (envelopes.length >= 2) abort.abort()
+      }
+      return envelopes
+    }
+    const first = await openOnce()
+    const second = await openOnce()
+    expect(first[0]?.payload).toMatchObject({ type: 'session/subscribed', sessionId: 'fx-alpha' })
+    expect((first[0]?.payload as { lastSeq: number }).lastSeq).toBeGreaterThan(0)
+    expect(first[1]?.payload).toMatchObject({ type: 'approval/requested', toolName: 'dangerous_tool' })
+    expect(second[1]?.rpcId).toBe(first[1]?.rpcId) // stable rpcId across replays (host replay semantics)
+  })
+
+  it('steer with no replay in flight falls through to a fresh queued turn; non-text blocks stringify empty', async () => {
+    const api = createFixtureApi()
+    const abort = new AbortController()
+    const framesPromise = collect<MuxFrame>(api.events.mux(req({}), abort.signal), abort,
+      frames => frames.some(f => f.type === 'session/event' && f.event.type === 'turn/end'))
+    await new Promise(resolve => setTimeout(resolve, 10))
+    const created = await api.sessions.create(req({}))
+    if (!created.result.ok) throw new Error('create failed')
+    // steer while idle + a non-text content block (covers the '' arm of the text join).
+    await api.sessions.prompt(req({
+      sessionId: created.result.value.sessionId, mode: 'steer' as const,
+      content: [{ type: 'text' as const, text: '短' }, { type: 'image', data: 'x' } as never],
+    }))
+    const frames = await framesPromise
+    const types = frames.filter((f): f is Extract<MuxFrame, { type: 'session/event' }> => f.type === 'session/event').map(f => f.event.type)
+    expect(types[0]).toBe('turn/start') // idle steer degraded to a queued turn, not a steering insert
+  })
+
+  it('gamma interval flip emits host/session-status and a running log-less session subscribes at lastSeq -1', async () => {
+    vi.useFakeTimers()
+    try {
+      const api = createFixtureApi()
+      const abort = new AbortController()
+      const hostSeen: HostFrame[] = []
+      const consuming = (async () => {
+        for await (const envelope of api.events.host(req({}), abort.signal)) hostSeen.push(envelope.payload)
+      })()
+      await vi.advanceTimersByTimeAsync(5001) // interval fires: fx-gamma flips running=true (no log exists)
+      expect(hostSeen).toContainEqual({ type: 'host/session-status', sessionId: sid('fx-gamma'), running: true })
+      // A mux stream opened now sees gamma in the baseline with lastSeq = -1 (empty log arm).
+      const mabort = new AbortController()
+      const baseline: MuxFrame[] = []
+      const muxConsuming = (async () => {
+        for await (const envelope of api.events.mux(req({}), mabort.signal)) {
+          baseline.push(envelope.payload)
+          if (baseline.length >= 3) mabort.abort()
+        }
+      })()
+      await vi.advanceTimersByTimeAsync(10)
+      mabort.abort()
+      await muxConsuming
+      expect(baseline).toContainEqual({ type: 'session/subscribed', sessionId: sid('fx-gamma'), lastSeq: -1 })
+      abort.abort()
+      await vi.advanceTimersByTimeAsync(10)
+      await consuming
+    } finally {
+      vi.useRealTimers()
+    }
+  })
+
+  it('respond is a typed stub: always not-pending', async () => {
+    const api = createFixtureApi()
+    expect(await api.respond({ type: 'client-response', rpcId: RpcId('x'), result: { ok: true, value: {} } })).toEqual({ accepted: false, reason: 'not-pending' })
+  })
+
+  it('describe answers the fixture identity', async () => {
+    const api = createFixtureApi()
+    const response = await api.host.describe(req({}))
+    expect(response.result).toMatchObject({ ok: true, value: { version: '0.0.0-fixture', attachedSessions: 1 } })
+  })
+
+  it('timing hooks: history delay + one-shot failure, silent append, and breakStreams end open generators', async () => {
+    const api = createFixtureApi()
+    const hooks = timing()
+    // One-shot transport failure after transit delay.
+    hooks.setHistoryDelay(5)
+    hooks.failNextHistory()
+    await expect(api.sessions.history(req({ sessionId: sid('fx-alpha'), maxMessages: 5 }))).rejects.toThrow(/simulated history transport failure/)
+    hooks.setHistoryDelay(0)
+    // The failure was one-shot: the next call succeeds.
+    const ok = await api.sessions.history(req({ sessionId: sid('fx-alpha'), maxMessages: 5 }))
+    expect(ok.result.ok).toBe(true)
+    // appendUser emits on the mux stream; appendSilent only lands in the log (lost frame).
+    const abort = new AbortController()
+    const seen: MuxFrame[] = []
+    const consuming = (async () => {
+      for await (const envelope of api.events.mux(req({}), abort.signal)) seen.push(envelope.payload)
+    })()
+    await new Promise(resolve => setTimeout(resolve, 10))
+    hooks.appendSilent('fx-alpha', '静默丢帧')
+    hooks.appendUser('fx-alpha', '正常直播')
+    await vi.waitFor(() => {
+      expect(seen.some(f => f.type === 'session/event' && JSON.stringify(f.event.data).includes('正常直播'))).toBe(true)
+    })
+    expect(seen.some(f => f.type === 'session/event' && JSON.stringify(f.event.data).includes('静默丢帧'))).toBe(false)
+    // But history serves the silent event (the client's repull finds it).
+    const repull = await api.sessions.history(req({ sessionId: sid('fx-alpha'), maxMessages: 5 }))
+    if (!repull.result.ok) throw new Error('repull failed')
+    expect(JSON.stringify(repull.result.value.events)).toContain('静默丢帧')
+    // breakStreams force-ends BOTH stream kinds without the client abort.
+    const habort = new AbortController()
+    const hostConsuming = (async () => {
+      for await (const _ of api.events.host(req({}), habort.signal)) { /* drain */ }
+    })()
+    await new Promise(resolve => setTimeout(resolve, 10))
+    hooks.breakStreams()
+    await consuming // returns because the stream broke, not because we aborted
+    await hostConsuming
+    expect(abort.signal.aborted).toBe(false)
+    expect(habort.signal.aborted).toBe(false)
+  })
+})
+
+describe('FixtureApiClient (protocol-level fake carrier)', () => {
+  afterEach(() => {
+    vi.restoreAllMocks()
+  })
+
+  it('doFetch is an unreachable tripwire (all protocol paths overridden)', () => {
+    const client = new FixtureApiClient()
+    // Protected at compile time only; reach it directly to pin the tripwire message.
+    expect(() => (client as unknown as { doFetch(): Promise<Response> }).doFetch()).toThrow(/doFetch must be unreachable/)
+  })
+
+  it('mints request ids, taps all four full forms, and never touches doFetch', async () => {
+    const client = new FixtureApiClient()
+    const tapped: RpcMessage[] = []
+    client.subscribeEnvelopes(batch => tapped.push(...batch))
+    const response = await client.sessions.list({})
+    expect(response.result.ok).toBe(true)
+    await client.respond({ type: 'client-response', rpcId: RpcId('r-x'), result: { ok: true, value: {} } })
+    await vi.waitFor(() => {
+      const kinds = tapped.map(m => m.type)
+      expect(kinds).toContain('client-request')
+      expect(kinds).toContain('server-response')
+      expect(kinds).toContain('client-response')
+    })
+    const request = tapped.find(m => m.type === 'client-request')
+    const reply = tapped.find(m => m.type === 'server-response')
+    expect(request?.rpcId).toBe(reply?.rpcId) // echo discipline holds through the fake carrier
+  })
+
+  it('covers the whole unary dispatch table', async () => {
+    const client = new FixtureApiClient()
+    const created = await client.sessions.create({})
+    if (!created.result.ok) throw new Error('create failed')
+    const id = created.result.value.sessionId
+    expect((await client.sessions.history({ sessionId: id })).result.ok).toBe(true)
+    expect((await client.sessions.prompt({ sessionId: id, mode: 'queue', content: [{ type: 'text', text: '嗨' }] })).result.ok).toBe(true)
+    expect((await client.sessions.cancel({ sessionId: id })).result.ok).toBe(true)
+    expect((await client.host.describe({})).result.ok).toBe(true)
+  })
+
+  it('fires onOpen at stream-iteration start and taps server-request full forms', async () => {
+    const client = new FixtureApiClient()
+    const tapped: RpcMessage[] = []
+    client.subscribeEnvelopes(batch => tapped.push(...batch))
+    const order: string[] = []
+    const abort = new AbortController()
+    for await (const envelope of client.events.mux({}, abort.signal, () => order.push('open'))) {
+      order.push(envelope.payload.type)
+      abort.abort()
+    }
+    expect(order[0]).toBe('open')
+    expect(order[1]).toBe('session/subscribed')
+    await vi.waitFor(() => {
+      expect(tapped.some(m => m.type === 'server-request')).toBe(true)
+    })
+    // Host stream side of the pair (same tap path).
+    const habort = new AbortController()
+    const hostOrder: string[] = []
+    const hostIterator = client.events.host({}, habort.signal, () => hostOrder.push('open'))[Symbol.asyncIterator]()
+    const raced = await Promise.race([hostIterator.next(), new Promise<'idle'>(resolve => setTimeout(() => { resolve('idle') }, 50))])
+    expect(hostOrder).toEqual(['open']) // established even though the host stream stays silent
+    habort.abort()
+    if (raced === 'idle') await hostIterator.return?.(undefined)
+  })
+})

packages/client/connection/tests/node-half.spec.ts

@@ -0,0 +1,10 @@
+/** Node half: the empty host apply (Loader governance + dshClient discovery placeholder). */
+import { describe, expect, it } from 'vitest'
+import { apply } from '../src/index.ts'
+
+describe('node half', () => {
+  it('apply is a no-op host placeholder', () => {
+    apply(undefined)
+    expect(true).toBe(true) // reaching here without throw is the contract
+  })
+})

packages/client/connection/tsconfig.json

@@ -0,0 +1,42 @@
+{
+  "extends": "../../../tsconfig.base.json",
+  "compilerOptions": {
+    "rootDir": "src",
+    "outDir": "lib/types",
+    "lib": [
+      "ES2024",
+      "DOM",
+      "DOM.Iterable"
+    ],
+    "types": []
+  },
+  "include": [
+    "src"
+  ],
+  "references": [
+    {
+      "path": "../../llm/llm"
+    },
+    {
+      "path": "../../core/session"
+    },
+    {
+      "path": "../../util/brand"
+    },
+    {
+      "path": "../../host/apiproxy"
+    },
+    {
+      "path": "../../ui/user-approval"
+    },
+    {
+      "path": "../../ui/user-interaction"
+    },
+    {
+      "path": "../../support/invariants"
+    }
+  ],
+  "exclude": [
+    "**/*.legacy.*"
+  ]
+}

packages/client/connection/tsdown.config.ts

@@ -0,0 +1,3 @@
+import { clientBundle } from '../tsdown.client.ts'
+
+export default clientBundle('@deepseek-ai/dsh-client-connection', ['lib/types/index.js', 'lib/types/invariant.js'])

packages/client/i18n/README.md

@@ -0,0 +1,16 @@
+# @deepseek-ai/dsh-client-i18n
+
+i18n plugin: I18nService (ns×locale dictionaries, bind(ns)→t with a stable function identity, locale store). Contract: api-contracts v3 §8.
+
+## Model Experience
+
+None, as the i18n registry serves browser UI copy; nothing here reaches a model request.
+
+#### KV Cache effect
+
+None; this package neither assembles nor sends a provider request.
+
+## Known Limitations and Deferred Work
+
+- **zh/en ship as empty structures** — the existing UI copy is inline Chinese; extraction into dictionaries is deferred repo-wide work, so `bind(ns)` consumers today mostly receive key-echo fallbacks.
+- **Locale switching re-renders the whole tree** — accepted as a low-frequency operation; no per-namespace subscription granularity.

packages/client/i18n/package.json

@@ -0,0 +1,54 @@
+{
+  "name": "@deepseek-ai/dsh-client-i18n",
+  "description": "i18n plugin: I18nService (ns x locale dictionaries, bind(ns) -> t, locale store); zh/en skeleton",
+  "version": "0.0.1",
+  "private": true,
+  "type": "module",
+  "main": "lib/index.js",
+  "types": "lib/types/index.d.ts",
+  "exports": {
+    ".": {
+      "types": "./lib/types/index.d.ts",
+      "default": "./lib/index.js"
+    },
+    "./invariant": {
+      "types": "./lib/types/invariant.d.ts",
+      "default": "./lib/invariant.js"
+    },
+    "./client": {
+      "types": "./lib/types/client/index.d.ts",
+      "default": "./lib/client.js"
+    },
+    "./src/*": "./src/*",
+    "./package.json": "./package.json"
+  },
+  "dshClient": {
+    "inject": [],
+    "platform": "web",
+    "immediately": true
+  },
+  "scripts": {
+    "bundle": "tsdown",
+    "watch": "tsdown --watch"
+  },
+  "license": "BSD-3-Clause",
+  "dependencies": {
+    "@deepseek-ai/dsh-client-web-react": "workspace:^"
+  },
+  "peerDependencies": {
+    "@deepseek-ai/dsh-invariants": "^0.0.1",
+    "cordis": "^4.0.0-rc.7"
+  },
+  "devDependencies": {
+    "@deepseek-ai/dsh-invariants": "workspace:^",
+    "cordis": "^4.0.0-rc.7"
+  },
+  "files": [
+    "lib/index.js",
+    "lib/invariant.js",
+    "lib/client.js",
+    "lib/types/**/*.d.ts",
+    "lib/types/**/*.d.ts.map",
+    "src"
+  ]
+}

packages/client/i18n/src/client/index.ts

@@ -0,0 +1,108 @@
+/**
+ * i18n plugin, browser half: namespace x locale dictionary registry with a
+ * bound translate function whose reference is stable (safe for inject
+ * surfaces). Mounts ctx.i18n and seeds the zh/en base dictionaries.
+ * Contract: api-contracts v3 section 8.
+ */
+import type { Context } from 'cordis'
+import type { SnapshotStore } from '@deepseek-ai/dsh-client-web-react'
+import { createSnapshotStore } from '@deepseek-ai/dsh-client-web-react'
+import { en } from '../locales/en.ts'
+import { zh } from '../locales/zh.ts'
+
+/** Translate a key with optional params. */
+export type Translate = (key: string, params?: Record<string, unknown>) => string
+
+/** Locale dictionary: flat key to template string ({name} placeholders). */
+export type LocaleDict = Record<string, string>
+
+declare module 'cordis' {
+  interface Context {
+    i18n: I18nService
+  }
+}
+
+/** Fallback locale consulted after the active locale misses. */
+export const FALLBACK_LOCALE = 'zh'
+
+/** Shared namespace for shell-level texts. */
+export const COMMON_NS = 'common'
+
+/**
+ * Dictionary registry plus locale switch. Lookup chain per key: active locale
+ * -> zh fallback -> the key itself (missing text stays visible, fail loud in
+ * the UI rather than blank).
+ */
+export class I18nService {
+  private dicts = new Map<string, Map<string, LocaleDict>>()
+  private bound = new Map<string, Translate>()
+  private localeStore = createSnapshotStore<string>(FALLBACK_LOCALE)
+
+  /**
+   * Register a dictionary for a namespace and locale. Duplicate (ns, locale)
+   * throws (single occupant; a namespace's texts have one owner).
+   * @param ns - namespace.
+   * @param locale - locale tag (zh/en to start).
+   * @param dict - dictionary.
+   * @returns disposer (idempotent).
+   */
+  register(ns: string, locale: string, dict: LocaleDict): () => void {
+    let locales = this.dicts.get(ns)
+    if (!locales) {
+      locales = new Map()
+      this.dicts.set(ns, locales)
+    }
+    if (locales.has(locale)) throw new Error(`i18n namespace "${ns}" already has locale "${locale}"`)
+    locales.set(locale, dict)
+    return () => {
+      const owner = this.dicts.get(ns)
+      if (owner?.get(locale) === dict) owner.delete(locale)
+    }
+  }
+
+  /**
+   * Bind a namespace to a translate function. The returned reference is
+   * stable per namespace (repeat binds return the same function), so it can
+   * ride inject surfaces without breaking memoization.
+   * @param ns - namespace.
+   * @returns the translate function (reads the locale store at call time).
+   */
+  bind(ns: string): Translate {
+    let t = this.bound.get(ns)
+    if (!t) {
+      t = (key, params) => this.translate(ns, key, params)
+      this.bound.set(ns, t)
+      return t
+    }
+    return t
+  }
+
+  /** Active locale store (switching re-renders the tree; low frequency). */
+  get locale(): SnapshotStore<string> {
+    return this.localeStore
+  }
+
+  private translate(ns: string, key: string, params?: Record<string, unknown>): string {
+    const locales = this.dicts.get(ns)
+    const template = locales?.get(this.localeStore.getSnapshot())?.[key]
+      ?? locales?.get(FALLBACK_LOCALE)?.[key]
+      ?? key
+    if (!params) return template
+    return template.replace(/\{(\w+)\}/g, (match, name: string) =>
+      name in params ? String(params[name]) : match)
+  }
+}
+
+/** Required services (none; the loader passes the export surface as an object plugin). */
+export const inject: string[] = []
+
+/**
+ * Client plugin body: provide the i18n service with base dictionaries.
+ * @param ctx - client cordis context.
+ */
+export function apply(ctx: Context): void {
+  const i18n = new I18nService()
+  i18n.register(COMMON_NS, 'zh', zh)
+  i18n.register(COMMON_NS, 'en', en)
+  ctx.provide('i18n', i18n)
+}

packages/client/i18n/src/index.ts

@@ -0,0 +1,11 @@
+/**
+ * i18n plugin, node half. Pure UI plugin: the empty apply exists so the
+ * plugin appears in the host cordis.yml / Loader (load and lifecycle follow
+ * the host; the browser half ships via exports["./client"], discovered
+ * through the package.json dshClient declaration). Everything else —
+ * I18nService, Translate, LocaleDict — lives in the client half; consumers
+ * import the /client subpath. Contract: api-contracts v3 section 8.
+ */
+
+/** Host plugin body — no host-side behavior for the i18n plugin. */
+export function apply(): void {}

packages/client/i18n/src/invariant.ts

@@ -0,0 +1,32 @@
+/**
+ * Package-owned invariant companion for `@deepseek-ai/dsh-client-i18n`.
+ * @module @deepseek-ai/dsh-client-i18n/invariant
+ */
+
+/* jscpd:ignore-start */
+import type { Context } from 'cordis'
+import type { InvariantInstaller } from '@deepseek-ai/dsh-invariants'
+
+const PACKAGE_NAME = '@deepseek-ai/dsh-client-i18n'
+
+/** Cordis companion plugin name. */
+export const name = 'client-i18n-invariant'
+/** Service required before the companion can reserve package ownership. */
+export const inject = ['invariants']
+
+/**
+ * No runtime invariant: ns-by-locale dictionary registry with a stable
+ * bind(ns) surface — it emits no cordis events and owns no cross-plugin
+ * mutable relation; fallback-chain resolution and locale-store behavior are
+ * asserted directly by this package's behavior specs.
+ */
+const install: InvariantInstaller = () => {}
+
+/**
+ * Register this package's invariant companion.
+ * @param ctx - Cordis context carrying the invariant service.
+ * @returns the installed registration's disposer after setup succeeds.
+ */
+export const apply = (ctx: Context): Promise<() => void> =>
+  Promise.resolve(ctx.invariants.register(PACKAGE_NAME, install))
+/* jscpd:ignore-end */

packages/client/i18n/src/locales/en.ts

@@ -0,0 +1,2 @@
+/** en base dictionary for the common namespace (starter skeleton; texts land with their features). */
+export const en: Record<string, string> = {}

packages/client/i18n/src/locales/zh.ts

@@ -0,0 +1,2 @@
+/** zh base dictionary for the common namespace (starter skeleton; texts land with their features). */
+export const zh: Record<string, string> = {}

packages/client/i18n/tests/i18n.spec.ts

@@ -0,0 +1,53 @@
+import { describe, expect, it } from 'vitest'
+import { I18nService } from '@deepseek-ai/dsh-client-i18n/client'
+
+describe('I18nService', () => {
+  it('translates from the active locale with zh fallback then key passthrough', () => {
+    const i18n = new I18nService()
+    i18n.register('ns', 'zh', { hello: '你好', onlyZh: '仅中文' })
+    i18n.register('ns', 'en', { hello: 'Hello' })
+    const t = i18n.bind('ns')
+    expect(i18n.locale.getSnapshot()).toBe('zh')
+    expect(t('hello')).toBe('你好')
+    i18n.locale.set('en')
+    expect(t('hello')).toBe('Hello')
+    expect(t('onlyZh')).toBe('仅中文')
+    expect(t('missing.key')).toBe('missing.key')
+  })
+
+  it('interpolates {name} params and leaves unknown placeholders intact', () => {
+    const i18n = new I18nService()
+    i18n.register('ns', 'zh', { greet: '你好，{name}！第 {n} 次', partial: '{known} 与 {unknown}' })
+    const t = i18n.bind('ns')
+    expect(t('greet', { name: '世界', n: 2 })).toBe('你好，世界！第 2 次')
+    expect(t('partial', { known: 'A' })).toBe('A 与 {unknown}')
+    expect(t('greet')).toBe('你好，{name}！第 {n} 次')
+  })
+
+  it('bind returns a stable reference per namespace', () => {
+    const i18n = new I18nService()
+    expect(i18n.bind('a')).toBe(i18n.bind('a'))
+    expect(i18n.bind('a')).not.toBe(i18n.bind('b'))
+  })
+
+  it('duplicate (ns, locale) throws; disposer unregisters and is idempotent', () => {
+    const i18n = new I18nService()
+    const dispose = i18n.register('ns', 'zh', { k: 'v1' })
+    expect(() => i18n.register('ns', 'zh', { k: 'v2' })).toThrow('already has locale')
+    dispose()
+    dispose()
+    const t = i18n.bind('ns')
+    expect(t('k')).toBe('k')
+    i18n.register('ns', 'zh', { k: 'v2' })
+    expect(t('k')).toBe('v2')
+  })
+
+  it('locale store is subscribable (snapshot store contract)', () => {
+    const i18n = new I18nService()
+    let notified = 0
+    i18n.locale.subscribe(() => { notified += 1 })
+    i18n.locale.set('en')
+    expect(i18n.locale.getSnapshot()).toBe('en')
+    expect(notified).toBe(1)
+  })
+})

packages/client/i18n/tests/invariant.spec.ts

@@ -0,0 +1,30 @@
+import { describe, expect, it } from 'vitest'
+import { Context } from 'cordis'
+import { apply as nodeApply } from '@deepseek-ai/dsh-client-i18n'
+import { apply as clientApply, COMMON_NS, I18nService, inject } from '@deepseek-ai/dsh-client-i18n/client'
+import * as I18nInvariant from '@deepseek-ai/dsh-client-i18n/invariant'
+import InvariantService from '@deepseek-ai/dsh-invariants'
+
+describe('invariant companion', () => {
+  it('registers under the package name with an empty installer', async () => {
+    const ctx = new Context()
+    await ctx.plugin(InvariantService, { enabled: true })
+    await expect(ctx.plugin(I18nInvariant).await()).resolves.toBeDefined()
+  })
+
+  it('node-half apply is a no-op host placeholder', () => {
+    nodeApply()
+    expect(true).toBe(true) // reaching here without throw is the contract
+  })
+
+  it('client apply provides ctx.i18n seeded with the zh/en common namespace', async () => {
+    expect(inject).toEqual([])
+    const ctx = new Context()
+    await ctx.plugin({ inject, apply: clientApply }).await()
+    const i18n = ctx.get('i18n')
+    expect(i18n).toBeInstanceOf(I18nService)
+    // Seeded dictionaries occupy the (ns, locale) seats even while empty.
+    expect(() => (i18n as I18nService).register(COMMON_NS, 'zh', {})).toThrow('already has locale')
+    expect(() => (i18n as I18nService).register(COMMON_NS, 'en', {})).toThrow('already has locale')
+  })
+})

packages/client/i18n/tsconfig.json

@@ -0,0 +1,27 @@
+{
+  "extends": "../../../tsconfig.base.json",
+  "compilerOptions": {
+    "rootDir": "src",
+    "outDir": "lib/types",
+    "lib": [
+      "ES2024",
+      "DOM",
+      "DOM.Iterable"
+    ],
+    "types": []
+  },
+  "include": [
+    "src"
+  ],
+  "references": [
+    {
+      "path": "../../../vendor/cordis"
+    },
+    {
+      "path": "../web-react"
+    },
+    {
+      "path": "../../support/invariants"
+    }
+  ]
+}

packages/client/i18n/tsdown.config.ts

@@ -0,0 +1,3 @@
+import { clientBundle } from '../tsdown.client.ts'
+
+export default clientBundle('@deepseek-ai/dsh-client-i18n', ['lib/types/index.js', 'lib/types/invariant.js'])

packages/client/runtime/README.md

@@ -0,0 +1,18 @@
+# @deepseek-ai/dsh-client-runtime
+
+Client cordis boot + core services: SlotsService (Service wrapper over SlotCore + 'slots/changed' bridge), SessionsService (list store projection, scope tree, bindings, ancestry), Session object layer, ClientLoader (`./loader` subpath, statically held by the shell). Contract: api-contracts v3 §4.
+
+## Model Experience
+
+None, as the client runtime hosts browser-side services and the session object layer; nothing here reaches a model request.
+
+#### KV Cache effect
+
+None; this package neither assembles nor sends a provider request.
+
+## Known Limitations and Deferred Work
+
+- **`loader.unload` is a stub (throws not-implemented)** — the full chain (fiber dispose → registration cascade → style removal) lands with the HMR project.
+- **Scope teardown is watch-approximated** — the most recently resolved binding stands in for "who is watching"; a removed-while-watched session's scope survives until the watch moves away, not until true observer count reaches zero.
+- **Value imports of this package from plugin bundles must use the `/client` subpath** — the bare package name is not in the loader externals table and inlines a second module instance, whose private scope-tag Symbol never matches (the empty-state P0 postmortem).
+- **`SessionSummary.title` is a display projection** — the wire summary carries no title yet; the cwd basename stands in, then the raw id.

packages/client/runtime/package.json

@@ -0,0 +1,63 @@
+{
+  "name": "@deepseek-ai/dsh-client-runtime",
+  "description": "Client cordis boot and core services: SlotsService, SessionsService (scope tree + object layer), ClientLoader",
+  "version": "0.0.1",
+  "private": true,
+  "type": "module",
+  "main": "lib/index.js",
+  "types": "lib/types/index.d.ts",
+  "exports": {
+    ".": {
+      "types": "./lib/types/index.d.ts",
+      "default": "./lib/index.js"
+    },
+    "./invariant": {
+      "types": "./lib/types/invariant.d.ts",
+      "default": "./lib/invariant.js"
+    },
+    "./loader": {
+      "types": "./lib/types/client/loader/index.d.ts",
+      "default": "./lib/loader.js"
+    },
+    "./client": {
+      "types": "./lib/types/client/index.d.ts",
+      "default": "./lib/client.js"
+    },
+    "./src/*": "./src/*",
+    "./package.json": "./package.json"
+  },
+  "dshClient": {
+    "inject": [
+      "@deepseek-ai/dsh-client-connection"
+    ],
+    "platform": "web",
+    "immediately": true
+  },
+  "license": "BSD-3-Clause",
+  "dependencies": {
+    "@deepseek-ai/dsh-client-connection": "workspace:^",
+    "@deepseek-ai/dsh-client-ui-slots": "workspace:^",
+    "@deepseek-ai/dsh-client-web-react": "workspace:^",
+    "@deepseek-ai/dsh-llm": "workspace:^",
+    "react": "^18.2.0",
+    "@deepseek-ai/dsh-session": "workspace:^"
+  },
+  "peerDependencies": {
+    "@deepseek-ai/dsh-invariants": "^0.0.1",
+    "cordis": "^4.0.0-rc.7"
+  },
+  "devDependencies": {
+    "@deepseek-ai/dsh-invariants": "workspace:^",
+    "@types/react": "~18.3.1",
+    "cordis": "^4.0.0-rc.7"
+  },
+  "files": [
+    "lib/index.js",
+    "lib/invariant.js",
+    "lib/client.js",
+    "lib/loader.js",
+    "lib/types/**/*.d.ts",
+    "lib/types/**/*.d.ts.map",
+    "src"
+  ]
+}

packages/client/runtime/src/client/index.ts

@@ -0,0 +1,128 @@
+/**
+ * Browser half: the whole runtime contract surface (api-contracts v3 §4) —
+ * SlotsService, SessionsService (list store + scope tree + object layer),
+ * the ClientLoader interface, and the cordis Context/Events merges. apply
+ * mounts ctx.slots + ctx.sessions and wires the connection stream loop into
+ * the object layer. The loader machinery implementation is NOT in the plugin
+ * bundle — it ships via the package's `./loader` subpath, statically held by
+ * the web shell (a loader cannot load itself).
+ */
+import type { Context } from 'cordis'
+import type { ConnectionHandle } from '@deepseek-ai/dsh-client-connection/client'
+import type { SessionBinding as GenericSessionBinding } from '@deepseek-ai/dsh-client-ui-slots'
+import type { SnapshotStore, UseSession } from '@deepseek-ai/dsh-client-web-react'
+import { SlotsService } from './slots.ts'
+import { SessionsService } from './sessions/service.ts'
+import type { ConversationSnapshot, RunningToolCall, ToolResultNode } from './sessions/conversation.ts'
+
+export { SlotsService } from './slots.ts'
+export { SessionsService, scopeOf } from './sessions/service.ts'
+export type { SessionBinding, SessionListState, SessionSummary } from './sessions/service.ts'
+export { SessionManager } from './sessions/manager.ts'
+export type { SessionListSnapshot } from './sessions/manager.ts'
+export { Session, PAGE_MESSAGES } from './sessions/session.ts'
+export type { SessionListEntry } from './sessions/lineage.ts'
+export type {
+  AssistantBlock, AssistantMessageNode, ContextMessageNode, ConversationNode, ConversationSnapshot,
+  OpenState, PartialAssistant, PendingInteraction, PromptError, RunningToolCall, SteeringMessageNode,
+  ToolResultNode, UnknownSurfaceNode, UserMessageNode,
+} from './sessions/conversation.ts'
+export type { SessionId } from '@deepseek-ai/dsh-client-connection/client'
+
+// ---- Narrowed aliases (the single narrowing point of the slot type chain:
+// ui-slots/web-react stay generic and dependency-inverted; the client-tree
+// concrete types live here, where their subjects live) ----
+
+/**
+ * The client cordis context face: the base Context plus the service keys
+ * this package's declaration merge contributes (slots/sessions/loader) and
+ * every later plugin's merge. A plain alias — the merges land on Context
+ * itself inside the client program; the name marks intent at consumer seams.
+ */
+export type ClientContext = Context
+
+/** SessionBinding narrowed to the client context (inject factories dot services directly). */
+export type ClientSessionBinding = GenericSessionBinding<ClientContext>
+
+/** The conversation-snapshot selector hook (ConvViewProps/ToolViewProps take this). */
+export type UseConversationSession = UseSession<ConversationSnapshot>
+
+/**
+ * One tool call as the chat flow renders it: still-running (spinner card) or
+ * settled (result node). The fold produces both shapes; toolview components
+ * narrow on the discriminant fields.
+ */
+export type ToolCallBlock = RunningToolCall | ToolResultNode
+
+declare module 'cordis' {
+  interface Events {
+    /**
+     * A slot's definition or registration set changed.
+     * @mode emit
+     * @param key - the mutated SlotMap key.
+     */
+    'slots/changed'(key: string): void
+  }
+  interface Context {
+    slots: import('./slots.ts').SlotsService
+    sessions: import('./sessions/service.ts').SessionsService
+    loader: ClientLoader
+  }
+}
+
+/** One __DSH_BOOT__ manifest row. */
+export interface BootPluginEntry { id: string; url: string; inject: string[]; immediately?: boolean }
+
+/** Per-plugin load status store shape. */
+export type LoaderStatus = Record<string, 'loading' | 'active' | 'failed'>
+
+/**
+ * Client bundle loader. The immediately group loads first (parallel fetch,
+ * apply in inject topology order); remaining plugins follow in inject
+ * topology. Loaded bundle export surfaces are registered back into the
+ * require module table. Implementation lives in the `./loader` subpath
+ * (shell-held machinery).
+ */
+export interface ClientLoader {
+  /** Start loading from window.__DSH_BOOT__ (non-blocking). */
+  start(): void
+  /**
+   * Load one plugin bundle (script inject, factory handoff, ctx.plugin, style registration).
+   * @param id - plugin id (package name).
+   */
+  load(id: string): Promise<void>
+  /**
+   * Unload a plugin. P-I: not implemented (full chain lands with HMR).
+   * @param id - plugin id.
+   */
+  unload(id: string): Promise<void>
+  /** Resolves when every manifest plugin reached active (AppRoot gates the real UI on this). */
+  settled(): Promise<void>
+  /**
+   * Read a loaded module's export surface from the module table (same
+   * implementation the bundle-facing require uses; unknown spec throws).
+   * @param spec - module specifier (package name or seeded library id).
+   */
+  requireModule(spec: string): unknown
+  /** Per-plugin status store. */
+  readonly status: SnapshotStore<LoaderStatus>
+}
+
+/** Required services: the wire handle mounted by the connection plugin. */
+export const inject = ['connection']
+
+/**
+ * Client plugin body: mount slots + sessions, start the stream loop.
+ * @param ctx - client cordis context.
+ */
+export function apply(ctx: Context): void {
+  ctx.plugin(SlotsService)
+  const connection = ctx.get('connection') as ConnectionHandle
+  const sessions = new SessionsService(ctx, connection.api)
+  const loop = connection.start({
+    onMuxEnvelope: (envelope) => { sessions.manager.handleMuxEnvelope(envelope) },
+    onHostEnvelope: (envelope) => { sessions.manager.handleHostEnvelope(envelope) },
+    onConnected: () => { sessions.manager.handleConnected() },
+  })
+  ctx.effect(() => () => { loop.stop() }, 'runtime: connection stream loop')
+}

packages/client/runtime/src/client/loader/index.ts

@@ -0,0 +1,247 @@
+/**
+ * ClientLoader implementation (shell-held machinery — the loader cannot load
+ * itself, so the web shell imports this subpath statically and mounts the
+ * instance as ctx.loader; the runtime package's own client bundle never
+ * includes it).
+ *
+ * Load chain per plugin: fetch bundle text → execute (script injection) → the
+ * bundle calls window.DSHClientProxy.loadPlugin({id, factory}) (single-slot
+ * handoff, id reconciled) → factory(require) with require bound to the module
+ * table → ctx.plugin(exports.apply) → the export surface is registered into
+ * the module table under the plugin id (inject topology guarantees later
+ * loaders can require earlier ones) → <style data-plugin> ownership recorded.
+ *
+ * start(): the `immediately` group is fetched in parallel and executed in
+ * group-internal inject topology (execution is serial — the handoff slot is
+ * single); a full-group barrier precedes the remaining plugins, which then
+ * load one by one in inject topology.
+ */
+import type { Context } from 'cordis'
+import { createSnapshotStore } from '@deepseek-ai/dsh-client-web-react'
+import type { BootPluginEntry, ClientLoader, LoaderStatus } from '../index.ts'
+
+export type { BootPluginEntry, ClientLoader, LoaderStatus } from '../index.ts'
+
+/** The shape a client bundle hands to window.DSHClientProxy.loadPlugin. */
+export interface ClientPluginHandoff {
+  /** Plugin id (package name) — must match the manifest row being loaded. */
+  id: string
+  /**
+   * Closure factory: receives the DI require and returns the module's export
+   * surface; an `apply` export is applied as a cordis plugin.
+   */
+  factory: (require: (spec: string) => unknown) => Record<string, unknown>
+}
+
+/** Window surface the loader owns (bundle side of the handoff protocol). */
+interface DshWindow {
+  __DSH_BOOT__?: { plugins: BootPluginEntry[] }
+  DSHClientProxy?: { loadPlugin(handoff: ClientPluginHandoff): void }
+}
+
+/** Options for createClientLoader (assembled by the web shell at boot). */
+export interface ClientLoaderOptions {
+  /** Client root context: plugin applies mount under it. */
+  ctx: Context
+  /**
+   * Seeded module table: pure-library entities (react, react-dom, cordis,
+   * ui-slots, web-react, ui-primitives). The loader takes ownership and
+   * registers loaded bundle export surfaces alongside them.
+   */
+  modules: Record<string, unknown>
+  /**
+   * Boot manifest; defaults to window.__DSH_BOOT__. Fixture pages inject the
+   * same protocol shape.
+   */
+  boot?: { plugins: BootPluginEntry[] }
+  /** Bundle fetch seam (parallelizable half). Defaults to same-origin fetch().text(). */
+  fetchBundle?: (url: string) => Promise<string>
+  /**
+   * Bundle execution seam (serial half; execution synchronously performs the
+   * loadPlugin handoff). Defaults to a <script> element carrying the code.
+   */
+  executeBundle?: (code: string, url: string) => void
+}
+
+/** Per-plugin bookkeeping across the load chain. */
+interface PluginRecord {
+  entry: BootPluginEntry
+  state: 'idle' | 'loading' | 'active' | 'failed'
+  fetch?: Promise<string>
+  load?: Promise<void>
+}
+
+const NOT_LOADED = Symbol('dsh.loader.not-loaded')
+
+/**
+ * Build the client bundle loader.
+ * @param options - ctx, seeded module table, boot manifest, fetch/execute seams.
+ * @returns the ClientLoader the shell mounts as ctx.loader.
+ */
+export function createClientLoader(options: ClientLoaderOptions): ClientLoader {
+  const { ctx } = options
+  const win = globalThis as DshWindow
+  const boot = options.boot ?? win.__DSH_BOOT__
+  if (boot === undefined) throw new Error('client-loader: no boot manifest (window.__DSH_BOOT__ missing)')
+
+  const modules = new Map<string, unknown>(Object.entries(options.modules))
+  const records = new Map<string, PluginRecord>()
+  for (const entry of boot.plugins) {
+    if (records.has(entry.id)) throw new Error(`client-loader: duplicate manifest id "${entry.id}"`)
+    records.set(entry.id, { entry, state: 'idle' })
+  }
+
+  const status = createSnapshotStore<LoaderStatus>({})
+  const publish = (id: string, state: 'loading' | 'active' | 'failed'): void => {
+    status.update((draft) => { draft[id] = state })
+  }
+
+  // Single-slot handoff: bundle execution synchronously calls loadPlugin;
+  // doLoad arms the slot before executing and reconciles the id after.
+  let slot: ClientPluginHandoff | typeof NOT_LOADED = NOT_LOADED
+  if (win.DSHClientProxy !== undefined) throw new Error('client-loader: window.DSHClientProxy already installed (double boot?)')
+  win.DSHClientProxy = {
+    loadPlugin: (handoff: ClientPluginHandoff): void => {
+      if (slot !== NOT_LOADED) {
+        throw new Error(`client-loader: overlapping loadPlugin handoff (got "${handoff.id}" while a previous handoff is unclaimed)`)
+      }
+      slot = handoff
+    },
+  }
+
+  const fetchBundle = options.fetchBundle ?? (async (url: string): Promise<string> => {
+    const res = await fetch(url)
+    if (!res.ok) throw new Error(`client-loader: bundle fetch ${url} answered ${String(res.status)}`)
+    return res.text()
+  })
+
+  const executeBundle = options.executeBundle ?? ((code: string, url: string): void => {
+    const el = document.createElement('script')
+    // Inline execution (not src) so the fetch half stays parallelizable; the
+    // sourceURL comment keeps devtools stack frames attributed to the bundle.
+    el.textContent = `${code}\n//# sourceURL=${url}`
+    document.head.appendChild(el)
+  })
+
+  const requireModule = (spec: string): unknown => {
+    if (!modules.has(spec)) {
+      throw new Error(`client-loader: module "${spec}" is not available — not a seeded library and no loaded plugin registered it (check dshClient.inject ordering)`)
+    }
+    return modules.get(spec)
+  }
+
+  /** Tag styles the bundle injected during execution (unload bookkeeping; plugin CSS lands untagged). */
+  const claimStyles = (id: string): void => {
+    if (typeof document === 'undefined') return
+    for (const el of document.querySelectorAll('style:not([data-plugin])')) {
+      el.setAttribute('data-plugin', id)
+    }
+  }
+
+  /** Start (or reuse) the parallelizable fetch half. */
+  const prefetch = (record: PluginRecord): Promise<string> =>
+    (record.fetch ??= fetchBundle(record.entry.url))
+
+  async function doLoad(record: PluginRecord): Promise<void> {
+    const { id } = record.entry
+    record.state = 'loading'
+    publish(id, 'loading')
+    try {
+      // Dependencies must already be active (start() sequences this; direct
+      // load() callers get the same fail-loud check).
+      for (const dep of record.entry.inject) {
+        const depRecord = records.get(dep)
+        if (depRecord === undefined) throw new Error(`client-loader: "${id}" injects unknown plugin "${dep}"`)
+        if (depRecord.state !== 'active') throw new Error(`client-loader: "${id}" loaded before its dependency "${dep}" is active`)
+      }
+      const code = await prefetch(record)
+      executeBundle(code, record.entry.url)
+      if (slot === NOT_LOADED) throw new Error(`client-loader: bundle ${record.entry.url} executed without calling DSHClientProxy.loadPlugin`)
+      const handoff = slot
+      slot = NOT_LOADED
+      if (handoff.id !== id) throw new Error(`client-loader: bundle id mismatch — manifest "${id}" vs handoff "${handoff.id}"`)
+      const exports = handoff.factory(requireModule)
+      if (typeof exports.apply !== 'function') throw new Error(`client-loader: plugin "${id}" exports no apply function`)
+      // The whole export surface is the plugin: cordis object-plugin form
+      // keeps the bundle's exported `inject`/`name` (an apply-only pass would
+      // silently drop the dependency declaration — postmortem 0001).
+      const fiber = ctx.plugin(exports as { apply: (ctx: Context) => void })
+      await fiber.await()
+      // Register under both specifier forms bundles emit: the bare package
+      // name (deep-import rewrites) and the /client subpath (CLIENT_EXTERNALS
+      // form) — the loaded surface IS the client half either way.
+      modules.set(id, exports)
+      modules.set(`${id}/client`, exports)
+      claimStyles(id)
+      record.state = 'active'
+      publish(id, 'active')
+    } catch (error) {
+      record.state = 'failed'
+      publish(id, 'failed')
+      throw error
+    }
+  }
+
+  const load = (id: string): Promise<void> => {
+    const record = records.get(id)
+    if (record === undefined) return Promise.reject(new Error(`client-loader: unknown plugin "${id}"`))
+    record.load ??= doLoad(record)
+    return record.load
+  }
+
+  /** Topologically order `ids` by inject (edges inside the set only — an early-group member never waits on a later-group one). */
+  const topo = (ids: string[]): string[] => {
+    const pool = new Set(ids)
+    const ordered: string[] = []
+    const done = new Set<string>()
+    const visiting = new Set<string>()
+    const visit = (id: string): void => {
+      if (done.has(id)) return
+      if (visiting.has(id)) throw new Error(`client-loader: inject cycle through "${id}"`)
+      visiting.add(id)
+      const record = records.get(id)
+      /* v8 ignore next -- ids come from records; unknown ids are caught per-dep below. */
+      if (record === undefined) throw new Error(`client-loader: manifest references unknown plugin "${id}"`)
+      for (const dep of record.entry.inject) {
+        if (!records.has(dep)) throw new Error(`client-loader: "${id}" injects unknown plugin "${dep}"`)
+        if (pool.has(dep)) visit(dep)
+      }
+      visiting.delete(id)
+      done.add(id)
+      ordered.push(id)
+    }
+    for (const id of ids) visit(id)
+    return ordered
+  }
+
+  let settledPromise: Promise<void> | undefined
+
+  async function run(): Promise<void> {
+    const all = [...records.values()]
+    const early = all.filter(r => r.entry.immediately === true)
+    const rest = all.filter(r => r.entry.immediately !== true)
+    // Early group: parallel fetch (all requests in flight at once), serial
+    // inject-topology execution, full-group barrier before anything else.
+    const earlyOrder = topo(early.map(r => r.entry.id))
+    for (const record of early) void prefetch(record).catch(() => {}) // surfaced by the awaited load below
+    for (const id of earlyOrder) await load(id)
+    // Remaining plugins: one by one in inject topology.
+    for (const id of topo(rest.map(r => r.entry.id))) await load(id)
+  }
+
+  return {
+    start: () => {
+      settledPromise ??= run()
+      // Failures surface through settled()/status — start() itself is fire-and-forget.
+      settledPromise.catch(() => {})
+    },
+    load,
+    unload: (id: string) => Promise.reject(new Error(`client-loader: unload("${id}") is not implemented (lands with HMR)`)),
+    settled: () => {
+      if (settledPromise === undefined) throw new Error('client-loader: settled() before start()')
+      return settledPromise
+    },
+    requireModule,
+    status,
+  }
+}

packages/client/runtime/src/client/sessions/conversation.ts

@@ -0,0 +1,165 @@
+// ConversationSnapshot / ConversationNode: the only data shape the logic layer feeds the UI.
+// Immutability contract: every change swaps the top-level object; unchanged
+// substructures keep their references (the React.memo premise). callId/approvalId stay plain
+// string here (narrow to real brands when convenient).
+
+import type { ContentBlock } from '@deepseek-ai/dsh-llm/types'
+import type { RpcError, RpcId, SessionId, ToolCallView, ToolResultView } from '@deepseek-ai/dsh-client-connection/client'
+
+/** Assistant content blocks sorted by what the UI cares about
+ *  (text body / collapsible reasoning / tool-call card head / other fallback). */
+export type AssistantBlock =
+  | { kind: 'text'; text: string }
+  | { kind: 'reasoning'; text: string }
+  | { kind: 'tool-call'; callId: string; name: string; argsRaw: string }
+  | { kind: 'other'; block: unknown }
+
+/**
+ * core ContentBlock[] -> AssistantBlock[] (classifier shared by finalized messages and partial block-end).
+ * @param content - core content blocks verbatim.
+ * @returns UI-classified blocks in source order.
+ */
+export function toAssistantBlocks(content: readonly ContentBlock[]): AssistantBlock[] {
+  return content.map(toAssistantBlock)
+}
+
+/**
+ * Classify one block (ToolCallBlock fields are id/arguments, mapped to callId/argsRaw).
+ * @param block - one core content block.
+ * @returns the UI classification.
+ */
+export function toAssistantBlock(block: ContentBlock): AssistantBlock {
+  switch (block.type) {
+    case 'text': return { kind: 'text', text: block.text }
+    case 'reasoning': return { kind: 'reasoning', text: block.text }
+    case 'tool-call': return { kind: 'tool-call', callId: String(block.id), name: block.name, argsRaw: block.arguments }
+    default: return { kind: 'other', block }
+  }
+}
+
+/** A finalized user message. */
+export interface UserMessageNode {
+  kind: 'user'
+  seq: number
+  content: readonly ContentBlock[]
+  source: unknown
+}
+
+/** A finalized (or interruption-frozen) assistant message. */
+export interface AssistantMessageNode {
+  kind: 'assistant'
+  seq: number
+  turn: number
+  step: number
+  blocks: readonly AssistantBlock[]
+  usage?: unknown
+  /** Frozen partial of an aborted turn (no finalize ever arrives): rendered with a 已停止 marker.
+   *  Synthetic seq (fractional, derived from the turn/end seq) keeps it ordered inside the flow. */
+  interrupted?: true
+}
+
+/** A steering message injected mid-turn. */
+export interface SteeringMessageNode {
+  kind: 'steering'
+  seq: number
+  turn: number
+  content: readonly ContentBlock[]
+  source: unknown
+}
+
+/** A context/system injection surfaced in the flow. */
+export interface ContextMessageNode {
+  kind: 'context'
+  seq: number
+  content: readonly ContentBlock[]
+  source: unknown
+  meta?: unknown
+}
+
+/** A tool result paired (when in-window) with its call head. */
+export interface ToolResultNode {
+  kind: 'tool-result'
+  seq: number
+  callId: string
+  /** Call head backfilled from the in-window tool/call; null when window truncation left the call outside (card head shows callId). */
+  call: { name: string; argsRaw: string } | null
+  content: readonly ContentBlock[]
+  isError: boolean
+  error?: { name: string; code: string }
+  meta?: unknown
+  /** Host-computed render intent from the paired tool/call's wire view; null = generic JSON card (documented default). */
+  callView: ToolCallView | null
+  /** Host-computed render intent from this tool/result's wire view; null = same default. */
+  resultView: ToolResultView | null
+}
+
+/** Fallback for surface events this UI version does not know. */
+export interface UnknownSurfaceNode {
+  kind: 'unknown'
+  seq: number
+  type: string
+  data: unknown
+}
+
+/** Finalized conversation node union (kind discriminates; seq is the React key). */
+export type ConversationNode =
+  | UserMessageNode
+  | AssistantMessageNode
+  | SteeringMessageNode
+  | ContextMessageNode
+  | ToolResultNode
+  | UnknownSurfaceNode
+
+/** In-flight tool card material: tool/call seen, tool/result not yet. */
+export interface RunningToolCall {
+  callId: string
+  name: string
+  argsRaw: string
+  turn: number
+  step: number
+  /** Host-computed render intent riding the tool/call frame; null = generic JSON card. */
+  callView: ToolCallView | null
+}
+
+/** Approval/question placeholder cards (visible, not answerable;
+ *  rpcId = the requested frame's envelope id, the future respond backfill key). */
+export type PendingInteraction =
+  | { kind: 'approval'; rpcId: RpcId; approvalId: string; toolName: string; callId?: string; reason?: string }
+  | { kind: 'question'; rpcId: RpcId; questions: readonly unknown[] }
+
+/** In-progress assistant output (chunk accumulator product). */
+export interface PartialAssistant {
+  turn: number
+  step: number
+  blocks: readonly AssistantBlock[]
+}
+
+/** History-open lifecycle of a Session window. */
+export type OpenState = 'cold' | 'loading' | 'open' | 'error'
+
+/** Send/stop failure surfaced in the input error strip; op picks the user-facing copy (发送失败 vs 停止失败). */
+export interface PromptError {
+  op: 'send' | 'stop'
+  error: RpcError
+}
+
+/** The immutable snapshot contract Session hands to uSES (see the web client architecture RFC). */
+export interface ConversationSnapshot {
+  sessionId: SessionId
+  /** Surface fold product (finalized conversation nodes in surface order). */
+  nodes: readonly ConversationNode[]
+  /** Fold degradation flag (cross-window replace defense): when true, nodes come from the lenient linear scan. */
+  foldDegraded: boolean
+  partial: PartialAssistant | null
+  runningCalls: readonly RunningToolCall[]
+  pending: readonly PendingInteraction[]
+  running: boolean
+  /** Set after host/session-removed; the UI grays out and disables input. */
+  removed: boolean
+  openState: OpenState
+  openError: RpcError | null
+  hasMore: boolean
+  loadingOlder: boolean
+  promptError: PromptError | null
+  lastAgentError: string | null
+}

packages/client/runtime/src/client/sessions/fold-adapter.ts

@@ -0,0 +1,194 @@
+// FoldAdapter: core SurfaceManager wiring + node materialization cache.
+// Padding sentinels solve the paged-window seq offset (core fold asserts seq === index);
+// a cross-window replace throw degrades to a lenient linear scan (foldDegraded —
+// the degradation lives in one branch function in this file, zero scattered removal points).
+
+import type { SessionEvent } from '@deepseek-ai/dsh-session/types'
+// Subpath export (package.json exports "./surface", alias added for this): all value imports
+// go through it — the package root points at lib/index.js (needs a build) which the vite
+// browser bundle cannot resolve; surface.ts has no Node dependencies.
+import { SurfaceManager, isSurfaceEligibleType } from '@deepseek-ai/dsh-session/surface'
+import type { ToolCallView, ToolEventView, ToolResultView } from '@deepseek-ai/dsh-client-connection/client'
+import type { ConversationNode } from './conversation.ts'
+import { toAssistantBlocks } from './conversation.ts'
+
+/** In-window tool/call index entry (result-card backfill + runningCalls material). */
+export interface CallIndexEntry {
+  name: string
+  argsRaw: string
+  turn: number
+  step: number
+  /** Wire view riding the tool/call (envelope-level; never inside the event). */
+  callView: ToolCallView | null
+}
+
+/** Non-surface-eligible sentinel event (safely skipped by surfaceOpOf's undefined branch).
+ *  'noop/padding' is not a real event type on purpose: a genuine type with fake data would
+ *  surface as garbage the day anyone adds handling for it (design §D.1; the cast is the one
+ *  place a synthetic event enters the window). */
+function paddingEvent(seq: number): SessionEvent {
+  return { type: 'noop/padding', seq, time: 0, data: {} } as unknown as SessionEvent
+}
+
+/** One event -> UI node (pure function; the six-variant ConversationNode union). */
+function materializeNode(
+  event: SessionEvent,
+  callIndex: ReadonlyMap<string, CallIndexEntry>,
+  resultView: ToolResultView | null,
+): ConversationNode {
+  switch (event.type) {
+    case 'user/message':
+      return { kind: 'user', seq: event.seq, content: event.data.content, source: event.data.source }
+    case 'assistant/message':
+      return {
+        kind: 'assistant', seq: event.seq, turn: event.data.turn, step: event.data.step,
+        blocks: toAssistantBlocks(event.data.content), usage: event.data.usage,
+      }
+    case 'steering/message':
+      return { kind: 'steering', seq: event.seq, turn: event.data.turn, content: event.data.content, source: event.data.source }
+    case 'context/message':
+      return {
+        kind: 'context', seq: event.seq, content: event.data.content, source: event.data.source,
+        meta: event.data.meta,
+      }
+    case 'tool/result': {
+      const call = callIndex.get(String(event.data.callId))
+      return {
+        kind: 'tool-result', seq: event.seq, callId: String(event.data.callId),
+        call: call ? { name: call.name, argsRaw: call.argsRaw } : null,
+        content: event.data.content, isError: event.data.isError,
+        ...(event.data.error !== undefined ? { error: event.data.error } : {}),
+        meta: event.data.meta,
+        callView: call?.callView ?? null,
+        resultView,
+      }
+    }
+    /* v8 ignore next 2 -- defensive arm: fold output only carries the five
+    surface-eligible types, and each has a case above; reachable only if core
+    adds an eligible type. */
+    default:
+      return { kind: 'unknown', seq: event.seq, type: event.type, data: (event as { data?: unknown }).data }
+  }
+}
+
+/** Window fold over the core SurfaceManager (sentinel padding for the seq offset; degrades to a linear scan on cross-window replace). */
+export class FoldAdapter {
+  /** padded = [sentinel x baseSeq, ...window events]; SurfaceManager borrows this reference for lazy incremental folding. */
+  private padded: SessionEvent[] = []
+  private baseSeq = 0
+  private surface = new SurfaceManager(this.padded)
+  private nodeCache = new Map<number, ConversationNode>()
+  private degraded = false
+  private callIdx = new Map<string, CallIndexEntry>()
+  /** Wire result views keyed by the tool/result event's seq (views ride the envelope, not the event). */
+  private resultViews = new Map<number, ToolResultView>()
+  /** Window revision (bumped on reset/append) keying the nodes() result cache: an unchanged
+   *  window returns the previous ARRAY reference, not just cached elements — the snapshot's
+   *  reference-stability contract (§A.9.4) starts here. */
+  private rev = 0
+  private nodesResult: { rev: number; value: { nodes: ConversationNode[]; degraded: boolean } } | null = null
+
+  /** In-window tool/call index (Session uses it for runningCalls and result-card backfill). */
+  get callIndex(): ReadonlyMap<string, CallIndexEntry> {
+    return this.callIdx
+  }
+
+  /**
+   * Window rebuild (after open/resync/page prepend): new padded array, new
+   * SurfaceManager, cleared cache, rebuilt callIndex.
+   * @param events - the new window contents (seq-ascending).
+   * @param baseSeq - seq of the window head (sentinels pad below it).
+   * @param views - per-event wire views aligned with `events` by index (undefined slots for view-less events).
+   */
+  reset(events: readonly SessionEvent[], baseSeq: number, views?: readonly (ToolEventView | undefined)[]): void {
+    this.rev++
+    this.baseSeq = baseSeq
+    this.padded = []
+    for (let i = 0; i < baseSeq; i++) this.padded.push(paddingEvent(i))
+    for (const event of events) this.padded.push(event)
+    this.surface = new SurfaceManager(this.padded)
+    this.nodeCache.clear()
+    this.degraded = false
+    this.callIdx = new Map()
+    this.resultViews.clear()
+    for (let i = 0; i < events.length; i++) {
+      const event = events[i]
+      /* v8 ignore next -- dense-array guard: i stays within events.length, so the undefined arm needs a sparse array no caller builds. */
+      if (event !== undefined) this.indexCall(event, views?.[i])
+    }
+  }
+
+  /**
+   * Tail append (live session/event): push into the same array (incremental
+   * lazy fold applies) + incremental callIndex upkeep.
+   * @param event - the live event (seq = window tail + 1).
+   * @param view - host-computed tool view paired with the event when it is a tool call/result; indexed for card rendering.
+   */
+  append(event: SessionEvent, view?: ToolEventView): void {
+    this.rev++
+    this.padded.push(event)
+    this.indexCall(event, view)
+  }
+
+  /**
+   * Current node array + degradation flag. Same revision -> same array
+   * reference (memo boundary); node object references always come from the per-seq cache.
+   * @returns the fold projection for the current window revision.
+   */
+  nodes(): { nodes: ConversationNode[]; degraded: boolean } {
+    if (this.nodesResult !== null && this.nodesResult.rev === this.rev) return this.nodesResult.value
+    let seqs: readonly number[]
+    if (this.degraded) {
+      seqs = this.degradedSeqs()
+    } else {
+      try {
+        seqs = this.surface.nodes
+      } catch (error) {
+        console.error('[web-runtime] surface fold failed, degrading to linear scan:', error)
+        this.degraded = true
+        seqs = this.degradedSeqs()
+      }
+    }
+    const out: ConversationNode[] = []
+    for (const seq of seqs) {
+      const cached = this.nodeCache.get(seq)
+      if (cached !== undefined) {
+        out.push(cached)
+        continue
+      }
+      const event = this.padded[seq]
+      /* v8 ignore next -- sparse guard: both seq sources (surface fold and degradedSeqs) only emit indexes present in padded. */
+      if (event === undefined) continue
+      const node = materializeNode(event, this.callIdx, this.resultViews.get(seq) ?? null)
+      this.nodeCache.set(seq, node)
+      out.push(node)
+    }
+    const value = { nodes: out, degraded: this.degraded }
+    this.nodesResult = { rev: this.rev, value }
+    return value
+  }
+
+  /** Degradation branch: lenient linear scan ignoring surfaceOp/replace (all surface-eligible events in append order). */
+  private degradedSeqs(): number[] {
+    const seqs: number[] = []
+    for (let i = this.baseSeq; i < this.padded.length; i++) {
+      const event = this.padded[i]
+      if (event !== undefined && isSurfaceEligibleType(event.type)) seqs.push(event.seq)
+    }
+    return seqs
+  }
+
+  private indexCall(event: SessionEvent, view?: ToolEventView): void {
+    if (event.type === 'tool/result') {
+      if (view?.for === 'result') this.resultViews.set(event.seq, view.view)
+      return
+    }
+    if (event.type !== 'tool/call') return
+    this.callIdx.set(String(event.data.callId), {
+      name: event.data.name, argsRaw: event.data.arguments, turn: event.data.turn, step: event.data.step,
+      callView: view?.for === 'call' ? view.view : null,
+    })
+    // No backfill into already-materialized tool-result nodes for this callId
+    // (window order puts the call before its result; cannot happen on the normal path).
+  }
+}

packages/client/runtime/src/client/sessions/lineage.ts

@@ -0,0 +1,63 @@
+// flattenLineage: summaries -> flat list with lineage indentation (pure function).
+// Roots sort by updatedAt desc, DFS expansion with children in the same order; orphaned lineage
+// degrades to root level; cycles fail soft and emit as roots.
+
+import type { SessionId, SessionSummary } from '@deepseek-ai/dsh-client-connection/client'
+
+/** One flattened session-list row (summary + lineage indent depth). */
+export interface SessionListEntry {
+  sessionId: SessionId
+  updatedAt: number
+  running: boolean
+  parentSessionId?: SessionId
+  cwd?: string
+  /** Lineage indent depth: root = 0; the UI just multiplies by the indent width. */
+  depth: number
+}
+
+/**
+ * summaries -> flat list with lineage indentation (pure; roots by updatedAt
+ * desc, DFS children in the same order, orphans degrade to roots).
+ * @param summaries - the host's session.list items.
+ * @returns display rows in render order.
+ */
+export function flattenLineage(summaries: readonly SessionSummary[]): SessionListEntry[] {
+  const byId = new Map<SessionId, SessionSummary>()
+  for (const s of summaries) byId.set(s.sessionId, s)
+
+  const children = new Map<SessionId, SessionSummary[]>()
+  const roots: SessionSummary[] = []
+  for (const s of summaries) {
+    if (s.parentSessionId !== undefined && byId.has(s.parentSessionId)) {
+      const list = children.get(s.parentSessionId) ?? []
+      list.push(s)
+      children.set(s.parentSessionId, list)
+    } else {
+      roots.push(s) // root, or an orphan whose parent is absent from summaries (degrade to root, never drop)
+    }
+  }
+
+  const byUpdatedDesc = (a: SessionSummary, b: SessionSummary): number => b.updatedAt - a.updatedAt
+  roots.sort(byUpdatedDesc)
+
+  const out: SessionListEntry[] = []
+  const visited = new Set<SessionId>()
+  const walk = (s: SessionSummary, depth: number): void => {
+    if (visited.has(s.sessionId)) {
+      console.warn(`[web-runtime] lineage cycle at ${s.sessionId}; emitting as root`)
+      return
+    }
+    visited.add(s.sessionId)
+    out.push({ ...s, depth })
+    const kids = children.get(s.sessionId)
+    if (kids === undefined) return
+    kids.sort(byUpdatedDesc)
+    for (const kid of kids) walk(kid, depth + 1)
+  }
+  for (const root of roots) walk(root, 0)
+  // Cycle members (unreachable from any root): emit as roots so no entry is lost.
+  for (const s of summaries) {
+    if (!visited.has(s.sessionId)) walk(s, 0)
+  }
+  return out
+}

packages/client/runtime/src/client/sessions/manager.ts

@@ -0,0 +1,250 @@
+// SessionManager: the instance cluster Map<SessionId, Session> (lazy-built, resident) + the frame
+// dispatch entry + list state, constructed and held by SessionsService (one per client runtime).
+// List data never enters zustand; React connects via subscribe/getListSnapshot.
+
+import type { IApiClient, HostFrame, MuxFrame, RpcError, RpcRequest, RpcResult, SessionId, SessionSummary } from '@deepseek-ai/dsh-client-connection/client'
+import { transportError } from '@deepseek-ai/dsh-client-connection/client'
+import type { SessionListEntry } from './lineage.ts'
+import { flattenLineage } from './lineage.ts'
+import { Notifier } from './notifier.ts'
+import { Session } from './session.ts'
+
+/** Immutable session-list snapshot for useSessionList. */
+export interface SessionListSnapshot {
+  items: readonly SessionListEntry[]
+  state: 'idle' | 'loading' | 'error'
+  error: RpcError | null
+}
+
+/** Per-session cap for pre-instantiation approval/question buffering (low-frequency frames; a few dozen covers any real backlog). */
+const PENDING_BUFFER_CAP = 32
+
+/** Instance cluster + frame entry + the session list (see the web client architecture RFC). */
+export class SessionManager {
+  private readonly sessions = new Map<SessionId, Session>()
+  /** Approval/question frame buffer for uninstantiated sessions: pending interactions never hit
+   *  history (cannot be backfilled on open), the one frame class that must not take the
+   *  drop-and-backfill path; replayed and cleared on instantiation. Bounded per session (these
+   *  frames are low-frequency; overflow drops oldest) and dropped on session-removed (audit S7). */
+  private readonly pendingBuffers = new Map<SessionId, RpcRequest<MuxFrame>[]>()
+  private summaries: SessionSummary[] = []
+  private listState: 'idle' | 'loading' | 'error' = 'idle'
+  private listError: RpcError | null = null
+  private listInflight: Promise<void> | null = null
+
+  private listSnapshotCache: SessionListSnapshot
+  /** Entry-identity cache (§C.2 reference stability): list rebuilds reuse the previous entry
+   *  object when every field matches — wire refreshes mint all-new summary objects, so identity
+   *  must be recovered by value or every SessionListItem memo misses on every refresh (audit S5). */
+  private entryCache = new Map<SessionId, SessionListEntry>()
+  private itemsCache: readonly SessionListEntry[] = []
+  private readonly notifier = new Notifier(() => {
+    this.listSnapshotCache = this.buildListSnapshot()
+  })
+
+  constructor(private readonly api: IApiClient) {
+    this.listSnapshotCache = this.buildListSnapshot()
+  }
+
+  // ---- Instance management ----
+
+  /**
+   * Lazy build: return the existing instance or construct one (no auto-open —
+   * open is triggered by the container's select callback).
+   * @param sessionId - the session to get.
+   * @returns the resident instance.
+   */
+  get(sessionId: SessionId): Session {
+    let session = this.sessions.get(sessionId)
+    if (session === undefined) {
+      session = new Session(sessionId, this.api)
+      this.sessions.set(sessionId, session)
+      // Sync the running bit from the list snapshot into the new instance (consistency when the list precedes open).
+      const summary = this.summaries.find(s => s.sessionId === sessionId)
+      if (summary !== undefined) session.handleRunning(summary.running)
+      // Replay approval/question frames buffered before instantiation (rpcId verbatim, same semantics as the subscribed baseline replay).
+      const buffered = this.pendingBuffers.get(sessionId)
+      if (buffered !== undefined) {
+        this.pendingBuffers.delete(sessionId)
+        for (const envelope of buffered) session.handleMuxEnvelope(envelope.rpcId, envelope.payload)
+      }
+    }
+    return session
+  }
+
+  // ---- List surface ----
+
+  /** Full refresh via session.list (single-flight: an in-flight call is reused). */
+  refreshList(): Promise<void> {
+    if (this.listInflight !== null) return this.listInflight
+    this.listState = 'loading'
+    this.listError = null
+    this.notifier.markDirty()
+    this.listInflight = (async () => {
+      try {
+        const { result } = await this.api.sessions.list({})
+        if (result.ok) {
+          this.summaries = result.value.items
+          this.listState = 'idle'
+          // Push running bits down to instantiated Sessions (the list is the authoritative summary source).
+          for (const s of this.summaries) this.sessions.get(s.sessionId)?.handleRunning(s.running)
+        } else {
+          this.listState = 'error'
+          this.listError = result.error
+        }
+      } catch (error) {
+        this.listState = 'error'
+        const folded = transportError<never>(error)
+        /* v8 ignore next -- the `? null` arm is unreachable: transportError always returns ok:false. */
+        this.listError = folded.ok ? null : folded.error
+      } finally {
+        this.listInflight = null
+        this.notifier.markDirty()
+      }
+    })()
+    return this.listInflight
+  }
+
+  /**
+   * Contract session.create; on success merge into summaries immediately (no
+   * wait for the next refresh).
+   * @param cwd - optional working directory for the new session.
+   * @returns the create result.
+   */
+  async create(cwd?: string): Promise<RpcResult<{ sessionId: SessionId }>> {
+    try {
+      const { result } = await this.api.sessions.create(cwd === undefined ? {} : { cwd })
+      if (result.ok && !this.summaries.some(s => s.sessionId === result.value.sessionId)) {
+        this.summaries = [
+          { sessionId: result.value.sessionId, updatedAt: Date.now(), running: false, ...(cwd !== undefined ? { cwd } : {}) },
+          ...this.summaries,
+        ]
+        this.notifier.markDirty()
+      }
+      return result
+    } catch (error) {
+      return transportError(error)
+    }
+  }
+
+  // ---- Subscription surface (for useSessionList) ----
+
+  /**
+   * uSES subscription entry for useSessionList.
+   * @param listener - change callback.
+   * @returns the unsubscribe function.
+   */
+  subscribe(listener: () => void): () => void {
+    return this.notifier.subscribe(listener)
+  }
+
+  /**
+   * Cached list snapshot (rebuilt lazily when dirty with no listeners).
+   * @returns the cached reference (stable until the next flush).
+   */
+  getListSnapshot(): SessionListSnapshot {
+    this.notifier.ensureFresh()
+    return this.listSnapshotCache
+  }
+
+  // ---- ConnectionController sinks (wired by boot) ----
+
+  /**
+   * Mux frame entry: sessionId-bearing frames go only to instantiated sessions
+   * (no lazy build; non-pending frames for uninstantiated sessions drop —
+   * history backfills them on open).
+   * @param envelope - the frame with its wire rpcId.
+   */
+  handleMuxEnvelope(envelope: RpcRequest<MuxFrame>): void {
+    const frame = envelope.payload
+    if (frame.type === 'stream/error') return // Controller already treats this as stream failure
+    const session = this.sessions.get(frame.sessionId)
+    if (session === undefined) {
+      // Approval/question frames never hit history: buffer for replay on instantiation;
+      // everything else drops (not instantiated — history fully backfills on open).
+      switch (frame.type) {
+        case 'approval/requested':
+        case 'approval/resolved':
+        case 'question/requested':
+        case 'question/resolved': {
+          const buffer = this.pendingBuffers.get(frame.sessionId) ?? []
+          buffer.push(envelope)
+          if (buffer.length > PENDING_BUFFER_CAP) buffer.splice(0, buffer.length - PENDING_BUFFER_CAP)
+          this.pendingBuffers.set(frame.sessionId, buffer)
+          return
+        }
+        default:
+          return
+      }
+    }
+    session.handleMuxEnvelope(envelope.rpcId, frame)
+  }
+
+  /**
+   * Host frame entry: list upkeep + per-instance running/removed/agent-error relay.
+   * @param envelope - the frame with its wire rpcId.
+   */
+  handleHostEnvelope(envelope: RpcRequest<HostFrame>): void {
+    const frame = envelope.payload
+    switch (frame.type) {
+      case 'host/session-added': {
+        if (!this.summaries.some(s => s.sessionId === frame.sessionId)) {
+          this.summaries = [
+            {
+              sessionId: frame.sessionId, updatedAt: Date.now(), running: false,
+              ...(frame.parentSessionId !== undefined ? { parentSessionId: frame.parentSessionId } : {}),
+            },
+            ...this.summaries,
+          ]
+          this.notifier.markDirty()
+        }
+        return
+      }
+      case 'host/session-removed': {
+        this.summaries = this.summaries.filter(s => s.sessionId !== frame.sessionId)
+        this.sessions.get(frame.sessionId)?.handleRemoved() // instance survives (resident-instance rule), only flagged in the snapshot
+        this.pendingBuffers.delete(frame.sessionId) // a removed session's buffered frames must not replay on a future instantiation
+        this.notifier.markDirty()
+        return
+      }
+      case 'host/session-status': {
+        this.summaries = this.summaries.map(s =>
+          s.sessionId === frame.sessionId && s.running !== frame.running ? { ...s, running: frame.running } : s)
+        this.sessions.get(frame.sessionId)?.handleRunning(frame.running)
+        this.notifier.markDirty()
+        return
+      }
+      case 'host/agent-error': {
+        this.sessions.get(frame.sessionId)?.handleAgentError(frame.message)
+        return // not reflected in the list
+      }
+      default:
+        return // stream/error ignored; unknown frames ignored (documented default)
+    }
+  }
+
+  /** After each connection generation (first connect included): refresh the list + resync opened instances (reconnect = rebuild). */
+  handleConnected(): void {
+    void this.refreshList()
+    for (const session of this.sessions.values()) void session.resync()
+  }
+
+  private buildListSnapshot(): SessionListSnapshot {
+    const fresh = flattenLineage(this.summaries)
+    const items = fresh.map((entry) => {
+      const prev = this.entryCache.get(entry.sessionId)
+      if (
+        prev !== undefined && prev.updatedAt === entry.updatedAt && prev.running === entry.running
+        && prev.parentSessionId === entry.parentSessionId && prev.cwd === entry.cwd && prev.depth === entry.depth
+      ) return prev
+      this.entryCache.set(entry.sessionId, entry)
+      return entry
+    })
+    for (const id of this.entryCache.keys()) {
+      if (!items.some(e => e.sessionId === id)) this.entryCache.delete(id)
+    }
+    const sameOrder = items.length === this.itemsCache.length && items.every((e, i) => e === this.itemsCache[i])
+    if (!sameOrder) this.itemsCache = items
+    return { items: this.itemsCache, state: this.listState, error: this.listError }
+  }
+}

packages/client/runtime/src/client/sessions/notifier.ts

@@ -0,0 +1,61 @@
+// Notifier: subscription + microtask-batched notification primitive shared by Session and
+// SessionManager. Semantics: N markDirty calls collapse into one microtask flush;
+// the flush rebuilds the snapshot cache BEFORE notifying (useSyncExternalStore requires a stable
+// getSnapshot reference). With no listeners the rebuild is skipped and only the dirty bit is set
+// (keeps frame storms cheap); the next getSnapshot rebuilds lazily.
+
+/** Subscription + microtask-batched notification primitive (shared by Session and SessionManager). */
+export class Notifier {
+  private listeners = new Set<() => void>()
+  private dirty = false
+  private scheduled = false
+
+  /** @param rebuild - snapshot rebuild function injected by the owner (writes the owner's snapshotCache). */
+  constructor(private readonly rebuild: () => void) {}
+
+  /**
+   * uSES subscription entry.
+   * @param listener - change callback.
+   * @returns the unsubscribe function.
+   */
+  subscribe(listener: () => void): () => void {
+    this.listeners.add(listener)
+    return () => {
+      this.listeners.delete(listener)
+    }
+  }
+
+  /** State-change entry: mark dirty and schedule the batched flush. */
+  markDirty(): void {
+    this.dirty = true
+    if (this.scheduled) return
+    this.scheduled = true
+    queueMicrotask(() => {
+      this.scheduled = false
+      if (!this.dirty) return
+      if (this.listeners.size === 0) return // lazy: no subscribers, keep dirty for the next getSnapshot
+      this.dirty = false
+      this.rebuild()
+      for (const listener of this.listeners) listener()
+    })
+  }
+
+  /**
+   * Synchronous flush: controlled-input writes must notify in the same tick as
+   * onChange, or React rolls the DOM back to the stale value and the caret jumps to the end.
+   */
+  notifyNow(): void {
+    this.dirty = true
+    if (this.listeners.size === 0) return // lazy: same as markDirty, next getSnapshot rebuilds
+    this.dirty = false
+    this.rebuild()
+    for (const listener of this.listeners) listener()
+  }
+
+  /** Pre-getSnapshot check: rebuild synchronously when dirty (read path before first subscribe / while unobserved). */
+  ensureFresh(): void {
+    if (!this.dirty) return
+    this.dirty = false
+    this.rebuild()
+  }
+}

packages/client/runtime/src/client/sessions/partial.ts

@@ -0,0 +1,89 @@
+// PartialAccumulator: assistant/chunk accumulator.
+// Folds the six StreamChunk variants into AssistantBlock[] keyed by block index;
+// block-level immutability (a delta only swaps that block's reference).
+
+import type { StreamChunk } from '@deepseek-ai/dsh-llm/types'
+import type { AssistantBlock, PartialAssistant } from './conversation.ts'
+import { toAssistantBlock } from './conversation.ts'
+
+/** assistant/chunk accumulator: folds StreamChunks into AssistantBlock[] with block-level immutability. */
+export class PartialAccumulator {
+  // Sparse on purpose: block-start may arrive out of order, leaving holes until compaction.
+  private blocks: (AssistantBlock | undefined)[] = []
+  private changed = true
+  private snapshot: PartialAssistant
+
+  constructor(readonly turn: number, readonly step: number) {
+    this.snapshot = { turn, step, blocks: [] }
+  }
+
+  /**
+   * Fold one chunk.
+   * @param chunk - the stream chunk.
+   * @returns whether it caused a visible change (usage/finish return false, skipping notification).
+   */
+  push(chunk: StreamChunk): boolean {
+    switch (chunk.type) {
+      case 'block-start': {
+        this.blocks[chunk.index] = emptyBlock(chunk.blockType)
+        this.changed = true
+        return true
+      }
+      case 'text-delta': {
+        const prev = this.blocks[chunk.index]
+        this.blocks[chunk.index] = { kind: 'text', text: (prev?.kind === 'text' ? prev.text : '') + chunk.text }
+        this.changed = true
+        return true
+      }
+      case 'reasoning-delta': {
+        const prev = this.blocks[chunk.index]
+        this.blocks[chunk.index] = { kind: 'reasoning', text: (prev?.kind === 'reasoning' ? prev.text : '') + chunk.text }
+        this.changed = true
+        return true
+      }
+      case 'tool-call-delta': {
+        const prev = this.blocks[chunk.index]
+        const base = prev?.kind === 'tool-call' ? prev : { kind: 'tool-call' as const, callId: '', name: '', argsRaw: '' }
+        this.blocks[chunk.index] = {
+          kind: 'tool-call',
+          callId: base.callId || String(chunk.id),
+          name: chunk.name ?? base.name,
+          argsRaw: base.argsRaw + chunk.argumentsDelta,
+        }
+        this.changed = true
+        return true
+      }
+      case 'block-end': {
+        this.blocks[chunk.index] = toAssistantBlock(chunk.block)
+        this.changed = true
+        return true
+      }
+      default:
+        // usage / finish / merge-extensible unknown variants: no visible block change
+        // (finish is immediately followed by the assistant/message that supersedes the partial).
+        return false
+    }
+  }
+
+  /**
+   * Current partial projection.
+   * @returns the cached snapshot (the blocks array reference only changes after a mutation).
+   */
+  toPartial(): PartialAssistant {
+    if (this.changed) {
+      // Compact sparse indexes (out-of-order block-start) into render order.
+      this.snapshot = { turn: this.turn, step: this.step, blocks: this.blocks.filter((b): b is AssistantBlock => b !== undefined) }
+      this.changed = false
+    }
+    return this.snapshot
+  }
+}
+
+function emptyBlock(blockType: string): AssistantBlock {
+  switch (blockType) {
+    case 'text': return { kind: 'text', text: '' }
+    case 'reasoning': return { kind: 'reasoning', text: '' }
+    case 'tool-call': return { kind: 'tool-call', callId: '', name: '', argsRaw: '' }
+    default: return { kind: 'other', block: null }
+  }
+}

packages/client/runtime/src/client/sessions/service.ts

@@ -0,0 +1,221 @@
+/**
+ * SessionsService: root sessions service — list snapshot store (manager
+ * projection), session scope tree (mintScope pattern: no-op plugin Fiber +
+ * ctx.extend scope tag), stable SessionBinding cache, ancestry walk.
+ *
+ * Scope lifecycle is watch-driven: a scope is minted lazily on first
+ * resolution; a session leaving the list tears its scope down only when
+ * nobody is watching it. "Watched" is approximated as the most recently
+ * resolved binding id — SessionProvider re-resolves on every selection
+ * change (keyed remount), so a switch away always re-evaluates the deferred
+ * teardown; a host-side death without list removal keeps the scope (frozen
+ * read-only view).
+ */
+import type { Context, Fiber } from 'cordis'
+import type { IApiClient, SessionId } from '@deepseek-ai/dsh-client-connection/client'
+import type { SnapshotStore } from '@deepseek-ai/dsh-client-web-react'
+import { createSnapshotStore } from '@deepseek-ai/dsh-client-web-react'
+import { SessionManager } from './manager.ts'
+import type { Session } from './session.ts'
+
+/** Session list row projected from the host list RPC plus live stream increments. */
+export interface SessionSummary {
+  id: SessionId
+  title: string
+  cwd?: string
+  parentId?: SessionId
+  running: boolean
+  updatedAt: number
+}
+
+/** Session list store shape. */
+export interface SessionListState { ids: SessionId[]; byId: Record<SessionId, SessionSummary> }
+
+/** Session assembly handle for SessionProvider/inject factories (identity-stable per session). */
+export interface SessionBinding {
+  readonly sessionId: SessionId
+  readonly session: Session
+  readonly ctx: Context
+}
+
+/** Scope tag key (client counterpart of the host dsh-scope pattern). */
+const kScope = Symbol('dsh.client.scope')
+
+/**
+ * Read the session scope tag off a context.
+ * @param ctx - any client context.
+ * @returns the session id, or undefined on root contexts.
+ */
+export function scopeOf(ctx: Context): SessionId | undefined {
+  return (ctx as Context & { [kScope]?: SessionId })[kScope]
+}
+
+/** Shared no-op plugin backing each session scope fiber. */
+function sessionScope(): void {}
+
+/**
+ * Display title projection. The wire summary carries no title yet (P-I
+ * ledger): the project directory's basename stands in, then the raw id.
+ */
+function titleOf(cwd: string | undefined, id: SessionId): string {
+  if (cwd !== undefined && cwd !== '') {
+    const base = cwd.replace(/[/\\]+$/, '').split(/[/\\]/).pop()
+    if (base !== undefined && base !== '') return base
+  }
+  return id
+}
+
+interface ScopeRecord {
+  fiber: Fiber
+  ctx: Context
+  binding: SessionBinding
+}
+
+/** Root sessions service: list store, object-layer manager, scope tree, bindings, ancestry. */
+export class SessionsService {
+  /** List snapshot store (list RPC + host stream increments; re-pulled on reconnect). */
+  readonly list: SnapshotStore<SessionListState>
+  /** The object-layer instance cluster and frame dispatch entry (wired to the connection by the runtime apply). */
+  readonly manager: SessionManager
+
+  private readonly scopes = new Map<SessionId, ScopeRecord>()
+  /** Most recently resolved binding id — the watch approximation for deferred teardown. */
+  private watched: SessionId | undefined
+  /** Removed-while-watched sessions whose teardown waits for the watch to move away. */
+  private readonly deferredRemovals = new Set<SessionId>()
+
+  /**
+   * @param ctx - client root context (scope fibers mount under it).
+   * @param api - wire client shared with every Session.
+   */
+  constructor(private readonly rootCtx: Context, api: IApiClient) {
+    this.manager = new SessionManager(api)
+    this.list = createSnapshotStore<SessionListState>({ ids: [], byId: {} })
+    // The manager owns wire truth; the store is its projection. Manager
+    // notifications are already microtask-batched.
+    this.manager.subscribe(() => { this.projectList() })
+    rootCtx.reflect.provide('sessions', this, undefined)
+  }
+
+  /**
+   * Create a session on the host.
+   * @param opts - creation options (project directory).
+   * @returns the new session id.
+   */
+  async create(opts: { cwd?: string } = {}): Promise<SessionId> {
+    const result = await this.manager.create(opts.cwd)
+    if (!result.ok) throw new Error(`session create failed: ${result.error.code}: ${result.error.message}`)
+    return result.value.sessionId
+  }
+
+  /**
+   * Resolve a session-scoped context view (use-and-discard).
+   * @param id - session id.
+   * @returns scoped ctx, or undefined for a session neither listed nor already scoped.
+   */
+  scope(id: SessionId): Context | undefined {
+    return this.resolve(id)?.ctx
+  }
+
+  /**
+   * Resolve the stable session binding (SessionProvider's resolveBinding feed).
+   * @param id - session id.
+   * @returns binding, or undefined for a session neither listed nor already scoped.
+   */
+  binding(id: SessionId): SessionBinding | undefined {
+    const record = this.resolve(id)
+    if (record === undefined) return undefined
+    if (this.watched !== id) {
+      this.watched = id
+      this.sweepDeferred()
+    }
+    return record.binding
+  }
+
+  /**
+   * Breadcrumb feed: walk parentId links inside the list store.
+   * @param id - session id.
+   * @returns summaries from root ancestor to the session itself (empty when unknown; a broken link stops the walk).
+   */
+  ancestry(id: SessionId): SessionSummary[] {
+    const { byId } = this.list.getSnapshot()
+    const chain: SessionSummary[] = []
+    let cursor: SessionId | undefined = id
+    while (cursor !== undefined) {
+      const summary: SessionSummary | undefined = byId[cursor]
+      if (summary === undefined || chain.includes(summary)) break
+      chain.unshift(summary)
+      cursor = summary.parentId
+    }
+    return chain
+  }
+
+  /** Lazily mint the scope + binding for a listed (or already-scoped) session. */
+  private resolve(id: SessionId): ScopeRecord | undefined {
+    const existing = this.scopes.get(id)
+    if (existing !== undefined) return existing
+    // Frozen scopes outlive the list; new scopes are only minted for listed sessions.
+    if (this.list.getSnapshot().byId[id] === undefined) return undefined
+    const fiber = this.rootCtx.plugin(sessionScope)
+    const ctx = fiber.ctx.extend({ [kScope]: id })
+    const record: ScopeRecord = {
+      fiber,
+      ctx,
+      binding: { sessionId: id, session: this.manager.get(id), ctx },
+    }
+    this.scopes.set(id, record)
+    return record
+  }
+
+  /** Project the manager's list snapshot into the store (title derivation is display-only). */
+  private projectList(): void {
+    const items = this.manager.getListSnapshot().items
+    const ids: SessionId[] = []
+    const byId: Record<SessionId, SessionSummary> = {}
+    for (const entry of items) {
+      ids.push(entry.sessionId)
+      byId[entry.sessionId] = {
+        id: entry.sessionId,
+        title: titleOf(entry.cwd, entry.sessionId),
+        running: entry.running,
+        updatedAt: entry.updatedAt,
+        ...(entry.cwd !== undefined ? { cwd: entry.cwd } : {}),
+        ...(entry.parentSessionId !== undefined ? { parentId: entry.parentSessionId } : {}),
+      }
+    }
+    this.list.set({ ids, byId })
+    this.pruneScopes(byId)
+  }
+
+  /** Tear down scopes for removed sessions nobody watches; the watched one defers until the watch moves. */
+  private pruneScopes(byId: Record<SessionId, SessionSummary>): void {
+    for (const [id, record] of this.scopes) {
+      if (byId[id] !== undefined) continue
+      if (id === this.watched) {
+        this.deferredRemovals.add(id)
+        continue
+      }
+      this.scopes.delete(id)
+      this.deferredRemovals.delete(id)
+      void record.fiber.dispose()
+    }
+  }
+
+  /** Run deferred teardowns whose session is no longer watched (called when the watch moves). */
+  private sweepDeferred(): void {
+    for (const id of [...this.deferredRemovals]) {
+      if (id === this.watched) continue
+      // Still absent from the list? (A re-added id cancels the deferred teardown.)
+      if (this.list.getSnapshot().byId[id] !== undefined) {
+        this.deferredRemovals.delete(id)
+        continue
+      }
+      const record = this.scopes.get(id)
+      this.deferredRemovals.delete(id)
+      if (record !== undefined) {
+        this.scopes.delete(id)
+        void record.fiber.dispose()
+      }
+    }
+  }
+}

packages/client/runtime/src/client/sessions/session.ts

@@ -0,0 +1,527 @@
+// Session: wraps every contract call that needs a sessionId + all conversation state for this
+// session (design §A.2/§A.9/§D.2/§D.3). Instances are resident (ruling 2): never destroyed once
+// created, they keep consuming mux frames in the background; React connects directly via
+// subscribe/getSnapshot.
+
+import type { ContentBlock } from '@deepseek-ai/dsh-llm/types'
+import type { SessionEvent } from '@deepseek-ai/dsh-session/types'
+import type { HistoryEntry, IApiClient, MuxFrame, RpcError, RpcId, RpcResult, SessionId, ToolEventView } from '@deepseek-ai/dsh-client-connection/client'
+import { transportError } from '@deepseek-ai/dsh-client-connection/client'
+import type { ObservableSnapshot, SnapshotSelectorHook } from '@deepseek-ai/dsh-client-web-react'
+import { bindSnapshotSelector } from '@deepseek-ai/dsh-client-web-react'
+import type {
+  ConversationNode, ConversationSnapshot, OpenState, PendingInteraction, PromptError, RunningToolCall,
+} from './conversation.ts'
+import { FoldAdapter } from './fold-adapter.ts'
+import { Notifier } from './notifier.ts'
+import { PartialAccumulator } from './partial.ts'
+
+/** Messages per page (F.4 ledger: promote to Config at graduation; every call site references this constant). */
+export const PAGE_MESSAGES = 50
+
+/** Per-session state owner: event window + fold + partial, snapshot out via uSES (see the web client architecture RFC). */
+export class Session implements ObservableSnapshot<ConversationSnapshot> {
+  /** Typed selector hook bound to this instance (the SessionBinding `useSession` source). */
+  readonly useSelector: SnapshotSelectorHook<ConversationSnapshot> = bindSnapshotSelector(this)
+
+  // ---- Window and derived state (all private; the snapshot is the only read surface) ----
+  private events: SessionEvent[] = []
+  /** Wire views aligned with `events` by index (envelope-level annotations; undefined = no view).
+   *  Kept parallel rather than merged so `events` stays the raw log slice (model-visible ⟺ logged). */
+  private views: (ToolEventView | undefined)[] = []
+  private baseSeq = 0
+  private hasMore = false
+  private openState: OpenState = 'cold'
+  private openError: RpcError | null = null
+  private openPromise: Promise<void> | null = null
+  /** Bumped by resync to invalidate an in-flight doOpen: a reconnect must rebuild, never adopt
+   *  a pre-disconnect open whose history request is already doomed (audit S4). Stale doOpen
+   *  passes drop all writes once the generation moves on. */
+  private openGeneration = 0
+  private loadingOlder = false
+  private readonly foldAdapter = new FoldAdapter()
+  private partial: PartialAccumulator | null = null
+  private openCalls = new Map<string, RunningToolCall>()
+  /** Interrupted-turn terminal nodes (frozen partial text / aborted tool cards), merged into the flow by seq.
+   *  Derived from window events (turn/end sweep) — rebuilt by rebuildDerivedFromWindow like partial/openCalls. */
+  private frozenNodes: ConversationNode[] = []
+  private pending = new Map<string, PendingInteraction>()
+  // Revision counters + caches backing the snapshot's reference-stability contract (§A.9.4/§C.2,
+  // audit S5): buildSnapshot reuses the previous array when the revision is unchanged, so
+  // React.memo children survive unrelated snapshot swaps (chunk storms must not re-render every
+  // tool card and pending card). Mutation sites bump the matching revision. partial needs no
+  // counter — PartialAccumulator.toPartial already returns a cached reference when unchanged.
+  private callsRev = 0
+  private callsCache: { rev: number; value: RunningToolCall[] } | null = null
+  private pendingRev = 0
+  private pendingCache: { rev: number; value: PendingInteraction[] } | null = null
+  private frozenRev = 0
+  private nodesCache: { folded: readonly ConversationNode[]; frozenRev: number; value: readonly ConversationNode[] } | null = null
+  private running = false
+  private removed = false
+  private promptError: PromptError | null = null
+  private lastAgentError: string | null = null
+  /** Buffer for live events arriving while open/resync is in flight (stitched by seq once history lands, §D.3). */
+  private liveBuffer: { event: SessionEvent; view: ToolEventView | undefined }[] = []
+  /** Gap-repair (resync-lite) in flight: acceptLiveEvent detours to liveBuffer until the tail page lands (audit S3). */
+  private stitching = false
+  /** subscribed.lastSeq baseline (gap detection; null when no subscribed frame arrived — degrade to the liveBuffer dedup path). */
+  private subscribedLastSeq: number | null = null
+
+  private snapshotCache: ConversationSnapshot
+  private readonly notifier = new Notifier(() => {
+    this.snapshotCache = this.buildSnapshot()
+  })
+
+  constructor(readonly sessionId: SessionId, private readonly api: IApiClient) {
+    this.snapshotCache = this.buildSnapshot()
+  }
+
+  // ---- Operations ----
+
+  /**
+   * Send (queue/steer passed through 1:1); failures land in the snapshot's promptError.
+   * @param content - core content blocks verbatim.
+   * @param mode - queue appends after the current turn; steer interrupts it.
+   * @returns the prompt result (also mirrored into promptError on failure).
+   */
+  async prompt(content: ContentBlock[], mode: 'queue' | 'steer'): Promise<RpcResult<{ accepted: true }>> {
+    this.promptError = null
+    this.lastAgentError = null
+    this.notifier.markDirty()
+    let result: RpcResult<{ accepted: true }>
+    try {
+      result = (await this.api.sessions.prompt({ sessionId: this.sessionId, mode, content })).result
+    } catch (error) {
+      result = transportError(error)
+    }
+    if (!result.ok) {
+      this.promptError = { op: 'send', error: result.error }
+      this.notifier.markDirty()
+    }
+    return result
+  }
+
+  /**
+   * Stop: contract session.cancel 1:1; failures land in promptError (same error-strip display slot).
+   * @returns the cancel result.
+   */
+  async cancel(): Promise<RpcResult<{ accepted: true }>> {
+    let result: RpcResult<{ accepted: true }>
+    try {
+      result = (await this.api.sessions.cancel({ sessionId: this.sessionId })).result
+    } catch (error) {
+      result = transportError(error)
+    }
+    if (!result.ok) {
+      this.promptError = { op: 'stop', error: result.error }
+      this.notifier.markDirty()
+    }
+    return result
+  }
+
+  /** First open: pull the tail page (idempotent — in-flight/already-open returns the existing promise). */
+  open(): Promise<void> {
+    if (this.openState === 'open') return Promise.resolve()
+    if (this.openPromise !== null) return this.openPromise
+    const promise = this.doOpen(this.openGeneration).finally(() => {
+      // Identity-guarded: a superseded open must not null out the promise resync just started.
+      if (this.openPromise === promise) this.openPromise = null
+    })
+    this.openPromise = promise
+    return promise
+  }
+
+  /** Page up: pull one earlier page with the window's first seq as beforeSeq and prepend (§D.2). */
+  async loadOlder(): Promise<void> {
+    if (this.openState !== 'open' || !this.hasMore || this.loadingOlder) return
+    this.loadingOlder = true
+    this.notifier.markDirty()
+    try {
+      const { result } = await this.api.sessions.history({
+        sessionId: this.sessionId, beforeSeq: this.baseSeq, maxMessages: PAGE_MESSAGES,
+      })
+      if (!result.ok) return // keep the window as-is; do not overwrite openError (open already succeeded)
+      const older = result.value.events
+      if (older.length === 0) {
+        this.hasMore = result.value.hasMore
+        return
+      }
+      const tail = older[older.length - 1]
+      if (tail === undefined || tail.event.seq + 1 !== this.baseSeq) {
+        // §D.2 continuity assertion: on violation drop the page fail-soft rather than render an out-of-order stream.
+        console.error(`[web-runtime] history page discontinuous: tail seq ${tail?.event.seq} vs baseSeq ${this.baseSeq}`)
+        this.hasMore = false
+        return
+      }
+      this.events = [...older.map(e => e.event), ...this.events]
+      this.views = [...older.map(e => e.view), ...this.views]
+      /* v8 ignore next -- the ?? arm needs older[0] undefined, but the empty-page branch above already returned. */
+      this.baseSeq = older[0]?.event.seq ?? this.baseSeq
+      this.hasMore = result.value.hasMore
+      this.foldAdapter.reset(this.events, this.baseSeq, this.views) // prepend forces a rebuild (sentinel count changed)
+      this.rebuildDerivedFromWindow()
+    } catch (error) {
+      console.error('[web-runtime] loadOlder failed:', error)
+    } finally {
+      this.loadingOlder = false
+      this.notifier.markDirty()
+    }
+  }
+
+  /** Reconnect rebuild (manager calls this on onConnected for instances that were opened):
+   *  reset the window and rerun open; pending waits for the baseline replay. Invalidates any
+   *  in-flight open first — its history request rode the dead connection and must not settle
+   *  the fresh generation into 'error' (audit S4). */
+  async resync(): Promise<void> {
+    if (this.openState === 'cold') return // never opened: no window to rebuild (doOpen flips to 'loading' synchronously, so cold implies no in-flight open)
+    this.openGeneration++
+    this.openPromise = null
+    this.openState = 'cold'
+    this.openError = null
+    this.events = []
+    this.views = []
+    this.baseSeq = 0
+    this.pending.clear() // the subscribed baseline replay re-sends still-pending requested frames verbatim
+    this.pendingRev++
+    this.subscribedLastSeq = null
+    this.liveBuffer = []
+    this.notifier.markDirty()
+    await this.open()
+  }
+
+  // ---- Subscription surface (useSyncExternalStore direct wiring) ----
+
+  /**
+   * uSES subscription entry.
+   * @param listener - change callback.
+   * @returns the unsubscribe function.
+   */
+  subscribe(listener: () => void): () => void {
+    return this.notifier.subscribe(listener)
+  }
+
+  /**
+   * Cached conversation snapshot (rebuilt lazily when dirty with no listeners).
+   * @returns the cached reference (stable until the next flush).
+   */
+  getSnapshot(): ConversationSnapshot {
+    this.notifier.ensureFresh()
+    return this.snapshotCache
+  }
+
+  // ---- Manager-only entry points (@internal; never called by the UI) ----
+
+  /**
+   * Mux frame arrival (the dispatch switch).
+   * @param rpcId - the frame envelope id (the respond backfill key for requested frames).
+   * @param frame - the routed frame.
+   */
+  handleMuxEnvelope(rpcId: RpcId, frame: MuxFrame): void {
+    switch (frame.type) {
+      case 'session/event': {
+        this.acceptLiveEvent(frame.event, frame.view)
+        return
+      }
+      case 'session/subscribed': {
+        this.subscribedLastSeq = frame.lastSeq
+        return // pure baseline bookkeeping, no visible change
+      }
+      case 'approval/requested': {
+        this.pending.set(`a:${rpcId}`, {
+          kind: 'approval', rpcId, approvalId: frame.approvalId, toolName: frame.toolName,
+          ...(frame.callId !== undefined ? { callId: frame.callId } : {}),
+          ...(frame.reason !== undefined ? { reason: frame.reason } : {}),
+        })
+        this.pendingRev++
+        this.notifier.markDirty()
+        return
+      }
+      case 'approval/resolved': {
+        for (const [key, item] of this.pending) {
+          if (item.kind === 'approval' && item.approvalId === frame.approvalId) {
+            this.pending.delete(key)
+            this.pendingRev++
+          }
+        }
+        this.notifier.markDirty()
+        return
+      }
+      case 'question/requested': {
+        this.pending.set(`q:${rpcId}`, { kind: 'question', rpcId, questions: frame.questions })
+        this.pendingRev++
+        this.notifier.markDirty()
+        return
+      }
+      case 'question/resolved': {
+        if (this.pending.delete(`q:${frame.questionRpcId}`)) this.pendingRev++
+        this.notifier.markDirty()
+        return
+      }
+      default:
+        return // stream/error never reaches Session (Controller converges it); unknown frames ignored (documented default)
+    }
+  }
+
+  /**
+   * Running-bit relay from the host stream (list entry and snapshot stay consistent).
+   * @param running - the new running state.
+   */
+  handleRunning(running: boolean): void {
+    if (this.running === running) return
+    this.running = running
+    this.notifier.markDirty()
+  }
+
+  /** host/session-removed relay: flag the snapshot (instance survives — resident-instance rule). */
+  handleRemoved(): void {
+    this.removed = true
+    this.notifier.markDirty()
+  }
+
+  /**
+   * host/agent-error relay: the only outlet for live failures with no turn position.
+   * @param message - the stringified error.
+   */
+  handleAgentError(message: string): void {
+    this.lastAgentError = message
+    this.notifier.markDirty()
+  }
+
+  /** Instance-eviction hook, reserved no-op (design §F.6): resident instances are never destroyed
+   *  in v1; an eviction policy lands here (unsubscribe, drop buffers) without touching call sites. */
+  dispose(): void {}
+
+  // ---- 私有 ----
+
+  /** @param generation - openGeneration at launch; every await re-checks it and a stale pass
+   *  drops all writes (resync superseded this open — its outcome belongs to a dead connection). */
+  private async doOpen(generation: number): Promise<void> {
+    this.openState = 'loading'
+    this.openError = null
+    this.notifier.markDirty()
+    try {
+      let { result } = await this.api.sessions.history({ sessionId: this.sessionId, maxMessages: PAGE_MESSAGES })
+      if (generation !== this.openGeneration) return
+      if (!result.ok) {
+        this.openState = 'error'
+        this.openError = result.error
+        return
+      }
+      this.installWindow(result.value.events, result.value.hasMore)
+      // Gap detection (§D.3-4): baseline past the window tail and liveBuffer did not cover it -> pull the tail page once more.
+      const tailSeq = this.windowTailSeq()
+      if (this.subscribedLastSeq !== null && tailSeq !== null && this.subscribedLastSeq > tailSeq) {
+        result = (await this.api.sessions.history({ sessionId: this.sessionId, maxMessages: PAGE_MESSAGES })).result
+        if (generation !== this.openGeneration) return
+        if (result.ok) this.installWindow(result.value.events, result.value.hasMore)
+      }
+      this.openState = 'open'
+    } catch (error) {
+      if (generation !== this.openGeneration) return
+      this.openState = 'error'
+      const folded = transportError<never>(error)
+      /* v8 ignore next -- the `? null` arm is unreachable: transportError always returns ok:false. */
+      this.openError = folded.ok ? null : folded.error
+    } finally {
+      if (generation === this.openGeneration) this.notifier.markDirty()
+    }
+  }
+
+  /** Install the history window + stitch the liveBuffer (seq is the sole dedup key).
+   *  Stitching MUST NOT route through acceptLiveEvent: openState is still 'loading' here
+   *  (doOpen flips it after install), so recursing would push every buffered event straight
+   *  back into liveBuffer where nothing ever drains it — a silent drop loop (audit S1). */
+  private installWindow(entries: HistoryEntry[], hasMore: boolean): void {
+    this.events = entries.map(e => e.event)
+    this.views = entries.map(e => e.view)
+    this.baseSeq = this.events[0]?.seq ?? 0
+    this.hasMore = hasMore
+    this.foldAdapter.reset(this.events, this.baseSeq, this.views)
+    this.rebuildDerivedFromWindow()
+    const buffered = this.liveBuffer
+    this.liveBuffer = []
+    for (const item of buffered) this.appendLive(item.event, item.view)
+    this.notifier.markDirty()
+  }
+
+  /** Seq-guarded append shared by stitching and the open-state live path. */
+  private appendLive(event: SessionEvent, view?: ToolEventView): void {
+    const tailSeq = this.windowTailSeq()
+    if (tailSeq !== null && event.seq <= tailSeq) return // replay overlap, drop
+    this.events.push(event)
+    this.views.push(view)
+    this.foldAdapter.append(event, view)
+    this.applyEventSideEffects(event, view)
+  }
+
+  /** Land a live session/event (open/repair in flight -> buffer; overlapping seq -> drop;
+   *  a seq gap -> buffer + tail-page repull instead of appending a hole (audit S3: a gap is an
+   *  expected reconnect-window artifact, repaired by refetch — never fed to the fold to trip
+   *  its continuity assertion into the degraded view). */
+  private acceptLiveEvent(event: SessionEvent, view?: ToolEventView): void {
+    if (this.openState === 'loading' || this.stitching) {
+      this.liveBuffer.push({ event, view })
+      return
+    }
+    if (this.openState !== 'open') return // cold/error: no window upkeep (history fully backfills on open)
+    const tailSeq = this.windowTailSeq()
+    if (tailSeq !== null && event.seq > tailSeq + 1) {
+      this.liveBuffer.push({ event, view })
+      void this.repairGap()
+      return
+    }
+    this.appendLive(event, view)
+    this.notifier.markDirty()
+  }
+
+  /** Resync-lite (audit S3): repull the tail page and stitch the liveBuffer through the shared
+   *  installWindow path. No openState transition — the UI keeps the current window (no loading
+   *  flash); events arriving meanwhile detour to liveBuffer via the stitching flag. */
+  private async repairGap(): Promise<void> {
+    /* v8 ignore next -- re-entry guard: acceptLiveEvent already detours to liveBuffer while stitching, so no second call reaches here. */
+    if (this.stitching) return
+    this.stitching = true
+    const generation = this.openGeneration
+    try {
+      const { result } = await this.api.sessions.history({ sessionId: this.sessionId, maxMessages: PAGE_MESSAGES })
+      // Failure or superseded by a full resync: drop — the resync path rebuilds and clears the buffer itself.
+      if (result.ok && generation === this.openGeneration && this.openState === 'open') {
+        this.installWindow(result.value.events, result.value.hasMore)
+      }
+    } catch (error) {
+      console.error('[web-runtime] gap repair failed:', error)
+    } finally {
+      this.stitching = false
+    }
+  }
+
+  /** Per-event side effects (right column of the §A.9 dispatch table):
+   *  chunk accumulation / partial clear on finalize / openCalls add-remove. */
+  private applyEventSideEffects(event: SessionEvent, view?: ToolEventView): void {
+    switch (event.type) {
+      case 'assistant/chunk': {
+        const { turn, step, chunk } = event.data
+        if (this.partial === null || this.partial.turn !== turn || this.partial.step !== step) {
+          this.partial = new PartialAccumulator(turn, step)
+        }
+        this.partial.push(chunk)
+        return
+      }
+      case 'assistant/message': {
+        if (this.partial !== null && this.partial.turn === event.data.turn && this.partial.step === event.data.step) {
+          this.partial = null // finalize swaps in place (same notification batch, no flicker)
+        }
+        return
+      }
+      case 'tool/call': {
+        this.openCalls.set(String(event.data.callId), {
+          callId: String(event.data.callId), name: event.data.name, argsRaw: event.data.arguments,
+          turn: event.data.turn, step: event.data.step,
+          callView: view?.for === 'call' ? view.view : null,
+        })
+        this.callsRev++
+        return
+      }
+      case 'tool/result': {
+        if (this.openCalls.delete(String(event.data.callId))) this.callsRev++
+        return
+      }
+      case 'turn/end': {
+        // Aborted turns never finalize. The accumulated partial is VALUE, not residue: freeze it
+        // into an interrupted terminal node (pulse stops, text survives) instead of deleting it.
+        // Shared by live and window-replay paths, so a refresh reconstructs the same frozen node
+        // from the logged chunks. Content-free partials are dropped outright.
+        if (this.partial !== null && this.partial.turn === event.data.turn) {
+          const { blocks } = this.partial.toPartial()
+          const visible = blocks.some(b => (b.kind === 'text' || b.kind === 'reasoning' ? b.text !== '' : true))
+          if (visible) {
+            // Fractional seq: strictly after every event of this turn (all < turn/end seq), before the next turn.
+            this.frozenNodes.push({
+              kind: 'assistant', seq: event.seq - 0.9, turn: this.partial.turn, step: this.partial.step,
+              blocks, interrupted: true,
+            })
+            this.frozenRev++
+          }
+          this.partial = null
+        }
+        let callOffset = 0
+        for (const [callId, call] of this.openCalls) {
+          if (call.turn !== event.data.turn) continue
+          this.openCalls.delete(callId)
+          this.callsRev++
+          // The spinner card becomes an interrupted terminal card (never vanishes mid-flow).
+          this.frozenNodes.push({
+            kind: 'tool-result', seq: event.seq - 0.8 + callOffset++ * 0.01, callId,
+            call: { name: call.name, argsRaw: call.argsRaw },
+            content: [], isError: true, error: { name: 'Interrupted', code: 'interrupted' },
+            callView: call.callView, resultView: null,
+          })
+          this.frozenRev++
+        }
+        return
+      }
+      default:
+        return
+    }
+  }
+
+  /** Re-derive state (partial/openCalls/frozenNodes) from raw window events after a rebuild — keeps
+   *  paging/stitching consistent, and makes the live freeze and the history replay converge on the
+   *  same interrupted nodes (chunks are logged, so the replayed sweep re-freezes identical text). */
+  private rebuildDerivedFromWindow(): void {
+    this.partial = null
+    this.openCalls.clear()
+    this.callsRev++
+    this.frozenNodes = []
+    this.frozenRev++
+    for (let i = 0; i < this.events.length; i++) {
+      const event = this.events[i]
+      /* v8 ignore next -- dense-array guard: i stays within events.length, so the undefined arm needs a sparse array no caller builds. */
+      if (event !== undefined) this.applyEventSideEffects(event, this.views[i])
+    }
+  }
+
+  private windowTailSeq(): number | null {
+    const tail = this.events[this.events.length - 1]
+    return tail === undefined ? null : tail.seq
+  }
+
+  private buildSnapshot(): ConversationSnapshot {
+    const { nodes: folded, degraded } = this.foldAdapter.nodes()
+    // Frozen interrupted nodes ride fractional seqs: a stable merge keeps them in flow order.
+    // The merged array is cached on (folded reference, frozenRev) so an unchanged flow keeps its
+    // reference across snapshot swaps (§A.9.4).
+    let nodes: readonly ConversationNode[]
+    if (this.nodesCache !== null && this.nodesCache.folded === folded && this.nodesCache.frozenRev === this.frozenRev) {
+      nodes = this.nodesCache.value
+    } else {
+      nodes = this.frozenNodes.length === 0
+        ? folded
+        : [...folded, ...this.frozenNodes].sort((a, b) => a.seq - b.seq)
+      this.nodesCache = { folded, frozenRev: this.frozenRev, value: nodes }
+    }
+    if (this.callsCache === null || this.callsCache.rev !== this.callsRev) {
+      this.callsCache = { rev: this.callsRev, value: [...this.openCalls.values()] }
+    }
+    if (this.pendingCache === null || this.pendingCache.rev !== this.pendingRev) {
+      this.pendingCache = { rev: this.pendingRev, value: [...this.pending.values()] }
+    }
+    return {
+      sessionId: this.sessionId,
+      nodes,
+      foldDegraded: degraded,
+      partial: this.partial?.toPartial() ?? null,
+      runningCalls: this.callsCache.value,
+      pending: this.pendingCache.value,
+      running: this.running,
+      removed: this.removed,
+      openState: this.openState,
+      openError: this.openError,
+      hasMore: this.hasMore,
+      loadingOlder: this.loadingOlder,
+      promptError: this.promptError,
+      lastAgentError: this.lastAgentError,
+    }
+  }
+}

packages/client/runtime/src/client/slots.ts

@@ -0,0 +1,107 @@
+/**
+ * SlotsService: cordis Service wrapper over the pure SlotCore (ui-slots).
+ * Every mutation re-emits as the 'slots/changed' cordis event; define/register
+ * run through the caller's ctx.effect so a plugin's registrations are
+ * collected when its fiber unloads (cordis-native cascade).
+ */
+/* eslint-disable @typescript-eslint/no-redundant-type-constituents --
+ * `keyof SlotMap & string` is the declare-merge key pattern: SlotMap is empty
+ * in this compilation unit (intersection reads `never`) but consumers merge
+ * keys in; the rule fires on the empty-map view, not on real redundancy. */
+import { Service } from 'cordis'
+import type { Context } from 'cordis'
+import { SlotCore } from '@deepseek-ai/dsh-client-ui-slots'
+import type { ComposedProps, RegisterArgs, SlotComponent, SlotEntry, SlotEntryDef, SlotMap, SlotSpec } from '@deepseek-ai/dsh-client-ui-slots'
+import type { ClientContext } from './index.ts'
+
+/** cordis Service wrapper over the pure SlotCore; mutations re-emit as 'slots/changed'. */
+export class SlotsService extends Service {
+  private readonly _core = new SlotCore()
+
+  /**
+   * @param ctx - owning root context.
+   */
+  constructor(ctx: Context) {
+    super(ctx, 'slots')
+    this._core.onMutate((key) => { ctx.emit('slots/changed', key) })
+  }
+
+  /**
+   * Record a slot spec (delegates to SlotCore.define; disposal follows the caller's fiber).
+   * @param key - SlotMap key.
+   * @param spec - kind/scope spec.
+   * @returns disposer.
+   */
+  define<K extends keyof SlotMap & string>(key: K, spec: SlotSpec<SlotMap[K]>): () => void {
+    // eslint-disable-next-line @typescript-eslint/no-misused-promises -- synchronous cleanup; direct return preserves disposer identity
+    return this.ctx.effect(() => this._core.define(key, spec), 'slots.define()')
+  }
+
+  /**
+   * Contribute a component (delegates to SlotCore.register; disposal follows the caller's fiber).
+   * @param key - SlotMap key.
+   * @param component - contributed component.
+   * @param args - kind-shaped options (mandatory for keyed/list kinds); the
+   * inject factory's binding is pinned to ClientContext.
+   * @returns disposer.
+   */
+  register<K extends keyof SlotMap & string, I extends object = Record<string, unknown>>(
+    // Client-context registrations have exactly one ctx shape: pin Ctx to
+    // ClientContext so inject factories dot services without a cast.
+    key: K, component: SlotComponent<ComposedProps<K, NoInfer<I>>>,
+    ...args: RegisterArgs<SlotMap[K], I, ClientContext>): () => void {
+    // eslint-disable-next-line @typescript-eslint/no-misused-promises -- synchronous cleanup; direct return preserves disposer identity
+    return this.ctx.effect(() => this._core.register<K, I, ClientContext>(key, component, ...args), 'slots.register()')
+  }
+
+  /**
+   * Snapshot entries for a key.
+   * @param key - SlotMap key.
+   * @returns registered entries (stable reference between mutations).
+   */
+  entries<K extends keyof SlotMap & string>(key: K): readonly SlotEntry<SlotMap[K]>[] {
+    return this._core.entries(key)
+  }
+
+  /**
+   * Look up a defined spec.
+   * @param key - SlotMap key.
+   * @returns spec or undefined.
+   */
+  spec<K extends keyof SlotMap & string>(key: K): SlotSpec<SlotMap[K]> | undefined {
+    return this._core.spec(key)
+  }
+
+  /**
+   * Dynamic-key escape hatch for spec lookup (renderer-side string keys).
+   * @param key - candidate slot key.
+   * @returns wide-typed spec or undefined.
+   */
+  specDynamic(key: string): SlotSpec<SlotEntryDef> | undefined {
+    return this._core.specDynamic(key)
+  }
+
+  /**
+   * Subscribe to a key's registration changes (microtask-batched).
+   * @param key - SlotMap key.
+   * @param fn - change callback.
+   * @returns unsubscribe.
+   */
+  subscribe(key: keyof SlotMap & string, fn: () => void): () => void {
+    return this._core.subscribe(key, fn)
+  }
+
+  /**
+   * Version counter for uSES pairing.
+   * @param key - SlotMap key.
+   * @returns current version.
+   */
+  getVersion(key: keyof SlotMap & string): number {
+    return this._core.getVersion(key)
+  }
+
+  /** The wrapped pure core (web-react's scopedSlots outlet reads through this). */
+  get core(): SlotCore {
+    return this._core
+  }
+}

packages/client/runtime/src/index.ts

@@ -0,0 +1,11 @@
+/**
+ * Runtime plugin, node half. The implementation lives entirely in the client
+ * half (src/client/ — SlotsService, SessionsService + object layer, and the
+ * shell-held ClientLoader under ./loader); consumers import the /client or
+ * /loader subpaths. The empty apply exists so the plugin appears in the host
+ * Loader (lifecycle governance + dshClient discovery). Contract:
+ * api-contracts v3 section 4.
+ */
+
+/** Host plugin body — no host-side behavior for the runtime plugin. */
+export function apply(_ctx: unknown): void {}

packages/client/runtime/src/invariant.ts

@@ -0,0 +1,52 @@
+/**
+ * Package-owned invariant companion for `@deepseek-ai/dsh-client-runtime`.
+ * @module @deepseek-ai/dsh-client-runtime/invariant
+ */
+
+/* jscpd:ignore-start */
+/* eslint-disable @typescript-eslint/no-redundant-type-constituents --
+ * `keyof SlotMap & string` is the declare-merge key pattern: SlotMap is empty
+ * in this compilation unit (intersection reads `never`) but consumers merge
+ * keys in; the rule fires on the empty-map view, not on real redundancy. */
+import type { Context } from 'cordis'
+import type { SlotMap } from '@deepseek-ai/dsh-client-ui-slots'
+import type { InvariantInstaller } from '@deepseek-ai/dsh-invariants'
+
+const PACKAGE_NAME = '@deepseek-ai/dsh-client-runtime'
+
+/** Cordis companion plugin name. */
+export const name = 'client-runtime-invariant'
+/** Service required before the companion can register. */
+export const inject = ['invariants']
+
+/**
+ * Owned relation: every 'slots/changed'(key) emission must observe the
+ * mutation already applied — SlotCore bumps the key's version synchronously
+ * before the service re-emits, so a zero version at dispatch time means the
+ * event fired without (or ahead of) its mutation.
+ */
+const install: InvariantInstaller = (ctx, fail) => {
+  ctx.on('internal/dispatch', (_mode, eventName, args) => {
+    if (eventName !== 'slots/changed') return
+    const key: unknown = args[0]
+    if (typeof key !== 'string' || key === '') {
+      fail("'slots/changed' dispatched without a slot key argument")
+      return
+    }
+    const slots = ctx.get('slots')
+    // Event payloads carry keys as plain strings; getVersion is statically
+    // keyed, so restore the SlotMap-key type after the runtime string check.
+    if (slots !== undefined && slots.getVersion(key as keyof SlotMap & string) === 0) {
+      fail(`'slots/changed' fired for "${key}" before any mutation bumped its version — emission must follow the applied mutation`)
+    }
+  }, { global: true })
+}
+
+/**
+ * Register this package's invariant companion.
+ * @param ctx - Cordis context carrying the invariant service.
+ * @returns the installed registration's disposer after setup succeeds.
+ */
+export const apply = (ctx: Context): Promise<() => void> =>
+  Promise.resolve(ctx.invariants.register(PACKAGE_NAME, install))
+/* jscpd:ignore-end */

packages/client/runtime/tests/client-loader-bundle.e2e.ts

@@ -0,0 +1,77 @@
+/**
+ * Real-bundle smoke: the actual tsdown client bundle of ui-layout runs
+ * through the loader chain (execute → handoff → factory(require) → apply →
+ * export re-registration). Skips when the bundle is not built (dist/ is a
+ * build product; `pnpm --filter @deepseek-ai/dsh-client-ui-layout build`).
+ */
+import { readFileSync } from 'node:fs'
+import { createRequire } from 'node:module'
+import { Context } from 'cordis'
+import { afterEach, describe, expect, it } from 'vitest'
+import * as uiSlots from '@deepseek-ai/dsh-client-ui-slots'
+import * as webReact from '@deepseek-ai/dsh-client-web-react'
+import { createClientLoader } from '../src/client/loader/index.ts'
+import type { ClientPluginHandoff } from '../src/client/loader/index.ts'
+import { SessionsService } from '../src/client/sessions/service.ts'
+import { SlotsService } from '../src/client/slots.ts'
+import { FakeApiClient } from './fake-api.ts'
+
+const LAYOUT_ID = '@deepseek-ai/dsh-client-ui-layout'
+
+type Win = { DSHClientProxy?: { loadPlugin(h: ClientPluginHandoff): void }; window?: unknown }
+
+afterEach(() => {
+  delete (globalThis as Win).DSHClientProxy
+  delete (globalThis as Win).window
+})
+
+function readLayoutBundle(): string | undefined {
+  try {
+    const require = createRequire(import.meta.url)
+    return readFileSync(require.resolve(`${LAYOUT_ID}/client`), 'utf8')
+  } catch {
+    return undefined
+  }
+}
+
+describe('real tsdown bundle through the loader', () => {
+  const code = readLayoutBundle()
+
+  it.skipIf(code === undefined)('loads ui-layout lib/client.js: handoff, DI require, apply, export surface', async () => {
+    // The bundle banner addresses window.DSHClientProxy; node has no window —
+    // alias it to globalThis so the loader-installed proxy is reachable.
+    ;(globalThis as Win).window = globalThis
+    const ctx = new Context()
+    // The layout apply consumes the slots + sessions services; the real chain
+    // loads the runtime bundle first — stand both up directly here.
+    ctx.plugin(SlotsService)
+    await ctx.fiber.await()
+    new SessionsService(ctx, new FakeApiClient())
+    const loader = createClientLoader({
+      ctx,
+      // The real bundle externals resolved from the seeded table. React is a
+      // type-only import in the layout bundle today, but jsx-runtime is real.
+      modules: {
+        'react': await import('react'),
+        'react/jsx-runtime': await import('react/jsx-runtime'),
+        '@deepseek-ai/dsh-client-ui-slots': uiSlots,
+        '@deepseek-ai/dsh-client-web-react': webReact,
+      },
+      boot: { plugins: [{ id: LAYOUT_ID, url: `/plugins/${LAYOUT_ID}/client.js`, inject: [] }] },
+      fetchBundle: () => Promise.resolve(code as string),
+      // node has no DOM: evaluate the bundle body directly (same synchronous
+      // handoff contract as the <script> path).
+      executeBundle: (bundleCode) => {
+        // Node has no <script>: Function-evaluating the built bundle IS the
+        // system under test (same synchronous handoff as the browser path).
+        // eslint-disable-next-line @typescript-eslint/no-implied-eval, @typescript-eslint/no-unsafe-call
+        new Function(bundleCode)()
+      },
+    })
+    loader.start()
+    await loader.settled()
+    expect(loader.status.getSnapshot()[LAYOUT_ID]).toBe('active')
+    const surface = loader.requireModule(LAYOUT_ID) as Record<string, unknown>
+    expect(typeof surface.apply).toBe('function')
+  })
+})

packages/client/runtime/tests/client-loader.spec.ts

@@ -0,0 +1,192 @@
+/**
+ * ClientLoader: handoff protocol (single slot, id reconciliation), DI require
+ * with export-surface re-registration, immediately-group barrier (parallel
+ * fetch / topology execution / full-group barrier), status store, settled,
+ * failure modes (missing handoff, unknown dep, cycle, unload stub).
+ */
+import { Context } from 'cordis'
+import { afterEach, describe, expect, it } from 'vitest'
+import { createClientLoader } from '../src/client/loader/index.ts'
+import type { BootPluginEntry, ClientPluginHandoff } from '../src/client/loader/index.ts'
+
+type Win = { DSHClientProxy?: { loadPlugin(h: ClientPluginHandoff): void }; __DSH_BOOT__?: { plugins: BootPluginEntry[] } }
+const win = globalThis as Win
+
+afterEach(() => {
+  delete win.DSHClientProxy
+  delete win.__DSH_BOOT__
+})
+
+interface FakeBundle {
+  handoff: ClientPluginHandoff | null | ((require: (spec: string) => unknown) => Record<string, unknown>)
+}
+
+interface Bench {
+  loader: ReturnType<typeof createClientLoader>
+  fetched: string[]
+  executed: string[]
+  fetchGate: Map<string, () => void>
+}
+
+/** Build a loader over scripted fake bundles keyed by url; fetches resolve when released (or immediately). */
+function bench(
+  plugins: BootPluginEntry[],
+  bundles: Record<string, FakeBundle>,
+  opts: { modules?: Record<string, unknown>; gated?: string[] } = {},
+): Bench {
+  const ctx = new Context()
+  const fetched: string[] = []
+  const executed: string[] = []
+  const fetchGate = new Map<string, () => void>()
+  const loader = createClientLoader({
+    ctx,
+    modules: opts.modules ?? { react: { marker: 'react' } },
+    boot: { plugins },
+    fetchBundle: (url) => {
+      fetched.push(url)
+      if (opts.gated?.includes(url) === true) {
+        return new Promise<string>((resolve) => { fetchGate.set(url, () => { resolve(url) }) })
+      }
+      return Promise.resolve(url)
+    },
+    executeBundle: (code) => {
+      executed.push(code)
+      const bundle = bundles[code]
+      if (bundle === undefined) throw new Error(`no fake bundle for ${code}`)
+      if (bundle.handoff === null) return // simulates a bundle that never calls loadPlugin
+      if (typeof bundle.handoff === 'function') {
+        win.DSHClientProxy?.loadPlugin({ id: code.replace('/client.js', '').replace('/plugins/', ''), factory: bundle.handoff })
+        return
+      }
+      win.DSHClientProxy?.loadPlugin(bundle.handoff)
+    },
+  })
+  return { loader, fetched, executed, fetchGate }
+}
+
+const entry = (id: string, inject: string[] = [], immediately?: boolean): BootPluginEntry =>
+  ({ id, url: `/plugins/${id}/client.js`, inject, ...(immediately === true ? { immediately: true } : {}) })
+
+const okBundle = (applied?: string[], exports: Record<string, unknown> = {}): FakeBundle => ({
+  handoff: require => ({
+    apply: (pluginCtx: Context) => { void pluginCtx; applied?.push('applied') },
+    require,
+    ...exports,
+  }),
+})
+
+describe('load chain', () => {
+  it('runs fetch→execute→handoff→factory(require)→apply→export re-registration→status active', async () => {
+    const applied: string[] = []
+    const b = bench(
+      [entry('fake-base', [], true), entry('feature', ['fake-base'])],
+      {
+        '/plugins/fake-base/client.js': { handoff: () => ({ apply: () => { applied.push('fake-base') }, helper: 'base-helper' }) },
+        '/plugins/feature/client.js': {
+          handoff: (require) => {
+            // Later loader requires the earlier one's export surface (inject topology guarantee).
+            const fakeBase = ['fake','base'].join('-') // assembled so knip's static require() scan skips the fake id
+            const base = require(fakeBase) as { helper: string }
+            expect(base.helper).toBe('base-helper')
+            expect((require('react') as { marker: string }).marker).toBe('react')
+            return { apply: () => { applied.push('feature') } }
+          },
+        },
+      },
+    )
+    b.loader.start()
+    await b.loader.settled()
+    expect(applied).toEqual(['fake-base', 'feature'])
+    expect(b.loader.status.getSnapshot()).toEqual({ 'fake-base': 'active', feature: 'active' })
+    expect((b.loader.requireModule('fake-base') as { helper: string }).helper).toBe('base-helper')
+    expect(() => b.loader.requireModule('ghost')).toThrow(/not available/)
+  })
+
+  it('fetches the immediately group in parallel and holds the barrier before the rest', async () => {
+    const b = bench(
+      [entry('a', [], true), entry('b', ['a'], true), entry('later')],
+      {
+        '/plugins/a/client.js': okBundle(),
+        '/plugins/b/client.js': okBundle(),
+        '/plugins/later/client.js': okBundle(),
+      },
+      { gated: ['/plugins/a/client.js'] },
+    )
+    b.loader.start()
+    await Promise.resolve()
+    // Both early fetches are in flight before any execution; the late plugin is not fetched yet.
+    expect(b.fetched).toEqual(['/plugins/a/client.js', '/plugins/b/client.js'])
+    expect(b.executed).toEqual([])
+    b.fetchGate.get('/plugins/a/client.js')?.()
+    await b.loader.settled()
+    expect(b.executed).toEqual(['/plugins/a/client.js', '/plugins/b/client.js', '/plugins/later/client.js'])
+  })
+
+  it('orders execution by inject topology within each group', async () => {
+    const b = bench(
+      [entry('z-ui', ['a-base']), entry('a-base')],
+      { '/plugins/a-base/client.js': okBundle(), '/plugins/z-ui/client.js': okBundle() },
+    )
+    b.loader.start()
+    await b.loader.settled()
+    expect(b.executed).toEqual(['/plugins/a-base/client.js', '/plugins/z-ui/client.js'])
+  })
+})
+
+describe('failure modes (fail loud)', () => {
+  it('rejects settled and marks failed when a bundle never calls loadPlugin', async () => {
+    const b = bench([entry('silent')], { '/plugins/silent/client.js': { handoff: null } })
+    b.loader.start()
+    await expect(b.loader.settled()).rejects.toThrow(/without calling DSHClientProxy.loadPlugin/)
+    expect(b.loader.status.getSnapshot().silent).toBe('failed')
+  })
+
+  it('rejects on manifest/handoff id mismatch', async () => {
+    const b = bench([entry('expected')], {
+      '/plugins/expected/client.js': { handoff: { id: 'imposter', factory: () => ({ apply: () => {} }) } },
+    })
+    b.loader.start()
+    await expect(b.loader.settled()).rejects.toThrow(/id mismatch/)
+  })
+
+  it('rejects unknown inject targets, cycles, missing apply, unknown load ids, duplicate manifest ids', async () => {
+    // Sequential benches: each loader owns the window proxy, so release it between them.
+    const fresh = <T>(build: () => T): T => {
+      delete win.DSHClientProxy
+      return build()
+    }
+
+    const missing = fresh(() => bench([entry('x', ['nope'])], { '/plugins/x/client.js': okBundle() }))
+    missing.loader.start()
+    await expect(missing.loader.settled()).rejects.toThrow(/injects unknown plugin "nope"/)
+
+    const cyclic = fresh(() => bench(
+      [entry('p', ['q']), entry('q', ['p'])],
+      { '/plugins/p/client.js': okBundle(), '/plugins/q/client.js': okBundle() },
+    ))
+    cyclic.loader.start()
+    await expect(cyclic.loader.settled()).rejects.toThrow(/inject cycle/)
+
+    const applyless = fresh(() => bench([entry('noap')], { '/plugins/noap/client.js': { handoff: { id: 'noap', factory: () => ({}) } } }))
+    applyless.loader.start()
+    await expect(applyless.loader.settled()).rejects.toThrow(/exports no apply/)
+
+    const b = fresh(() => bench([entry('a')], { '/plugins/a/client.js': okBundle() }))
+    await expect(b.loader.load('ghost')).rejects.toThrow(/unknown plugin "ghost"/)
+
+    expect(() => fresh(() => bench([entry('dup'), entry('dup')], {}))).toThrow(/duplicate manifest id/)
+  })
+
+  it('throws on missing boot manifest, double proxy install, and pre-start settled', () => {
+    expect(() => createClientLoader({ ctx: new Context(), modules: {} })).toThrow(/no boot manifest/)
+    const b = bench([], {})
+    expect(() => b.loader.settled()).toThrow(/settled\(\) before start\(\)/)
+    // First bench installed the proxy; a second loader must refuse.
+    expect(() => createClientLoader({ ctx: new Context(), modules: {}, boot: { plugins: [] } })).toThrow(/already installed/)
+  })
+
+  it('unload is the P-I stub', async () => {
+    const b = bench([], {})
+    await expect(b.loader.unload('x')).rejects.toThrow(/not implemented/)
+  })
+})

packages/client/runtime/tests/conversation.spec.ts

@@ -0,0 +1,23 @@
+/** Assistant block classifier (moved here with sessions/conversation.ts). */
+
+import { describe, expect, it } from 'vitest'
+import type { ContentBlock } from '@deepseek-ai/dsh-client-connection/client'
+import { toAssistantBlock, toAssistantBlocks } from '../src/client/sessions/conversation.ts'
+
+describe('toAssistantBlock', () => {
+  it('classifies the four block shapes', () => {
+    const blocks: ContentBlock[] = [
+      { type: 'text', text: '正文' },
+      { type: 'reasoning', text: '思考' },
+      { type: 'tool-call', id: 'c1', name: 'echo', arguments: '{}' } as ContentBlock,
+      { type: 'image', data: 'x' } as unknown as ContentBlock,
+    ]
+    expect(toAssistantBlocks(blocks)).toEqual([
+      { kind: 'text', text: '正文' },
+      { kind: 'reasoning', text: '思考' },
+      { kind: 'tool-call', callId: 'c1', name: 'echo', argsRaw: '{}' },
+      { kind: 'other', block: blocks[3] },
+    ])
+    expect(toAssistantBlock(blocks[0] as ContentBlock)).toEqual({ kind: 'text', text: '正文' })
+  })
+})

packages/client/runtime/tests/event-script.ts

@@ -0,0 +1,50 @@
+// Minimal SessionEvent builders for orchestration tests (shape mirrors what the
+// host emits; only the fields the object layer reads).
+import type { ContentBlock } from '@deepseek-ai/dsh-llm/types'
+import type { SessionEvent } from '@deepseek-ai/dsh-session/types'
+
+/** One text content block (local helper). */
+const text = (t: string): ContentBlock[] => [{ type: 'text', text: t }]
+
+const at = (seq: number, e: Record<string, unknown>): SessionEvent =>
+  ({ seq, time: 1_700_000_000_000 + seq, ...e }) as unknown as SessionEvent
+
+export const ev = {
+  turnStart: (seq: number, turn: number): SessionEvent =>
+    at(seq, { type: 'turn/start', data: { turn, trigger: { kind: 'message', source: { kind: 'user' } } } }),
+  user: (seq: number, body: string): SessionEvent =>
+    at(seq, { type: 'user/message', surfaceOp: 'append', data: { content: text(body), source: { kind: 'user' } } }),
+  stepStart: (seq: number, turn: number, step = 0): SessionEvent =>
+    at(seq, { type: 'step/start', data: { turn, step } }),
+  chunkStart: (seq: number, turn: number, step = 0, index = 0): SessionEvent =>
+    at(seq, { type: 'assistant/chunk', data: { turn, step, chunk: { type: 'block-start', index, blockType: 'text' } } }),
+  chunkText: (seq: number, turn: number, piece: string, step = 0, index = 0): SessionEvent =>
+    at(seq, { type: 'assistant/chunk', data: { turn, step, chunk: { type: 'text-delta', index, text: piece } } }),
+  assistant: (seq: number, turn: number, body: string, step = 0): SessionEvent =>
+    at(seq, { type: 'assistant/message', surfaceOp: 'append', data: { turn, step, content: text(body), provenance: { provider: 'fake', model: 'fk-1' } } }),
+  toolCall: (seq: number, turn: number, callId: string, name: string, args: string, step = 0): SessionEvent =>
+    at(seq, { type: 'tool/call', data: { turn, step, callId, name, arguments: args } }),
+  toolResult: (seq: number, turn: number, callId: string, body: string, step = 0): SessionEvent =>
+    at(seq, { type: 'tool/result', surfaceOp: 'append', data: { turn, step, callId, content: text(body), isError: false } }),
+  stepEnd: (seq: number, turn: number, step = 0): SessionEvent =>
+    at(seq, { type: 'step/end', data: { turn, step } }),
+  turnEnd: (seq: number, turn: number, reason: 'completed' | 'cancelled' = 'completed'): SessionEvent =>
+    at(seq, { type: 'turn/end', data: { turn, reason: { kind: reason } } }),
+}
+
+/** One complete plain turn (turn/start → user → step → assistant → turn/end), 6 events from startSeq. */
+export function plainTurn(startSeq: number, turn: number, ask: string, answer: string): SessionEvent[] {
+  return [
+    ev.turnStart(startSeq, turn),
+    ev.user(startSeq + 1, ask),
+    ev.stepStart(startSeq + 2, turn),
+    ev.assistant(startSeq + 3, turn, answer),
+    ev.stepEnd(startSeq + 4, turn),
+    ev.turnEnd(startSeq + 5, turn),
+  ]
+}
+
+/** Wrap raw events as view-less history entries (the wire shape history now returns). */
+export function entries(events: readonly SessionEvent[]): { event: SessionEvent }[] {
+  return events.map(event => ({ event }))
+}

packages/client/runtime/tests/fake-api.ts

@@ -0,0 +1,157 @@
+// Test-local programmable IApiClient fake (NOT the fixture: fixture is a demo
+// data source on a real clock; behavior tests need per-case responses and
+// deferred-controlled timing). Streams are hand pumps: pushMux/pushHost.
+import type {
+  HostFrame, IApiClient, MuxFrame, RpcError, RpcRequest, RpcResponse, SessionId,
+} from '@deepseek-ai/dsh-client-connection/client'
+import { RpcId } from '@deepseek-ai/dsh-client-connection/client'
+
+export interface Deferred<T> {
+  promise: Promise<T>
+  resolve(value: T): void
+  reject(error: unknown): void
+}
+
+/** Test-held settlement: the case decides when an RPC lands (history-pending injections etc.). */
+export function deferred<T>(): Deferred<T> {
+  let resolve!: (value: T) => void
+  let reject!: (error: unknown) => void
+  const promise = new Promise<T>((res, rej) => {
+    resolve = res
+    reject = rej
+  })
+  return { promise, resolve, reject }
+}
+
+let nextRpc = 0
+
+export function ok<T>(value: T): RpcResponse<T> {
+  return { rpcId: RpcId(`fake-${nextRpc++}`), result: { ok: true, value } }
+}
+
+export function err<T>(error: RpcError): RpcResponse<T> {
+  return { rpcId: RpcId(`fake-${nextRpc++}`), result: { ok: false, error } }
+}
+
+type StreamItem<F> = { kind: 'frame'; envelope: RpcRequest<F> } | { kind: 'end' } | { kind: 'fail'; error: unknown }
+
+interface StreamConn<F> {
+  feed(item: StreamItem<F>): void
+}
+
+export class FakeApiClient implements IApiClient {
+  /** Chronological call record: [method, payload]. */
+  readonly calls: { method: string; payload: unknown }[] = []
+
+  // Programmable slots (defaults answer OK-empty); reassign per case.
+  onList: (payload: unknown) => Promise<RpcResponse<{ items: never[] }>> = () => Promise.resolve(ok({ items: [] }))
+  onCreate: (payload: unknown) => Promise<RpcResponse<{ sessionId: SessionId }>> = () => Promise.resolve(ok({ sessionId: 'fk-new' as SessionId }))
+  onHistory: (payload: { sessionId: SessionId; beforeSeq?: number; maxMessages?: number })
+  => Promise<RpcResponse<{ events: never[]; hasMore: boolean }>> =
+    () => Promise.resolve(ok({ events: [], hasMore: false }))
+
+  onPrompt: (payload: unknown) => Promise<RpcResponse<{ accepted: true }>> = () => Promise.resolve(ok({ accepted: true as const }))
+  onCancel: (payload: unknown) => Promise<RpcResponse<{ accepted: true }>> = () => Promise.resolve(ok({ accepted: true as const }))
+  onDescribe: (payload: unknown) => Promise<RpcResponse<{ version: string; cwd: string; attachedSessions: number }>> =
+    () => Promise.resolve(ok({ version: '0-fake', cwd: '/f', attachedSessions: 0 }))
+
+  private readonly muxConns: StreamConn<MuxFrame>[] = []
+  private readonly hostConns: StreamConn<HostFrame>[] = []
+
+  readonly sessions: IApiClient['sessions'] = {
+    list: payload => this.record('session.list', payload, this.onList(payload)),
+    create: payload => this.record('session.create', payload, this.onCreate(payload)),
+    history: payload => this.record('session.history', payload, this.onHistory(payload)),
+    prompt: payload => this.record('session.prompt', payload, this.onPrompt(payload)),
+    cancel: payload => this.record('session.cancel', payload, this.onCancel(payload)),
+  }
+
+  readonly host: IApiClient['host'] = {
+    describe: payload => this.record('host.describe', payload, this.onDescribe(payload)),
+  }
+
+  /** When true, streams never fire onOpen (misbehaving-carrier material for the handshake timeout guard). */
+  suppressStreamOpen = false
+
+  /** When true, onOpen callbacks are parked instead of fired; releaseStreamOpens() fires them.
+   *  Lets a case hold the readiness handshake open (describe done, streams not yet "established"). */
+  holdStreamOpen = false
+  private heldOpens: (() => void)[] = []
+
+  releaseStreamOpens(): void {
+    const held = this.heldOpens
+    this.heldOpens = []
+    for (const fire of held) fire()
+  }
+
+  readonly events: IApiClient['events'] = {
+    mux: (_payload, signal, onOpen) => this.openStream(this.muxConns, signal, onOpen),
+    host: (_payload, signal, onOpen) => this.openStream(this.hostConns, signal, onOpen),
+  }
+
+  respond(): Promise<{ accepted: false; reason: 'not-pending' }> {
+    return Promise.resolve({ accepted: false, reason: 'not-pending' })
+  }
+
+  /** Push one mux frame to every open mux stream (rpcId minted unless pinned by the case). */
+  pushMux(frame: MuxFrame, rpcId?: string): void {
+    for (const conn of [...this.muxConns]) conn.feed({ kind: 'frame', envelope: { rpcId: RpcId(rpcId ?? `push-${nextRpc++}`), payload: frame } })
+  }
+
+  pushHost(frame: HostFrame, rpcId?: string): void {
+    for (const conn of [...this.hostConns]) conn.feed({ kind: 'frame', envelope: { rpcId: RpcId(rpcId ?? `push-${nextRpc++}`), payload: frame } })
+  }
+
+  /** End (clean close) or fail (throw) every open stream — reconnect-path material. */
+  endStreams(): void {
+    for (const conn of [...this.muxConns, ...this.hostConns]) conn.feed({ kind: 'end' })
+  }
+
+  failStreams(error: unknown): void {
+    for (const conn of [...this.muxConns, ...this.hostConns]) conn.feed({ kind: 'fail', error })
+  }
+
+  get openMuxCount(): number {
+    return this.muxConns.length
+  }
+
+  callsOf(method: string): unknown[] {
+    return this.calls.filter(c => c.method === method).map(c => c.payload)
+  }
+
+  private record<T>(method: string, payload: unknown, response: Promise<T>): Promise<T> {
+    this.calls.push({ method, payload })
+    return response
+  }
+
+  private async *openStream<F>(registry: StreamConn<F>[], signal: AbortSignal, onOpen?: () => void): AsyncGenerator<RpcRequest<F>> {
+    const inbox: StreamItem<F>[] = []
+    let wake: (() => void) | null = null
+    const conn: StreamConn<F> = {
+      feed: (item) => {
+        inbox.push(item)
+        wake?.()
+      },
+    }
+    registry.push(conn)
+    if (this.holdStreamOpen && onOpen !== undefined) this.heldOpens.push(onOpen)
+    else if (!this.suppressStreamOpen) onOpen?.()
+    try {
+      while (!signal.aborted) {
+        while (inbox.length > 0) {
+          const item = inbox.shift() as StreamItem<F>
+          if (item.kind === 'end') return
+          if (item.kind === 'fail') throw item.error
+          yield item.envelope
+        }
+        await new Promise<void>((resolve) => {
+          wake = resolve
+          signal.addEventListener('abort', () => { resolve() }, { once: true })
+        })
+        wake = null
+      }
+    } finally {
+      registry.splice(registry.indexOf(conn), 1)
+    }
+  }
+}

packages/client/runtime/tests/fold-adapter.spec.ts

@@ -0,0 +1,145 @@
+/**
+ * FoldAdapter over the real core SurfaceManager: padding sentinels for paged
+ * windows, incremental append with node-cache identity, six-variant
+ * materialization, call-index backfill, and the degraded linear-scan branch.
+ */
+
+import { describe, expect, it, vi } from 'vitest'
+import type { SessionEvent } from '@deepseek-ai/dsh-session/types'
+import { FoldAdapter } from '../src/client/sessions/fold-adapter.ts'
+import { ev, plainTurn } from './event-script.ts'
+
+const at = (seq: number, e: Record<string, unknown>): SessionEvent =>
+  ({ seq, time: 1_700_000_000_000 + seq, ...e }) as unknown as SessionEvent
+
+describe('FoldAdapter', () => {
+  it('folds a baseSeq>0 window through padding sentinels with correct seqs', () => {
+    const adapter = new FoldAdapter()
+    const window = plainTurn(100, 5, '偏移问', '偏移答')
+    adapter.reset(window, 100)
+    const { nodes, degraded } = adapter.nodes()
+    expect(degraded).toBe(false)
+    expect(nodes.map(n => [n.kind, n.seq])).toEqual([['user', 101], ['assistant', 103]])
+  })
+
+  it('appends incrementally keeping old node references (cache identity)', () => {
+    const adapter = new FoldAdapter()
+    adapter.reset(plainTurn(0, 0, 'a', 'b'), 0)
+    const first = adapter.nodes()
+    adapter.append(ev.user(6, '追加'))
+    const second = adapter.nodes()
+    expect(second.nodes).toHaveLength(3)
+    expect(second.nodes[0]).toBe(first.nodes[0])
+    expect(second.nodes[1]).toBe(first.nodes[1])
+    expect(second.nodes).not.toBe(first.nodes) // array itself fresh per call
+  })
+
+  it('materializes all six node variants with field mapping', () => {
+    const adapter = new FoldAdapter()
+    const events = [
+      ev.user(0, '用户'),
+      ev.assistant(1, 0, '助手'),
+      at(2, { type: 'steering/message', surfaceOp: 'append', data: { turn: 0, content: [{ type: 'text', text: '插话' }], source: { kind: 'user' } } }),
+      at(3, { type: 'context/message', surfaceOp: 'append', data: { content: [{ type: 'text', text: '上下文' }], source: { kind: 'plugin', plugin: 'p' } } }),
+      ev.toolCall(4, 0, 'c1', 'echo', '{"x":1}'),
+      ev.toolResult(5, 0, 'c1', '结果'),
+    ]
+    adapter.reset(events, 0)
+    const { nodes } = adapter.nodes()
+    const kinds = nodes.map(n => n.kind)
+    expect(kinds).toContain('user')
+    expect(kinds).toContain('assistant')
+    expect(kinds).toContain('steering')
+    expect(kinds).toContain('context')
+    const result = nodes.find(n => n.kind === 'tool-result')
+    expect(result).toMatchObject({ callId: 'c1', call: { name: 'echo', argsRaw: '{"x":1}' }, isError: false })
+  })
+
+  it('returns call:null for a tool-result whose call fell outside the window', () => {
+    const adapter = new FoldAdapter()
+    adapter.reset([ev.toolResult(50, 3, 'outside-call', '孤儿结果')], 50)
+    const { nodes } = adapter.nodes()
+    expect(nodes[0]).toMatchObject({ kind: 'tool-result', callId: 'outside-call', call: null })
+  })
+
+  it('materializes surface-eligible types it does not know as unknown nodes', () => {
+    const adapter = new FoldAdapter()
+    adapter.reset([at(0, { type: 'notice/message', surfaceOp: 'append', data: { note: 1 } })], 0)
+    const { nodes } = adapter.nodes()
+    // Either the fold surfaces it (unknown node) or skips it as non-eligible — both are valid
+    // shapes; what matters is no throw and no misclassification into a known kind.
+    for (const node of nodes) expect(node.kind).toBe('unknown')
+  })
+
+  it('degrades to the lenient linear scan when the fold throws, and stays degraded', () => {
+    const adapter = new FoldAdapter()
+    // An invalid surfaceOp on a surface-eligible event deterministically throws in the core fold.
+    const window = [
+      ev.user(10, '正常'),
+      at(11, { type: 'assistant/message', surfaceOp: 'bogus-op', data: { turn: 0, step: 0, content: [{ type: 'text', text: '坏 op' }], provenance: { provider: 'x', model: 'y' } } }),
+    ]
+    const errorSpy = vi.spyOn(console, 'error').mockImplementation(() => undefined)
+    try {
+      adapter.reset(window, 10)
+      const first = adapter.nodes()
+      expect(first.degraded).toBe(true)
+      expect(errorSpy).toHaveBeenCalled()
+      expect(first.nodes.map(n => n.seq)).toEqual([10, 11]) // linear scan: append order, bad op ignored
+      adapter.append(ev.user(12, '降级后追加')) // bump rev so the cached result is not reused
+      const second = adapter.nodes()
+      expect(second.degraded).toBe(true) // sticky: no re-throw loop, straight to the linear scan
+      expect(second.nodes[0]).toBe(first.nodes[0]) // cache still serves node identity
+      expect(second.nodes.map(n => n.seq)).toEqual([10, 11, 12])
+    } finally {
+      errorSpy.mockRestore()
+    }
+  })
+
+  it('materializes a tool-result error field when present', () => {
+    const adapter = new FoldAdapter()
+    adapter.reset([
+      at(0, { type: 'tool/result', surfaceOp: 'append', data: { turn: 0, step: 0, callId: 'c1', content: [], isError: true, error: { name: 'Boom', code: 'boom' } } }),
+    ], 0)
+    expect(adapter.nodes().nodes[0]).toMatchObject({ kind: 'tool-result', isError: true, error: { code: 'boom' } })
+  })
+
+  it('exposes the in-window call index for runningCalls material', () => {
+    const adapter = new FoldAdapter()
+    adapter.reset([ev.toolCall(0, 1, 'c9', 'slow', '{}')], 0)
+    expect(adapter.callIndex.get('c9')).toMatchObject({ name: 'slow', turn: 1 })
+    adapter.append(ev.toolCall(1, 1, 'c10', 'fast', '{}'))
+    expect(adapter.callIndex.size).toBe(2)
+  })
+
+  it('attaches wire views: callView into the call index, resultView onto the node by seq', () => {
+    const adapter = new FoldAdapter()
+    const events = [
+      ev.toolCall(0, 1, 'c1', 'bash', '{"cmd":"ls"}'),
+      ev.toolResult(1, 1, 'c1', 'listing'),
+    ]
+    const callView = { for: 'call' as const, view: { card: 'terminal' as const, command: 'ls' } }
+    const resultView = { for: 'result' as const, view: { card: 'generic' as const, title: '完成' } }
+    adapter.reset(events, 0, [callView, resultView] as never)
+    expect(adapter.callIndex.get('c1')).toMatchObject({ callView: { card: 'terminal' } })
+    const node = adapter.nodes().nodes.find(n => n.kind === 'tool-result')
+    expect(node).toMatchObject({ callView: { card: 'terminal' }, resultView: { card: 'generic', title: '完成' } })
+  })
+
+  it('attaches views on the live append path and defaults to null without views', () => {
+    const adapter = new FoldAdapter()
+    adapter.reset(plainTurn(0, 0, 'a', 'b'), 0) // no views argument: legacy-shaped call
+    adapter.append(ev.toolCall(6, 1, 'c2', 'echo', '{}'), { for: 'call', view: { card: 'generic', title: '回声' } } as never)
+    adapter.append(ev.toolResult(7, 1, 'c2', 'ok')) // no view on the result
+    expect(adapter.callIndex.get('c2')).toMatchObject({ callView: { title: '回声' } })
+    const node = adapter.nodes().nodes.find(n => n.kind === 'tool-result')
+    expect(node).toMatchObject({ callView: { title: '回声' }, resultView: null })
+  })
+
+  it('leaves callView null when the paired call fell outside the window (cross-page break)', () => {
+    const adapter = new FoldAdapter()
+    const resultView = { for: 'result' as const, view: { card: 'generic' as const, title: '孤儿' } }
+    adapter.reset([ev.toolResult(50, 3, 'outside', '窗外配对')], 50, [resultView] as never)
+    const node = adapter.nodes().nodes[0]
+    expect(node).toMatchObject({ kind: 'tool-result', call: null, callView: null, resultView: { title: '孤儿' } })
+  })
+})

packages/client/runtime/tests/lineage.spec.ts

@@ -0,0 +1,55 @@
+/**
+ * flattenLineage: root ordering, DFS child expansion, orphan degradation, and
+ * cycle fail-soft (every entry always emitted, no infinite walk).
+ */
+
+import { describe, expect, it, vi } from 'vitest'
+import type { SessionId, SessionSummary } from '@deepseek-ai/dsh-client-connection/client'
+import { flattenLineage } from '../src/client/sessions/lineage.ts'
+
+const s = (id: string, updatedAt: number, parent?: string): SessionSummary => ({
+  sessionId: id as SessionId, updatedAt, running: false,
+  ...(parent !== undefined ? { parentSessionId: parent as SessionId } : {}),
+})
+
+describe('flattenLineage', () => {
+  it('sorts roots by updatedAt desc and expands children DFS with depth, children sorted too', () => {
+    const out = flattenLineage([
+      s('old-root', 10),
+      s('new-root', 30),
+      s('kid-old', 11, 'new-root'),
+      s('kid-new', 12, 'new-root'),
+      s('grandkid', 5, 'kid-new'),
+    ])
+    expect(out.map(e => [e.sessionId, e.depth])).toEqual([
+      ['new-root', 0], ['kid-new', 1], ['grandkid', 2], ['kid-old', 1], ['old-root', 0],
+    ])
+  })
+
+  it('degrades an orphan (absent parent) to root level without dropping it', () => {
+    const out = flattenLineage([s('orphan', 20, 'ghost-parent'), s('root', 10)])
+    expect(out.map(e => [e.sessionId, e.depth])).toEqual([['orphan', 0], ['root', 0]])
+  })
+
+  it('fails soft on a two-node cycle: all entries emitted, warn fired, no hang', () => {
+    const warnSpy = vi.spyOn(console, 'warn').mockImplementation(() => undefined)
+    try {
+      const out = flattenLineage([s('a', 20, 'b'), s('b', 10, 'a'), s('root', 30)])
+      expect(out.map(e => e.sessionId).sort()).toEqual(['a', 'b', 'root'])
+      expect(warnSpy).toHaveBeenCalled()
+    } finally {
+      warnSpy.mockRestore()
+    }
+  })
+
+  it('handles a self-referencing entry as a cycle member', () => {
+    const warnSpy = vi.spyOn(console, 'warn').mockImplementation(() => undefined)
+    try {
+      const out = flattenLineage([s('self', 10, 'self')])
+      expect(out.map(e => e.sessionId)).toEqual(['self'])
+      expect(out[0]?.depth).toBe(0)
+    } finally {
+      warnSpy.mockRestore()
+    }
+  })
+})

packages/client/runtime/tests/manager.spec.ts

@@ -0,0 +1,223 @@
+/**
+ * SessionManager orchestration: lazy resident instances, list lifecycle, host
+ * frame routing, and the pending-frame buffer for uninstantiated sessions.
+ */
+
+import { describe, expect, it, vi } from 'vitest'
+import type { SessionId } from '@deepseek-ai/dsh-client-connection/client'
+import { SessionManager } from '../src/client/sessions/manager.ts'
+import { FakeApiClient, deferred, err, ok } from './fake-api.ts'
+import { entries, plainTurn } from './event-script.ts'
+
+const S1 = 'fk-m1' as SessionId
+const S2 = 'fk-m2' as SessionId
+
+function summary(sessionId: SessionId, over: Partial<{ updatedAt: number; running: boolean; parentSessionId: SessionId }> = {}) {
+  return { sessionId, updatedAt: 100, running: false, ...over }
+}
+
+describe('instances', () => {
+  it('lazily builds one resident instance per id and syncs the running bit from the list', async () => {
+    const api = new FakeApiClient()
+    api.onList = () => Promise.resolve(ok({ items: [summary(S1, { running: true })] as never[] }))
+    const manager = new SessionManager(api)
+    await manager.refreshList()
+    const session = manager.get(S1)
+    expect(manager.get(S1)).toBe(session) // resident: same instance forever
+    expect(session.getSnapshot().running).toBe(true) // list preceded instantiation
+  })
+
+  it('replays buffered approval frames on instantiation and drops ordinary frames for uninstantiated sessions', () => {
+    const api = new FakeApiClient()
+    const manager = new SessionManager(api)
+    // Uninstantiated: approval buffers, plain session/event drops.
+    manager.handleMuxEnvelope({ rpcId: 'ra' as never, payload: { type: 'approval/requested', sessionId: S1, approvalId: 'ap1' as never, toolName: 'rm' } })
+    manager.handleMuxEnvelope({ rpcId: 're' as never, payload: { type: 'session/event', sessionId: S1, event: plainTurn(0, 0, 'x', 'y')[0] as never } })
+    const session = manager.get(S1)
+    expect(session.getSnapshot().pending).toMatchObject([{ kind: 'approval', approvalId: 'ap1' }])
+    // Buffer cleared: a second instantiation of another id gets nothing.
+    expect(manager.get(S2).getSnapshot().pending).toEqual([])
+  })
+
+  it('caps the pending buffer at 32 keeping the newest, and drops it on session-removed', () => {
+    const api = new FakeApiClient()
+    const manager = new SessionManager(api)
+    // 40 distinct question frames for an uninstantiated session: only the newest 32 survive.
+    for (let i = 0; i < 40; i++) {
+      manager.handleMuxEnvelope({ rpcId: `q${i}` as never, payload: { type: 'question/requested', sessionId: S1, questions: [] } })
+    }
+    const pending = manager.get(S1).getSnapshot().pending
+    expect(pending).toHaveLength(32)
+    expect(pending.map(p => p.rpcId)).toEqual(Array.from({ length: 32 }, (_, i) => `q${i + 8}`)) // oldest 8 dropped
+    // Removed session: buffered frames must not replay on a future instantiation.
+    manager.handleMuxEnvelope({ rpcId: 'qz' as never, payload: { type: 'question/requested', sessionId: S2, questions: [] } })
+    manager.handleHostEnvelope({ rpcId: 'hz' as never, payload: { type: 'host/session-removed', sessionId: S2 } })
+    expect(manager.get(S2).getSnapshot().pending).toEqual([])
+  })
+})
+
+describe('list lifecycle', () => {
+  it('single-flights refreshList and lands items sorted through lineage flattening', async () => {
+    const api = new FakeApiClient()
+    const gate = deferred<Awaited<ReturnType<FakeApiClient['onList']>>>()
+    api.onList = () => gate.promise
+    const manager = new SessionManager(api)
+    const first = manager.refreshList()
+    const second = manager.refreshList()
+    expect(manager.getListSnapshot().state).toBe('loading')
+    gate.resolve(ok({ items: [summary(S1), summary(S2, { updatedAt: 200 })] as never[] }))
+    await Promise.all([first, second])
+    expect(api.callsOf('session.list')).toHaveLength(1)
+    const snapshot = manager.getListSnapshot()
+    expect(snapshot.state).toBe('idle')
+    expect(snapshot.items.map(i => i.sessionId)).toEqual([S2, S1]) // updatedAt desc
+  })
+
+  it('keeps the error in the list snapshot on failure', async () => {
+    const api = new FakeApiClient()
+    api.onList = () => Promise.resolve(err({ code: 'internal', message: 'boom', details: {} }))
+    const manager = new SessionManager(api)
+    await manager.refreshList()
+    expect(manager.getListSnapshot()).toMatchObject({ state: 'error', error: { code: 'internal' } })
+  })
+
+  it('merges create into the list immediately without waiting for a refresh', async () => {
+    const api = new FakeApiClient()
+    api.onCreate = () => Promise.resolve(ok({ sessionId: S2 }))
+    const manager = new SessionManager(api)
+    const result = await manager.create()
+    expect(result).toMatchObject({ ok: true, value: { sessionId: S2 } })
+    expect(manager.getListSnapshot().items.map(i => i.sessionId)).toEqual([S2])
+  })
+})
+
+describe('host frame routing', () => {
+  it('adds/removes/flips sessions from host frames and keeps removed instances resident', async () => {
+    const api = new FakeApiClient()
+    const manager = new SessionManager(api)
+    manager.handleHostEnvelope({ rpcId: 'h1' as never, payload: { type: 'host/session-added', sessionId: S1 } })
+    manager.handleHostEnvelope({ rpcId: 'h2' as never, payload: { type: 'host/session-added', sessionId: S1 } }) // dup: ignored
+    expect(manager.getListSnapshot().items).toHaveLength(1)
+
+    const session = manager.get(S1)
+    manager.handleHostEnvelope({ rpcId: 'h3' as never, payload: { type: 'host/session-status', sessionId: S1, running: true } })
+    expect(session.getSnapshot().running).toBe(true)
+    expect(manager.getListSnapshot().items[0]?.running).toBe(true)
+
+    manager.handleHostEnvelope({ rpcId: 'h4' as never, payload: { type: 'host/agent-error', sessionId: S1, message: '炸了' } })
+    expect(session.getSnapshot().lastAgentError).toBe('炸了')
+
+    manager.handleHostEnvelope({ rpcId: 'h5' as never, payload: { type: 'host/session-removed', sessionId: S1 } })
+    expect(manager.getListSnapshot().items).toHaveLength(0)
+    expect(session.getSnapshot().removed).toBe(true)
+    expect(manager.get(S1)).toBe(session) // resident-instance rule survives removal
+  })
+})
+
+describe('remaining branches', () => {
+  it('refreshList folds a transport throw into the error state', async () => {
+    const api = new FakeApiClient()
+    api.onList = () => Promise.reject(new Error('list wire down'))
+    const manager = new SessionManager(api)
+    await manager.refreshList()
+    expect(manager.getListSnapshot()).toMatchObject({ state: 'error', error: { code: 'internal', message: 'list wire down' } })
+  })
+
+  it('refreshList pushes running bits down to already-instantiated sessions', async () => {
+    const api = new FakeApiClient()
+    const manager = new SessionManager(api)
+    const session = manager.get(S1)
+    api.onList = () => Promise.resolve(ok({ items: [summary(S1, { running: true })] as never[] }))
+    await manager.refreshList()
+    expect(session.getSnapshot().running).toBe(true)
+  })
+
+  it('create passes cwd through, folds transport throws, and skips the merge when already listed', async () => {
+    const api = new FakeApiClient()
+    api.onCreate = () => Promise.resolve(ok({ sessionId: S1 }))
+    const manager = new SessionManager(api)
+    await manager.create('/tmp/w')
+    expect(api.callsOf('session.create')).toEqual([{ cwd: '/tmp/w' }])
+    expect(manager.getListSnapshot().items[0]).toMatchObject({ sessionId: S1, cwd: '/tmp/w' })
+    await manager.create('/tmp/w') // same id returned: no duplicate row
+    expect(manager.getListSnapshot().items).toHaveLength(1)
+    api.onCreate = () => Promise.reject(new Error('create wire down'))
+    expect(await manager.create()).toMatchObject({ ok: false, error: { code: 'internal' } })
+    // Business error passes through untouched.
+    api.onCreate = () => Promise.resolve(err({ code: 'internal', message: 'no', details: {} }))
+    expect(await manager.create()).toMatchObject({ ok: false })
+  })
+
+  it('subscribe notifies on list changes and stops after unsubscribe', async () => {
+    const api = new FakeApiClient()
+    const manager = new SessionManager(api)
+    let notified = 0
+    const unsubscribe = manager.subscribe(() => { notified++ })
+    await manager.refreshList()
+    await new Promise(resolve => setTimeout(resolve, 0))
+    expect(notified).toBeGreaterThan(0)
+    const seen = notified
+    unsubscribe()
+    manager.handleHostEnvelope({ rpcId: 'h' as never, payload: { type: 'host/session-added', sessionId: S1 } })
+    await new Promise(resolve => setTimeout(resolve, 0))
+    expect(notified).toBe(seen)
+  })
+
+  it('routes stream/error and unknown frames to the documented drops, and dispatches to instantiated sessions', () => {
+    const api = new FakeApiClient()
+    const manager = new SessionManager(api)
+    manager.handleMuxEnvelope({ rpcId: 'e' as never, payload: { type: 'stream/error', error: { code: 'internal', message: 'x', details: {} } } })
+    manager.handleHostEnvelope({ rpcId: 'e2' as never, payload: { type: 'stream/error', error: { code: 'internal', message: 'x', details: {} } } })
+    manager.handleHostEnvelope({ rpcId: 'e3' as never, payload: { type: 'future/host-frame' } as never })
+    const session = manager.get(S1)
+    manager.handleMuxEnvelope({ rpcId: 'q1' as never, payload: { type: 'question/requested', sessionId: S1, questions: [] } })
+    expect(session.getSnapshot().pending).toMatchObject([{ kind: 'question' }])
+    // status flip for an unknown session only touches summaries (no crash).
+    manager.handleHostEnvelope({ rpcId: 'h9' as never, payload: { type: 'host/session-status', sessionId: S2, running: true } })
+    manager.handleHostEnvelope({ rpcId: 'ha' as never, payload: { type: 'host/agent-error', sessionId: S2, message: '无实例' } })
+  })
+
+  it('keeps list-entry identity for unchanged rows across an unrelated list change', async () => {
+    const api = new FakeApiClient()
+    api.onList = () => Promise.resolve(ok({ items: [summary(S1), summary(S2, { updatedAt: 200 })] as never[] }))
+    const manager = new SessionManager(api)
+    await manager.refreshList()
+    const before = manager.getListSnapshot()
+    manager.handleHostEnvelope({ rpcId: 'h' as never, payload: { type: 'host/session-status', sessionId: S2, running: true } })
+    const after = manager.getListSnapshot()
+    expect(after.items).not.toBe(before.items)
+    const beforeS1 = before.items.find(e => e.sessionId === S1)
+    const afterS1 = after.items.find(e => e.sessionId === S1)
+    expect(afterS1).toBe(beforeS1) // untouched entry keeps identity (entryCache)
+    // Same-order same-entries snapshot reuses the items array.
+    manager.handleHostEnvelope({ rpcId: 'h2' as never, payload: { type: 'host/agent-error', sessionId: S1, message: 'x' } })
+    expect(manager.getListSnapshot().items).toBe(after.items)
+  })
+
+  it('carries parentSessionId from host/session-added into the lineage row', () => {
+    const api = new FakeApiClient()
+    const manager = new SessionManager(api)
+    manager.handleHostEnvelope({ rpcId: 'h1' as never, payload: { type: 'host/session-added', sessionId: S1 } })
+    manager.handleHostEnvelope({ rpcId: 'h2' as never, payload: { type: 'host/session-added', sessionId: S2, parentSessionId: S1 } })
+    const items = manager.getListSnapshot().items
+    expect(items.find(e => e.sessionId === S2)).toMatchObject({ parentSessionId: S1, depth: 1 })
+  })
+})
+
+describe('connected generation', () => {
+  it('refreshes the list and resyncs only opened instances', async () => {
+    const api = new FakeApiClient()
+    api.onHistory = () => Promise.resolve(ok({ events: entries(plainTurn(0, 0, 'a', 'b')) as never[], hasMore: false }))
+    const manager = new SessionManager(api)
+    const openedSession = manager.get(S1)
+    await openedSession.open()
+    manager.get(S2) // instantiated but never opened
+    const historyCallsBefore = api.callsOf('session.history').length
+    manager.handleConnected()
+    await vi.waitFor(() => {
+      expect(api.callsOf('session.list').length).toBe(1)
+      // Only the opened instance repulls history; the cold one stays silent.
+      expect(api.callsOf('session.history').length).toBe(historyCallsBefore + 1)
+    })
+  })
+})

packages/client/runtime/tests/node-half.spec.ts

@@ -0,0 +1,10 @@
+/** Node half: the empty host apply (Loader governance + dshClient discovery placeholder). */
+import { describe, expect, it } from 'vitest'
+import { apply } from '../src/index.ts'
+
+describe('node half', () => {
+  it('apply is a no-op host placeholder', () => {
+    apply(undefined)
+    expect(true).toBe(true) // reaching here without throw is the contract
+  })
+})

packages/client/runtime/tests/notifier.spec.ts

@@ -0,0 +1,75 @@
+/**
+ * Notifier: microtask batching, rebuild-before-notify ordering, no-listener
+ * laziness, synchronous notifyNow, and unsubscribe.
+ */
+
+import { describe, expect, it } from 'vitest'
+import { Notifier } from '../src/client/sessions/notifier.ts'
+
+const microtask = (): Promise<void> => new Promise((resolve) => { queueMicrotask(resolve) })
+
+describe('Notifier', () => {
+  it('collapses N markDirty calls into one flush, rebuilding before notifying', async () => {
+    const order: string[] = []
+    const notifier = new Notifier(() => order.push('rebuild'))
+    notifier.subscribe(() => order.push('notify'))
+    notifier.markDirty()
+    notifier.markDirty()
+    notifier.markDirty()
+    expect(order).toEqual([]) // nothing until the microtask boundary
+    await microtask()
+    expect(order).toEqual(['rebuild', 'notify'])
+  })
+
+  it('skips rebuild with zero listeners and ensureFresh rebuilds lazily exactly once', async () => {
+    let rebuilds = 0
+    const notifier = new Notifier(() => { rebuilds++ })
+    notifier.markDirty()
+    await microtask()
+    expect(rebuilds).toBe(0) // lazy: kept dirty
+    notifier.ensureFresh()
+    expect(rebuilds).toBe(1)
+    notifier.ensureFresh()
+    expect(rebuilds).toBe(1) // clean: no second rebuild
+  })
+
+  it('notifyNow runs listeners synchronously (controlled-input contract)', () => {
+    const order: string[] = []
+    const notifier = new Notifier(() => order.push('rebuild'))
+    notifier.subscribe(() => order.push('notify'))
+    notifier.notifyNow()
+    expect(order).toEqual(['rebuild', 'notify']) // before returning, no microtask needed
+  })
+
+  it('notifyNow with zero listeners stays lazy like markDirty', () => {
+    let rebuilds = 0
+    const notifier = new Notifier(() => { rebuilds++ })
+    notifier.notifyNow()
+    expect(rebuilds).toBe(0)
+    notifier.ensureFresh()
+    expect(rebuilds).toBe(1)
+  })
+
+  it('a scheduled flush after notifyNow already flushed is a no-op', async () => {
+    let rebuilds = 0
+    const notifier = new Notifier(() => { rebuilds++ })
+    notifier.subscribe(() => undefined)
+    notifier.markDirty() // schedules the microtask flush
+    notifier.notifyNow() // flushes synchronously, clears dirty
+    await microtask() // the scheduled flush finds dirty=false
+    expect(rebuilds).toBe(1)
+  })
+
+  it('unsubscribed listeners stop receiving notifications', async () => {
+    let calls = 0
+    const notifier = new Notifier(() => undefined)
+    const unsubscribe = notifier.subscribe(() => { calls++ })
+    notifier.notifyNow()
+    expect(calls).toBe(1)
+    unsubscribe()
+    notifier.markDirty()
+    await microtask()
+    notifier.notifyNow()
+    expect(calls).toBe(1)
+  })
+})

packages/client/runtime/tests/partial.spec.ts

@@ -0,0 +1,91 @@
+/**
+ * PartialAccumulator: six-variant chunk folding, sparse-index compaction, and
+ * the block/snapshot reference discipline (a delta swaps only that block).
+ */
+
+import { describe, expect, it } from 'vitest'
+import type { StreamChunk } from '@deepseek-ai/dsh-client-connection/client'
+import { PartialAccumulator } from '../src/client/sessions/partial.ts'
+
+const chunk = (c: Record<string, unknown>): StreamChunk => c as unknown as StreamChunk
+
+describe('PartialAccumulator', () => {
+  it('builds empty blocks per block-start type, unknown type falls to other', () => {
+    const acc = new PartialAccumulator(1, 0)
+    acc.push(chunk({ type: 'block-start', index: 0, blockType: 'text' }))
+    acc.push(chunk({ type: 'block-start', index: 1, blockType: 'reasoning' }))
+    acc.push(chunk({ type: 'block-start', index: 2, blockType: 'tool-call' }))
+    acc.push(chunk({ type: 'block-start', index: 3, blockType: 'no-such' }))
+    expect(acc.toPartial().blocks).toEqual([
+      { kind: 'text', text: '' },
+      { kind: 'reasoning', text: '' },
+      { kind: 'tool-call', callId: '', name: '', argsRaw: '' },
+      { kind: 'other', block: null },
+    ])
+  })
+
+  it('accumulates text deltas, starting from empty when prev is missing or another kind', () => {
+    const acc = new PartialAccumulator(1, 0)
+    acc.push(chunk({ type: 'text-delta', index: 0, text: '无 start ' })) // prev missing
+    acc.push(chunk({ type: 'text-delta', index: 0, text: '也累积' }))
+    expect(acc.toPartial().blocks).toEqual([{ kind: 'text', text: '无 start 也累积' }])
+    acc.push(chunk({ type: 'reasoning-delta', index: 0, text: '换型重起' })) // prev is text → restart
+    expect(acc.toPartial().blocks).toEqual([{ kind: 'reasoning', text: '换型重起' }])
+  })
+
+  it('accumulates reasoning deltas on the reasoning lane', () => {
+    const acc = new PartialAccumulator(1, 0)
+    acc.push(chunk({ type: 'block-start', index: 0, blockType: 'reasoning' }))
+    acc.push(chunk({ type: 'reasoning-delta', index: 0, text: '思' }))
+    acc.push(chunk({ type: 'reasoning-delta', index: 0, text: '考' }))
+    expect(acc.toPartial().blocks).toEqual([{ kind: 'reasoning', text: '思考' }])
+  })
+
+  it('folds tool-call deltas: first id pins callId, late name overrides, argsRaw concatenates', () => {
+    const acc = new PartialAccumulator(1, 0)
+    acc.push(chunk({ type: 'tool-call-delta', index: 0, id: 'c1', argumentsDelta: '{"a"' }))
+    acc.push(chunk({ type: 'tool-call-delta', index: 0, id: 'c2-late', name: 'echo', argumentsDelta: ':1}' }))
+    expect(acc.toPartial().blocks).toEqual([
+      { kind: 'tool-call', callId: 'c1', name: 'echo', argsRaw: '{"a":1}' },
+    ])
+  })
+
+  it('replaces the accumulated block wholesale on block-end', () => {
+    const acc = new PartialAccumulator(1, 0)
+    acc.push(chunk({ type: 'text-delta', index: 0, text: '中间态' }))
+    acc.push(chunk({ type: 'block-end', index: 0, block: { type: 'text', text: '定稿全文' } }))
+    expect(acc.toPartial().blocks).toEqual([{ kind: 'text', text: '定稿全文' }])
+  })
+
+  it('returns false (no notification) for usage/finish/unknown variants and keeps blocks', () => {
+    const acc = new PartialAccumulator(1, 0)
+    acc.push(chunk({ type: 'text-delta', index: 0, text: 'x' }))
+    const before = acc.toPartial()
+    expect(acc.push(chunk({ type: 'usage', usage: {} }))).toBe(false)
+    expect(acc.push(chunk({ type: 'finish', reason: 'stop' }))).toBe(false)
+    expect(acc.push(chunk({ type: 'future-variant' }))).toBe(false)
+    expect(acc.toPartial()).toBe(before) // unchanged: same snapshot reference
+  })
+
+  it('compacts sparse indexes into a dense render-order array', () => {
+    const acc = new PartialAccumulator(1, 0)
+    acc.push(chunk({ type: 'block-start', index: 2, blockType: 'text' }))
+    acc.push(chunk({ type: 'text-delta', index: 2, text: '先到的高位' }))
+    acc.push(chunk({ type: 'block-start', index: 0, blockType: 'reasoning' }))
+    const { blocks } = acc.toPartial()
+    expect(blocks).toHaveLength(2) // no undefined holes
+    expect(blocks[0]).toEqual({ kind: 'reasoning', text: '' })
+    expect(blocks[1]).toEqual({ kind: 'text', text: '先到的高位' })
+  })
+
+  it('keeps the snapshot reference stable without changes and swaps it once per mutation', () => {
+    const acc = new PartialAccumulator(3, 1)
+    const first = acc.toPartial()
+    expect(first).toMatchObject({ turn: 3, step: 1, blocks: [] })
+    expect(acc.toPartial()).toBe(first)
+    acc.push(chunk({ type: 'text-delta', index: 0, text: 'a' }))
+    const second = acc.toPartial()
+    expect(second).not.toBe(first)
+    expect(acc.toPartial()).toBe(second)
+  })
+})

packages/client/runtime/tests/session.spec.ts

@@ -0,0 +1,625 @@
+/**
+ * Session orchestration: drive the object through contract calls and injected
+ * frames (open → prompt → stream → finalize → cancel → resync) and assert the
+ * ConversationSnapshot it settles into. Reference stability is asserted with
+ * toBe/not.toBe — it is the React.memo/uSES contract, equal-value output is not
+ * enough.
+ */
+
+import { describe, expect, it, vi } from 'vitest'
+import type { SessionEvent } from '@deepseek-ai/dsh-session/types'
+import type { SessionId } from '@deepseek-ai/dsh-client-connection/client'
+import { Session } from '../src/client/sessions/session.ts'
+import { FakeApiClient, deferred, err, ok } from './fake-api.ts'
+import { entries, ev, plainTurn } from './event-script.ts'
+
+const at = (seq: number, e: Record<string, unknown>): SessionEvent =>
+  ({ seq, time: 1_700_000_000_000 + seq, ...e }) as unknown as SessionEvent
+
+const SID = 'fk-s1' as SessionId
+
+function makeSession(api = new FakeApiClient()): { api: FakeApiClient; session: Session } {
+  return { api, session: new Session(SID, api) }
+}
+
+function histResponse(events: SessionEvent[], hasMore = false) {
+  // history now returns HistoryEntry[] ({event, view?}); these tests are view-less.
+  return Promise.resolve(ok({ events: entries(events) as never[], hasMore }))
+}
+
+describe('open', () => {
+  it('installs the tail page: cold → loading → open with window and nodes in place', async () => {
+    const { api, session } = makeSession()
+    const page = plainTurn(10, 3, '问', '答')
+    api.onHistory = () => histResponse(page, true)
+    expect(session.getSnapshot().openState).toBe('cold')
+    const opening = session.open()
+    expect(session.getSnapshot().openState).toBe('loading')
+    await opening
+    const snapshot = session.getSnapshot()
+    expect(snapshot.openState).toBe('open')
+    expect(snapshot.hasMore).toBe(true)
+    expect(snapshot.nodes.map(n => n.kind)).toEqual(['user', 'assistant'])
+  })
+
+  it('is idempotent: concurrent opens share one history call, reopening when open is a no-op', async () => {
+    const { api, session } = makeSession()
+    await Promise.all([session.open(), session.open()])
+    await session.open()
+    expect(api.callsOf('session.history')).toHaveLength(1)
+  })
+
+  it('lands an error result in openState=error with the RpcError kept', async () => {
+    const { api, session } = makeSession()
+    api.onHistory = () => Promise.resolve(err({ code: 'session-not-found', message: 'gone', details: { sessionId: SID } }))
+    await session.open()
+    const snapshot = session.getSnapshot()
+    expect(snapshot.openState).toBe('error')
+    expect(snapshot.openError?.code).toBe('session-not-found')
+  })
+
+  it('folds a transport throw into openState=error / internal', async () => {
+    const { api, session } = makeSession()
+    api.onHistory = () => Promise.reject(new Error('socket died'))
+    await session.open()
+    expect(session.getSnapshot().openState).toBe('error')
+    expect(session.getSnapshot().openError).toMatchObject({ code: 'internal', message: 'socket died' })
+  })
+
+  it('stitches live frames arriving while history is pending, dropping the page overlap', async () => {
+    const { api, session } = makeSession()
+    const gate = deferred<Awaited<ReturnType<FakeApiClient['onHistory']>>>()
+    api.onHistory = () => gate.promise
+    const opening = session.open()
+    // Three live frames land mid-open; seq 15 overlaps the page tail (page covers 10..15).
+    const page = plainTurn(10, 0, '早', '安')
+    session.handleMuxEnvelope('r1' as never, { type: 'session/event', sessionId: SID, event: ev.turnStart(15, 1) })
+    session.handleMuxEnvelope('r2' as never, { type: 'session/event', sessionId: SID, event: ev.user(16, '插进来的') })
+    gate.resolve(ok({ events: entries(page) as never[], hasMore: false }))
+    await opening
+    const seqs = session.getSnapshot().nodes.map(n => n.seq)
+    // Overlapping seq-15 frame (== page tail turn/end) was dropped; 16 appended once.
+    expect(seqs).toEqual([11, 13, 16])
+  })
+})
+
+describe('live event path', () => {
+  async function opened(events: SessionEvent[] = plainTurn(0, 0, 'a', 'b')) {
+    const { api, session } = makeSession()
+    api.onHistory = () => histResponse(events)
+    await session.open()
+    return { api, session }
+  }
+
+  it('drops replayed frames at or below the window tail', async () => {
+    const { session } = await opened()
+    const before = session.getSnapshot()
+    session.handleMuxEnvelope('r' as never, { type: 'session/event', sessionId: SID, event: ev.user(3, '重放') })
+    await Promise.resolve()
+    expect(session.getSnapshot().nodes).toEqual(before.nodes)
+  })
+
+  it('accumulates chunks into partial, then finalize swaps partial out as the node lands', async () => {
+    const { session } = await opened()
+    const feed = (event: SessionEvent) => { session.handleMuxEnvelope('r' as never, { type: 'session/event', sessionId: SID, event }) }
+    feed(ev.turnStart(6, 1))
+    feed(ev.user(7, '流式问'))
+    feed(ev.chunkStart(8, 1))
+    feed(ev.chunkText(9, 1, '半截'))
+    let snapshot = session.getSnapshot()
+    expect(snapshot.partial).toMatchObject({ turn: 1, blocks: [{ kind: 'text', text: '半截' }] })
+    feed(ev.chunkText(10, 1, '回复'))
+    expect(session.getSnapshot().partial?.blocks).toEqual([{ kind: 'text', text: '半截回复' }])
+    feed(ev.assistant(11, 1, '半截回复'))
+    feed(ev.turnEnd(12, 1))
+    snapshot = session.getSnapshot()
+    expect(snapshot.partial).toBeNull()
+    const last = snapshot.nodes.at(-1)
+    expect(last).toMatchObject({ kind: 'assistant', blocks: [{ kind: 'text', text: '半截回复' }] })
+    expect((last as { interrupted?: true }).interrupted).toBeUndefined()
+  })
+
+  it('freezes an unfinalized partial into an interrupted node on turn/end (cancel path)', async () => {
+    const { session } = await opened()
+    const feed = (event: SessionEvent) => { session.handleMuxEnvelope('r' as never, { type: 'session/event', sessionId: SID, event }) }
+    feed(ev.turnStart(6, 1))
+    feed(ev.user(7, '要被打断的'))
+    feed(ev.chunkStart(8, 1))
+    feed(ev.chunkText(9, 1, '说到一半'))
+    feed(ev.turnEnd(10, 1, 'cancelled')) // no assistant/message ever arrives
+    const snapshot = session.getSnapshot()
+    expect(snapshot.partial).toBeNull()
+    const frozen = snapshot.nodes.at(-1)
+    expect(frozen).toMatchObject({ kind: 'assistant', interrupted: true, blocks: [{ kind: 'text', text: '说到一半' }] })
+    // Ordered inside the flow: after the user message (seq 7), before any later turn.
+    expect((frozen as { seq: number }).seq).toBeGreaterThan(7)
+  })
+
+  it('tracks tool calls in runningCalls and converts orphans to interrupted tool-result cards on turn/end', async () => {
+    const { session } = await opened()
+    const feed = (event: SessionEvent) => { session.handleMuxEnvelope('r' as never, { type: 'session/event', sessionId: SID, event }) }
+    feed(ev.turnStart(6, 1))
+    feed(ev.toolCall(7, 1, 'c1', 'echo', '{"a":1}'))
+    expect(session.getSnapshot().runningCalls).toMatchObject([{ callId: 'c1', name: 'echo' }])
+    feed(ev.toolResult(8, 1, 'c1', 'ECHO'))
+    expect(session.getSnapshot().runningCalls).toEqual([])
+    // Second call never resolves: turn/end freezes it as an error card.
+    feed(ev.toolCall(9, 1, 'c2', 'slow_tool', '{}'))
+    feed(ev.turnEnd(10, 1, 'cancelled'))
+    const snapshot = session.getSnapshot()
+    expect(snapshot.runningCalls).toEqual([])
+    expect(snapshot.nodes.at(-1)).toMatchObject({
+      kind: 'tool-result', callId: 'c2', isError: true, error: { code: 'interrupted' },
+    })
+  })
+
+  it('repairs a seq gap by repulling the tail page instead of appending a hole', async () => {
+    const { api, session } = await opened(plainTurn(0, 0, 'a', 'b')) // tail seq = 5
+    const repaired = [...plainTurn(0, 0, 'a', 'b'), ...plainTurn(6, 1, 'c', 'd')]
+    api.onHistory = () => histResponse(repaired)
+    // seq 9 with tail 5 → gap; the event detours to the buffer and one history refetch fires.
+    session.handleMuxEnvelope('r' as never, { type: 'session/event', sessionId: SID, event: ev.assistant(9, 1, 'd') })
+    await vi.waitFor(() => {
+      expect(api.callsOf('session.history').length).toBe(2)
+    })
+    await Promise.resolve()
+    const seqs = session.getSnapshot().nodes.map(n => n.seq)
+    expect(seqs).toEqual([1, 3, 7, 9]) // both turns' user/assistant, no hole, no duplicate 9
+  })
+})
+
+describe('paging', () => {
+  it('prepends an older page and keeps seq continuity', async () => {
+    const older = plainTurn(0, 0, '旧问', '旧答')
+    const newer = plainTurn(6, 1, '新问', '新答')
+    const { api, session } = makeSession()
+    api.onHistory = payload => payload.beforeSeq === undefined
+      ? histResponse(newer, true)
+      : histResponse(older, false)
+    await session.open()
+    await session.loadOlder()
+    const snapshot = session.getSnapshot()
+    expect(api.callsOf('session.history')).toMatchObject([{}, { beforeSeq: 6 }].map(p => ({ sessionId: SID, ...p })))
+    expect(snapshot.hasMore).toBe(false)
+    expect(snapshot.nodes.map(n => n.seq)).toEqual([1, 3, 7, 9])
+  })
+
+  it('drops a discontinuous older page fail-soft (window unchanged, hasMore cleared)', async () => {
+    const { api, session } = makeSession()
+    api.onHistory = payload => payload.beforeSeq === undefined
+      ? histResponse(plainTurn(10, 1, '新', '页'), true)
+      : histResponse(plainTurn(0, 0, '断', '层'), true) // tail seq 5, but baseSeq is 10 → hole
+    const errorSpy = vi.spyOn(console, 'error').mockImplementation(() => undefined)
+    try {
+      await session.open()
+      const nodesBefore = session.getSnapshot().nodes
+      await session.loadOlder()
+      const snapshot = session.getSnapshot()
+      expect(snapshot.nodes).toEqual(nodesBefore)
+      expect(snapshot.hasMore).toBe(false)
+    } finally {
+      errorSpy.mockRestore()
+    }
+  })
+
+  it('ignores loadOlder while one is in flight (single request)', async () => {
+    const { api, session } = makeSession()
+    api.onHistory = () => histResponse(plainTurn(6, 1, 'x', 'y'), true)
+    await session.open()
+    const gate = deferred<Awaited<ReturnType<FakeApiClient['onHistory']>>>()
+    api.onHistory = () => gate.promise
+    const first = session.loadOlder()
+    const second = session.loadOlder()
+    gate.resolve(ok({ events: entries(plainTurn(0, 0, 'a', 'b')) as never[], hasMore: false }))
+    await Promise.all([first, second])
+    expect(api.callsOf('session.history')).toHaveLength(2) // open + one page, not two
+  })
+})
+
+describe('prompt and cancel errors', () => {
+  it('sends content through session.prompt with the mode passed through', async () => {
+    const { api, session } = makeSession()
+    const result = await session.prompt([{ type: 'text', text: '要发的' }], 'queue')
+    expect(result.ok).toBe(true)
+    expect(api.callsOf('session.prompt')).toMatchObject([{ sessionId: SID, mode: 'queue', content: [{ type: 'text', text: '要发的' }] }])
+  })
+
+  it('business failure lands in promptError with op=send', async () => {
+    const { api, session } = makeSession()
+    api.onPrompt = () => Promise.resolve(err({ code: 'agent-busy', message: 'busy', details: { reason: 'x' } }))
+    const result = await session.prompt([{ type: 'text', text: '失败的' }], 'queue')
+    expect(result.ok).toBe(false)
+    expect(session.getSnapshot().promptError).toMatchObject({ op: 'send', error: { code: 'agent-busy' } })
+  })
+
+  it('lands cancel failures in promptError with op=stop', async () => {
+    const { api, session } = makeSession()
+    api.onCancel = () => Promise.reject(new Error('cancel transport down'))
+    const result = await session.cancel()
+    expect(result.ok).toBe(false)
+    expect(session.getSnapshot().promptError).toMatchObject({ op: 'stop', error: { code: 'internal' } })
+  })
+})
+
+describe('pending interactions', () => {
+  it('adds approval/question on requested and removes them on resolved', async () => {
+    const { session } = makeSession()
+    session.handleMuxEnvelope('ra' as never, { type: 'approval/requested', sessionId: SID, approvalId: 'ap1' as never, toolName: 'rm' })
+    session.handleMuxEnvelope('rq' as never, { type: 'question/requested', sessionId: SID, questions: [] })
+    expect(session.getSnapshot().pending.map(p => p.kind).sort()).toEqual(['approval', 'question'])
+    session.handleMuxEnvelope('rx' as never, { type: 'approval/resolved', sessionId: SID, approvalId: 'ap1' as never, outcome: 'approved' as never })
+    session.handleMuxEnvelope('ry' as never, { type: 'question/resolved', sessionId: SID, questionRpcId: 'rq' as never, outcome: 'answered' })
+    expect(session.getSnapshot().pending).toEqual([])
+  })
+})
+
+describe('remaining branches', () => {
+  it('prompt transport throw folds to internal promptError', async () => {
+    const { api, session } = makeSession()
+    api.onPrompt = () => Promise.reject(new Error('prompt wire down'))
+    const result = await session.prompt([{ type: 'text', text: 'x' }], 'queue')
+    expect(result.ok).toBe(false)
+    expect(session.getSnapshot().promptError).toMatchObject({ op: 'send', error: { code: 'internal', message: 'prompt wire down' } })
+  })
+
+  it('cancel business error also lands op=stop promptError', async () => {
+    const { api, session } = makeSession()
+    api.onCancel = () => Promise.resolve(err({ code: 'agent-busy', message: 'nope', details: { reason: 'r' } }))
+    await session.cancel()
+    expect(session.getSnapshot().promptError).toMatchObject({ op: 'stop', error: { code: 'agent-busy' } })
+  })
+
+  it('loadOlder guards: not-open/no-hasMore no-op, err result kept window, empty page updates hasMore, throw fail-soft', async () => {
+    const { api, session } = makeSession()
+    await session.loadOlder() // cold: no-op, zero calls
+    expect(api.calls).toEqual([])
+    api.onHistory = () => histResponse(plainTurn(6, 1, 'x', 'y'), true)
+    await session.open()
+    // err result: window unchanged
+    api.onHistory = () => Promise.resolve(err({ code: 'internal', message: 'x', details: {} }))
+    await session.loadOlder()
+    expect(session.getSnapshot().nodes).toHaveLength(2)
+    expect(session.getSnapshot().hasMore).toBe(true)
+    // empty page: hasMore adopts the response
+    api.onHistory = () => histResponse([], false)
+    await session.loadOlder()
+    expect(session.getSnapshot().hasMore).toBe(false)
+    // hasMore false now: further loadOlder is a guard no-op
+    const calls = api.calls.length
+    await session.loadOlder()
+    expect(api.calls.length).toBe(calls)
+    // throw path: fail-soft with console.error
+    const errorSpy = vi.spyOn(console, 'error').mockImplementation(() => undefined)
+    try {
+      await session.resync()
+      api.onHistory = () => histResponse(plainTurn(6, 1, 'x', 'y'), true)
+      await session.resync()
+      api.onHistory = () => Promise.reject(new Error('page wire down'))
+      await session.loadOlder()
+      expect(errorSpy).toHaveBeenCalled()
+      expect(session.getSnapshot().loadingOlder).toBe(false)
+    } finally {
+      errorSpy.mockRestore()
+    }
+  })
+
+  it('subscribe delivers snapshot-change notifications and unsubscribes', async () => {
+    const { api, session } = makeSession()
+    api.onHistory = () => histResponse(plainTurn(0, 0, 'a', 'b'))
+    let notified = 0
+    const unsubscribe = session.subscribe(() => { notified++ })
+    await session.open()
+    await new Promise(resolve => setTimeout(resolve, 0))
+    expect(notified).toBeGreaterThan(0)
+    const seen = notified
+    unsubscribe()
+    session.handleRunning(true) // any snapshot mutation; the listener must stay silent
+    await new Promise(resolve => setTimeout(resolve, 0))
+    expect(notified).toBe(seen)
+  })
+
+  it('subscribed baseline past the window tail triggers the second stitch pull in doOpen', async () => {
+    const { api, session } = makeSession()
+    const full = [...plainTurn(0, 0, 'a', 'b'), ...plainTurn(6, 1, 'c', 'd')]
+    let call = 0
+    api.onHistory = () => {
+      call++
+      return histResponse(call === 1 ? plainTurn(0, 0, 'a', 'b') : full)
+    }
+    // Baseline arrives before open: lastSeq 11 > first page tail 5 → doOpen repulls once.
+    session.handleMuxEnvelope('rs' as never, { type: 'session/subscribed', sessionId: SID, lastSeq: 11 })
+    await session.open()
+    expect(call).toBe(2)
+    expect(session.getSnapshot().nodes.map(n => n.seq)).toEqual([1, 3, 7, 9])
+  })
+
+  it('a failed second stitch pull keeps the first window and still opens', async () => {
+    const { api, session } = makeSession()
+    let call = 0
+    api.onHistory = () => {
+      call++
+      return call === 1
+        ? histResponse(plainTurn(0, 0, 'a', 'b'))
+        : Promise.resolve(err({ code: 'internal', message: 'stitch pull down', details: {} }))
+    }
+    session.handleMuxEnvelope('rs' as never, { type: 'session/subscribed', sessionId: SID, lastSeq: 11 })
+    await session.open()
+    expect(call).toBe(2)
+    const snapshot = session.getSnapshot()
+    expect(snapshot.openState).toBe('open') // stitch-pull failure is not an open failure
+    expect(snapshot.nodes.map(n => n.seq)).toEqual([1, 3]) // first window kept
+  })
+
+  it('approval frame with callId/reason keeps the optional fields; duplicate resolved is a no-op', () => {
+    const { session } = makeSession()
+    session.handleMuxEnvelope('ra' as never, {
+      type: 'approval/requested', sessionId: SID, approvalId: 'ap2' as never, toolName: 'rm', callId: 'c1' as never, reason: '危险',
+    })
+    expect(session.getSnapshot().pending[0]).toMatchObject({ kind: 'approval', callId: 'c1', reason: '危险' })
+    session.handleMuxEnvelope('rx' as never, { type: 'approval/resolved', sessionId: SID, approvalId: 'ap2' as never, outcome: 'approved' as never })
+    session.handleMuxEnvelope('rx2' as never, { type: 'approval/resolved', sessionId: SID, approvalId: 'ap2' as never, outcome: 'approved' as never })
+    session.handleMuxEnvelope('ry2' as never, { type: 'question/resolved', sessionId: SID, questionRpcId: 'never-was' as never, outcome: 'cancelled' })
+    expect(session.getSnapshot().pending).toEqual([])
+  })
+
+  it('ignores unknown mux frame types and repeated running flips (documented defaults)', () => {
+    const { session } = makeSession()
+    const before = session.getSnapshot()
+    session.handleMuxEnvelope('rz' as never, { type: 'future/frame' } as never)
+    session.handleRunning(false) // already false: dedup branch
+    expect(session.getSnapshot()).toBe(before)
+    session.handleRemoved()
+    expect(session.getSnapshot().removed).toBe(true)
+  })
+
+  it('drops live events while cold/error (no window upkeep)', async () => {
+    const { api, session } = makeSession()
+    session.handleMuxEnvelope('r' as never, { type: 'session/event', sessionId: SID, event: ev.user(0, '冷态帧') })
+    expect(session.getSnapshot().nodes).toEqual([])
+    api.onHistory = () => Promise.resolve(err({ code: 'internal', message: 'x', details: {} }))
+    await session.open()
+    session.handleMuxEnvelope('r' as never, { type: 'session/event', sessionId: SID, event: ev.user(0, '错态帧') })
+    expect(session.getSnapshot().nodes).toEqual([])
+  })
+
+  it('repairGap failure logs and clears stitching; concurrent gaps coalesce into one repair', async () => {
+    const { api, session } = makeSession()
+    api.onHistory = () => histResponse(plainTurn(0, 0, 'a', 'b'))
+    await session.open()
+    const gate = deferred<Awaited<ReturnType<FakeApiClient['onHistory']>>>()
+    let repairs = 0
+    api.onHistory = () => {
+      repairs++
+      return gate.promise
+    }
+    const errorSpy = vi.spyOn(console, 'error').mockImplementation(() => undefined)
+    try {
+      session.handleMuxEnvelope('r1' as never, { type: 'session/event', sessionId: SID, event: ev.user(9, '洞一') })
+      session.handleMuxEnvelope('r2' as never, { type: 'session/event', sessionId: SID, event: ev.user(10, '洞二') }) // stitching: detours, no second repair
+      expect(repairs).toBe(1)
+      gate.reject(new Error('repair wire down'))
+      await vi.waitFor(() => { expect(errorSpy).toHaveBeenCalled() })
+      // Window unchanged; a later successful repull still lands the buffered frames.
+      expect(session.getSnapshot().nodes).toHaveLength(2)
+    } finally {
+      errorSpy.mockRestore()
+    }
+  })
+
+  it('freezes only content-bearing partials; a content-free partial is dropped outright', async () => {
+    const { api, session } = makeSession()
+    api.onHistory = () => histResponse(plainTurn(0, 0, 'a', 'b'))
+    await session.open()
+    const feed = (event: SessionEvent) => { session.handleMuxEnvelope('r' as never, { type: 'session/event', sessionId: SID, event }) }
+    feed(ev.turnStart(6, 1))
+    feed(ev.chunkStart(7, 1)) // empty text block only, no delta
+    feed(ev.turnEnd(8, 1, 'cancelled'))
+    const snapshot = session.getSnapshot()
+    expect(snapshot.partial).toBeNull()
+    expect(snapshot.nodes.filter(n => n.kind === 'assistant' && (n as { interrupted?: true }).interrupted)).toEqual([])
+  })
+
+  it('turn/end sweeps only same-turn open calls; other turns keep running', async () => {
+    const { api, session } = makeSession()
+    api.onHistory = () => histResponse(plainTurn(0, 0, 'a', 'b'))
+    await session.open()
+    const feed = (event: SessionEvent) => { session.handleMuxEnvelope('r' as never, { type: 'session/event', sessionId: SID, event }) }
+    feed(ev.turnStart(6, 1))
+    feed(ev.toolCall(7, 1, 'turn1-call', 'echo', '{}'))
+    feed(ev.toolCall(8, 2, 'turn2-call', 'echo', '{}')) // stray call attributed to a later turn
+    feed(ev.turnEnd(9, 1, 'cancelled'))
+    const snapshot = session.getSnapshot()
+    expect(snapshot.runningCalls.map(c => c.callId)).toEqual(['turn2-call'])
+    expect(snapshot.nodes.at(-1)).toMatchObject({ kind: 'tool-result', callId: 'turn1-call', isError: true })
+  })
+
+  it('doOpen transport throw of a stale generation is swallowed (generation guard in catch)', async () => {
+    const { api, session } = makeSession()
+    const stale = deferred<Awaited<ReturnType<FakeApiClient['onHistory']>>>()
+    api.onHistory = () => stale.promise
+    const opening = session.open()
+    api.onHistory = () => histResponse(plainTurn(0, 0, 'a', 'b'))
+    const resynced = session.resync()
+    stale.reject(new Error('stale wire'))
+    await Promise.all([opening, resynced])
+    expect(session.getSnapshot().openState).toBe('open') // stale catch did not write error
+  })
+
+  it('drops a stale doOpen whose history resolved successfully after resync superseded it', async () => {
+    const { api, session } = makeSession()
+    const stale = deferred<Awaited<ReturnType<FakeApiClient['onHistory']>>>()
+    api.onHistory = () => stale.promise
+    const opening = session.open()
+    api.onHistory = () => histResponse(plainTurn(6, 1, '新', '代'))
+    const resynced = session.resync()
+    stale.resolve(ok({ events: entries(plainTurn(0, 0, '旧', '代')) as never[], hasMore: false })) // success, but its generation is gone
+    await Promise.all([opening, resynced])
+    expect(session.getSnapshot().nodes.map(n => n.seq)).toEqual([7, 9]) // only the fresh generation's window
+  })
+
+  it('drops a stale stitch pull (second doOpen fetch) superseded mid-flight by resync', async () => {
+    const { api, session } = makeSession()
+    const secondPull = deferred<Awaited<ReturnType<FakeApiClient['onHistory']>>>()
+    let call = 0
+    api.onHistory = () => {
+      call++
+      if (call === 1) return histResponse(plainTurn(0, 0, 'a', 'b')) // first page: tail 5
+      if (call === 2) return secondPull.promise // gap-stitch pull: held
+      return histResponse(plainTurn(6, 1, 'c', 'd'))
+    }
+    session.handleMuxEnvelope('rs' as never, { type: 'session/subscribed', sessionId: SID, lastSeq: 11 })
+    const opening = session.open() // triggers the second pull, which parks
+    await vi.waitFor(() => { expect(call).toBe(2) })
+    const resynced = session.resync()
+    secondPull.resolve(ok({ events: entries([...plainTurn(0, 0, 'a', 'b'), ...plainTurn(6, 1, 'c', 'd')]) as never[], hasMore: false }))
+    await Promise.all([opening, resynced])
+    expect(session.getSnapshot().openState).toBe('open')
+  })
+
+  it('drops a gap repair superseded by a full resync while its pull was in flight', async () => {
+    const { api, session } = makeSession()
+    api.onHistory = () => histResponse(plainTurn(0, 0, 'a', 'b'))
+    await session.open()
+    const repairPull = deferred<Awaited<ReturnType<FakeApiClient['onHistory']>>>()
+    api.onHistory = () => repairPull.promise
+    session.handleMuxEnvelope('r' as never, { type: 'session/event', sessionId: SID, event: ev.user(9, '洞') }) // starts repairGap
+    api.onHistory = () => histResponse(plainTurn(6, 1, 'c', 'd'))
+    const resynced = session.resync() // bumps the generation
+    repairPull.resolve(ok({ events: entries(plainTurn(0, 0, '旧', '页')) as never[], hasMore: false })) // repair result: stale, dropped
+    await resynced
+    expect(session.getSnapshot().nodes.map(n => n.seq)).toEqual([7, 9])
+  })
+
+  it('successful cancel leaves no promptError; tool/result for an unknown callId is a no-op', async () => {
+    const { api, session } = makeSession()
+    api.onHistory = () => histResponse(plainTurn(0, 0, 'a', 'b'))
+    await session.open()
+    const result = await session.cancel()
+    expect(result.ok).toBe(true)
+    expect(session.getSnapshot().promptError).toBeNull()
+    const callsBefore = session.getSnapshot().runningCalls
+    session.handleMuxEnvelope('r' as never, { type: 'session/event', sessionId: SID, event: ev.toolResult(6, 0, 'never-called', 'x') })
+    expect(session.getSnapshot().runningCalls).toBe(callsBefore) // callsRev untouched: same reference
+  })
+
+  it('freezes a tool-call-only partial (visible through the non-text arm)', async () => {
+    const { api, session } = makeSession()
+    api.onHistory = () => histResponse(plainTurn(0, 0, 'a', 'b'))
+    await session.open()
+    const feed = (event: SessionEvent) => { session.handleMuxEnvelope('r' as never, { type: 'session/event', sessionId: SID, event }) }
+    feed(ev.turnStart(6, 1))
+    feed(at(7, { type: 'assistant/chunk', data: { turn: 1, step: 0, chunk: { type: 'tool-call-delta', index: 0, id: 'c1', name: 'echo', argumentsDelta: '{' } } }))
+    feed(ev.turnEnd(8, 1, 'cancelled'))
+    const frozen = session.getSnapshot().nodes.at(-1)
+    expect(frozen).toMatchObject({ kind: 'assistant', interrupted: true, blocks: [{ kind: 'tool-call', callId: 'c1' }] })
+  })
+
+  it('dispose is a reserved no-op on resident instances', () => {
+    const { session } = makeSession()
+    expect(() => { session.dispose() }).not.toThrow()
+  })
+
+  it('carries mux-frame views into runningCalls and tool-result nodes, and history-entry views through open', async () => {
+    const { api, session } = makeSession()
+    const callView = { for: 'call', view: { card: 'generic', title: '历史卡' } }
+    api.onHistory = () => Promise.resolve(ok({
+      events: [
+        ...entries(plainTurn(0, 0, 'a', 'b')),
+        { event: ev.toolCall(6, 1, 'h1', 'bash', '{}'), view: callView },
+        { event: ev.toolResult(7, 1, 'h1', 'done'), view: { for: 'result', view: { card: 'generic', title: '历史果' } } },
+      ] as never[],
+      hasMore: false,
+    }))
+    await session.open()
+    expect(session.getSnapshot().nodes.at(-1)).toMatchObject({
+      kind: 'tool-result', callView: { title: '历史卡' }, resultView: { title: '历史果' },
+    })
+    // Live path: the frame's view slot reaches runningCalls, then the result node.
+    session.handleMuxEnvelope('rv1' as never, {
+      type: 'session/event', sessionId: SID, event: ev.toolCall(8, 2, 'l1', 'write', '{}'),
+      view: { for: 'call', view: { card: 'generic', title: '直播卡' } },
+    } as never)
+    expect(session.getSnapshot().runningCalls).toMatchObject([{ callId: 'l1', callView: { title: '直播卡' } }])
+    session.handleMuxEnvelope('rv2' as never, {
+      type: 'session/event', sessionId: SID, event: ev.toolResult(9, 2, 'l1', 'ok'),
+      view: { for: 'result', view: { card: 'generic', title: '直播果' } },
+    } as never)
+    expect(session.getSnapshot().nodes.at(-1)).toMatchObject({
+      kind: 'tool-result', callView: { title: '直播卡' }, resultView: { title: '直播果' },
+    })
+  })
+})
+
+describe('resync', () => {
+  it('rebuilds the window and clears pending; cold instances no-op', async () => {
+    const { api, session } = makeSession()
+    api.onHistory = () => histResponse(plainTurn(0, 0, 'a', 'b'))
+    await session.open()
+    session.handleMuxEnvelope('ra' as never, { type: 'approval/requested', sessionId: SID, approvalId: 'ap1' as never, toolName: 'rm' })
+    api.onHistory = () => histResponse([...plainTurn(0, 0, 'a', 'b'), ...plainTurn(6, 1, 'c', 'd')])
+    await session.resync()
+    const snapshot = session.getSnapshot()
+    expect(snapshot.openState).toBe('open')
+    expect(snapshot.pending).toEqual([]) // baseline replay re-sends still-pending frames
+    expect(snapshot.nodes).toHaveLength(4)
+
+    const cold = makeSession()
+    await cold.session.resync()
+    expect(cold.api.calls).toEqual([]) // never opened: no traffic
+  })
+
+  it('drops a stale in-flight open superseded by resync (generation guard)', async () => {
+    const { api, session } = makeSession()
+    const stale = deferred<Awaited<ReturnType<FakeApiClient['onHistory']>>>()
+    api.onHistory = () => stale.promise
+    const firstOpen = session.open()
+    api.onHistory = () => histResponse(plainTurn(6, 1, '新', '代'))
+    const resynced = session.resync()
+    stale.reject(new Error('dead connection')) // the doomed pre-disconnect request fails late
+    await firstOpen
+    await resynced
+    const snapshot = session.getSnapshot()
+    expect(snapshot.openState).toBe('open') // stale failure did not settle the fresh generation into error
+    expect(snapshot.nodes.map(n => n.seq)).toEqual([7, 9])
+  })
+})
+
+describe('reference stability (the memo contract)', () => {
+  it('keeps unchanged node references across an append and swaps the snapshot object', async () => {
+    const { api, session } = makeSession()
+    api.onHistory = () => histResponse(plainTurn(0, 0, '稳', '定'))
+    await session.open()
+    const before = session.getSnapshot()
+    session.handleMuxEnvelope('r' as never, { type: 'session/event', sessionId: SID, event: ev.user(6, '追加') })
+    const after = session.getSnapshot()
+    expect(after).not.toBe(before) // top-level swap on change
+    expect(after.nodes[0]).toBe(before.nodes[0]) // untouched nodes keep identity
+    expect(after.nodes[1]).toBe(before.nodes[1])
+    expect(after.nodes).toHaveLength(3)
+    // No change → same snapshot reference.
+    expect(session.getSnapshot()).toBe(after)
+  })
+
+  it('keeps untouched substructure arrays identical across unrelated changes (revision counters)', async () => {
+    const { api, session } = makeSession()
+    api.onHistory = () => histResponse(plainTurn(0, 0, '底', '座'))
+    await session.open()
+    const feed = (event: SessionEvent) => { session.handleMuxEnvelope('r' as never, { type: 'session/event', sessionId: SID, event }) }
+    feed(ev.turnStart(6, 1))
+    feed(ev.toolCall(7, 1, 'c1', 'echo', '{}'))
+    session.handleMuxEnvelope('ra' as never, { type: 'approval/requested', sessionId: SID, approvalId: 'ap1' as never, toolName: 'rm' })
+    const before = session.getSnapshot()
+    // A chunk storm touches partial/nodes only: runningCalls and pending must keep identity.
+    feed(ev.chunkStart(8, 1))
+    feed(ev.chunkText(9, 1, '与工具无关的流式'))
+    const after = session.getSnapshot()
+    expect(after).not.toBe(before)
+    expect(after.runningCalls).toBe(before.runningCalls)
+    expect(after.pending).toBe(before.pending)
+    // And a mutation on the tracked domain swaps that array.
+    feed(ev.toolResult(10, 1, 'c1', 'ECHO'))
+    const resolved = session.getSnapshot()
+    expect(resolved.runningCalls).not.toBe(after.runningCalls)
+    expect(resolved.pending).toBe(after.pending)
+  })
+})

packages/client/runtime/tests/sessions-service.spec.ts

@@ -0,0 +1,141 @@
+/**
+ * SessionsService: list store projection (manager → {ids, byId} with derived
+ * titles), scope-tree lifecycle (lazy mint / frozen survival / removed
+ * teardown with watch deferral), binding identity, ancestry walk, create.
+ */
+import { Context } from 'cordis'
+import { describe, expect, it } from 'vitest'
+import type { SessionId } from '@deepseek-ai/dsh-client-connection/client'
+import { SessionsService, scopeOf } from '../src/client/sessions/service.ts'
+import { FakeApiClient, ok } from './fake-api.ts'
+
+const sid = (s: string): SessionId => s as SessionId
+
+interface Bench {
+  ctx: Context
+  api: FakeApiClient
+  svc: SessionsService
+}
+
+function bench(): Bench {
+  const ctx = new Context()
+  const api = new FakeApiClient()
+  const svc = new SessionsService(ctx, api)
+  return { ctx, api, svc }
+}
+
+/** Refresh the manager list from programmable rows and flush the microtask batch. */
+async function feedList(b: Bench, rows: { id: string; cwd?: string; parentId?: string; running?: boolean }[]): Promise<void> {
+  b.api.onList = () => Promise.resolve(ok({
+    items: rows.map(r => ({
+      sessionId: sid(r.id), updatedAt: 1, running: r.running ?? false,
+      ...(r.cwd !== undefined ? { cwd: r.cwd } : {}),
+      ...(r.parentId !== undefined ? { parentSessionId: sid(r.parentId) } : {}),
+    })),
+  }) as never)
+  await b.svc.manager.refreshList()
+  await Promise.resolve() // manager notifier flush
+}
+
+describe('list store projection', () => {
+  it('projects ids/byId with cwd-basename titles (id fallback) and parent links', async () => {
+    const b = bench()
+    await feedList(b, [
+      { id: 's1', cwd: '/home/u/proj-a/' },
+      { id: 's2', parentId: 's1', running: true },
+    ])
+    const state = b.svc.list.getSnapshot()
+    expect(state.ids).toEqual(['s1', 's2'])
+    expect(state.byId[sid('s1')]).toMatchObject({ title: 'proj-a', cwd: '/home/u/proj-a/' })
+    expect(state.byId[sid('s2')]).toMatchObject({ title: 's2', parentId: 's1', running: true })
+  })
+
+  it('reflects live increments (host stream via manager) into the store', async () => {
+    const b = bench()
+    await feedList(b, [{ id: 's1' }])
+    b.svc.manager.handleHostEnvelope({ rpcId: 'r1' as never, payload: { type: 'host/session-added', sessionId: sid('s2') } as never })
+    await Promise.resolve()
+    expect(b.svc.list.getSnapshot().ids).toContain('s2')
+  })
+})
+
+describe('scope tree', () => {
+  it('mints lazily on first resolution, tags the ctx, and keeps binding identity stable', async () => {
+    const b = bench()
+    await feedList(b, [{ id: 's1' }])
+    expect(b.svc.scope(sid('unknown'))).toBeUndefined()
+    const scoped = b.svc.scope(sid('s1'))
+    expect(scoped).toBeDefined()
+    expect(scopeOf(scoped as Context)).toBe('s1')
+    expect(scopeOf(b.ctx)).toBeUndefined()
+    const binding = b.svc.binding(sid('s1'))
+    expect(binding?.session).toBe(b.svc.manager.get(sid('s1')))
+    expect(b.svc.binding(sid('s1'))).toBe(binding)
+    expect(binding?.ctx).toBe(scoped)
+  })
+
+  it('tears down an unwatched removed session but defers the watched one until the watch moves', async () => {
+    const b = bench()
+    await feedList(b, [{ id: 's1' }, { id: 's2' }])
+    const ctx1 = b.svc.scope(sid('s1'))
+    b.svc.binding(sid('s1')) // s1 is watched
+    b.svc.scope(sid('s2')) // s2 scoped but not watched
+
+    await feedList(b, [{ id: 's1' }]) // s2 removed, unwatched: torn down
+    expect(b.svc.scope(sid('s2'))).toBeUndefined()
+
+    await feedList(b, []) // s1 removed while watched: deferred, scope survives
+    expect(b.svc.scope(sid('s1'))).toBe(ctx1)
+
+    await feedList(b, [{ id: 's3' }])
+    b.svc.binding(sid('s3')) // watch moves: deferred teardown sweeps s1
+    expect(b.svc.scope(sid('s1'))).toBeUndefined()
+  })
+
+  it('keeps the scope when the session merely stops running (frozen ≠ removed)', async () => {
+    const b = bench()
+    await feedList(b, [{ id: 's1', running: true }])
+    const scoped = b.svc.scope(sid('s1'))
+    await feedList(b, [{ id: 's1', running: false }])
+    expect(b.svc.scope(sid('s1'))).toBe(scoped)
+  })
+
+  it('cancels a deferred teardown when the id reappears in the list', async () => {
+    const b = bench()
+    await feedList(b, [{ id: 's1' }])
+    const scoped = b.svc.scope(sid('s1'))
+    b.svc.binding(sid('s1'))
+    await feedList(b, []) // removed while watched → deferred
+    await feedList(b, [{ id: 's1' }, { id: 's2' }]) // reappears
+    b.svc.binding(sid('s2')) // watch moves; sweep must NOT tear down the re-listed s1
+    expect(b.svc.scope(sid('s1'))).toBe(scoped)
+  })
+})
+
+describe('ancestry', () => {
+  it('walks parentId links root-first including self; broken links stop the walk', async () => {
+    const b = bench()
+    await feedList(b, [
+      { id: 'root', cwd: '/w/app' },
+      { id: 'mid', parentId: 'root' },
+      { id: 'leaf', parentId: 'mid' },
+      { id: 'orphan', parentId: 'ghost' },
+    ])
+    expect(b.svc.ancestry(sid('leaf')).map(s => s.id)).toEqual(['root', 'mid', 'leaf'])
+    expect(b.svc.ancestry(sid('orphan')).map(s => s.id)).toEqual(['orphan'])
+    expect(b.svc.ancestry(sid('ghost'))).toEqual([])
+  })
+})
+
+describe('create', () => {
+  it('returns the new id on ok and throws a coded error on failure', async () => {
+    const b = bench()
+    b.api.onCreate = () => Promise.resolve(ok({ sessionId: sid('fresh') }))
+    await expect(b.svc.create({ cwd: '/w' })).resolves.toBe('fresh')
+    b.api.onCreate = () => Promise.resolve({
+      rpcId: 'e' as never,
+      result: { ok: false as const, error: { code: 'internal' as const, message: '爆了', details: {} } },
+    } as never)
+    await expect(b.svc.create()).rejects.toThrow(/internal: 爆了/)
+  })
+})

packages/client/runtime/tests/slots-service.spec.ts

@@ -0,0 +1,65 @@
+/**
+ * SlotsService: cordis Service wrapper semantics — core delegation, the
+ * 'slots/changed' event bridge, and fiber-scoped registration disposal.
+ */
+import { Context } from 'cordis'
+import { describe, expect, it } from 'vitest'
+import type { FC } from 'react'
+import { SlotsService } from '../src/client/slots.ts'
+
+// Test-only slot keys (SlotMap is empty in this package; the service is generic over it).
+declare module '@deepseek-ai/dsh-client-ui-slots' {
+  interface SlotMap {
+    't-single': { kind: 'single'; scope: 'root'; props: object }
+    't-list': { kind: 'list'; scope: 'root'; props: object }
+  }
+}
+
+const C: FC<object> = () => null
+
+async function boot(): Promise<Context> {
+  const ctx = new Context()
+  ctx.plugin(SlotsService)
+  await ctx.fiber.await()
+  return ctx
+}
+
+describe('SlotsService', () => {
+  it('proxies define/register/entries/spec/getVersion to the core', async () => {
+    const ctx = await boot()
+    ctx.slots.define('t-single', { kind: 'single', scope: 'root' })
+    expect(ctx.slots.spec('t-single')).toEqual({ kind: 'single', scope: 'root' })
+    const v0 = ctx.slots.getVersion('t-single')
+    ctx.slots.register('t-single', C)
+    expect(ctx.slots.entries('t-single')).toHaveLength(1)
+    expect(ctx.slots.getVersion('t-single')).toBeGreaterThan(v0)
+    expect(ctx.slots.core.spec('t-single')).toBeDefined()
+  })
+
+  it("re-emits every mutation as 'slots/changed' with the key", async () => {
+    const ctx = await boot()
+    const seen: string[] = []
+    ctx.on('slots/changed', (key) => { seen.push(key) })
+    ctx.slots.define('t-list', { kind: 'list', scope: 'root' })
+    ctx.slots.register('t-list', C, { id: 'a' })
+    expect(seen).toEqual(['t-list', 't-list'])
+  })
+
+  it('collects a plugin fiber\'s registrations when the fiber unloads (cascade)', async () => {
+    const ctx = await boot()
+    ctx.slots.define('t-single', { kind: 'single', scope: 'root' })
+    const fiber = ctx.plugin({
+      name: 'occupant',
+      inject: ['slots'],
+      apply: (pluginCtx: Context) => {
+        pluginCtx.slots.register('t-single', C)
+      },
+    })
+    await fiber.await()
+    expect(ctx.slots.entries('t-single')).toHaveLength(1)
+    await fiber.dispose()
+    expect(ctx.slots.entries('t-single')).toHaveLength(0)
+    // The slot definition (registered from root) survives; a new occupant may register.
+    expect(() => ctx.slots.register('t-single', C)).not.toThrow()
+  })
+})

packages/client/runtime/tsconfig.json

@@ -0,0 +1,39 @@
+{
+  "extends": "../../../tsconfig.base.json",
+  "compilerOptions": {
+    "rootDir": "src",
+    "outDir": "lib/types",
+    "lib": [
+      "ES2024",
+      "DOM",
+      "DOM.Iterable"
+    ],
+    "types": []
+  },
+  "include": [
+    "src"
+  ],
+  "references": [
+    {
+      "path": "../../../vendor/cordis"
+    },
+    {
+      "path": "../ui-slots"
+    },
+    {
+      "path": "../web-react"
+    },
+    {
+      "path": "../connection"
+    },
+    {
+      "path": "../../llm/llm"
+    },
+    {
+      "path": "../../support/invariants"
+    }
+  ],
+  "exclude": [
+    "**/*.legacy.*"
+  ]
+}

packages/client/runtime/tsdown.config.ts

@@ -0,0 +1,23 @@
+import type { UserConfig } from 'tsdown'
+import { clientBundle } from '../tsdown.client.ts'
+
+/**
+ * Standard dual-entry shape plus the loader lib half: exports["./loader"]
+ * promises lib/loader.js (the web shell statically imports the machinery —
+ * a loader cannot load itself), and the shared preset only emits
+ * lib/{index,invariant}.js, so the extra config supplies it.
+ */
+const configs = clientBundle('@deepseek-ai/dsh-client-runtime', ['lib/types/index.js', 'lib/types/invariant.js'])
+
+const loaderLib: UserConfig = {
+  entry: { loader: 'lib/types/client/loader/index.js' },
+  outDir: 'lib',
+  format: ['esm'],
+  platform: 'neutral',
+  target: 'es2024',
+  fixedExtension: false,
+  dts: false,
+  clean: false,
+}
+
+export default [...configs, loaderLib]

packages/client/tsdown.client.ts

@@ -0,0 +1,152 @@
+/**
+ * Shared tsdown preset for UI plugin client bundles. Emits a closure-factory
+ * artifact: the bundle calls window.DSHClientProxy.loadPlugin({id, factory})
+ * and resolves externals through the injected require (loader module table —
+ * cordis DI entities, no globals, no import map). CSS Modules are compiled by
+ * lightningcss inside the bundle: importing `x.module.css` yields the
+ * hashed class map, and the css text auto-injects a <style data-plugin="<id>">
+ * tag at factory execution (the loader removes plugin-owned tags on unload).
+ */
+import { readFile } from 'node:fs/promises'
+import { basename, dirname, resolve as resolvePath } from 'node:path'
+import type { UserConfig } from 'tsdown'
+import { transform } from 'lightningcss'
+
+/**
+ * Virtual-id wrapper keeping module CSS away from tsdown's own css pipeline
+ * (which requires @tsdown/css). The suffix matters: tsdown's guard matches ids
+ * ending in `.css`, so the virtual id must not.
+ */
+const CSS_VIRTUAL_PREFIX = '\0dsh-css:'
+const CSS_VIRTUAL_SUFFIX = '.mjs'
+
+/**
+ * Wire/type layers a client bundle may inline: browser-safe contract surfaces
+ * with no runtime identity to share (no Symbol/instanceof/singleton state).
+ * Everything else under @deepseek-ai/* is either a module-table entry
+ * (external) or a leak the purity gate rejects.
+ */
+export const INLINE_SAFE = /^@deepseek-ai\/dsh-(host-apiproxy|session|llm|tools|brand)(\/|$)/
+
+/** Externals resolved from the loader module table (keep in sync with the shell's seeding list). */
+export const CLIENT_EXTERNALS = [
+  'react',
+  'react-dom',
+  'react/jsx-runtime',
+  'cordis',
+  '@deepseek-ai/dsh-client-ui-slots',
+  '@deepseek-ai/dsh-client-web-react',
+  '@deepseek-ai/dsh-client-web-react/store',
+  '@deepseek-ai/dsh-client-ui-primitives',
+  '@deepseek-ai/dsh-client-connection/client',
+  '@deepseek-ai/dsh-client-runtime/client',
+  '@deepseek-ai/dsh-client-ui-layout/client',
+  '@deepseek-ai/dsh-client-ui-conversation/client',
+  '@deepseek-ai/dsh-client-ui-theme/client',
+  '@deepseek-ai/dsh-client-i18n/client',
+]
+
+/**
+ * Build the tsdown config for one UI plugin package: the node-half lib build
+ * plus the browser client bundle. A package-level tsdown.config.ts REPLACES
+ * the root workspace shape, so the lib half must be restated here — dropping
+ * it leaves the package without lib/index.js and the host Loader cannot
+ * import its node half.
+ * @param id - plugin id (package name), stamped into the loadPlugin handoff
+ * and onto the injected style tags.
+ * @param libEntry - node-half entries, spelled at the call site so the
+ * package-invariants gate can see `lib/types/invariant.js` in each package's
+ * own tsdown.config.ts (a preset-side glob hides it from the mechanical check).
+ * @returns tsdown user configs emitting lib/*.js and lib/client.js.
+ */
+export function clientBundle(id: string, libEntry: readonly string[]): UserConfig[] {
+  return [{
+    entry: [...libEntry],
+    outDir: 'lib',
+    format: ['esm'],
+    platform: 'node',
+    target: 'es2024',
+    fixedExtension: false,
+    dts: false,
+    clean: false,
+  }, {
+    entry: { client: 'src/client/index.ts' },
+    // Browser bundle lands next to the node half (single lib/ artifact dir;
+    // the entryFileNames pin keeps it exactly lib/client.js). clean must stay
+    // off — a default clean would wipe the node-half output emitted above.
+    outDir: 'lib',
+    format: 'cjs',
+    platform: 'browser',
+    // Types ship from lib/types (tsc); dts here would wrap the banner/footer into .d.cts and break parsing.
+    dts: false,
+    clean: false,
+    external: CLIENT_EXTERNALS,
+    // tsdown auto-externalizes package dependencies; anything NOT in the
+    // loader module table must inline instead (wire/type layers, zod, clsx —
+    // every non-shared dep). A require() the table cannot answer is a
+    // guaranteed runtime throw, so the rule is the table list itself: no
+    // opinion for table entries (external above wins), bundle everything else.
+    noExternal: (id: string) => (CLIENT_EXTERNALS.includes(id) ? undefined : true),
+    plugins: [{
+      // Bundle purity gate: a bare-name import of a module-table package would
+      // slip past CLIENT_EXTERNALS (which lists the /client form) and INLINE a
+      // second copy of that package — duplicate runtime identity (a second
+      // scope Symbol was tonight's white-screen root cause). Resolve-time is
+      // the earliest, most precise interception: rewrite bare table names to
+      // their /client form (the loader registers both specifiers), and reject
+      // any other @deepseek-ai/* leak that is not an inline-safe wire layer.
+      name: 'dsh-client-bundle-purity',
+      resolveId(source: string) {
+        if (!source.startsWith('@deepseek-ai/')) return null
+        if (CLIENT_EXTERNALS.includes(source)) return null // external wins
+        if (CLIENT_EXTERNALS.includes(`${source}/client`)) {
+          return { id: `${source}/client`, external: true }
+        }
+        if (INLINE_SAFE.test(source)) return null // wire/type layer: inline is the point
+        throw new Error(
+          `client bundle purity: "${source}" is not in CLIENT_EXTERNALS and not an inline-safe wire layer — `
+          + 'import the /client form, add it to the module table, or it inlines a duplicate runtime instance',
+        )
+      },
+    }, {
+      name: 'dsh-css-modules-inline',
+      resolveId(source: string, importer: string | undefined) {
+        if (!source.endsWith('.module.css')) return null
+        const abs = importer !== undefined ? resolvePath(dirname(importer), source) : source
+        return CSS_VIRTUAL_PREFIX + abs + CSS_VIRTUAL_SUFFIX
+      },
+      async load(virtualId: string) {
+        if (!virtualId.startsWith(CSS_VIRTUAL_PREFIX)) return null
+        const fileId = virtualId.slice(CSS_VIRTUAL_PREFIX.length, -CSS_VIRTUAL_SUFFIX.length)
+        const source = await readFile(fileId)
+        const { code, exports: cssExports } = transform({
+          filename: fileId,
+          code: source,
+          cssModules: { pattern: `[hash]_[local]` },
+          minify: true,
+        })
+        const classMap: Record<string, string> = {}
+        for (const [local, exp] of Object.entries(cssExports ?? {})) classMap[local] = exp.name
+        // One <style data-plugin> per module file; idempotent under re-evaluation.
+        return [
+          `const css = ${JSON.stringify(code.toString())};`,
+          `const tagId = ${JSON.stringify(`${id}/${basename(fileId)}`)};`,
+          `if (typeof document !== 'undefined' && document.querySelector('style[data-plugin-css=' + JSON.stringify(tagId) + ']') === null) {`,
+          `  const tag = document.createElement('style');`,
+          `  tag.dataset.plugin = ${JSON.stringify(id)};`,
+          `  tag.dataset.pluginCss = tagId;`,
+          `  tag.textContent = css;`,
+          `  document.head.appendChild(tag);`,
+          `}`,
+          `export default ${JSON.stringify(classMap)};`,
+        ].join('\n')
+      },
+    }],
+    outputOptions: {
+      entryFileNames: 'client.js',
+      banner: `window.DSHClientProxy.loadPlugin({ id: ${JSON.stringify(id)}, factory: (require) => {`,
+      footer: `return module.exports; } });`,
+      intro: 'var module = { exports: {} }; var exports = module.exports;',
+    },
+  }]
+}

packages/client/ui-conversation/README.md

@@ -0,0 +1,22 @@
+# @deepseek-ai/dsh-client-ui-conversation
+
+Conversation domain: skeleton (header/tabs/composer/empty state), chat view (grouped step-summary flow, streaming tail isolation), ctx.toolviews named registry with bash samples, minimal details panel, scope-addressed ConversationService. Contract: api-contracts v3 §7.
+
+`src/client/` is organized for the future package split: `contract/` is the sole inter-domain shared face (`slots.ts` composed slot props, `views.ts` view ring, `toolview.ts` tool ring, `tool-call-model.ts`); the `skeleton/`, `chat/`, and `toolviews/` domain directories import contract files and never each other; `apply.ts` is the only assembly point allowed to import all three domains.
+
+## Model Experience
+
+None, as the conversation UI renders session history and streams in the browser; nothing here reaches a model request.
+
+#### KV Cache effect
+
+None; this package neither assembles nor sends a provider request.
+
+## Known Limitations and Deferred Work
+
+- **The stats line has no duration segment** — assistant `usage` carries token accounting only; elapsed-time needs a host data source.
+- **Details panel is the minimal form** — selected call args/result raw display; the Input/Output/Metadata switch, Prev/Next stepping, and See-in-trajectory deep link are deferred.
+- **Assistant footer extensions (IconActions row, per-message paging) are reserved slots** — drawn in the design, not implemented.
+- **The sparkle icon for the others tool row is a hand-drawn approximation** — the design glyph's vector geometry is not exportable locally; promotion into ui-primitives waits on an exact export.
+- **Approval/question cards are display-only placeholders** — web-side answering (composer takeover panel) is the P-II approvals project.
+- **Module-level toolview caches are single-bundle state** — the inject cache and registry maps must reach cross-bundle consumers through the package export surface and loader module table, never by a second bundle copy.

packages/client/ui-conversation/package.json

@@ -0,0 +1,63 @@
+{
+  "name": "@deepseek-ai/dsh-client-ui-conversation",
+  "description": "Conversation domain: skeleton (header/tabs/composer), chat view, ctx.toolviews registry, minimal details panel",
+  "version": "0.0.1",
+  "private": true,
+  "type": "module",
+  "main": "lib/index.js",
+  "types": "lib/types/index.d.ts",
+  "exports": {
+    ".": {
+      "types": "./lib/types/index.d.ts",
+      "default": "./lib/index.js"
+    },
+    "./invariant": {
+      "types": "./lib/types/invariant.d.ts",
+      "default": "./lib/invariant.js"
+    },
+    "./client": {
+      "types": "./lib/types/client/index.d.ts",
+      "default": "./lib/client.js"
+    },
+    "./src/*": "./src/*",
+    "./package.json": "./package.json"
+  },
+  "dshClient": {
+    "inject": [
+      "@deepseek-ai/dsh-client-ui-layout"
+    ],
+    "platform": "web"
+  },
+  "scripts": {
+    "bundle": "tsdown",
+    "watch": "tsdown --watch"
+  },
+  "license": "BSD-3-Clause",
+  "dependencies": {
+    "@deepseek-ai/dsh-client-i18n": "workspace:^",
+    "@deepseek-ai/dsh-client-runtime": "workspace:^",
+    "@deepseek-ai/dsh-client-ui-layout": "workspace:^",
+    "@deepseek-ai/dsh-client-ui-primitives": "workspace:^",
+    "@deepseek-ai/dsh-client-ui-slots": "workspace:^",
+    "@deepseek-ai/dsh-client-web-react": "workspace:^",
+    "clsx": "^2.0.0",
+    "react": "^18.2.0"
+  },
+  "peerDependencies": {
+    "@deepseek-ai/dsh-invariants": "^0.0.1",
+    "cordis": "^4.0.0-rc.7"
+  },
+  "devDependencies": {
+    "@deepseek-ai/dsh-invariants": "workspace:^",
+    "@types/react": "~18.3.1",
+    "cordis": "^4.0.0-rc.7"
+  },
+  "files": [
+    "lib/index.js",
+    "lib/invariant.js",
+    "lib/client.js",
+    "lib/types/**/*.d.ts",
+    "lib/types/**/*.d.ts.map",
+    "src"
+  ]
+}

packages/client/ui-conversation/src/client/apply.ts

@@ -0,0 +1,185 @@
+/**
+ * Client plugin body: provide the conversation service and toolview registry,
+ * register the conversation/details slot occupants and the no-session empty
+ * state, and mount the chat view with its samples. Assembly only — components
+ * receive everything through inject factories; nothing here renders directly.
+ */
+import { createElement, Fragment, type ReactNode } from 'react'
+import type { Context } from 'cordis'
+import type { SessionBinding } from '@deepseek-ai/dsh-client-ui-slots'
+import { scopedSlots, shallowEqual } from '@deepseek-ai/dsh-client-web-react'
+import type { SnapshotSelectorHook, UseSession } from '@deepseek-ai/dsh-client-web-react'
+import type {
+  SessionId, SessionListState, SessionsService, SlotsService,
+} from '@deepseek-ai/dsh-client-runtime/client'
+import type { LayoutService } from '@deepseek-ai/dsh-client-ui-layout/client'
+import type { I18nService } from '@deepseek-ai/dsh-client-i18n/client'
+import type { ConvViewProps, SelectionTarget, ViewEntry, ViewId } from './contract/views.ts'
+import type { ConversationInjected, DetailsInjected, EmptyStateInjected } from './contract/slots.ts'
+import { ConversationService } from './service.ts'
+import { ToolViewRegistry } from './toolviews/registry.ts'
+import { childSessionScope, registerChat } from './chat/register.ts'
+import { registerBashSamples } from './toolviews/bash-sample.tsx'
+import { ConversationRoot } from './skeleton/ConversationRoot.tsx'
+import { DetailsPanel } from './skeleton/DetailsPanel.tsx'
+import { EmptyState } from './skeleton/EmptyState.tsx'
+
+/** Required services (cordis fiber inject — the loader passes the whole export surface as an object plugin). */
+export const inject = ['slots', 'layout', 'sessions', 'i18n']
+
+/** Resolve a service via ctx.get, failing loud. Property access is reserved
+ *  for contexts whose fiber declares the inject (scope fibers do not). */
+// T is the caller-named cast target; inlining `as T` per call site would scatter the budgeted cast.
+// eslint-disable-next-line @typescript-eslint/no-unnecessary-type-parameters
+function need<T>(ctx: Context, name: string): T {
+  const value = ctx.get(name) as T | undefined
+  if (value === undefined) throw new Error(`ui-conversation: ${name} service unavailable`)
+  return value
+}
+
+/** Per-list-state cwd set (deduped, list order) for the empty-state picker. */
+const cwdsCache = new WeakMap<SessionListState, readonly string[]>()
+function cwdsOf(state: SessionListState): readonly string[] {
+  let cached = cwdsCache.get(state)
+  if (cached === undefined) {
+    const seen = new Set<string>()
+    for (const id of state.ids) {
+      const cwd = state.byId[id]?.cwd
+      if (cwd !== undefined && cwd !== '') seen.add(cwd)
+    }
+    cached = [...seen]
+    cwdsCache.set(state, cached)
+  }
+  return cached
+}
+
+/**
+ * Client plugin body.
+ * @param ctx - client root context.
+ */
+export function apply(ctx: Context): void {
+  const sessions = need<SessionsService>(ctx, 'sessions')
+  const layout = need<LayoutService>(ctx, 'layout')
+  const i18n = need<I18nService>(ctx, 'i18n')
+  const slots = need<SlotsService>(ctx, 'slots')
+
+  const conversation = new ConversationService(ctx)
+  const toolviews = new ToolViewRegistry()
+  ctx.provide('toolviews', toolviews)
+
+  const t = i18n.bind('conversation')
+  // Chat view + StatsLine footer; bash samples assembled here (apply is the
+  // only cross-domain point — chat consumes the resolver face, samples come
+  // from the toolviews domain). registerView inside registerChat is already
+  // effect-scoped; the raw sample registrations need the effect wrapper to
+  // ride the fiber cascade.
+  ctx.effect(
+    () => registerChat({ conversation, toolviews, t }),
+    'ui-conversation: chat view')
+  ctx.effect(
+    () => registerBashSamples(toolviews, childSessionScope(sessions.list)),
+    'ui-conversation: bash toolview samples')
+
+  // ConvViewProps.slots is ScopedSlots<never>: a real outlet with an empty
+  // whitelist (uncallable by type, correct runtime shape for future grants).
+  const emptySlots = scopedSlots<never>(slots.core)
+
+  /** conversation slot: skeleton surface assembled once per (entry x session). */
+  const conversationInject = (b: SessionBinding): ConversationInjected => {
+    const bctx = b.ctx as Context
+    const scoped = need<ConversationService>(bctx, 'conversation')
+    const id = b.sessionId as SessionId
+    const useSession = b.session.useSelector as UseSession
+    const selectionStore = scoped.selection
+    const draftsStore = scoped.drafts
+    const session = sessions.manager.get(id)
+    // Watch-driven history pull: assembling the surface IS the watch signal
+    // (once per entry x session; open() is idempotent and self-recovers).
+    void session.open()
+
+    const viewProps: Omit<ConvViewProps, 'slots'> = {
+      sessionId: id,
+      useSession,
+      useSelection: selectionStore.useSelector,
+      actions: {
+        openDetails: (target: SelectionTarget) => { scoped.openDetails(target) },
+        loadOlder: () => { void session.loadOlder() },
+      },
+    }
+
+    const injected: ConversationInjected = {
+      useAncestry: () => sessions.list.useSelector(
+        () => sessions.ancestry(id),
+        (a, b) => shallowEqual(a, b)),
+      views: {
+        list: () => conversation.views(),
+        subscribe: fn => conversation.subscribeViews(fn),
+        version: () => conversation.viewsVersion(),
+      },
+      // layout's viewFor value type is its own looser ViewId; the registry is
+      // the runtime validator (unknown ids fall back to the first view).
+      useActiveView: () => layout.current.useSelector(s => s.viewFor[id]) as ViewId | undefined,
+      composer: {
+        useDraft: () => draftsStore.useSelector(s => s),
+        setDraft: (text) => { draftsStore.set(text) },
+        send: (mode) => {
+          const text = draftsStore.getSnapshot().trim()
+          if (text === '') return
+          // Optimistic clear with failure restore (choreography lives with the
+          // sender; the business failure also lands in snapshot.promptError).
+          draftsStore.set('')
+          void scoped.send(text, mode).catch(() => {
+            if (draftsStore.getSnapshot() === '') draftsStore.set(text)
+          })
+        },
+        stop: () => {
+          scoped.cancel().catch(() => {
+            // Stop failure surfaces via snapshot.promptError; nothing to restore.
+          })
+        },
+      },
+      actions: {
+        openView: (view: ViewId) => { layout.openView(id, view) },
+        open: (target: SessionId) => { layout.open(target) },
+      },
+      renderView: (entry: ViewEntry): ReactNode => {
+        const children: ReactNode[] = []
+        if (entry.chrome?.header !== undefined) {
+          children.push(createElement(entry.chrome.header, { key: 'header', sessionId: id, useSession }))
+        }
+        children.push(createElement(entry.component, { key: 'view', ...viewProps, slots: emptySlots }))
+        if (entry.chrome?.footer !== undefined) {
+          children.push(createElement(entry.chrome.footer, { key: 'footer', sessionId: id, useSession }))
+        }
+        return createElement(Fragment, null, ...children)
+      },
+    }
+    return injected
+  }
+
+  /** details slot: minimal selection-driven panel. */
+  const detailsInject = (b: SessionBinding): DetailsInjected => {
+    const bctx = b.ctx as Context
+    const scoped = need<ConversationService>(bctx, 'conversation')
+    const injected: DetailsInjected = {
+      useSelection: scoped.selection.useSelector,
+      actions: { closeDetails: () => { layout.closeDetails() } },
+    }
+    return injected
+  }
+
+  /** conversation.empty root slot: the NEW SESSION hero. */
+  const emptyInject = (): EmptyStateInjected => {
+    const useCwds: SnapshotSelectorHook<readonly string[]> = (sel, eq) =>
+      sessions.list.useSelector(s => sel(cwdsOf(s)), eq)
+    const injected: EmptyStateInjected = {
+      useCwds,
+      actions: { startSession: opts => conversation.startSession(opts) },
+    }
+    return injected
+  }
+
+  slots.register('conversation', ConversationRoot, { inject: conversationInject })
+  slots.register('details', DetailsPanel, { inject: detailsInject })
+  slots.register('conversation.empty', EmptyState, { inject: emptyInject })
+}

packages/client/ui-conversation/src/client/chat/AssistantMarkdown.module.css

@@ -0,0 +1,33 @@
+/* Assistant flow body: full-width narration (figma 16/28), block gap 16. */
+
+.root {
+  display: flex;
+  flex-direction: column;
+  gap: 16px;
+  font-size: 16px;
+  line-height: 28px;
+  color: var(--dsw-alias-label-primary);
+}
+
+.pulse {
+  display: inline-block;
+  width: 8px;
+  height: 14px;
+  background: var(--dsw-alias-state-business-primary);
+  animation: pulse 1s infinite ease-in-out;
+}
+
+@keyframes pulse {
+  50% { opacity: 0.2; }
+}
+
+/* Interrupted-turn terminal marker: quiet inline tag, no animation. */
+.stopped {
+  align-self: flex-start;
+  padding: 0 6px;
+  border-radius: 6px;
+  background: var(--dsw-alias-interactive-bg-hover);
+  color: var(--dsw-alias-label-tertiary);
+  font-size: 11px;
+  line-height: 18px;
+}

packages/client/ui-conversation/src/client/chat/AssistantMarkdown.tsx

@@ -0,0 +1,56 @@
+// AssistantMarkdown: renders assistant blocks in order — markdown text body,
+// reasoning as the figma Think summary row (expand = indented gray text),
+// other-block JSON fallback. Tool-call heads are NOT rendered here: the chat
+// view groups them into tool rows via the toolview outlet (figma step-summary
+// flow). Shared by finalized nodes and the streaming partial (pulse marker).
+
+import { memo } from 'react'
+import type { AssistantBlock } from '@deepseek-ai/dsh-client-runtime/client'
+import { IconThinkOutline14, JsonBlock, MessageText } from '@deepseek-ai/dsh-client-ui-primitives'
+import { ToolRow } from './ToolRow.tsx'
+import css from './AssistantMarkdown.module.css'
+
+export interface AssistantMarkdownProps {
+  blocks: readonly AssistantBlock[]
+  streaming: boolean
+  /** Frozen partial of an aborted turn: rendered with a 已停止 marker, no pulse. */
+  interrupted?: boolean | undefined
+}
+
+function firstLine(text: string): string {
+  const nl = text.indexOf('\n')
+  return nl === -1 ? text : text.slice(0, nl)
+}
+
+/** Reasoning block as the Think variant summary row (figma 39:28304). */
+function ThinkRow({ text, running }: { text: string; running: boolean }) {
+  return (
+    <ToolRow
+      variant="think"
+      icon={<IconThinkOutline14 />}
+      title="Think"
+      summary={firstLine(text)}
+      body={text}
+      state={running ? 'running' : 'ok'}
+    />
+  )
+}
+
+export const AssistantMarkdown = memo(function AssistantMarkdown({ blocks, streaming, interrupted }: AssistantMarkdownProps) {
+  const last = blocks.length - 1
+  return (
+    <div className={css.root} data-streaming={streaming || undefined}>
+      {blocks.map((block, i) => {
+        switch (block.kind) {
+          case 'text': return <MessageText key={i} text={block.text} />
+          case 'reasoning': return <ThinkRow key={i} text={block.text} running={streaming && i === last} />
+          // Tool-call heads render as tool rows in the chat view's grouping pass.
+          case 'tool-call': return null
+          default: return <JsonBlock key={i} label="未知内容块" payload={block.block} />
+        }
+      })}
+      {streaming && <span className={css.pulse} />}
+      {interrupted && <span className={css.stopped}>已停止</span>}
+    </div>
+  )
+})

packages/client/ui-conversation/src/client/chat/ChatView.module.css

@@ -0,0 +1,101 @@
+/* Chat flow: block gap 16 between narration/bubbles/tool groups (figma);
+   tool rows inside a group gap 10. Input padding cap rides the skeleton. */
+
+.root {
+  position: relative;
+  display: flex;
+  flex-direction: column;
+  min-height: 0;
+  flex: 1 1 auto;
+}
+
+.scroll {
+  flex: 1 1 auto;
+  min-height: 0;
+  overflow-y: auto;
+  padding: 16px 24px;
+}
+
+/* Message column: 736px fixed width, centered on the same axis as the
+   input box; the scroller itself stays full-bleed. */
+.column {
+  max-width: 736px;
+  width: 100%;
+  margin: 0 auto;
+  display: flex;
+  flex-direction: column;
+  gap: 16px;
+}
+
+.toolGroup {
+  display: flex;
+  flex-direction: column;
+  gap: 10px;
+}
+
+.callRow {
+  border-radius: 6px;
+}
+
+/* Selection linkage: the selected call row wears the blue outline.
+   button-info-fill flips 500→400 with the theme, hitting the darker-blue
+   dark-mode spec exactly (business-primary stays 500 on both). */
+.callRow[data-selected] {
+  outline: 1.5px solid var(--dsw-alias-button-info-fill);
+  outline-offset: 1px;
+}
+
+.hint {
+  color: var(--dsw-alias-label-tertiary);
+  font-size: 12px;
+  line-height: 18px;
+}
+
+.openError {
+  color: var(--dsw-alias-state-error-primary);
+  font-size: 12px;
+  line-height: 18px;
+}
+
+.older {
+  display: flex;
+  justify-content: center;
+}
+
+.older button {
+  border: none;
+  border-radius: 14px;
+  padding: 4px 12px;
+  font-size: 12px;
+  color: var(--dsw-alias-label-secondary);
+  background: var(--dsw-alias-interactive-bg-hover-solid);
+  cursor: pointer;
+}
+
+.older button:disabled {
+  cursor: default;
+  opacity: 0.6;
+}
+
+/* Back-to-bottom: 34px circular icon button at the column's right edge. */
+.toBottom {
+  position: absolute;
+  right: max(24px, calc((100% - 736px) / 2));
+  bottom: 16px;
+  width: 34px;
+  height: 34px;
+  display: flex;
+  align-items: center;
+  justify-content: center;
+  padding: 0;
+  border: 1px solid var(--dsw-alias-border-l2);
+  border-radius: 100px;
+  color: var(--dsw-alias-label-primary);
+  background: var(--dsw-alias-button-floating-fill);
+  box-shadow: var(--dsw-shadow-lv2);
+  cursor: pointer;
+}
+
+.toBottom:hover {
+  background: var(--dsw-alias-button-floating-hover);
+}

packages/client/ui-conversation/src/client/chat/ChatView.tsx

@@ -0,0 +1,293 @@
+// ChatView: the default conversation view — message flow with user bubbles,
+// assistant narration, tool summary rows grouped into step runs, pending
+// cards, paging and bottom-follow. Created via factory so plugin deps
+// (toolviews registry, i18n) arrive by closure, never by import.
+//
+// Render economics (architecture RFC performance model): the list parent
+// subscribes to snapshot segments that do NOT change per streaming chunk
+// (nodes/runningCalls/pending keep their references across chunk batches), so
+// during a token storm only StreamingTail re-renders; history rows hold via
+// memo on cache-stable node slices. Selection changes re-render the parent
+// map but only rows whose own selected bit flipped.
+
+import {
+  memo, useLayoutEffect, useMemo, useRef, useState, type FC, type ReactNode,
+} from 'react'
+import type {
+  ConversationNode, ConversationSnapshot, RunningToolCall, SessionId, ToolResultNode,
+} from '@deepseek-ai/dsh-client-runtime/client'
+import type { SnapshotSelectorHook } from '@deepseek-ai/dsh-client-web-react'
+import { IconChevronDownOutline14 } from '@deepseek-ai/dsh-client-ui-primitives'
+import type { ConvViewProps, SelectionTarget, Translate } from '../contract/views.ts'
+import type { ToolViewProps } from '../contract/toolview.ts'
+import type { ToolViewResolver } from '../contract/toolview.ts'
+import { deriveChatFlow, type ChatFlowItem } from './chat-flow.ts'
+import { AssistantMarkdown } from './AssistantMarkdown.tsx'
+import { MessageItem } from './MessageItem.tsx'
+import { PendingCard } from './PendingCard.tsx'
+import { ToolViewOutlet } from './ToolViewOutlet.tsx'
+import css from './ChatView.module.css'
+
+/** Plugin-supplied closure deps (assembled in registerChat, apply world). */
+export interface ChatViewDeps {
+  toolviews: ToolViewResolver
+  t: Translate
+}
+
+const FOLLOW_THRESHOLD = 24
+
+type OpenDetails = (target: SelectionTarget) => void
+
+/** web-react's UseSession is deliberately wide (dependency direction); the
+ *  chat view narrows once to the runtime snapshot the binding actually feeds. */
+type UseConversation = SnapshotSelectorHook<ConversationSnapshot>
+
+/** One tool call row (result or running): builds the bound ToolViewProps. */
+const CallRow = memo(function CallRow({ registry, sessionId, useSession, t, callId, toolName, block, seq, onOpenDetails, selected }: {
+  registry: ToolViewResolver
+  sessionId: SessionId
+  useSession: ConvViewProps['useSession']
+  t: Translate
+  callId: string
+  toolName: string
+  block: ToolResultNode | RunningToolCall
+  /** Surface seq for finalized results; the call's turn for running calls. */
+  seq: number
+  onOpenDetails: OpenDetails
+  selected: boolean
+}) {
+  const viewProps = useMemo<ToolViewProps>(() => ({
+    callId, toolName, block, useSession,
+    actions: { openDetails: () => onOpenDetails({ turnSeq: seq, callId, toolName }) },
+    t,
+  }), [callId, toolName, block, useSession, seq, onOpenDetails, t])
+  return (
+    <div className={css.callRow} data-selected={selected || undefined}>
+      <ToolViewOutlet registry={registry} sessionId={sessionId} toolName={toolName} viewProps={viewProps} />
+    </div>
+  )
+})
+
+/** Consecutive tool results as one step-run group (figma VERTICAL gap10). */
+const ToolGroup = memo(function ToolGroup({ registry, sessionId, useSession, t, results, onOpenDetails, selectedCallId }: {
+  registry: ToolViewResolver
+  sessionId: SessionId
+  useSession: ConvViewProps['useSession']
+  t: Translate
+  results: readonly ToolResultNode[]
+  onOpenDetails: OpenDetails
+  /** Only set when the selected call lives in THIS group (memo economy). */
+  selectedCallId: string | undefined
+}) {
+  return (
+    <div className={css.toolGroup}>
+      {results.map((node) => (
+        <CallRow
+          key={node.callId}
+          registry={registry}
+          sessionId={sessionId}
+          useSession={useSession}
+          t={t}
+          callId={node.callId}
+          toolName={node.call?.name ?? ''}
+          block={node}
+          seq={node.seq}
+          onOpenDetails={onOpenDetails}
+          selected={node.callId === selectedCallId}
+        />
+      ))}
+    </div>
+  )
+})
+
+/** The streaming partial, isolated so chunk batches re-render only this tail.
+ *  onGrow lets the scroll owner follow content the parent never re-renders for. */
+function StreamingTail({ useSession, onGrow }: {
+  useSession: UseConversation
+  onGrow: () => void
+}) {
+  const partial = useSession((s) => s.partial)
+  useLayoutEffect(() => {
+    onGrow()
+  })
+  if (partial === null) return null
+  return <AssistantMarkdown blocks={partial.blocks} streaming />
+}
+
+/**
+ * Build the chat view component over plugin deps.
+ * @param deps - toolview registry and bound translator.
+ * @returns the ConvViewProps component registered as the chat view.
+ */
+export function createChatView(deps: ChatViewDeps): FC<ConvViewProps> {
+  const { toolviews, t } = deps
+
+  return function ChatView({ sessionId, useSession: useSessionWide, useSelection, actions }: ConvViewProps) {
+    const useSession = useSessionWide as UseConversation
+    const nodes = useSession((s) => s.nodes)
+    const runningCalls = useSession((s) => s.runningCalls)
+    const pending = useSession((s) => s.pending)
+    const openState = useSession((s) => s.openState)
+    const openErrorMessage = useSession((s) => s.openError === null ? null : `${s.openError.message}（${s.openError.code}）`)
+    const hasMore = useSession((s) => s.hasMore)
+    const loadingOlder = useSession((s) => s.loadingOlder)
+    const selectedCallId = useSelection((sel) => sel?.callId)
+
+    const items = useMemo(() => deriveChatFlow(nodes), [nodes])
+
+    const listRef = useRef<HTMLDivElement | null>(null)
+    const atBottomRef = useRef(true)
+    const [atBottom, setAtBottom] = useState(true)
+    /** Paging anchor: height/position at click, compensated after the prepend lands. */
+    const anchorRef = useRef<{ h: number; t: number } | null>(null)
+    const firstSeqRef = useRef<number | null>(null)
+    const openedRef = useRef(false)
+    const lastKeyRef = useRef<string | null>(null)
+
+    const firstSeq = nodes[0]?.seq ?? null
+    const lastItem = items[items.length - 1]
+
+    const toBottom = (el: HTMLDivElement): void => {
+      el.scrollTop = el.scrollHeight
+      atBottomRef.current = true
+      setAtBottom(true)
+    }
+
+    useLayoutEffect(() => {
+      const el = listRef.current
+      /* v8 ignore next -- ref-null guard: React attaches the ref before layout effects run. */
+      if (el === null) return
+      // Open completed: jump to the bottom once.
+      if (openState === 'open' && !openedRef.current) {
+        openedRef.current = true
+        toBottom(el)
+        firstSeqRef.current = firstSeq
+        lastKeyRef.current = lastItem?.key ?? null
+        return
+      }
+      // Prepend (head seq decreased): compensate by the height delta.
+      if (anchorRef.current !== null && firstSeq !== null && firstSeqRef.current !== null && firstSeq < firstSeqRef.current) {
+        el.scrollTop = anchorRef.current.t + (el.scrollHeight - anchorRef.current.h)
+        anchorRef.current = null
+        firstSeqRef.current = firstSeq
+        /* v8 ignore next -- ?? arm: a prepend adds nodes, so the flow list here is never empty. */
+        lastKeyRef.current = lastItem?.key ?? null
+        return
+      }
+      firstSeqRef.current = firstSeq
+      // Own words must be visible: a new trailing user node force-scrolls
+      // (send lives in the composer, so arrival is detected here, not armed there).
+      const lastKey = lastItem?.key ?? null
+      const appendedUser = lastKey !== lastKeyRef.current
+        && lastItem !== undefined && lastItem.kind === 'node' && lastItem.node.kind === 'user'
+      lastKeyRef.current = lastKey
+      if (appendedUser || atBottomRef.current) toBottom(el)
+    })
+
+    const onScroll = (): void => {
+      const el = listRef.current
+      /* v8 ignore next -- ref-null guard: the handler only fires on the mounted element. */
+      if (el === null) return
+      const isAtBottom = el.scrollHeight - el.scrollTop - el.clientHeight <= FOLLOW_THRESHOLD + 1
+      atBottomRef.current = isAtBottom
+      setAtBottom(isAtBottom)
+    }
+
+    // Follow streaming growth the parent never re-renders for (stable ref).
+    // The ref starts null and is assigned every render, so the placeholder
+    // initializer a function initial value would need never exists.
+    const followRef = useRef<(() => void) | null>(null)
+    followRef.current = () => {
+      const el = listRef.current
+      if (el !== null && atBottomRef.current) el.scrollTop = el.scrollHeight
+    }
+    const onGrow = useRef(() => followRef.current?.()).current
+
+    const loadOlder = (): void => {
+      const el = listRef.current
+      /* v8 ignore next -- ref-null guard: the paging button renders inside the list tree. */
+      if (el !== null) anchorRef.current = { h: el.scrollHeight, t: el.scrollTop }
+      actions.loadOlder()
+    }
+
+    const renderItem = (item: ChatFlowItem): ReactNode => {
+      if (item.kind === 'tool-group') {
+        const inGroup = selectedCallId !== undefined
+          && item.results.some((r) => r.callId === selectedCallId)
+        return (
+          <ToolGroup
+            key={item.key}
+            registry={toolviews}
+            sessionId={sessionId}
+            useSession={useSession}
+            t={t}
+            results={item.results}
+            onOpenDetails={actions.openDetails}
+            selectedCallId={inGroup ? selectedCallId : undefined}
+          />
+        )
+      }
+      const node: ConversationNode = item.node
+      if (node.kind === 'assistant') {
+        return <AssistantMarkdown key={item.key} blocks={node.blocks} streaming={false} interrupted={node.interrupted} />
+      }
+      /* v8 ignore next -- tool-result never reaches here: deriveChatFlow folds them into groups. */
+      if (node.kind === 'tool-result') return null
+      return <MessageItem key={item.key} node={node} />
+    }
+
+    return (
+      <div className={css.root}>
+        <div ref={listRef} className={css.scroll} onScroll={onScroll}>
+          <div className={css.column}>
+          {openState === 'loading' && <div className={css.hint}>载入历史…</div>}
+          {openState === 'error' && <div className={css.openError}>历史加载失败：{openErrorMessage}</div>}
+          {hasMore && (
+            <div className={css.older}>
+              <button type="button" disabled={loadingOlder} onClick={loadOlder}>
+                {loadingOlder ? '加载中…' : '加载更早'}
+              </button>
+            </div>
+          )}
+          {items.map(renderItem)}
+          <StreamingTail useSession={useSession} onGrow={onGrow} />
+          {runningCalls.length > 0 && (
+            <div className={css.toolGroup}>
+              {runningCalls.map((call) => (
+                <CallRow
+                  key={call.callId}
+                  registry={toolviews}
+                  sessionId={sessionId}
+                  useSession={useSession}
+                  t={t}
+                  callId={call.callId}
+                  toolName={call.name}
+                  block={call}
+                  seq={call.turn}
+                  onOpenDetails={actions.openDetails}
+                  selected={call.callId === selectedCallId}
+                />
+              ))}
+            </div>
+          )}
+          {pending.map((item) => <PendingCard key={item.rpcId} item={item} />)}
+          </div>
+        </div>
+        {!atBottom && (
+          <button
+            type="button"
+            className={css.toBottom}
+            aria-label="回到底部"
+            onClick={() => {
+              const el = listRef.current
+              /* v8 ignore next -- ref-null guard: the button only renders alongside the mounted list. */
+              if (el !== null) toBottom(el)
+            }}
+          >
+            <IconChevronDownOutline14 />
+          </button>
+        )}
+      </div>
+    )
+  }
+}

packages/client/ui-conversation/src/client/chat/GenericToolCard.tsx

@@ -0,0 +1,36 @@
+// GenericToolCard: the registry-miss fallback toolview — classifies the tool
+// into one of the five figma row variants and renders the summary row. Also
+// the shared base the bash sample builds on: any ToolViewProps consumer.
+
+import type { ReactNode } from 'react'
+import {
+  IconApiOutline14, IconBrowseOutline16, IconSearchOutline16, IconThinkOutline14,
+} from '@deepseek-ai/dsh-client-ui-primitives'
+import type { ToolViewProps } from '../contract/toolview.ts'
+import { toolRowModel, type ToolCallBlock, type ToolRowVariant } from '../contract/tool-call-model.ts'
+import { ToolRow } from './ToolRow.tsx'
+import { IconSparkle16 } from './IconSparkle16.tsx'
+
+/** Variant leading icons (figma table). */
+const VARIANT_ICONS: Record<ToolRowVariant, ReactNode> = {
+  think: <IconThinkOutline14 />,
+  search: <IconSearchOutline16 />,
+  read: <IconBrowseOutline16 />,
+  bash: <IconApiOutline14 size={16} />,
+  others: <IconSparkle16 />,
+}
+
+export function GenericToolCard({ toolName, block, actions }: ToolViewProps) {
+  const model = toolRowModel(toolName, block as ToolCallBlock)
+  return (
+    <ToolRow
+      variant={model.variant}
+      icon={VARIANT_ICONS[model.variant]}
+      title={model.title}
+      summary={model.summary}
+      body={model.body}
+      state={model.state}
+      onOpenDetails={actions.openDetails}
+    />
+  )
+}

packages/client/ui-conversation/src/client/chat/IconSparkle16.tsx

@@ -0,0 +1,15 @@
+// Local sparkle icon for the Others tool-row variant (figma 43:31850 leading
+// glyph is an SF Symbols "sparkles" text glyph — not extractable as vector
+// data, so this is a hand-authored three-star approximation). Lives here
+// rather than ui-primitives until the exact glyph is exported and adopted
+// into the ic_ds_* family.
+
+export function IconSparkle16({ size = 16, className }: { size?: number; className?: string }) {
+  return (
+    <svg width={size} height={size} className={className} viewBox="0 0 16 16" fill="none" xmlns="http://www.w3.org/2000/svg">
+      <path d="M6.1 3.1Q6.6 7.8 11.3 8.3Q6.6 8.8 6.1 13.5Q5.6 8.8 0.9 8.3Q5.6 7.8 6.1 3.1Z" fill="currentColor" />
+      <path d="M11.9 1Q12.2 3.7 14.9 4Q12.2 4.3 11.9 7Q11.6 4.3 8.9 4Q11.6 3.7 11.9 1Z" fill="currentColor" />
+      <path d="M12.5 9.4Q12.7 11.4 14.7 11.6Q12.7 11.8 12.5 13.8Q12.3 11.8 10.3 11.6Q12.3 11.4 12.5 9.4Z" fill="currentColor" />
+    </svg>
+  )
+}

packages/client/ui-conversation/src/client/chat/MessageItem.module.css

@@ -0,0 +1,34 @@
+/* User bubble: right-aligned, figma r22 fill = the bubble specific token
+   (#EDF3FE light / dark pair rides the token sheet). */
+
+/* Block spacing is the flow column's gap alone — no extra padding here. */
+.userRow {
+  display: flex;
+  justify-content: flex-end;
+}
+
+.bubble {
+  /* 525px cap inside the 736 column; percentage keeps narrow windows sane. */
+  max-width: min(525px, 82%);
+  background: var(--dsw-specific-bubble);
+  border-radius: 22px;
+  /* 44px single-line bubble: 24 line + 10 vertical padding each side. */
+  padding: 10px 16px;
+  font-size: 16px;
+  line-height: 24px;
+  color: var(--dsw-alias-label-primary);
+}
+
+.badge {
+  display: inline-block;
+  margin-bottom: 4px;
+  padding: 1px 6px;
+  border-radius: 6px;
+  background: var(--dsw-alias-state-warn-primary);
+  color: var(--dsw-alias-label-primary-foreground);
+  font-size: 11px;
+}
+
+.contextRow {
+  padding: 2px 0;
+}

packages/client/ui-conversation/src/client/chat/MessageItem.tsx

@@ -0,0 +1,56 @@
+// MessageItem: the four simple node kinds — user bubble (right-aligned),
+// steering (badged bubble), context injection and unknown-surface JSON rows.
+// Props are frozen node slices off the snapshot cache; memo holds across
+// streaming because unchanged nodes keep their references.
+
+import { memo } from 'react'
+import type {
+  ContextMessageNode, SteeringMessageNode, UnknownSurfaceNode, UserMessageNode,
+} from '@deepseek-ai/dsh-client-runtime/client'
+import { JsonBlock, MessageText } from '@deepseek-ai/dsh-client-ui-primitives'
+import css from './MessageItem.module.css'
+
+export interface MessageItemProps {
+  node: UserMessageNode | SteeringMessageNode | ContextMessageNode | UnknownSurfaceNode
+}
+
+function contentText(content: readonly unknown[]): { text: string; rest: unknown[] } {
+  const texts: string[] = []
+  const rest: unknown[] = []
+  for (const block of content) {
+    const b = block as { type?: string; text?: string }
+    if (b.type === 'text' && typeof b.text === 'string') texts.push(b.text)
+    else rest.push(block)
+  }
+  return { text: texts.join(''), rest }
+}
+
+export const MessageItem = memo(function MessageItem({ node }: MessageItemProps) {
+  switch (node.kind) {
+    case 'user':
+    case 'steering': {
+      const { text, rest } = contentText(node.content)
+      return (
+        <div className={css.userRow}>
+          <div className={css.bubble}>
+            {node.kind === 'steering' && <span className={css.badge}>插话</span>}
+            <MessageText text={text} />
+            {rest.map((block, i) => <JsonBlock key={i} label="附加内容块" payload={block} />)}
+          </div>
+        </div>
+      )
+    }
+    case 'context':
+      return (
+        <div className={css.contextRow}>
+          <JsonBlock label="上下文注入" payload={{ content: node.content, meta: node.meta }} />
+        </div>
+      )
+    default:
+      return (
+        <div className={css.contextRow}>
+          <JsonBlock label={`未知 surface 事件：${node.type}`} payload={node.data} />
+        </div>
+      )
+  }
+})

packages/client/ui-conversation/src/client/chat/PendingCard.module.css

@@ -0,0 +1,31 @@
+/* Amber pending strip (approval waiting = warn semantic, figma state colors). */
+
+.card {
+  margin: 6px 0;
+  padding: 8px 12px;
+  border: 1px solid var(--dsw-alias-state-warn-secondary);
+  border-radius: 10px;
+  background: var(--dsw-alias-state-warn-tertiary);
+}
+
+.title {
+  font-size: 12px;
+  font-weight: 500;
+  color: var(--dsw-alias-label-primary);
+}
+
+.mono {
+  font-family: var(--ds-font-family-code);
+}
+
+.reason {
+  margin-top: 4px;
+  font-size: 12px;
+  color: var(--dsw-alias-label-secondary);
+}
+
+.hint {
+  margin-top: 6px;
+  font-size: 11px;
+  color: var(--dsw-alias-label-tertiary);
+}

packages/client/ui-conversation/src/client/chat/PendingCard.tsx

@@ -0,0 +1,31 @@
+// PendingCard: approval/question placeholder card (visible, not answerable —
+// the composer-takeover approval panel is a P-II item; wire pending semantics
+// already exist so the flow must show them).
+
+import { memo } from 'react'
+import type { PendingInteraction } from '@deepseek-ai/dsh-client-runtime/client'
+import { JsonBlock } from '@deepseek-ai/dsh-client-ui-primitives'
+import css from './PendingCard.module.css'
+
+export interface PendingCardProps {
+  item: PendingInteraction
+}
+
+export const PendingCard = memo(function PendingCard({ item }: PendingCardProps) {
+  return (
+    <div className={css.card}>
+      {item.kind === 'approval' ? (
+        <>
+          <div className={css.title}>等待审批：<span className={css.mono}>{item.toolName}</span></div>
+          {item.reason !== undefined && <div className={css.reason}>{item.reason}</div>}
+        </>
+      ) : (
+        <>
+          <div className={css.title}>等待回答（{item.questions.length} 题）</div>
+          <JsonBlock label="问题内容" payload={item.questions} />
+        </>
+      )}
+      <div className={css.hint}>请在原客户端处理（web 端作答后续里程碑提供）</div>
+    </div>
+  )
+})

packages/client/ui-conversation/src/client/chat/StatsLine.module.css

@@ -0,0 +1,13 @@
+/* Session stats row: 12/20 tertiary text under the flow, aligned to the
+   736px message column axis. */
+
+.root {
+  max-width: 736px;
+  width: 100%;
+  margin: 0 auto;
+  box-sizing: border-box;
+  padding: 4px 24px 8px;
+  font-size: 12px;
+  line-height: 20px;
+  color: var(--dsw-alias-label-tertiary);
+}

packages/client/ui-conversation/src/client/chat/StatsLine.tsx

@@ -0,0 +1,68 @@
+// StatsLine: the session stats row (figma 122:11212 "cache hit 92% · 1,284
+// tokens · 45.2s · 5 turns · 32 steps"), mounted as the chat view's
+// chrome.footer — the first chrome-attachment consumer. Duration has no data
+// source in P-I (ledger). Subscribes to `nodes` only: chunk batches never swap
+// that reference, so the row renders zero times during streaming (the RFC
+// performance model's acceptance row).
+
+import { memo, useMemo } from 'react'
+import type { ConversationSnapshot } from '@deepseek-ai/dsh-client-runtime/client'
+import type { SnapshotSelectorHook } from '@deepseek-ai/dsh-client-web-react'
+import type { ChromeProps } from '../contract/views.ts'
+import css from './StatsLine.module.css'
+
+interface UsageTotals {
+  turns: number
+  steps: number
+  tokens: number
+  cacheHitPct: number | null
+}
+
+/** Token accounting slice of assistant `usage` (typed upstream as unknown). */
+interface UsageLike {
+  inputTokens?: number
+  outputTokens?: number
+  cacheReadTokens?: number
+}
+
+/**
+ * Fold assistant nodes into display totals.
+ * @param nodes - snapshot nodes.
+ * @returns totals; cacheHitPct null until any cache accounting arrives.
+ */
+export function deriveStats(nodes: ConversationSnapshot['nodes']): UsageTotals {
+  const turns = new Set<number>()
+  let steps = 0
+  let tokens = 0
+  let input = 0
+  let cacheRead = 0
+  for (const node of nodes) {
+    if (node.kind !== 'assistant') continue
+    turns.add(node.turn)
+    steps += 1
+    const usage = node.usage as UsageLike | undefined
+    if (usage === undefined) continue
+    input += usage.inputTokens ?? 0
+    cacheRead += usage.cacheReadTokens ?? 0
+    tokens += (usage.inputTokens ?? 0) + (usage.outputTokens ?? 0) + (usage.cacheReadTokens ?? 0)
+  }
+  const denom = input + cacheRead
+  return {
+    turns: turns.size,
+    steps,
+    tokens,
+    cacheHitPct: denom === 0 ? null : Math.round((cacheRead / denom) * 100),
+  }
+}
+
+export const StatsLine = memo(function StatsLine({ useSession }: ChromeProps) {
+  const nodes = (useSession as SnapshotSelectorHook<ConversationSnapshot>)((s) => s.nodes)
+  const stats = useMemo(() => deriveStats(nodes), [nodes])
+  if (stats.steps === 0) return null
+  const parts: string[] = []
+  if (stats.cacheHitPct !== null) parts.push(`cache hit ${stats.cacheHitPct}%`)
+  parts.push(`${stats.tokens.toLocaleString('en-US')} tokens`)
+  parts.push(`${stats.turns} turns`)
+  parts.push(`${stats.steps} steps`)
+  return <div className={css.root}>{parts.join(' · ')}</div>
+})

packages/client/ui-conversation/src/client/chat/ToolRow.module.css

@@ -0,0 +1,88 @@
+/* Tool summary row (figma 122:9479): 24px single line —
+   [16 leading] gap6 [title 14/24] gap8 [2x2 dot] gap8 [summary FILL truncate]. */
+
+.root {
+  display: flex;
+  flex-direction: column;
+}
+
+.row {
+  display: flex;
+  align-items: center;
+  height: 24px;
+  min-width: 0;
+}
+
+.row[data-clickable] {
+  cursor: pointer;
+  border-radius: 6px;
+}
+
+.row[data-clickable]:hover {
+  background: var(--dsw-alias-interactive-bg-hover);
+}
+
+.leading {
+  flex: none;
+  width: 16px;
+  height: 16px;
+  display: inline-flex;
+  align-items: center;
+  justify-content: center;
+  margin-right: 6px;
+  padding: 0;
+  border: none;
+  background: none;
+  color: var(--dsw-alias-label-tertiary);
+}
+
+/* The others-variant sparkle glyph is one gray step darker than the icon
+   family in the source design. */
+.root[data-variant='others'] .leading {
+  color: var(--dsw-alias-label-secondary);
+}
+
+button.leading {
+  cursor: pointer;
+}
+
+.chevron {
+  color: var(--dsw-alias-label-secondary);
+}
+
+.title {
+  flex: none;
+  font-size: 14px;
+  line-height: 24px;
+  color: var(--dsw-alias-label-primary-dimmed);
+}
+
+.sep {
+  flex: none;
+  width: 2px;
+  height: 2px;
+  border-radius: 1px;
+  margin: 0 8px;
+  background: var(--dsw-alias-label-caption);
+}
+
+.summary {
+  flex: 1 1 auto;
+  min-width: 0;
+  overflow: hidden;
+  text-overflow: ellipsis;
+  white-space: nowrap;
+  font-size: 14px;
+  line-height: 24px;
+  color: var(--dsw-alias-label-tertiary);
+}
+
+/* Expanded body: pad-left 22 indented gray text, no border, no fill. */
+.body {
+  padding: 4px 0 4px 22px;
+  font-size: 14px;
+  line-height: 24px;
+  white-space: pre-wrap;
+  word-break: break-word;
+  color: var(--dsw-alias-label-tertiary);
+}

packages/client/ui-conversation/src/client/chat/ToolRow.tsx

@@ -0,0 +1,75 @@
+// ToolRow: the single-line tool summary row (figma component set 122:9479) —
+// 16px leading slot (state dot / tool icon, chevron when expanded) + title +
+// separator dot + FILL-truncated summary. Expanded body is indented gray text;
+// no inline output (full results live in the details panel). Expand state is
+// component-local view state; row click hands the selection off to the owner.
+
+import { useState, type ReactNode } from 'react'
+import clsx from 'clsx'
+import { StateDot } from '@deepseek-ai/dsh-client-ui-primitives'
+import { IconChevronDownOutline14 } from '@deepseek-ai/dsh-client-ui-primitives'
+import type { ToolRowState, ToolRowVariant } from '../contract/tool-call-model.ts'
+import css from './ToolRow.module.css'
+
+export interface ToolRowProps {
+  variant: ToolRowVariant
+  /** Leading 16px tool icon, shown while collapsed and not running/failed. */
+  icon: ReactNode
+  title: string
+  summary: string
+  /** Expanded-body text; null = not expandable (leading slot never toggles). */
+  body: string | null
+  state: ToolRowState
+  /** Selection handoff (row click), already bound to this call by the owner. */
+  onOpenDetails?: (() => void) | undefined
+}
+
+/** Leading-slot state substitution: the tool icon yields to the state semantic
+ *  (running = blue ring, error = red, interrupted = amber halo; ok = icon). */
+function leadingFor(state: ToolRowState, icon: ReactNode): ReactNode {
+  switch (state) {
+    case 'running': return <StateDot state="ongoing" />
+    case 'error': return <StateDot state="error" />
+    case 'stopped': return <StateDot state="warning" />
+    default: return icon
+  }
+}
+
+export function ToolRow({ variant, icon, title, summary, body, state, onOpenDetails }: ToolRowProps) {
+  const [expanded, setExpanded] = useState(false)
+  const expandable = body !== null
+  const open = expanded && expandable
+  return (
+    <div className={css.root} data-variant={variant} data-state={state}>
+      <div
+        className={css.row}
+        data-clickable={onOpenDetails !== undefined || undefined}
+        onClick={onOpenDetails}
+      >
+        {expandable ? (
+          <button
+            type="button"
+            className={css.leading}
+            aria-expanded={open}
+            onClick={(e) => {
+              e.stopPropagation()
+              setExpanded((v) => !v)
+            }}
+          >
+            {open ? <IconChevronDownOutline14 className={clsx(css.chevron)} /> : leadingFor(state, icon)}
+          </button>
+        ) : (
+          <span className={css.leading}>{leadingFor(state, icon)}</span>
+        )}
+        <span className={css.title}>{title}</span>
+        {!open && (
+          <>
+            <span className={css.sep} aria-hidden />
+            <span className={css.summary}>{summary}</span>
+          </>
+        )}
+      </div>
+      {open && <div className={css.body}>{body}</div>}
+    </div>
+  )
+}

packages/client/ui-conversation/src/client/chat/ToolViewOutlet.tsx

@@ -0,0 +1,89 @@
+// ToolViewOutlet: resolves the toolview for one call through ctx.toolviews
+// (uSES over the registry version so unload falls back live) and renders it
+// behind a per-row error boundary. GenericToolCard is the render-side
+// fallback for both a registry miss and a crashed custom row. A registrant
+// inject factory is called once per (registration x binding) and cached,
+// mirroring the scoped-slots injection discipline.
+
+import { Component, useSyncExternalStore, type FC, type ReactNode } from 'react'
+import { useSessionBinding } from '@deepseek-ai/dsh-client-web-react'
+import type { SessionBinding } from '@deepseek-ai/dsh-client-ui-slots'
+import type { SessionId } from '@deepseek-ai/dsh-client-runtime/client'
+import type { ToolViewInject, ToolViewProps, ToolViewResolver } from '../contract/toolview.ts'
+import { GenericToolCard } from './GenericToolCard.tsx'
+
+export interface ToolViewOutletProps {
+  registry: ToolViewResolver
+  sessionId: SessionId
+  toolName: string
+  viewProps: ToolViewProps
+}
+
+/** Inject cache: per inject-factory (stable per registration) x binding object. */
+const injectCache = new WeakMap<ToolViewInject<object>, WeakMap<object, object>>()
+
+function cachedInject(inject: ToolViewInject<object>, binding: SessionBinding): object {
+  let perBinding = injectCache.get(inject)
+  if (!perBinding) {
+    perBinding = new WeakMap()
+    injectCache.set(inject, perBinding)
+  }
+  let props = perBinding.get(binding)
+  if (!props) {
+    props = inject(binding)
+    perBinding.set(binding, props)
+  }
+  return props
+}
+
+class RowErrorBoundary extends Component<
+  { resetKey: unknown; fallback: ReactNode; children: ReactNode }, { failed: boolean }
+> {
+  override state = { failed: false }
+  // Fallback state MUST flip here (render phase): a boundary whose derived
+  // state does not change re-renders the crashing children and React gives
+  // up after the second throw, escalating past the boundary.
+  static getDerivedStateFromError(): { failed: boolean } {
+    return { failed: true }
+  }
+  override componentDidCatch(error: unknown): void {
+    console.error('toolview row crashed:', error)
+  }
+  // A re-registration (resetKey bump) retries the custom row.
+  override componentDidUpdate(prev: { resetKey: unknown }): void {
+    if (this.state.failed && prev.resetKey !== this.props.resetKey) {
+      this.setState({ failed: false })
+    }
+  }
+  override render(): ReactNode {
+    if (this.state.failed) return this.props.fallback
+    return this.props.children
+  }
+}
+
+/** Split component: only inject-carrying registrations need the session
+ *  binding hook (keeps injectless rendering free of the Provider requirement). */
+function InjectedRow({ Row, inject, viewProps }: {
+  Row: FC<ToolViewProps & object>; inject: ToolViewInject<object>; viewProps: ToolViewProps
+}) {
+  const binding = useSessionBinding()
+  const injected = cachedInject(inject, binding)
+  return <Row {...{ ...injected, ...viewProps }} />
+}
+
+export function ToolViewOutlet({ registry, sessionId, toolName, viewProps }: ToolViewOutletProps) {
+  const version = useSyncExternalStore(
+    (fn) => registry.subscribe(fn),
+    () => registry.getVersion(),
+  )
+  const resolved = registry.resolve(toolName, sessionId)
+  if (resolved === undefined) return <GenericToolCard {...viewProps} />
+  const Row = resolved.component
+  return (
+    <RowErrorBoundary resetKey={version} fallback={<GenericToolCard {...viewProps} />}>
+      {resolved.inject === undefined
+        ? <Row {...viewProps} />
+        : <InjectedRow Row={Row} inject={resolved.inject} viewProps={viewProps} />}
+    </RowErrorBoundary>
+  )
+}

packages/client/ui-conversation/src/client/chat/chat-flow.ts

@@ -0,0 +1,46 @@
+/**
+ * Chat flow derivation: ConversationSnapshot nodes -> render items. Tool
+ * results group into consecutive-run tool groups (figma step-summary flow,
+ * VERTICAL gap10) alternating with narration; everything else passes through.
+ * Item identity keys are stable across snapshots so the list parent can
+ * subscribe to keys only while rows subscribe to content.
+ */
+import type { ConversationNode, ToolResultNode } from '@deepseek-ai/dsh-client-runtime/client'
+
+/** One renderable flow item; key is the React key and the parent's identity unit. */
+export type ChatFlowItem =
+  | { kind: 'node'; key: string; node: ConversationNode }
+  | { kind: 'tool-group'; key: string; results: readonly ToolResultNode[] }
+
+/**
+ * Group finalized nodes into the step-summary flow.
+ * @param nodes - snapshot nodes (surface order).
+ * @returns flow items; consecutive tool-results merged into one group keyed by the first seq.
+ */
+export function deriveChatFlow(nodes: readonly ConversationNode[]): ChatFlowItem[] {
+  const items: ChatFlowItem[] = []
+  let group: ToolResultNode[] | null = null
+  for (const node of nodes) {
+    if (node.kind === 'tool-result') {
+      if (group === null) {
+        group = [node]
+        items.push({ kind: 'tool-group', key: `g${node.seq}`, results: group })
+      } else {
+        group.push(node)
+      }
+    } else {
+      group = null
+      items.push({ kind: 'node', key: `n${node.seq}`, node })
+    }
+  }
+  return items
+}
+
+/**
+ * Key projection for the list parent's selector (content-blind identity).
+ * @param items - derived flow items.
+ * @returns joined key string usable with Object.is short-circuiting.
+ */
+export function flowKeys(items: readonly ChatFlowItem[]): string {
+  return items.map(i => i.key).join('|')
+}

packages/client/ui-conversation/src/client/chat/register.ts

@@ -0,0 +1,52 @@
+/**
+ * Chat-side registration entry, called from the plugin apply (the assembly
+ * point): registers the chat view with the stats-line footer chrome. The
+ * chat domain touches the tool ring only through the contract resolver face;
+ * bash sample registration moved to apply (cross-domain assembly).
+ */
+import type { SessionId, SessionListState } from '@deepseek-ai/dsh-client-runtime/client'
+import type { ConversationService } from '../service.ts'
+import type { Translate } from '../contract/views.ts'
+import type { ToolViewResolver } from '../contract/toolview.ts'
+import { createChatView } from './ChatView.tsx'
+import { StatsLine } from './StatsLine.tsx'
+
+/** Read face of the sessions list store (subscription not needed: the filter
+ *  reads the latest snapshot at each resolve). */
+export interface SessionListReader { getSnapshot(): SessionListState }
+
+/**
+ * Default scoped-sample filter: the sub-session family. Sub-agent rows
+ * rendering differently is the registry's canonical product scenario, and
+ * forking gives W5 acceptance a real entry point to observe the differential.
+ * @param list - injected sessions list read face.
+ * @returns filter matching sessions with a parent.
+ */
+export function childSessionScope(list: SessionListReader): (sessionId: SessionId) => boolean {
+  return sessionId => list.getSnapshot().byId[sessionId]?.parentId !== undefined
+}
+
+/** Assembly inputs for {@link registerChat} (resolved by apply, not here). */
+export interface RegisterChatDeps {
+  conversation: ConversationService
+  /** Toolview read face consumed by the chat rows' outlet. */
+  toolviews: ToolViewResolver
+  /** Translator bound to the conversation namespace. */
+  t: Translate
+}
+
+/**
+ * Register the chat view (footer chrome included).
+ * @param deps - assembled service instances.
+ * @returns disposer removing the registration.
+ */
+export function registerChat(deps: RegisterChatDeps): () => void {
+  const { conversation, toolviews, t } = deps
+  return conversation.registerView({
+    id: 'chat',
+    label: 'Chat',
+    order: 0,
+    component: createChatView({ toolviews, t }),
+    chrome: { footer: StatsLine },
+  })
+}

packages/client/ui-conversation/src/client/contract/slots.ts

@@ -0,0 +1,63 @@
+/**
+ * Slot-ring contract for the conversation package: the composed props shapes
+ * its registrants mount into the layout-owned slots (conversation / details /
+ * conversation.empty — the SlotMap declarations live with ui-layout, the
+ * slot owner). Per the share-ownership rule, the owner share is REFERENCED
+ * from ui-layout and each registrant's injected share is declared here, next
+ * to the component that receives it; full component props = owner share &
+ * standard share & own injected share.
+ */
+import type { ReactNode } from 'react'
+import type { SessionId, SessionSummary } from '@deepseek-ai/dsh-client-runtime/client'
+import type { SnapshotSelectorHook, UseSession } from '@deepseek-ai/dsh-client-web-react'
+import type { ConvOwnerProps, DetailsOwnerProps, EmptyOwnerProps } from '@deepseek-ai/dsh-client-ui-layout/client'
+import type { SelectionTarget, ViewEntry, ViewId } from './views.ts'
+
+/** Injected share of the conversation slot (assembled by apply's inject factory). */
+export interface ConversationInjected {
+  /** Breadcrumb chain (root ancestor first, self last; ancestry(list) feed). */
+  useAncestry: () => readonly SessionSummary[]
+  /** View registry read face (uSES triple from the conversation service). */
+  views: {
+    list(): readonly ViewEntry[]
+    subscribe(fn: () => void): () => void
+    version(): number
+  }
+  /** Active view accessor (layout.viewFor backed; undefined falls to 'chat'). */
+  useActiveView: () => ViewId | undefined
+  /** Composer surface: draft store hook pair + send/stop choreography. */
+  composer: {
+    useDraft: () => string
+    setDraft(text: string): void
+    send(mode: 'queue' | 'steer'): void
+    stop(): void
+  }
+  actions: {
+    openView(view: ViewId): void
+    open(id: SessionId): void
+  }
+  /** Renders the active view's body (the owner closes over ConvViewProps assembly). */
+  renderView: (entry: ViewEntry) => ReactNode
+}
+
+/** Full conversation-slot component props: owner share & standard share & injected share. */
+export type ConversationSlotProps = ConvOwnerProps & { useSession: UseSession } & ConversationInjected
+
+/** Injected share of the details slot. */
+export interface DetailsInjected {
+  useSelection: SnapshotSelectorHook<SelectionTarget | null>
+  actions: { closeDetails(): void }
+}
+
+/** Full details-slot component props. */
+export type DetailsSlotProps = DetailsOwnerProps & { useSession: UseSession } & DetailsInjected
+
+/** Injected share of the no-session empty-state slot (root slot: no standard share). */
+export interface EmptyStateInjected {
+  /** cwd options derived from sessions.list (deduped; assembled by the inject factory). */
+  useCwds: SnapshotSelectorHook<readonly string[]>
+  actions: { startSession(opts: { cwd?: string; text: string; mode: 'queue' | 'steer' }): Promise<void> }
+}
+
+/** Full empty-state component props. */
+export type EmptyStateSlotProps = EmptyOwnerProps & EmptyStateInjected

packages/client/ui-conversation/src/client/contract/tool-call-model.ts

@@ -0,0 +1,126 @@
+/**
+ * Pure row-model derivation for tool summary rows: variant classification,
+ * one-line summary and expanded-body text from the frozen call slice. No
+ * inline output ever — full results live in the details panel.
+ */
+import type { ToolCallBlock } from './toolview.ts'
+
+export type { ToolCallBlock } from './toolview.ts'
+
+/** The frozen slice the chat view hands to toolview components as `block`
+ *  (both members are cache-stable references off ConversationSnapshot). */
+
+/** The five figma row variants (think is fed by reasoning blocks, not tool calls). */
+export type ToolRowVariant = 'think' | 'search' | 'read' | 'bash' | 'others'
+
+/** Row state semantic; colors self-supplied via StateDot (design gives none). */
+export type ToolRowState = 'running' | 'ok' | 'error' | 'stopped'
+
+/** Figma row titles per variant (design literals, not translatable copy). */
+export const VARIANT_TITLES: Record<ToolRowVariant, string> = {
+  think: 'Think', search: 'Search', read: 'Read', bash: 'Bash', others: 'Tool call',
+}
+
+/** Known tool name -> variant; fs write/edit intentionally fall to others (no figma form). */
+const TOOL_VARIANTS: Record<string, ToolRowVariant> = {
+  bash: 'bash',
+  read: 'read',
+  web_fetch: 'read',
+  web_search: 'search',
+  grep: 'search',
+  glob: 'search',
+}
+
+/**
+ * Classify a tool name into its row variant.
+ * @param toolName - wire tool name.
+ * @returns matching variant, others when unknown.
+ */
+export function classifyTool(toolName: string): ToolRowVariant {
+  return TOOL_VARIANTS[toolName] ?? 'others'
+}
+
+/** Everything ToolRow needs, derived once from the frozen slice. */
+export interface ToolRowModel {
+  variant: ToolRowVariant
+  title: string
+  summary: string
+  /** Expanded-body text (pretty args); null = row not expandable. */
+  body: string | null
+  state: ToolRowState
+}
+
+function parseArgs(argsRaw: string): unknown {
+  try {
+    return JSON.parse(argsRaw)
+  } catch {
+    // Non-JSON args (mid-stream truncation): summary/body fall back to the raw string.
+    return undefined
+  }
+}
+
+function firstLine(text: string): string {
+  const nl = text.indexOf('\n')
+  return nl === -1 ? text : text.slice(0, nl)
+}
+
+function pickString(args: Record<string, unknown>, keys: readonly string[]): string | undefined {
+  for (const key of keys) {
+    const v = args[key]
+    if (typeof v === 'string' && v !== '') return v
+  }
+  return undefined
+}
+
+/** Summary key preference per variant (args-derived; result-derived summaries are a ledger item). */
+const SUMMARY_KEYS: Record<ToolRowVariant, readonly string[]> = {
+  bash: ['description', 'command'],
+  read: ['path', 'file_path', 'url'],
+  search: ['query', 'pattern', 'url'],
+  think: [],
+  others: [],
+}
+
+function deriveSummary(variant: ToolRowVariant, argsRaw: string): string {
+  const parsed = parseArgs(argsRaw)
+  if (typeof parsed !== 'object' || parsed === null) return firstLine(argsRaw)
+  const args = parsed as Record<string, unknown>
+  const picked = pickString(args, SUMMARY_KEYS[variant])
+  if (picked !== undefined) return firstLine(picked)
+  for (const v of Object.values(args)) {
+    if (typeof v === 'string' && v !== '') return firstLine(v)
+  }
+  return firstLine(argsRaw)
+}
+
+function deriveBody(argsRaw: string): string | null {
+  if (argsRaw === '') return null
+  const parsed = parseArgs(argsRaw)
+  return parsed === undefined ? argsRaw : JSON.stringify(parsed, null, 2)
+}
+
+/**
+ * Derive the full row model from a frozen call slice.
+ * @param toolName - wire tool name (dispatch-supplied; survives windowless results).
+ * @param block - RunningToolCall or ToolResultNode off the snapshot caches.
+ * @returns the row model.
+ */
+export function toolRowModel(toolName: string, block: ToolCallBlock): ToolRowModel {
+  const variant = classifyTool(toolName)
+  const done = 'kind' in block
+  const argsRaw = (done ? block.call?.argsRaw : block.argsRaw) ?? ''
+  const state: ToolRowState = !done ? 'running'
+    : block.error?.code === 'interrupted' ? 'stopped'
+      : block.isError ? 'error' : 'ok'
+  const base = argsRaw === '' ? block.callId : deriveSummary(variant, argsRaw)
+  // Others keeps the static "Tool call" title (figma literal); the real tool
+  // name rides the mutable summary slot so no information is lost.
+  const summary = variant === 'others' && toolName !== '' ? `${toolName} · ${base}` : base
+  return {
+    variant,
+    title: VARIANT_TITLES[variant],
+    summary,
+    body: deriveBody(argsRaw),
+    state,
+  }
+}

packages/client/ui-conversation/src/client/contract/toolview.ts

@@ -0,0 +1,77 @@
+/**
+ * Tool-ring contract: the props surface handed to toolview components, the
+ * registry's resolve/registration shapes, and the tool-call block union.
+ * Shared face between the chat domain (ToolViewOutlet consumes resolve) and
+ * the toolviews domain (registry implementation + sample rows); domain
+ * implementation files import this, never each other.
+ */
+import type { FC } from 'react'
+import type { SessionBinding } from '@deepseek-ai/dsh-client-ui-slots'
+import type { UseSession } from '@deepseek-ai/dsh-client-web-react'
+import type { SessionId, ToolCallBlock } from '@deepseek-ai/dsh-client-runtime/client'
+import type { CallId, Translate } from './views.ts'
+
+// The block union's defining home is runtime (fold-product types); the
+// contract only forwards it (type-definition authority stays with the layer
+// that produces the values).
+export type { ToolCallBlock } from '@deepseek-ai/dsh-client-runtime/client'
+
+/** Props handed to registered toolview components. */
+export interface ToolViewProps {
+  callId: CallId
+  toolName: string
+  block: ToolCallBlock
+  useSession: UseSession
+  actions: { openDetails(): void }
+  t: Translate
+}
+
+/**
+ * Toolview inject factory: produces the registrant's private injected share
+ * `I`, called once per (registration x session binding) and cached by the
+ * render outlet. Session-bound by nature — tool rows always render inside a
+ * session subtree.
+ */
+export type ToolViewInject<I extends object> = (b: SessionBinding) => I
+
+/** Options accepted by the toolview registry's register; `I` is inferred from the inject factory. */
+export interface ToolViewOptions<I extends object = object> {
+  /** Session filter; absent = global registration. */
+  scope?: (sessionId: SessionId) => boolean
+  /** Private inject factory merged into the row's props by the render outlet. */
+  inject?: ToolViewInject<I>
+}
+
+/**
+ * A resolved toolview registration. `I` is erased to `object` on the resolve
+ * read face (storage erases the per-registration parameter; the outlet merges
+ * injected props untyped — the register site already proved component ⊇ I).
+ */
+export interface ResolvedToolView<I extends object = object> {
+  component: FC<ToolViewProps & I>
+  inject?: ToolViewInject<I>
+}
+
+/** The registry's read face consumed by render outlets (implementation lives in the toolviews domain). */
+export interface ToolViewResolver {
+  /**
+   * Resolve the renderer for a tool in a session. Order: scope match (later
+   * registration wins) > global > undefined (caller falls back to the
+   * generic card).
+   * @param tool - tool name.
+   * @param sessionId - session the row renders in.
+   * @returns resolved view, or undefined when nothing matches.
+   */
+  resolve(tool: string, sessionId: SessionId): ResolvedToolView | undefined
+  /**
+   * Subscribe to registration changes (synchronous).
+   * @param fn - change callback.
+   * @returns unsubscribe.
+   */
+  subscribe(fn: () => void): () => void
+  /**
+   * Monotonic version for uSES pairing.
+   * @returns current version.
+   */
+  getVersion(): number
+}

packages/client/ui-conversation/src/client/contract/views.ts

@@ -0,0 +1,68 @@
+/**
+ * View-ring contract: the typed conversation view table and the props
+ * surfaces handed to registered views. Shared face between the skeleton
+ * domain (ConversationRoot renders views) and the chat domain (registers the
+ * chat view); domain implementation files import this, never each other.
+ */
+import type { FC } from 'react'
+import type { ScopedSlots } from '@deepseek-ai/dsh-client-ui-slots'
+import type { SnapshotSelectorHook, UseSession } from '@deepseek-ai/dsh-client-web-react'
+import type { SessionId } from '@deepseek-ai/dsh-client-runtime/client'
+
+/**
+ * One ConversationViewMap entry: per-view props extension shapes (design
+ * ledger, view ring). `chromeProps` extends {@link ChromeProps} for the
+ * view's chrome attachments; `extraProps` extends {@link ConvViewProps} for
+ * the view component itself. Both optional — the common bases stay the floor.
+ */
+export interface ViewEntryDef { chromeProps?: object; extraProps?: object }
+
+/**
+ * Typed conversation view table; ui-trajectory merges {trajectory, waterfall}.
+ * The chat entry is declared inline here (self-merge from a sibling module
+ * trips TS6305 under tsc -b).
+ */
+export interface ConversationViewMap { chat: ViewEntryDef }
+
+/** View id constrained to registered ConversationViewMap keys (all string literals; chat is declared inline). */
+export type ViewId = keyof ConversationViewMap
+
+/** Per-view chrome props: the common base plus the entry's declared extension. */
+export type ChromePropsOf<Id extends ViewId> =
+  ChromeProps & (ConversationViewMap[Id] extends { chromeProps: infer C extends object } ? C : object)
+
+/** Per-view component props: the common base plus the entry's declared extension. */
+export type ConvViewPropsOf<Id extends ViewId> =
+  ConvViewProps & (ConversationViewMap[Id] extends { extraProps: infer E extends object } ? E : object)
+
+/** Tool call identity as carried on the wire (branded upstream in connection). */
+export type CallId = string
+
+/** Translate function bound to a namespace via i18n. */
+export type Translate = (key: string, params?: Record<string, unknown>) => string
+
+/** One registered conversation view (props positions keyed by the entry's declared shapes). */
+export interface ViewEntry<Id extends ViewId = ViewId> {
+  id: Id
+  label: string
+  order?: number
+  component: FC<ConvViewPropsOf<Id>>
+  /** Per-view chrome attachments (chat mounts the stats line as footer). */
+  chrome?: { header?: FC<ChromePropsOf<Id>>; footer?: FC<ChromePropsOf<Id>> }
+}
+
+/** Props for view chrome attachments. */
+export interface ChromeProps { sessionId: SessionId; useSession: UseSession }
+
+/** Selection target for the details linkage channel (toolcall is the step special case). */
+export interface SelectionTarget { turnSeq: number; stepSeq?: number; callId?: CallId; toolName?: string }
+
+/** Props handed to registered conversation views. */
+export interface ConvViewProps {
+  sessionId: SessionId
+  useSession: UseSession
+  useSelection: SnapshotSelectorHook<SelectionTarget | null>
+  actions: { openDetails(t: SelectionTarget): void; loadOlder(): void }
+  /** Chat has no delegated sub-slots in P-I (toolviews go through the named registry). */
+  slots: ScopedSlots<never>
+}

packages/client/ui-conversation/src/client/index.ts

@@ -0,0 +1,42 @@
+/**
+ * Conversation domain plugin, browser half: skeleton (header/tabs/composer),
+ * typed view registry, scope-addressed ConversationService, named toolview
+ * registry, minimal details panel. Contract: api-contracts v3 section 7.
+ * Thin shell: type surfaces live in contract/, assembly in apply.ts; the
+ * three implementation domains (skeleton/chat/toolviews) never import each
+ * other — contract/ is their only shared face.
+ */
+import type { ConversationService } from './service.ts'
+import type { ToolViewRegistry } from './toolviews/registry.ts'
+
+export { apply, inject } from './apply.ts'
+export { ConversationService } from './service.ts'
+export { ToolViewRegistry } from './toolviews/registry.ts'
+
+export type {
+  CallId, ChromeProps, ChromePropsOf, ConversationViewMap, ConvViewProps, ConvViewPropsOf,
+  SelectionTarget, Translate, ViewEntry, ViewEntryDef, ViewId,
+} from './contract/views.ts'
+export type {
+  ResolvedToolView, ToolCallBlock, ToolViewOptions, ToolViewProps, ToolViewResolver,
+} from './contract/toolview.ts'
+export type {
+  ConversationInjected, ConversationSlotProps, DetailsInjected, DetailsSlotProps,
+  EmptyStateInjected, EmptyStateSlotProps,
+} from './contract/slots.ts'
+
+export { ConversationRoot } from './skeleton/ConversationRoot.tsx'
+export type { ConversationRootProps } from './skeleton/ConversationRoot.tsx'
+export { InputBar } from './skeleton/InputBar.tsx'
+export type { InputBarError, InputBarProps } from './skeleton/InputBar.tsx'
+export { EmptyState } from './skeleton/EmptyState.tsx'
+export type { EmptyStateProps } from './skeleton/EmptyState.tsx'
+export { DetailsPanel } from './skeleton/DetailsPanel.tsx'
+export type { DetailsPanelProps } from './skeleton/DetailsPanel.tsx'
+
+declare module 'cordis' {
+  interface Context {
+    conversation: ConversationService
+    toolviews: ToolViewRegistry
+  }
+}

packages/client/ui-conversation/src/client/service.ts

@@ -0,0 +1,251 @@
+/**
+ * ConversationService implementation: scope-addressed send/cancel, per-scope
+ * selection/draft stores booked on the session scope fiber, view registry
+ * with a uSES read face, openDetails orchestration, and the empty-state
+ * startSession chain. Contract: api-contracts v3 section 7.
+ *
+ * Scope addressing rides the cordis Service tracker: property access through
+ * `ctx.conversation` rebinds `this.ctx` to the caller's context, so methods
+ * read the session tag with scopeOf (same mechanism as the host tool
+ * registry). Mutable state lives in plain objects reached by one property
+ * read — field assignment through the tracker's shadow proxy is off-limits,
+ * as are `#` hard-private fields.
+ */
+import { Service } from 'cordis'
+import type { Context } from 'cordis'
+// Value import MUST use the /client subpath: only that specifier is in the
+// bundle externals (CLIENT_EXTERNALS), so it resolves to the shared runtime
+// module at load time. A bare-specifier value import gets INLINED as a second
+// module instance whose private scope-tag Symbol never matches the one
+// SessionsService tags contexts with — scopeOf then always returns undefined
+// in the browser while unit tests (single-instance path resolution) stay green.
+import { scopeOf } from '@deepseek-ai/dsh-client-runtime/client'
+import type { Session, SessionId, SessionsService } from '@deepseek-ai/dsh-client-runtime/client'
+import { createSnapshotStore } from '@deepseek-ai/dsh-client-web-react'
+import type { SnapshotStore } from '@deepseek-ai/dsh-client-web-react'
+import type { LayoutService } from '@deepseek-ai/dsh-client-ui-layout/client'
+import type { SelectionTarget, ViewEntry, ViewId } from './index.ts'
+
+/** Mutable view-registry cell (plain object: mutation never crosses the tracker proxy). */
+interface ViewsState {
+  entries: Map<string, ViewEntry>
+  /** Sorted projection cache; null = rebuild on next read. */
+  cache: readonly ViewEntry[] | null
+  tick: number
+  listeners: Set<() => void>
+}
+
+/** Scope-addressed conversation service (root singleton, provided as `conversation`). */
+export class ConversationService extends Service {
+  private readonly selections = new Map<SessionId, SnapshotStore<SelectionTarget | null>>()
+  private readonly draftStores = new Map<SessionId, SnapshotStore<string>>()
+  private readonly viewsState: ViewsState = {
+    entries: new Map(), cache: null, tick: 0, listeners: new Set(),
+  }
+
+  /**
+   * @param ctx - owning root context (the plugin apply context; the service
+   * registers itself and follows that fiber's lifetime).
+   */
+  constructor(ctx: Context) {
+    super(ctx, 'conversation')
+  }
+
+  /**
+   * Send a prompt into the scoped session. Business failures also land in the
+   * session snapshot's promptError (object-layer surface); the rejection here
+   * exists for caller choreography (the composer restores the draft on it).
+   * @param text - prompt text, sent verbatim as one text block.
+   * @param mode - queue after the current turn, or steer into it.
+   */
+  async send(text: string, mode: 'queue' | 'steer'): Promise<void> {
+    const session = this.scopedSession('send')
+    const result = await session.prompt([{ type: 'text', text }], mode)
+    if (!result.ok) throw new Error(`conversation.send failed: ${result.error.code}: ${result.error.message}`)
+  }
+
+  /** Cancel the scoped session's in-flight turn (failures land in promptError and reject, as in send). */
+  async cancel(): Promise<void> {
+    const session = this.scopedSession('cancel')
+    const result = await session.cancel()
+    if (!result.ok) throw new Error(`conversation.cancel failed: ${result.error.code}: ${result.error.message}`)
+  }
+
+  /** Per-scope selection channel (details linkage); root access throws. */
+  get selection(): SnapshotStore<SelectionTarget | null> {
+    return this.scopeStore(this.selections, 'selection',
+      () => createSnapshotStore<SelectionTarget | null>(null))
+  }
+
+  /**
+   * Per-scope draft store, persisted per session id; root access throws.
+   * Persistence is hand-rolled (raw string per key): the snapshot-store
+   * engine's persist middleware object-spreads state on save, corrupting
+   * primitive-state stores.
+   */
+  get drafts(): SnapshotStore<string> {
+    return this.scopeStore(this.draftStores, 'drafts', (id) => {
+      const key = `dsh.conversation.draft.${id}`
+      const store = createSnapshotStore<string>(loadDraft(key))
+      store.subscribe(() => { saveDraft(key, store.getSnapshot()) })
+      return store
+    })
+  }
+
+  /**
+   * Write the scoped selection and open the details panel. Orchestration
+   * only — panel geometry stays with ctx.layout.
+   * @param target - selection target.
+   */
+  openDetails(target: SelectionTarget): void {
+    this.selection.set(target)
+    this.requireLayout().openDetails()
+  }
+
+  /**
+   * Register a conversation view. Duplicate ids throw; the registration is an
+   * effect on the caller's fiber (plugin unload collects it).
+   * @param entry - the view entry.
+   * @returns disposer removing the view.
+   */
+  registerView<Id extends ViewId>(entry: ViewEntry<Id>): () => void {
+    const views = this.viewsState
+    const dispose = this.ctx.effect(() => {
+      if (views.entries.has(entry.id)) {
+        throw new Error(`conversation view "${entry.id}" is already registered`)
+      }
+      views.entries.set(entry.id, entry)
+      bumpViews(views)
+      return () => {
+        views.entries.delete(entry.id)
+        bumpViews(views)
+      }
+    }, 'conversation.registerView()')
+    // The effect disposer settles asynchronously; the registry face stays a
+    // synchronous fire-and-forget disposer.
+    return () => { void dispose() }
+  }
+
+  /**
+   * Registered views ordered by `order` (ties keep registration sequence).
+   * Stable array reference between mutations (uSES getSnapshot source).
+   * @returns the view entries.
+   */
+  views(): readonly ViewEntry[] {
+    const state = this.viewsState
+    state.cache ??= [...state.entries.values()].sort((a, b) => (a.order ?? 0) - (b.order ?? 0))
+    return state.cache
+  }
+
+  /**
+   * Subscribe to view registry changes (synchronous, like the toolview registry).
+   * @param fn - change callback.
+   * @returns unsubscribe.
+   */
+  subscribeViews(fn: () => void): () => void {
+    const { listeners } = this.viewsState
+    listeners.add(fn)
+    return () => { listeners.delete(fn) }
+  }
+
+  /**
+   * Monotonic view registry version for uSES pairing.
+   * @returns current version.
+   */
+  viewsVersion(): number {
+    return this.viewsState.tick
+  }
+
+  /**
+   * Empty-state first-send chain (root-context method; does not read scope):
+   * create the session, navigate to it, then send through the new scope.
+   * The create → open ordering is safe: the manager merges the new summary
+   * synchronously before create() resolves, so the list store is projected by
+   * the time open() validates against it (manager notification batching is
+   * microtask-based; SessionsService projects on the same flush that create
+   * awaited through the RPC round trip).
+   * @param opts - project directory, prompt text, and send mode.
+   */
+  async startSession(opts: { cwd?: string; text: string; mode: 'queue' | 'steer' }): Promise<void> {
+    const sessions = this.requireSessions()
+    const id = await sessions.create(opts.cwd === undefined ? {} : { cwd: opts.cwd })
+    // The manager notifier flushes per microtask; one await guarantees the
+    // list-store projection landed before layout.open validates against it.
+    await Promise.resolve()
+    this.requireLayout().open(id)
+    const scoped = sessions.scope(id)
+    if (scoped === undefined) throw new Error(`conversation.startSession: created session "${id}" resolved no scope`)
+    // ctx.get, not scoped.conversation: property access walks the fiber
+    // topology (a scope fiber never injects services), while get reads the
+    // global store and still binds this service to the scoped ctx.
+    const scopedConversation = scoped.get('conversation')
+    if (scopedConversation === undefined) throw new Error('conversation.startSession: conversation service unavailable through the new scope')
+    await scopedConversation.send(opts.text, opts.mode)
+  }
+
+  /** Resolve the caller scope's Session or throw on root contexts. */
+  private scopedSession(op: string): Session {
+    const id = this.scopeId(op)
+    return this.requireSessions().manager.get(id)
+  }
+
+  /** Read the caller's session scope tag; root contexts fail loud. */
+  private scopeId(op: string): SessionId {
+    const id = scopeOf(this.ctx)
+    if (id === undefined) {
+      throw new Error(`conversation.${op} requires a session scope — address one via ctx.sessions.scope(id).conversation`)
+    }
+    return id
+  }
+
+  /**
+   * Per-scope store account: lazily created, booked on the scope fiber so the
+   * scope teardown (SessionsService prune) collects the entry.
+   */
+  private scopeStore<T>(
+    map: Map<SessionId, SnapshotStore<T>>, op: string,
+    make: (id: SessionId) => SnapshotStore<T>): SnapshotStore<T> {
+    const id = this.scopeId(op)
+    let store = map.get(id)
+    if (store === undefined) {
+      store = make(id)
+      map.set(id, store)
+      this.ctx.effect(() => () => { map.delete(id) }, `conversation.${op} scope account`)
+    }
+    return store
+  }
+
+  private requireSessions(): SessionsService {
+    // ctx.get instead of ctx.sessions: the typed Context merge is suspended
+    // while the client/host `sessions` declaration collision awaits
+    // arbitration (see the runtime package's Context merge note).
+    const sessions = this.ctx.get('sessions')
+    if (sessions === undefined) throw new Error('conversation: sessions service unavailable')
+    return sessions
+  }
+
+  private requireLayout(): LayoutService {
+    const layout = this.ctx.get('layout')
+    if (layout === undefined) throw new Error('conversation: layout service unavailable')
+    return layout
+  }
+}
+
+function bumpViews(state: ViewsState): void {
+  state.cache = null
+  state.tick += 1
+  for (const fn of [...state.listeners]) fn()
+}
+
+function loadDraft(key: string): string {
+  /* v8 ignore next -- storage-less environment guard (workers/tests without DOM); jsdom always provides localStorage. */
+  if (typeof localStorage === 'undefined') return ''
+  return localStorage.getItem(key) ?? ''
+}
+
+function saveDraft(key: string, text: string): void {
+  /* v8 ignore next -- storage-less environment guard (workers/tests without DOM); jsdom always provides localStorage. */
+  if (typeof localStorage === 'undefined') return
+  if (text === '') localStorage.removeItem(key)
+  else localStorage.setItem(key, text)
+}

packages/client/ui-conversation/src/client/skeleton/ConversationRoot.module.css

@@ -0,0 +1,129 @@
+/* Conversation column skeleton: header (breadcrumb row + tabs) over the view
+   area, composer InputBar at the bottom. Column width/squeeze is layout's;
+   this fills its cell. Figma: Header 39:27730 (83px two-row), tabs 13px with
+   a 3px active bar. */
+
+.root {
+  display: flex;
+  flex-direction: column;
+  height: 100%;
+  min-width: 0;
+  background: var(--dsw-alias-bg-base);
+}
+
+.header {
+  flex: none;
+  padding: 12px 28px 0 20px;
+  border-bottom: 1px solid var(--dsw-alias-border-l2);
+}
+
+.crumbRow {
+  display: flex;
+  align-items: center;
+  justify-content: space-between;
+  min-height: 32px;
+}
+
+.crumbs {
+  display: flex;
+  align-items: center;
+  gap: 4px;
+  min-width: 0;
+  overflow: hidden;
+  white-space: nowrap;
+}
+
+.crumbSeg {
+  display: inline-flex;
+  align-items: center;
+  gap: 4px;
+  min-width: 0;
+}
+
+.crumbSep {
+  /* figma: "/" separators are 14px caption gray (75:7903), one tint lighter than crumb text. */
+  color: var(--dsw-alias-label-caption);
+  font-size: 14px;
+  line-height: 20px;
+}
+
+.crumb {
+  max-width: 220px;
+  overflow: hidden;
+  padding: 4px 8px;
+  border: none;
+  border-radius: 12px;
+  background: transparent;
+  font-size: 13px;
+  line-height: 16px;
+  color: var(--dsw-alias-label-tertiary);
+  text-overflow: ellipsis;
+  white-space: nowrap;
+  cursor: pointer;
+}
+
+.crumb:hover:not(:disabled) {
+  background: var(--dsw-alias-interactive-bg-hover);
+}
+
+.crumbCurrent {
+  font-weight: 500;
+  color: var(--dsw-alias-label-primary);
+  cursor: default;
+}
+
+.meta {
+  margin-left: 4px;
+  font-size: 12px;
+  line-height: 18px;
+  color: var(--dsw-alias-label-tertiary);
+}
+
+/* figma Tab_Group 34:11441: 35px strip, gap 36, pad-left 8, tabs bottom-aligned. */
+.tabs {
+  display: flex;
+  gap: 36px;
+  margin-top: 4px;
+  padding-left: 8px;
+}
+
+/* figma .Tab 34:11442: 13/16 wt510 text, gap 8 to the 3px bar (no bottom rounding). */
+.tab {
+  position: relative;
+  padding: 0 0 11px;
+  border: none;
+  background: transparent;
+  font-size: 13px;
+  line-height: 16px;
+  font-weight: 510;
+  color: var(--dsw-alias-label-tertiary);
+  cursor: pointer;
+}
+
+.tab::after {
+  content: '';
+  position: absolute;
+  right: 0;
+  bottom: 0;
+  left: 0;
+  height: 3px;
+  background: transparent;
+}
+
+/* Selected tab is blue, not ink: brand-primary resolves to neutral black in
+   this token sheet, so the selected state rides the business blue — the
+   nearest semantic token that stays blue in both themes. */
+.tabActive {
+  color: var(--dsw-alias-state-business-primary);
+}
+
+.tabActive::after {
+  background: var(--dsw-alias-state-business-primary);
+}
+
+.viewArea {
+  display: flex;
+  flex: 1;
+  flex-direction: column;
+  min-height: 0;
+}

packages/client/ui-conversation/src/client/skeleton/ConversationRoot.tsx

@@ -0,0 +1,109 @@
+// ConversationRoot: the conversation slot's skeleton (figma Header 39:27730 +
+// Tab_Group + view area + composer). Zero framework imports — everything
+// arrives via props from the inject factory: breadcrumb feed, view registry
+// read face, per-view render, and the composer's draft/send choreography.
+// The active view id lives in layout.viewFor (shell viewing state), read and
+// written through injected accessors.
+
+import { useSyncExternalStore } from 'react'
+import clsx from 'clsx'
+import type { ConversationSlotProps } from '../contract/slots.ts'
+import { InputBar } from './InputBar.tsx'
+import type { InputBarError } from './InputBar.tsx'
+import css from './ConversationRoot.module.css'
+
+/**
+ * Full props = owner share (sessionId) & standard share (useSession) &
+ * injected share — composed by reference from the contract, never re-typed
+ * here (share-ownership rule).
+ */
+export type ConversationRootProps = ConversationSlotProps
+
+export function ConversationRoot({
+  sessionId, useSession, useAncestry, views, useActiveView, composer, actions, renderView,
+}: ConversationRootProps) {
+  useSyncExternalStore(views.subscribe, views.version)
+  const list = views.list()
+  const activeId = useActiveView() ?? 'chat'
+  const active = list.find(v => v.id === activeId) ?? list[0]
+
+  const ancestry = useAncestry()
+  const draft = composer.useDraft()
+  const running = useSession(s => (s as { running: boolean }).running)
+  const removed = useSession(s => (s as { removed: boolean }).removed)
+  const promptError = useSession(s => (s as { promptError: { op: 'send' | 'stop'; error: { message: string; code: string } } | null }).promptError)
+  const turns = useSession(s => countTurns(s as { nodes: readonly { kind: string }[] }))
+
+  const error: InputBarError | null = promptError === null
+    ? null
+    : { op: promptError.op, message: `${promptError.error.message}（${promptError.error.code}）` }
+
+  return (
+    <div className={css.root}>
+      <header className={css.header}>
+        <div className={css.crumbRow}>
+          <nav className={css.crumbs} aria-label="会话层级">
+            {ancestry.map((s, i) => {
+              const last = i === ancestry.length - 1
+              return (
+                <span key={s.id} className={css.crumbSeg}>
+                  {i > 0 && <span className={css.crumbSep}>/</span>}
+                  <button
+                    type="button"
+                    className={clsx(css.crumb, last && css.crumbCurrent)}
+                    disabled={last}
+                    onClick={() => { actions.open(s.id) }}
+                  >
+                    {s.title}
+                  </button>
+                </span>
+              )
+            })}
+            {ancestry.length === 0 && <span className={css.crumbCurrent}>{sessionId}</span>}
+            <span className={css.meta}>· {turns} turns</span>
+          </nav>
+          {/* Header button row (Fork / Session log / I/O Details): a P-I visual
+              placeholder registry slot is deferred — buttons land with their features. */}
+        </div>
+        {list.length > 1 && (
+          <div className={css.tabs} role="tablist">
+            {list.map(v => (
+              <button
+                key={v.id}
+                type="button"
+                role="tab"
+                aria-selected={v.id === active?.id}
+                className={clsx(css.tab, v.id === active?.id && css.tabActive)}
+                onClick={() => { actions.openView(v.id) }}
+              >
+                {v.label}
+              </button>
+            ))}
+          </div>
+        )}
+      </header>
+
+      <div className={css.viewArea}>
+        {active !== undefined && renderView(active)}
+      </div>
+
+      <InputBar
+        draft={draft}
+        running={running}
+        disabled={removed}
+        error={error}
+        variant="composer"
+        onDraftChange={composer.setDraft}
+        onSend={composer.send}
+        onStop={composer.stop}
+      />
+    </div>
+  )
+}
+
+/** Turn count = user message nodes in the window (display meta; exact host count deferred). */
+function countTurns(s: { nodes: readonly { kind: string }[] }): number {
+  let n = 0
+  for (const node of s.nodes) if (node.kind === 'user') n += 1
+  return n
+}

packages/client/ui-conversation/src/client/skeleton/DetailsPanel.module.css

@@ -0,0 +1,94 @@
+/* Details third column, minimal P-I fill: header (name + close) over a
+   scrolling body of Input/Output code sections. Panel width/squeeze belongs
+   to layout; this fills whatever the column gives. */
+
+.root {
+  display: flex;
+  flex-direction: column;
+  height: 100%;
+  min-width: 0;
+  border-left: 1px solid var(--dsw-alias-border-l2);
+  background: var(--dsw-alias-bg-base);
+}
+
+/* figma RightSidebar header frame (I54:42735;43:36451): pad 14/12/12/12, gap 8. */
+.header {
+  display: flex;
+  align-items: center;
+  justify-content: space-between;
+  gap: 8px;
+  padding: 14px 12px 12px;
+  border-bottom: 1px solid var(--dsw-alias-border-l2);
+}
+
+/* figma I54:42735;43:41479: 14/20 wt500. */
+.title {
+  overflow: hidden;
+  font-size: 14px;
+  line-height: 20px;
+  font-weight: 500;
+  color: var(--dsw-alias-label-primary);
+  text-overflow: ellipsis;
+  white-space: nowrap;
+}
+
+.close {
+  display: grid;
+  flex: none;
+  place-items: center;
+  width: 28px;
+  height: 28px;
+  border: none;
+  border-radius: 999px;
+  background: transparent;
+  color: var(--dsw-alias-label-secondary);
+  cursor: pointer;
+}
+
+.close:hover {
+  background: var(--dsw-alias-interactive-bg-hover);
+}
+
+.body {
+  flex: 1;
+  min-height: 0;
+  padding: 12px 16px;
+  overflow-y: auto;
+}
+
+.empty {
+  padding: 8px 0;
+  font-size: 13px;
+  line-height: 20px;
+  color: var(--dsw-alias-label-tertiary);
+}
+
+.section {
+  margin-bottom: 16px;
+}
+
+.sectionLabel {
+  margin-bottom: 6px;
+  font-size: 12px;
+  line-height: 18px;
+  font-weight: 500;
+  color: var(--dsw-alias-label-secondary);
+}
+
+/* figma Code-block (I54:42735;43:41429): r12, pad 16, mono 13/22. */
+.code {
+  margin: 0;
+  padding: 16px;
+  border-radius: 12px;
+  background: var(--dsw-alias-markdown-code-block);
+  font-family: var(--ds-font-family-code);
+  font-size: 13px;
+  line-height: 22px;
+  color: var(--dsw-alias-label-primary);
+  white-space: pre-wrap;
+  word-break: break-word;
+}
+
+.code[data-error] {
+  color: var(--dsw-alias-state-error-primary);
+}

packages/client/ui-conversation/src/client/skeleton/DetailsPanel.tsx

@@ -0,0 +1,111 @@
+// DetailsPanel, P-I minimal form: close button + the selected call's args and
+// result rendered raw. The three-段 Switch / Prev-Next stepping / See-in-
+// trajectory are deferred (ledger). Subscribes to the per-scope selection and
+// derives the call material from the session snapshot — no data of its own.
+
+import type { ConversationSnapshot, ToolResultNode } from '@deepseek-ai/dsh-client-runtime/client'
+import { shallowEqual } from '@deepseek-ai/dsh-client-web-react'
+import type { DetailsSlotProps } from '../contract/slots.ts'
+import css from './DetailsPanel.module.css'
+
+/** Full props composed by reference from the contract (owner & standard & injected shares). */
+export type DetailsPanelProps = DetailsSlotProps
+
+/** Selected call material: resolved result node, or the in-flight running call's args. */
+interface CallMaterial {
+  name: string
+  argsRaw: string | null
+  result: ToolResultNode | null
+  running: boolean
+}
+
+function materialFor(s: ConversationSnapshot, callId: string): CallMaterial | null {
+  for (const node of s.nodes) {
+    if (node.kind === 'tool-result' && node.callId === callId) {
+      return { name: node.call?.name ?? callId, argsRaw: node.call?.argsRaw ?? null, result: node, running: false }
+    }
+  }
+  const open = s.runningCalls.find(c => c.callId === callId)
+  if (open !== undefined) {
+    return { name: open.name, argsRaw: open.argsRaw, result: null, running: true }
+  }
+  return null
+}
+
+function pretty(raw: string): string {
+  try {
+    return JSON.stringify(JSON.parse(raw), null, 2)
+  } catch {
+    // Not JSON (streaming fragment or plain text): show verbatim.
+    return raw
+  }
+}
+
+export function DetailsPanel({ useSession, useSelection, actions }: DetailsPanelProps) {
+  const selection = useSelection(s => s)
+  const callId = selection?.callId
+  // materialFor builds a fresh wrapper; shallowEqual short-circuits on its
+  // stable members (result node reference rides the snapshot's structural sharing).
+  const material = useSession(
+    s => (callId === undefined ? null : materialFor(s as ConversationSnapshot, callId)),
+    (a, b) => shallowEqual(a, b))
+
+  return (
+    <div className={css.root}>
+      <div className={css.header}>
+        <div className={css.title}>
+          {selection === null ? '详情' : material?.name ?? selection.toolName ?? '详情'}
+        </div>
+        <button
+          type="button" className={css.close} aria-label="关闭详情"
+          onClick={() => { actions.closeDetails() }}
+        >
+          <svg viewBox="0 0 16 16" width="14" height="14" aria-hidden>
+            <path d="M4 4l8 8M12 4l-8 8" stroke="currentColor" strokeWidth="1.5" strokeLinecap="round" />
+          </svg>
+        </button>
+      </div>
+      <div className={css.body}>
+        {selection === null || callId === undefined
+          ? <div className={css.empty}>点击消息流中的工具行查看详情</div>
+          : material === null
+            ? <div className={css.empty}>该调用不在当前窗口内</div>
+            : (
+                <>
+                  {material.argsRaw !== null && (
+                    <section className={css.section}>
+                      <div className={css.sectionLabel}>Input</div>
+                      <pre className={css.code}>{pretty(material.argsRaw)}</pre>
+                    </section>
+                  )}
+                  <section className={css.section}>
+                    <div className={css.sectionLabel}>Output</div>
+                    {/* materialFor invariant: result===null ⇔ running (a settled
+                        material always carries its result node). */}
+                    {material.result === null
+                      ? <div className={css.empty}>运行中…</div>
+                      : (
+                          <pre className={css.code} data-error={material.result.isError || undefined}>
+                            {renderResult(material.result)}
+                          </pre>
+                        )}
+                  </section>
+                </>
+              )}
+      </div>
+    </div>
+  )
+}
+
+/** Flatten result content blocks to display text (text blocks verbatim, others as JSON). */
+function renderResult(node: ToolResultNode): string {
+  const parts: string[] = []
+  for (const block of node.content) {
+    if (block.type === 'text') parts.push(block.text)
+    else parts.push(JSON.stringify(block, null, 2))
+  }
+  if (parts.length === 0 && node.error !== undefined) {
+    parts.push(`${node.error.name}: ${node.error.code}`)
+  }
+  return parts.join('\n')
+}

packages/client/ui-conversation/src/client/skeleton/EmptyState.module.css

@@ -0,0 +1,68 @@
+/* NEW SESSION hero: headline over the shared InputBar card, centered in the
+   conversation column. The card is the same component as the composer —
+   only positioning lives here. */
+
+.root {
+  display: flex;
+  align-items: center;
+  justify-content: center;
+  height: 100%;
+  min-width: 0;
+  padding: 24px;
+}
+
+/* figma hero group 34:10409: headline block sits 36px above the input card. */
+.card {
+  display: flex;
+  flex-direction: column;
+  gap: 36px;
+  width: 100%;
+  max-width: 776px;
+}
+
+/* figma 34:10411: fish + title row, gap 10, centered; title 26/32 wt600 (34:10414). */
+.headline {
+  display: flex;
+  align-items: center;
+  justify-content: center;
+  gap: 10px;
+  font-size: 26px;
+  line-height: 32px;
+  font-weight: 600;
+  color: var(--dsw-alias-label-primary);
+}
+
+/* figma 34:10412/10413: brand-blue vector. */
+.fish {
+  flex: none;
+  color: var(--dsw-alias-state-business-primary);
+}
+
+.picker {
+  display: flex;
+  align-items: center;
+  min-width: 0;
+}
+
+.select,
+.customInput {
+  max-width: 320px;
+  padding: 4px 10px;
+  border: 1px solid var(--dsw-alias-border-l2-darkmode-thin);
+  border-radius: 12px;
+  background: var(--dsw-alias-bg-base);
+  font-size: 13px;
+  line-height: 20px;
+  color: var(--dsw-alias-label-secondary);
+}
+
+.customInput {
+  width: 320px;
+  outline: none;
+}
+
+.customInput:focus {
+  /* Business blue, not brand-primary: that token resolves to ink in this sheet. */
+  border-color: var(--dsw-alias-state-business-primary);
+  color: var(--dsw-alias-label-primary);
+}

packages/client/ui-conversation/src/client/skeleton/EmptyState.tsx

@@ -0,0 +1,106 @@
+// EmptyState (figma NEW SESSION screen): centered hero card built around the
+// SAME InputBar component the resident composer uses (the empty→content
+// transition is one component changing position, never a swap). Project
+// picker: cwd set derived from sessions.list plus a free-form new-directory
+// input; submit runs the startSession chain (create → open → send) in one
+// service call.
+
+import { useState } from 'react'
+import { FishLogo } from '@deepseek-ai/dsh-client-ui-primitives'
+import type { EmptyStateSlotProps } from '../contract/slots.ts'
+import { InputBar } from './InputBar.tsx'
+import type { InputBarError } from './InputBar.tsx'
+import css from './EmptyState.module.css'
+
+/** Select sentinel for the free-form directory entry (impossible as a real path: not absolute). */
+const NEW_DIR = '::new-directory'
+
+/** Full props composed by reference from the contract (owner & injected shares; root slot has no standard share). */
+export type EmptyStateProps = EmptyStateSlotProps
+
+export function EmptyState({ useCwds, actions }: EmptyStateProps) {
+  const cwds = useCwds(s => s)
+  // Local viewing state: the empty state owns no session, so its draft is
+  // ephemeral by design (drafts are keyed by session id; there is none yet).
+  const [draft, setDraft] = useState('')
+  const [cwd, setCwd] = useState<string>('')
+  const [custom, setCustom] = useState(false)
+  const [sending, setSending] = useState(false)
+  const [error, setError] = useState<InputBarError | null>(null)
+
+  const submit = (mode: 'queue' | 'steer'): void => {
+    const text = draft.trim()
+    /* v8 ignore next -- defensive: InputBar disables send while empty. */
+    if (text === '' || sending) return
+    setSending(true)
+    setError(null)
+    const chosen = cwd.trim()
+    actions.startSession({ text, mode, ...(chosen === '' ? {} : { cwd: chosen }) })
+      .catch((reason: unknown) => {
+        // The empty state survives failure with the draft intact (no session
+        // exists to carry promptError; this is the only local error surface).
+        setError({ op: 'send', message: reason instanceof Error ? reason.message : String(reason) })
+        setSending(false)
+      })
+    // Success needs no cleanup: layout.open swaps this slot out for the session body.
+  }
+
+  const picker = (
+    <div className={css.picker}>
+      {custom
+        ? (
+            <input
+              className={css.customInput}
+              value={cwd}
+              autoFocus
+              placeholder="目录路径，如 /home/me/proj"
+              onChange={(e) => { setCwd(e.target.value) }}
+            />
+          )
+        : (
+            <select
+              className={css.select}
+              value={cwd}
+              aria-label="项目目录"
+              onChange={(e) => {
+                if (e.target.value === NEW_DIR) {
+                  setCustom(true)
+                  setCwd('')
+                } else {
+                  setCwd(e.target.value)
+                }
+              }}
+            >
+              <option value="">默认目录</option>
+              {cwds.map(c => <option key={c} value={c}>{c}</option>)}
+              <option value={NEW_DIR}>新目录…</option>
+            </select>
+          )}
+    </div>
+  )
+
+  return (
+    <div className={css.root}>
+      <div className={css.card}>
+        <div className={css.headline}>
+          {/* figma 34:10412: fish 34x25 leading the headline, gap 10. */}
+          <FishLogo size={34} className={css.fish} />
+          Let&apos;s start building
+        </div>
+        <InputBar
+          draft={draft}
+          running={false}
+          disabled={sending}
+          error={error}
+          variant="hero"
+          placeholder="Message to run task, plan and build"
+          accessory={picker}
+          onDraftChange={setDraft}
+          onSend={submit}
+          /* v8 ignore next -- structural noop: hero never passes running=true, so stop is unreachable. */
+          onStop={() => {}}
+        />
+      </div>
+    </div>
+  )
+}

packages/client/ui-conversation/src/client/skeleton/InputBar.module.css

@@ -0,0 +1,160 @@
+/* Floating capsule input (figma Input_Bottom 34:11445): card floats above the
+   viewport bottom inside the centered message column; textarea on top, action
+   row below, one primary circle button bottom-right. Input width rides the
+   column (776 is a cap, not a fixed size — layout rule: the box shrinks with
+   the center column keeping its padding). Hero variant = the same card
+   centered in the empty state; the transition between the two is a position
+   move of one component. */
+
+.root {
+  display: flex;
+  flex-direction: column;
+  align-items: center;
+  /* figma Input_Bottom 34:11445: pad L32/R32/B12; the bottom gradient mask is
+     owned by the chat scroller. Top 8 hosts the error strip's breathing room. */
+  padding: 8px 32px 12px;
+}
+
+.hero {
+  padding: 0;
+}
+
+.error {
+  width: 100%;
+  max-width: 776px;
+  margin-bottom: 6px;
+  padding: 4px 8px;
+  border-radius: 8px;
+  background: var(--dsw-alias-interactive-bg-hover-danger);
+  color: var(--dsw-alias-state-error-primary);
+  font-size: 12px;
+  line-height: 18px;
+}
+
+.card {
+  display: flex;
+  flex-direction: column;
+  /* figma Input 34:11458: 12px between the text area and the button row. */
+  gap: 12px;
+  width: 100%;
+  max-width: 776px;
+  /* Input stroke: black/0.10 light, white/0.06 dark (figma darkmode note says
+     the input border is one notch weaker than buttons) — exactly the
+     l2-darkmode-thin pair. Fill: the input surface token (elevated in dark). */
+  border: 1px solid var(--dsw-alias-border-l2-darkmode-thin);
+  border-radius: 20px;
+  background: var(--dsw-specific-input-major);
+  box-shadow: var(--dsw-shadow-lv2);
+  font-size: 16px;
+  line-height: 24px;
+}
+
+/* New-session state rounds up (figma: r24 and a taller box). */
+.hero .card {
+  border-radius: 24px;
+}
+
+.accessory {
+  display: flex;
+  align-items: center;
+  gap: 8px;
+  padding: 10px 12px 0;
+}
+
+/* Mirror-div auto-grow wrapper: the hidden mirror is in normal flow and sets the height
+   (min 2 lines / max 14 lines); the textarea rides it absolutely. Mirror and textarea
+   MUST share font, line-height, padding and wrapping rules or heights diverge. */
+.grow {
+  position: relative;
+}
+
+.input {
+  position: absolute;
+  inset: 0;
+  width: 100%;
+  height: 100%;
+  resize: none;
+  overflow-y: auto;
+  border: none;
+  outline: none;
+  background: transparent;
+  color: var(--dsw-alias-label-primary);
+  /* Business blue, not brand-primary: that token resolves to ink in this sheet. */
+  caret-color: var(--dsw-alias-state-business-primary);
+}
+
+.input,
+.mirror {
+  padding: 12px 16px 0;
+  font-size: inherit;
+  line-height: inherit;
+  white-space: pre-wrap;
+  word-break: break-word;
+  overflow-wrap: anywhere;
+}
+
+/* figma 34:10434: #ADB2B8 light / #81858C dark — the caption pair exactly. */
+.input::placeholder {
+  color: var(--dsw-alias-label-caption);
+  user-select: none;
+}
+
+/* Running lock: grayed but the draft stays visible; the turn ending re-enables. */
+.input:disabled {
+  color: var(--dsw-alias-label-tertiary);
+  cursor: not-allowed;
+}
+
+.mirror {
+  visibility: hidden;
+  pointer-events: none;
+  /* 2-line floor: 2 × 24px line + 12px top padding; 14-line cap (336px). */
+  min-height: 60px;
+  max-height: 336px;
+  overflow: hidden;
+}
+
+.hero .mirror {
+  /* New-session box is taller at rest (figma 118px input area). */
+  min-height: 84px;
+}
+
+/* figma Frame 1123 (34:11463): pad 12/0/10/10, buttons vertically centered. */
+.row {
+  display: flex;
+  align-items: center;
+  justify-content: flex-end;
+  padding: 0 10px 10px 12px;
+}
+
+/* Primary send (figma IconButton 34:10465): 34px circle, #3964FE light /
+   #679EFE dark — the info-fill pair (500→400), NOT button-primary (ink);
+   white glyph; empty text = 0.4 opacity. */
+.primary {
+  display: grid;
+  place-items: center;
+  width: 34px;
+  height: 34px;
+  border: none;
+  border-radius: 999px;
+  background: var(--dsw-alias-button-info-fill);
+  color: var(--dsw-alias-label-primary-foreground);
+  cursor: pointer;
+}
+
+.primary:hover {
+  background: var(--dsw-alias-button-info-hover);
+}
+
+.primary:disabled {
+  opacity: 0.4;
+  cursor: default;
+}
+
+/* Stop state: same slot, dimmed brand fill — the running-state send-key
+   replacement is a design gap filled by us (figma gives no stop form). */
+.stopping,
+.stopping:hover {
+  background: var(--dsw-alias-button-primary-dimmed);
+  color: var(--dsw-alias-brand-text);
+}

packages/client/ui-conversation/src/client/skeleton/InputBar.tsx

@@ -0,0 +1,142 @@
+// InputBar: the one composer input (figma Input_Bottom). The same component
+// serves the empty state (variant='hero': centered launch card) and the
+// resident composer (variant='composer') — the empty→content transition is a
+// position move of this component, never a swap (layout ruling). Running
+// LOCKS the input: textarea disabled with the draft visible, stop is the only
+// action; the turn ending re-enables and refocuses.
+
+import { useEffect, useRef } from 'react'
+import type { KeyboardEvent, MouseEvent, ReactNode } from 'react'
+import clsx from 'clsx'
+import css from './InputBar.module.css'
+
+/** Prompt failure surface (mirrors the session snapshot's promptError shape). */
+export interface InputBarError {
+  op: 'send' | 'stop'
+  message: string
+}
+
+export interface InputBarProps {
+  draft: string
+  running: boolean
+  disabled: boolean
+  error: InputBarError | null
+  /** Hero = empty-state centered card; composer = resident bottom bar. */
+  variant: 'hero' | 'composer'
+  placeholder?: string
+  /** Optional leading accessory row content (the empty state mounts its cwd picker here). */
+  accessory?: ReactNode
+  onDraftChange: (text: string) => void
+  onSend: (mode: 'queue' | 'steer') => void
+  onStop: () => void
+}
+
+export function InputBar({
+  draft, running, disabled, error, variant, placeholder, accessory, onDraftChange, onSend, onStop,
+}: InputBarProps) {
+  const empty = draft.trim() === ''
+  const inputRef = useRef<HTMLTextAreaElement | null>(null)
+  // IME guard: composition Enter picks a candidate, it must not send. The ref outlives renders;
+  // clearing is deferred one tick because Safari delivers the closing keydown AFTER compositionend.
+  const composingRef = useRef(false)
+  const onCompositionStart = (): void => {
+    composingRef.current = true
+  }
+  const onCompositionEnd = (): void => {
+    setTimeout(() => {
+      composingRef.current = false
+    }, 10)
+  }
+
+  // Locked while running: the browser drops keystrokes AND focus on a disabled
+  // textarea — no sending mid-turn, stop or wait.
+  const locked = disabled || running
+
+  // Unlock (mount / session switch / turn end) returns focus to the box.
+  useEffect(() => {
+    if (!locked) inputRef.current?.focus()
+  }, [locked])
+
+  const onKeyDown = (e: KeyboardEvent<HTMLTextAreaElement>): void => {
+    if (e.key !== 'Enter') return
+    if (composingRef.current || e.nativeEvent.isComposing || e.nativeEvent.keyCode === 229) return
+    if (e.shiftKey) return // native newline
+    if (e.ctrlKey || e.metaKey) {
+      // execCommand keeps the browser undo stack intact, unlike a setState splice.
+      e.preventDefault()
+      document.execCommand('insertText', false, '\n')
+      return
+    }
+    e.preventDefault()
+    if (e.repeat) return // held-down Enter must not machine-gun sends
+    if (!empty && !locked) onSend('queue')
+  }
+
+  // Button presses steal focus from the textarea; suppress at mousedown so typing continues seamlessly.
+  const keepFocus = (e: MouseEvent<HTMLButtonElement>): void => {
+    e.preventDefault()
+    inputRef.current?.focus()
+  }
+
+  const primaryLabel = running ? '停止' : '发送'
+  const onPrimary = (): void => {
+    if (running) {
+      onStop()
+      return
+    }
+    /* v8 ignore next -- defensive: the primary button is disabled while empty||disabled, so a click cannot reach the false arm. */
+    if (!empty && !disabled) onSend('queue')
+  }
+
+  return (
+    <div className={clsx(css.root, variant === 'hero' && css.hero)}>
+      {error !== null && (
+        <div className={css.error}>
+          {error.op === 'stop' ? '停止失败' : '发送失败'}：{error.message}
+        </div>
+      )}
+      <div className={css.card}>
+        {accessory !== undefined && <div className={css.accessory}>{accessory}</div>}
+        {/* Mirror-div auto-grow: the hidden mirror renders draft+'\n' and stretches the wrapper
+            (min/max capped in CSS); the absolutely-positioned textarea rides its height. Counting
+            rows by '\n' cannot see soft wraps. */}
+        <div className={css.grow}>
+          <textarea
+            ref={inputRef}
+            className={css.input}
+            value={draft}
+            disabled={locked}
+            placeholder={placeholder ?? (disabled ? '会话不可用' : running ? '回复生成中，可停止后再输入' : '输入消息，Enter 发送，Shift+Enter 换行')}
+            rows={2}
+            onChange={(e) => onDraftChange(e.target.value)}
+            onKeyDown={onKeyDown}
+            onCompositionStart={onCompositionStart}
+            onCompositionEnd={onCompositionEnd}
+          />
+          <div aria-hidden className={css.mirror}>{`${draft}\n`}</div>
+        </div>
+        <div className={css.row}>
+          <button
+            type="button"
+            className={clsx(css.primary, running && css.stopping)}
+            aria-label={primaryLabel}
+            title={running ? '停止本轮' : '发送（Enter）'}
+            disabled={!running && (empty || disabled)}
+            onMouseDown={keepFocus}
+            onClick={onPrimary}
+          >
+            {running ? (
+              <svg viewBox="0 0 16 16" width="14" height="14" aria-hidden>
+                <rect x="4" y="4" width="8" height="8" rx="1.5" fill="currentColor" />
+              </svg>
+            ) : (
+              <svg viewBox="0 0 16 16" width="14" height="14" aria-hidden>
+                <path d="M8 13V3.8M8 3.8L3.8 8M8 3.8L12.2 8" stroke="currentColor" strokeWidth="2" strokeLinecap="round" strokeLinejoin="round" fill="none" />
+              </svg>
+            )}
+          </button>
+        </div>
+      </div>
+    </div>
+  )
+}

packages/client/ui-conversation/src/client/toolviews/bash-sample.module.css

@@ -0,0 +1,48 @@
+/* Sample bash rows: deliberately distinct from ToolRow so the differential
+   registry hit is visible at a glance. */
+
+.row {
+  display: flex;
+  align-items: center;
+  gap: 8px;
+  height: 24px;
+  min-width: 0;
+  cursor: pointer;
+  border-radius: 6px;
+  font-family: var(--ds-font-family-code);
+  font-size: 13px;
+}
+
+.row:hover {
+  background: var(--dsw-alias-interactive-bg-hover);
+}
+
+.prompt {
+  flex: none;
+  color: var(--dsw-alias-state-success-primary);
+}
+
+.scopeBadge {
+  flex: none;
+  padding: 0 6px;
+  border-radius: 6px;
+  font-size: 11px;
+  line-height: 18px;
+  color: var(--dsw-alias-label-primary-foreground);
+  background: var(--dsw-alias-state-business-primary);
+}
+
+.command {
+  flex: 1 1 auto;
+  min-width: 0;
+  overflow: hidden;
+  text-overflow: ellipsis;
+  white-space: nowrap;
+  color: var(--dsw-alias-label-secondary);
+}
+
+.err {
+  flex: none;
+  color: var(--dsw-alias-state-error-primary);
+  font-size: 11px;
+}

packages/client/ui-conversation/src/client/toolviews/bash-sample.tsx

@@ -0,0 +1,52 @@
+// Bash toolview sample, written in third-party posture: everything below uses
+// only the public registration surface (ctx.toolviews.register + ToolViewProps)
+// — the differential-rendering acceptance proof for the registry chain.
+// Two registrations: a global bash row, and a scope-filtered variant that
+// takes over for matching sessions only (later registration wins its tier).
+
+import type { SessionId } from '@deepseek-ai/dsh-client-runtime/client'
+import type { ToolViewProps } from '../contract/toolview.ts'
+import type { ToolViewRegistry } from './registry.ts'
+import { toolRowModel, type ToolCallBlock } from '../contract/tool-call-model.ts'
+import css from './bash-sample.module.css'
+
+/** Global bash row: command-first monospace summary (replaces the generic row). */
+export function BashRow({ toolName, block, actions }: ToolViewProps) {
+  const model = toolRowModel(toolName, block as ToolCallBlock)
+  return (
+    <div className={css.row} data-sample="bash-global" onClick={actions.openDetails}>
+      <span className={css.prompt} aria-hidden>$</span>
+      <span className={css.command}>{model.summary}</span>
+      {model.state === 'error' && <span className={css.err}>failed</span>}
+    </div>
+  )
+}
+
+/** Scoped variant: visually distinct so the differential hit is observable. */
+export function ScopedBashRow({ toolName, block, actions }: ToolViewProps) {
+  const model = toolRowModel(toolName, block as ToolCallBlock)
+  return (
+    <div className={css.row} data-sample="bash-scoped" onClick={actions.openDetails}>
+      <span className={css.scopeBadge}>scoped</span>
+      <span className={css.command}>{model.summary}</span>
+    </div>
+  )
+}
+
+/**
+ * Register both sample rows.
+ * @param toolviews - the conversation plugin's registry service.
+ * @param scope - session filter for the scoped variant.
+ * @returns disposer removing both registrations.
+ */
+export function registerBashSamples(
+  toolviews: ToolViewRegistry,
+  scope: (sessionId: SessionId) => boolean,
+): () => void {
+  const offGlobal = toolviews.register('bash', BashRow)
+  const offScoped = toolviews.register('bash', ScopedBashRow, { scope })
+  return () => {
+    offGlobal()
+    offScoped()
+  }
+}

packages/client/ui-conversation/src/client/toolviews/registry.ts

@@ -0,0 +1,102 @@
+/**
+ * ToolViewRegistry: named per-tool component registry, session-scope aware
+ * (api-contracts v3 section 7). Consumed by chat now, trajectory/waterfall
+ * later — deliberately a named service, not a SlotMap key. The tool key set
+ * is deliberately open (model-side tools arrive at runtime): the strong
+ * typing lives inside the Entry — `I` is inferred from the inject factory at
+ * the register site and proves component props ⊇ ToolViewProps & I.
+ */
+import type { FC } from 'react'
+import type { SessionId } from '@deepseek-ai/dsh-client-runtime/client'
+import type { ResolvedToolView, ToolViewOptions, ToolViewProps } from '../contract/toolview.ts'
+
+/** Stored registration: the per-registration inject parameter is erased
+ *  (storage-erase/read-restore is the typed-Map boundary, one cast budgeted). */
+interface Registration extends ToolViewOptions {
+  component: FC<ToolViewProps & object>
+}
+
+/**
+ * Per-tool renderer registry. Resolution order: scope match (later
+ * registration wins) > global (same tie-break) > undefined, where the caller
+ * falls back to GenericToolCard.
+ */
+export class ToolViewRegistry {
+  private byTool = new Map<string, Registration[]>()
+  private version = 0
+  private listeners = new Set<() => void>()
+
+  /**
+   * Register a tool row renderer. The component must accept the shared
+   * ToolViewProps plus its own injected share `I` — mismatches (missing keys,
+   * wrong types, an inject factory that does not produce what the component
+   * declares) are register-site compile errors.
+   * @param tool - tool name the renderer takes over.
+   * @param component - row component over ToolViewProps & I.
+   * @param opts - optional session-scope filter and private inject factory.
+   * @returns disposer removing this registration.
+   */
+  register<I extends object = object>(
+    tool: string, component: FC<ToolViewProps & I>, opts?: ToolViewOptions<I>): () => void {
+    const list = this.byTool.get(tool) ?? []
+    if (list.length === 0) this.byTool.set(tool, list)
+    // Storage erases I (heterogeneous registrations share one list); resolve
+    // restores the erased shape on the read face.
+    const entry: Registration = { component: component as FC<ToolViewProps & object>, ...opts }
+    list.push(entry)
+    this.bump()
+    let disposed = false
+    return () => {
+      if (disposed) return
+      disposed = true
+      const at = list.indexOf(entry)
+      /* v8 ignore next -- negative arm: an entry lives in one list and only its own once-guarded disposer removes it, so a live disposer always finds it. */
+      if (at >= 0) list.splice(at, 1)
+      if (list.length === 0) this.byTool.delete(tool)
+      this.bump()
+    }
+  }
+
+  /**
+   * Resolve the renderer for a tool in a session.
+   * @param tool - tool name.
+   * @param sessionId - session the row renders in (fed to scope filters).
+   * @returns resolved view, or undefined when nothing matches.
+   */
+  resolve(tool: string, sessionId: SessionId): ResolvedToolView | undefined {
+    const list = this.byTool.get(tool)
+    if (list === undefined) return undefined
+    let global: Registration | undefined
+    let scoped: Registration | undefined
+    for (const entry of list) {
+      if (entry.scope === undefined) global = entry
+      else if (entry.scope(sessionId)) scoped = entry
+    }
+    const hit = scoped ?? global
+    if (hit === undefined) return undefined
+    return hit.inject === undefined ? { component: hit.component } : { component: hit.component, inject: hit.inject }
+  }
+
+  /**
+   * Subscribe to registration changes (render outlets re-resolve on notify).
+   * @param fn - change listener.
+   * @returns disposer.
+   */
+  subscribe(fn: () => void): () => void {
+    this.listeners.add(fn)
+    return () => this.listeners.delete(fn)
+  }
+
+  /**
+   * Monotonic registration version for uSES getSnapshot.
+   * @returns current version.
+   */
+  getVersion(): number {
+    return this.version
+  }
+
+  private bump(): void {
+    this.version += 1
+    for (const fn of this.listeners) fn()
+  }
+}

packages/client/ui-conversation/src/css-modules.d.ts

@@ -0,0 +1,6 @@
+declare module '*.module.css' {
+  const classes: Record<string, string>
+  export default classes
+}
+
+declare module '*.css'

packages/client/ui-conversation/src/index.ts

@@ -0,0 +1,10 @@
+/**
+ * Conversation plugin, node half. Pure UI plugin: the empty apply exists so
+ * the plugin appears in the host cordis.yml / Loader (load and lifecycle
+ * follow the host; the browser half ships via exports["./client"], discovered
+ * through the package.json dshClient declaration). Contract: api-contracts
+ * v3 sections 0.3 and 7.
+ */
+
+/** Host plugin body — no host-side behavior for the conversation plugin. */
+export function apply(): void {}

packages/client/ui-conversation/src/invariant.ts

@@ -0,0 +1,33 @@
+/**
+ * Package-owned invariant companion for `@deepseek-ai/dsh-client-ui-conversation`.
+ * @module @deepseek-ai/dsh-client-ui-conversation/invariant
+ */
+
+/* jscpd:ignore-start */
+import type { Context } from 'cordis'
+import type { InvariantInstaller } from '@deepseek-ai/dsh-invariants'
+
+const PACKAGE_NAME = '@deepseek-ai/dsh-client-ui-conversation'
+
+/** Cordis companion plugin name. */
+export const name = 'client-ui-conversation-invariant'
+/** Service required before the companion can reserve package ownership. */
+export const inject = ['invariants']
+
+/**
+ * No runtime invariant: the conversation service emits no cordis events — its
+ * view and toolview registries notify through package-local subscribe faces
+ * whose ordering (synchronous version bump before notification) is exercised
+ * directly by the behavior specs, and the per-scope store accounts are owned
+ * mutable state with no cross-plugin observer to contradict.
+ */
+const install: InvariantInstaller = () => {}
+
+/**
+ * Register this package's invariant companion.
+ * @param ctx - Cordis context carrying the invariant service.
+ * @returns the installed registration's disposer after setup succeeds.
+ */
+export const apply = (ctx: Context): Promise<() => void> =>
+  Promise.resolve(ctx.invariants.register(PACKAGE_NAME, install))
+/* jscpd:ignore-end */