Merge origin/master into task/command-feedback-master

2026-08-06 16:02:25 +08:00
parent b8d51704f3 cb6fa78c8a
commit 96ac51f0c8
4077 changed files with 252322 additions and 59214 deletions
--- a/packages/client/connection/README.i18n.yaml
+++ b/packages/client/connection/README.i18n.yaml
@@ -2,5 +2,5 @@
 # side as of the last confirmed-consistent state. Both languages carry equal authority;
 # after editing either side, bring the other along and re-record with:
 #   pnpm run verify-translation-pairing --write packages/client/connection/README.md
-README.md: 173a9b9998e17d201b2d31d73ea74a94b319dae6
-README.zh.md: ca5da643db443956c25399f07c8b460900942ad4
+README.md: 1393e79aacecbbf7b186f19e4c42269595854b0e
+README.zh.md: 70380ceba1b16b2970e947fb6cd9b2af9085ae51
--- a/packages/client/connection/README.md
+++ b/packages/client/connection/README.md
@@ -2,15 +2,15 @@

 English | [中文](README.zh.md)

-Wire consumer layer: the client plugin's apply mounts `ctx.connection` (shared api client + single-consumer stream-loop starter); the export face carries the wire contract types, the `AbstractApiClient` seam, and the loop's sink/config types. The platform subclasses (WebApiClient/FixtureApiClient), the ConnectionController loop, and the fixture data source are package-internal — apply selects and drives them; tests reach them via src. Contract: api-contracts v3 §3.
+Wire consumer layer: the client plugin's apply mounts `ctx.connection` (shared api client + current-page loopback state + single-consumer stream-loop starter); the export face carries the wire contract types, the `AbstractApiClient` seam, and the loop's sink/config types. The browser carrier uses HTTP POST for unary and respond operations and opens one downlink-only WebSocket each for `events.mux` and `events.host`; the in-process carrier satisfies the same two-stream abstraction. Loopback hostname classification stays package-internal: the `/api` Host fence and WebSocket upgrades use it directly, while other client plugins consume the derived `ctx.connection.isLoopback` state. The node half's `/api` route pins the privileged method set (`host.pickDirectory`, `host.openPath`, and the whole configuration plane — `settings.describe`/`openDocument`/`update`/`replace`/`mutate` and `credentials.describe`/`set`/`unset`; reads and native actions included, since describing returns the exposed configuration, opening acts on the Host desktop, and probing an arbitrary reference reports where a credential comes from) to loopback by passing the trust fence with an empty trust list — a declared `trustedHosts` authority reaches every other method, while these stay loopback-local until a real authentication layer exists. The platform carriers and ConnectionController loop are package-internal; apply selects and drives them. The downlink boundary is documented in the [WebSocket downlink carrier Agent Note](../../../.agents/notes/implemented/architecture/2026-08-04-websocket-downlink-carrier.md); the protocol contract is api-contracts v3 §3.

 ## /api browser-trust fence

-The node half guards every request under `/api` before bridging (`src/api-request-trust.ts`). Every request — browser-marked or not — must present a `Host` that is a loopback authority or matches a `trustedHosts` entry: exact on `host:port` entries, any port on port-less entries, both sides compared through WHATWG normalization (DNS-rebinding defense). There is deliberately no shortcut for requests without browser markers: over plain HTTP a browser attaches neither `Origin` nor Fetch-Metadata to reads (EventSource, images, navigations — those headers go only to trustworthy destinations), so an unmarked request may still be a rebound browser read with a readable response, and Host is the one header rebinding cannot forge; non-browser clients pass the same fence via loopback, the CLI-derived LAN IP literals, or a declared authority. When markers are present, an attached `Origin` must equal the Host authority, and an explicit `sec-fetch-site: cross-site` marker is refused. A `trustedHosts` entry that is not a bare, canonical `host[:port]` authority — one WHATWG parsing reads back exactly as written — fails the plugin load loudly: parsing would otherwise quietly authorize the hostname inside `harness.internal/path`, or broaden a dangling-colon or zero-padded port to an any-port grant. Failures answer plain 403 before any RPC dispatch. A non-loopback (`--host 0.0.0.0`) deployment therefore needs its serving authorities trusted: the dsh CLI derives the machine's LAN IP literals itself and its `--trusted-host` flag declares named ones, so `trustedHosts` in cordis.yml is for compositions the CLI does not boot. The fence is deliberately not an authentication layer — reachability policy stays with the webserver binding, and auth remains deferred work. Decision record: [the api browser-trust boundary Agent Note](../../../.agents/notes/implemented/architecture/2026-07-28-api-browser-trust-boundary.md).
+The node half guards every entry under `/api` before bridging or upgrading (`src/api-request-trust.ts`). Every request — browser-marked or not — must present a `Host` that is a loopback authority or matches a `trustedHosts` entry: exact on `host:port` entries, any port on port-less entries, both sides compared through WHATWG normalization (DNS-rebinding defense). There is deliberately no shortcut for unmarked HTTP requests: over plain HTTP a browser attaches neither `Origin` nor Fetch-Metadata to image and navigation reads, so an unmarked request may still be a rebound browser read with a readable response, and Host is the one header rebinding cannot forge; a browser WebSocket handshake carries `Origin` and passes the same comparison. Non-browser clients pass the same fence via loopback, the CLI-derived LAN IP literals, or a declared authority. When markers are present, an attached `Origin` must equal the Host authority, and an explicit `sec-fetch-site: cross-site` marker is refused. A `trustedHosts` entry that is not a bare, canonical `host[:port]` authority — one WHATWG parsing reads back exactly as written — fails the plugin load loudly: parsing would otherwise quietly authorize the hostname inside `harness.internal/path`, or broaden a dangling-colon or zero-padded port to an any-port grant. HTTP failures answer plain 403 before any RPC dispatch; upgrade failures reject the handshake before any event stream starts. A non-loopback (`--host 0.0.0.0`) deployment therefore needs its serving authorities trusted: the dsh CLI derives the machine's LAN IP literals itself and its `--trusted-host` flag declares named ones, so `trustedHosts` in cordis.yml is for compositions the CLI does not boot. The fence is a reachability policy, not authentication; the Web carrier provides no authentication layer. Decision record: [the api browser-trust boundary Agent Note](../../../.agents/notes/implemented/architecture/2026-07-28-api-browser-trust-boundary.md).

-## Keyless fixture
+## `/api` WebSocket downlinks

-Any `fixture` query parameter selects the in-memory carrier. `fixture=empty` starts with no Workspace or Session; `fixturePrompt=reject` rejects prompts before acceptance; `fixtureAttach=fail` publishes a Session but rejects its Workspace attachment; `fixtureSessionCreate=drop-response` publishes and frames a Session before dropping the create response; and `fixtureFrames=workspace-first` reverses the default session-first create-frame order. Workspace creation by name/path and caller-preallocated SessionIds remain deterministic enough for assembled Web tests to reconcile list and frame arrival.
+`/api/events.mux` and `/api/events.host` each accept a WebSocket upgrade and send only the corresponding `ServerRequest` text messages to the browser; the client sends no application data over these sockets. If either socket ends, the current connection generation fails and rebuilds both streams; readiness still requires both sockets to be open and the `host.describe` HTTP call to succeed. Host teardown terminates both sockets, aborts their sources, and waits for source cleanup before returning. Ordinary network GETs to these paths return 426 with no SSE fallback; `toFetchHandler`'s SSE codec serves only the isomorphic in-process carrier.

 ## Model Experience

@@ -22,5 +22,4 @@ 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.
+- **History resumes an unattached session** — opening history may create the host-side agent and add latency to the first open; there is no persistence-only read path.
--- a/packages/client/connection/README.zh.md
+++ b/packages/client/connection/README.zh.md
@@ -2,15 +2,15 @@

 [English](README.md) | 中文

-协议消费层：客户端插件的 apply 会挂载 `ctx.connection`（共享 API 客户端 + 单消费方流循环启动器）；导出表层携带协议契约类型、`AbstractApiClient` seam，以及循环的 sink／配置类型。平台子类（WebApiClient/FixtureApiClient）、ConnectionController 循环和 fixture 数据源都属于包内部：apply 负责选择并驱动它们，测试则通过 src 访问。契约：api-contracts v3 §3。
+协议消费层：客户端插件的 apply 会挂载 `ctx.connection`（共享 API 客户端 + 当前页面的 loopback 状态 + 单消费方流循环启动器）；导出表层携带协议契约类型、`AbstractApiClient` seam，以及循环的 sink／配置类型。浏览器载体以 HTTP POST 发送 unary／respond，并为 `events.mux` 与 `events.host` 各开一条只下行的 WebSocket；进程内载体满足同一双流抽象。Loopback hostname 判定逻辑留在包内部：`/api` Host fence 与 WebSocket upgrade 会直接使用它，其他客户端插件则消费派生的 `ctx.connection.isLoopback` 状态。node 半侧的 `/api` 路由让特权方法集（`host.pickDirectory`、`host.openPath`，以及整个配置面——`settings.describe`/`openDocument`/`update`/`replace`/`mutate` 与 `credentials.describe`/`set`/`unset`；读取与原生操作也在内，因为 describe 会返回已暴露的配置、打开操作会作用于 Host 桌面，而探测任意引用会报出某条凭据来自何处）以空信任表过信任 fence，从而钉在回环——已声明的 `trustedHosts` 授权可达其余全部方法，而这些方法在真正的认证层出现之前仍只限回环本机。平台载体与 ConnectionController 循环属于包内部；apply 负责选择并驱动它们。下行边界见 [WebSocket 下行载体 Agent Note](../../../.agents/notes/implemented/architecture/2026-08-04-websocket-downlink-carrier.md)；协议契约见 api-contracts v3 §3。

 ## /api 浏览器信任栅栏

-node 半侧在桥接前守卫 `/api` 下的每个请求（`src/api-request-trust.ts`）。每个请求——无论是否带浏览器标记——`Host` 都必须是回环地址权威，或与某个 `trustedHosts` 条目匹配：带端口的 `host:port` 条目精确匹配，不带端口的条目匹配任意端口，两侧均经 WHATWG 归一化后比较（DNS rebinding 防御）。刻意不为无浏览器标记的请求开捷径：明文 HTTP 下浏览器的读取（EventSource、图片、导航——这些头只发给可信目标）既不带 `Origin` 也不带 Fetch-Metadata，因此无标记请求仍可能是被重绑页面发起的、响应可被读走的读取，而 Host 是重绑唯一伪造不了的请求头；非浏览器客户端经由回环地址、CLI 推导的 LAN IP 字面量或已声明的权威通过同一道栅栏。当标记存在时，`Origin` 必须与 Host 权威完全一致；显式的 `sec-fetch-site: cross-site` 标记一律拒绝。不是纯的、规范形 `host[:port]` 权威的 `trustedHosts` 条目——即 WHATWG 解析读回后与原文不完全一致的——会让插件加载大声失败：否则解析会悄悄授权 `harness.internal/path` 这类笔误里的 hostname，或把悬空冒号、补零端口放大成任意端口授权。失败在任何 RPC 分发之前以纯 403 应答。因此非回环（`--host 0.0.0.0`）部署需要让自己的服务权威被信任：dsh CLI 会自行推导本机的 LAN IP 字面量，其 `--trusted-host` flag 用于声明具名权威，所以 cordis.yml 中的 `trustedHosts` 面向 CLI 不参与引导的组合。这道栅栏刻意不承担认证职责——可达性策略归 webserver 绑定配置，认证仍是延期工作。决策记录：[api 浏览器信任边界 Agent Note](../../../.agents/notes/implemented/architecture/2026-07-28-api-browser-trust-boundary.md)。
+node 半侧在桥接或 upgrade 前守卫 `/api` 下的每个入口（`src/api-request-trust.ts`）。每个请求——无论是否带浏览器标记——`Host` 都必须是回环地址权威，或与某个 `trustedHosts` 条目匹配：带端口的 `host:port` 条目精确匹配，不带端口的条目匹配任意端口，两侧均经 WHATWG 归一化后比较（DNS rebinding 防御）。刻意不为无浏览器标记的 HTTP 请求开捷径：明文 HTTP 下浏览器的图片与导航读取既不带 `Origin` 也不带 Fetch-Metadata，因此无标记请求仍可能是被重绑页面发起的、响应可被读走的读取，而 Host 是重绑唯一伪造不了的请求头；WebSocket 浏览器握手会带 `Origin` 并通过同一道比较。非浏览器客户端经由回环地址、CLI 推导的 LAN IP 字面量或已声明的权威通过同一道栅栏。当标记存在时，`Origin` 必须与 Host 权威完全一致；显式的 `sec-fetch-site: cross-site` 标记一律拒绝。不是纯的、规范形 `host[:port]` 权威的 `trustedHosts` 条目——即 WHATWG 解析读回后与原文不完全一致的——会让插件加载大声失败：否则解析会悄悄授权 `harness.internal/path` 这类笔误里的 hostname，或把悬空冒号、补零端口放大成任意端口授权。HTTP 失败在任何 RPC 分发之前以纯 403 应答，upgrade 失败在启动任何 event stream 前拒绝握手。因此非回环（`--host 0.0.0.0`）部署需要让自己的服务权威被信任：dsh CLI 会自行推导本机的 LAN IP 字面量，其 `--trusted-host` flag 用于声明具名权威，所以 cordis.yml 中的 `trustedHosts` 面向 CLI 不参与引导的组合。这道栅栏是可达性策略，而不是认证；Web 载体不提供认证层。决策记录：[api 浏览器信任边界 Agent Note](../../../.agents/notes/implemented/architecture/2026-07-28-api-browser-trust-boundary.md)。

-## 无密钥 fixture
+## `/api` WebSocket 下行

-任何 `fixture` 查询参数都会选择内存载体。`fixture=empty` 启动时不含 Workspace 或 Session；`fixturePrompt=reject` 在接受前拒绝提示词；`fixtureAttach=fail` 发布 Session 但拒绝将其附加到 Workspace；`fixtureSessionCreate=drop-response` 在丢弃创建响应前发布 Session 并为其发出帧；`fixtureFrames=workspace-first` 则反转默认的 Session 优先创建帧顺序。按名称／路径创建 Workspace 以及由调用方预先分配 SessionId，均具有足够的确定性，组装后的 Web 测试可以据此协调列表与帧的到达。
+`/api/events.mux` 与 `/api/events.host` 各接受一条 WebSocket upgrade，并只向浏览器发送对应的 `ServerRequest` text message；客户端不会在这些 socket 上发送业务数据。任一 socket 结束都会使当前 connection generation 失败并重建两条流，连接就绪仍要求两条 socket open 且 `host.describe` HTTP 调用成功。Host teardown 会终止两条 socket、中止各自的 source，并等待 source 清理完成后再返回。普通网络 GET 这些路径会返回 426，不保留 SSE 回退；`toFetchHandler` 的 SSE 编解码只服务进程内同构载体。

 ## 模型体验

@@ -22,5 +22,4 @@ node 半侧在桥接前守卫 `/api` 下的每个请求（`src/api-request-trust

 ## 已知限制与暂缓事项

- **history 的隐式恢复存在争议**：在未附加的会话上打开 history，会在主机侧拉起 agent；纯持久化读取的替代方案记录在 rt-core 协调账本中，P-I 不作改变。该包的消费方会在首次打开时感受到这段延迟。
- **计划移除 `ToolEventView`／`ToolCallView`／`ToolResultView` 的重新导出**：当 toolview 迁移删除主机 `viewFor` 行时，它们会一并移除（呈现属于客户端）；在此之前，fixture 保留一份局部 `viewFor` 镜像。
+- **History 会恢复未附加的会话**：打开 history 可能创建宿主侧 agent，并增加首次打开的延迟；没有仅从持久化读取的路径。
--- a/packages/client/connection/package.json
+++ b/packages/client/connection/package.json
@@ -1,6 +1,6 @@
 {
  "name": "@deepseek-ai/dsh-client-connection",
-  "description": "Wire consumer layer: IApiClient subclasses, ConnectionController (SSE dual-stream + reconnect), fixture api (no cordis)",
+  "description": "Wire consumer layer: HTTP-up/WebSocket-down client, ConnectionController dual streams with reconnect, and fixture api",
  "version": "0.0.1",
  "private": true,
  "type": "module",
@@ -34,15 +34,14 @@
    "@deepseek-ai/dsh-llm": "workspace:^",
    "@deepseek-ai/dsh-session": "workspace:^",
    "@deepseek-ai/dsh-tools": "workspace:^",
-    "schemastery": "^3.18.0"
+    "schemastery": "^3.18.0",
+    "ws": "^8.21.0"
  },
  "files": [
    "lib/index.js",
    "lib/invariant.js",
    "lib/client.js",
-    "lib/types/**/*.d.ts",
-    "lib/types/**/*.d.ts.map",
-    "src"
+    "lib/types/**/*.d.ts"
  ],
  "peerDependencies": {
    "@deepseek-ai/dsh-host-webserver": "^0.0.1",
@@ -52,6 +51,7 @@
  "devDependencies": {
    "@deepseek-ai/dsh-host-webserver": "workspace:^",
    "@deepseek-ai/dsh-invariants": "workspace:^",
+    "@types/ws": "^8.18.1",
    "cordis": "^4.0.0-rc.7"
  }
 }
--- a/packages/client/connection/src/api-path.ts
+++ b/packages/client/connection/src/api-path.ts
@@ -1,8 +1,14 @@
 /**
 * The /api URL prefix — single source for both halves of the web transport.
- * The node half registers this prefix on the web server; browser-side path
- * literals currently live in the apiproxy client layer (out of scope here).
+ * The node half registers this prefix on the web server; both halves share the
+ * event paths below for the browser WebSocket downlinks.
 */

 /** Route prefix owning every api request (`/api` and `/api/<anything>`). */
 export const API_PATH = '/api'
+
+/** Browser mux-frame WebSocket pathname. */
+export const MUX_EVENTS_PATH = `${API_PATH}/events.mux`
+
+/** Browser host-frame WebSocket pathname. */
+export const HOST_EVENTS_PATH = `${API_PATH}/events.host`
--- a/packages/client/connection/src/api-request-trust.ts
+++ b/packages/client/connection/src/api-request-trust.ts
@@ -4,7 +4,7 @@
 * the attacker's domain while the socket reaches this server) and cross-site
 * requests fired from a malicious page. The Host fence binds every request,
 * browser-looking or not: over plain HTTP a browser attaches neither Origin
- * nor Fetch-Metadata to reads (EventSource, images, navigations — those
+ * nor Fetch-Metadata to reads (images and navigations — those
 * headers go only to trustworthy destinations), so an unmarked request may
 * still be a rebound browser read and Host is the one header rebinding cannot
 * forge. Non-browser and remote clients pass the same fence via loopback, the
@@ -14,6 +14,7 @@
 */

 import type { IncomingHttpHeaders } from 'node:http'
+import { isLoopbackHostname } from './loopback-hostname.ts'

 /** The request facts the fence reads (structural subset of IncomingMessage). */
 interface ApiTrustRequest {
@@ -25,14 +26,6 @@ function header(headers: IncomingHttpHeaders, name: string): string | undefined
  return typeof value === 'string' ? value : undefined
 }

-function isLoopbackHostname(hostname: string): boolean {
-  if (hostname === 'localhost' || hostname === '[::1]') return true
-  const parts = hostname.split('.')
-  return parts.length === 4
-    && parts[0] === '127'
-    && parts.every(part => /^\d{1,3}$/.test(part) && Number(part) <= 255)
-}
-
 /** Normalized URL of a Host-header authority (hostname lowercased, default port stripped, IPv6 bracketed), or undefined when unparsable. */
 function parseAuthority(authority: string): URL | undefined {
  try {
@@ -104,7 +97,7 @@ export function isTrustedApiRequest(request: ApiTrustRequest, trustedHosts: read
  // fills Host from the URL it believes it is talking to, so a rebound page
  // carries the attacker's domain here even though the socket lands on this
  // server. There is no marker shortcut — a browser read over plain HTTP
-  // (EventSource, images, navigations) arrives with neither Origin nor
+  // (images and navigations) arrives with neither Origin nor
  // Fetch-Metadata, indistinguishable from curl, and its response is readable
  // by the rebound page.
  const host = header(request.headers, 'host')
--- a/packages/client/connection/src/client/api.ts
+++ b/packages/client/connection/src/client/api.ts
@@ -1,19 +1,22 @@
 // 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.
+// Types and runtime protocol helpers/bounds come from the apiproxy api/ layer
+// (zero Node deps, browser-safe); AbstractApiClient is the client 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,
+  ApiProxy, SessionsApi, SessionSearchItem, SessionSummary, HostApi, EventsApi, MuxFrame, HostFrame,
  ApprovalResponsePayload, QuestionResponsePayload, HistoryEntry, ToolEventView,
  DirectoryEntry, DirectoryListing,
  WorkspaceApi, WorkspaceId, WorkspaceView,
  CommandsApi, CommandDescriptor, SkillsApi, SkillEntry,
  ModelCatalogFailure, ModelCatalogModel, ModelProviderGroup, ModelReasoning,
-  ModelReasoningEffort, ModelTarget, SessionModels,
+  ModelReasoningEffort, ModelTarget, QueueAction, QueuedInboxItem, SessionModels,
  GoalsApi, GoalRef,
+  SettingsApi, SettingsNamespaceView, SettingsPathOpView, SettingsSecretView,
+  CredentialsApi, CredentialView, ConfigurableProviderView, LlmApi,
+  SubagentsApi, SubagentAddress, SubagentCatalog, SubagentListEntry, SubagentPromptReceipt,
 } from '@deepseek-ai/dsh-host-apiproxy/api'
 export type { ToolCallView, ToolResultView } from '@deepseek-ai/dsh-tools/presentation'
 export type {
@@ -23,10 +26,15 @@ export type {
 // transportError moved down to the apiproxy api layer (it belongs beside
 // RpcResult, its subject); re-exported here so connection consumers keep one
 // contract entry point.
-export { RpcId, transportError } from '@deepseek-ai/dsh-host-apiproxy/api'
+export {
+  RpcId,
+  SESSION_SEARCH_RESULT_LIMIT,
+  transportError,
+} 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 { MessageId } from '@deepseek-ai/dsh-llm/brand'
 export type { ContentBlock, StreamChunk } from '@deepseek-ai/dsh-llm/types'

 import type { RpcResponse, RpcResult } from '@deepseek-ai/dsh-host-apiproxy/api'
--- a/packages/client/connection/src/client/connection.ts
+++ b/packages/client/connection/src/client/connection.ts
@@ -126,7 +126,7 @@ export class ConnectionController {

      try {
        // Strict readiness handshake (audit C2): describe proves unary reachability, onOpen
-        // proves each SSE transport is established (response headers in, before any frame) —
+        // proves each physical stream is established 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).
--- a/packages/client/connection/src/client/fixture.ts
+++ b/packages/client/connection/src/client/fixture.ts
--- a/packages/client/connection/src/client/index.ts
+++ b/packages/client/connection/src/client/index.ts
@@ -8,22 +8,30 @@ 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'
+import { isLoopbackHostname } from '../loopback-hostname.ts'

 // ---- Contract re-exports (browser-safe apiproxy channels + core types) ----
 export type {
-  ApiProxy, SessionsApi, SessionSummary, HostApi, EventsApi, MuxFrame, HostFrame,
+  ApiProxy, SessionsApi, SessionSearchItem, SessionSummary, HostApi, EventsApi, MuxFrame, HostFrame,
  ApprovalResponsePayload, QuestionResponsePayload, HistoryEntry, ToolEventView,
  DirectoryEntry, DirectoryListing,
  ToolCallView, ToolResultView, WorkspaceApi, WorkspaceId, WorkspaceView,
  CommandsApi, CommandDescriptor, SkillsApi, SkillEntry,
  ModelCatalogFailure, ModelCatalogModel, ModelProviderGroup, ModelReasoning,
-  ModelReasoningEffort, ModelTarget, SessionModels,
+  MessageId, ModelReasoningEffort, ModelTarget, QueueAction, QueuedInboxItem, SessionModels,
+  SubagentsApi, SubagentAddress, SubagentCatalog, SubagentListEntry, SubagentPromptReceipt,
  RpcRequest, RpcResponse, RpcResult, RpcError, RpcErrorCode,
  ClientRequest, ServerResponse, ServerRequest, ClientResponse, RpcMessage, RpcReceipt,
  IApiClient, SessionId, SessionEvent, ContentBlock, StreamChunk,
  GoalsApi, GoalRef,
+  SettingsApi, SettingsNamespaceView, SettingsPathOpView, SettingsSecretView,
+  CredentialsApi, CredentialView, ConfigurableProviderView, LlmApi,
+} from './api.ts'
+export {
+  RpcId,
+  AbstractApiClient,
+  transportError,
 } from './api.ts'
-export { RpcId, AbstractApiClient, transportError } from './api.ts'

 // Connection loop types are public through ConnectionHandle.start; the
 // controller remains package-internal.
@@ -41,6 +49,8 @@ export const inject: string[] = []
 export interface ConnectionHandle {
  /** Shared api client (fixture or real, decided at boot from the page URL). */
  readonly api: IApiClient
+  /** Whether the current page authority is loopback; non-browser contexts default to true. */
+  readonly isLoopback: boolean
  /**
   * Start the connect/pump/reconnect loop with the consumer's frame sinks.
   * One consumer owns the streams (the runtime object layer); a second call
@@ -57,11 +67,13 @@ export interface ConnectionHandle {
 * @param ctx - client cordis context.
 */
 export function apply(ctx: Context): void {
-  const fixture = typeof location !== 'undefined' && new URLSearchParams(location.search).has('fixture')
+  const pageLocation = typeof location === 'undefined' ? undefined : location
+  const fixture = pageLocation !== undefined && new URLSearchParams(pageLocation.search).has('fixture')
  const api: IApiClient = fixture ? new FixtureApiClient() : new WebApiClient()
  let started = false
  const handle: ConnectionHandle = {
    api,
+    isLoopback: pageLocation === undefined || isLoopbackHostname(pageLocation.hostname),
    start(sinks, config) {
      if (started) throw new Error('connection: the stream loop is already owned by another consumer')
      started = true
--- a/packages/client/connection/src/client/web-api-client.ts
+++ b/packages/client/connection/src/client/web-api-client.ts
@@ -1,12 +1,91 @@
-// 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).
+/** Browser API carrier: HTTP upstream plus one WebSocket per downstream event stream. */

+import type { ApiProxy, HostFrame, MuxFrame, RpcRequest, ServerRequest } from './api.ts'
 import { AbstractApiClient } from './api.ts'
+import { hostFrameSchema, muxFrameSchema } from '@deepseek-ai/dsh-host-apiproxy/api/events.schema'
+import { serverRequestSchema } from '@deepseek-ai/dsh-host-apiproxy/api/rpc.schema'
+import { HOST_EVENTS_PATH, MUX_EVENTS_PATH } from '../api-path.ts'

-/** Browser platform subclass: transport = global fetch over same-origin /api/*. */
+type SocketItem<F> = { kind: 'frame'; envelope: RpcRequest<F> } | { kind: 'end' }
+type Parser<F> = { parse(value: unknown): F }
+
+/** Browser platform subclass: unary/respond use fetch; mux/host use downlink-only WebSockets. */
 export class WebApiClient extends AbstractApiClient {
  protected doFetch(input: URL, init?: RequestInit): Promise<Response> {
    return globalThis.fetch(input, init)
  }
+
+  protected override openMux(
+    _payload: Parameters<ApiProxy['events']['mux']>[0]['payload'],
+    signal: AbortSignal,
+    onOpen?: () => void,
+  ): AsyncIterable<RpcRequest<MuxFrame>> {
+    return this.readWebSocket(MUX_EVENTS_PATH, signal, muxFrameSchema, onOpen)
+  }
+
+  protected override openHost(
+    _payload: Parameters<ApiProxy['events']['host']>[0]['payload'],
+    signal: AbortSignal,
+    onOpen?: () => void,
+  ): AsyncIterable<RpcRequest<HostFrame>> {
+    return this.readWebSocket(HOST_EVENTS_PATH, signal, hostFrameSchema, onOpen)
+  }
+
+  private async *readWebSocket<F extends MuxFrame | HostFrame>(
+    path: string,
+    signal: AbortSignal,
+    frameSchema: Parser<F>,
+    onOpen?: () => void,
+  ): AsyncGenerator<RpcRequest<F>> {
+    const url = new URL(path, this.resolveBase())
+    url.protocol = url.protocol === 'https:' ? 'wss:' : 'ws:'
+    const socket = new WebSocket(url)
+    const inbox: SocketItem<F>[] = []
+    let wake: (() => void) | undefined
+    const enqueue = (item: SocketItem<F>): void => {
+      inbox.push(item)
+      wake?.()
+      wake = undefined
+    }
+    const handleOpen = (): void => { onOpen?.() }
+    const handleMessage = (event: MessageEvent): void => {
+      let full: ServerRequest
+      let frame: F
+      try {
+        if (typeof event.data !== 'string') throw new Error('binary WebSocket frame')
+        full = serverRequestSchema.parse(JSON.parse(event.data))
+        frame = frameSchema.parse(full.payload)
+      } catch (error) {
+        console.error(`[client-connection] dropping malformed WebSocket frame on ${path}:`, error)
+        return
+      }
+      this.onEnvelope(full)
+      enqueue({ kind: 'frame', envelope: { rpcId: full.rpcId, payload: frame } })
+    }
+    const handleClose = (): void => { enqueue({ kind: 'end' }) }
+    const handleAbort = (): void => {
+      if (socket.readyState === WebSocket.CONNECTING || socket.readyState === WebSocket.OPEN) socket.close()
+    }
+    socket.addEventListener('open', handleOpen)
+    socket.addEventListener('message', handleMessage)
+    socket.addEventListener('close', handleClose, { once: true })
+    signal.addEventListener('abort', handleAbort, { once: true })
+    if (signal.aborted) handleAbort()
+    try {
+      while (true) {
+        while (inbox.length > 0) {
+          const item = inbox.shift() as SocketItem<F>
+          if (item.kind === 'end') return
+          yield item.envelope
+        }
+        await new Promise<void>((resolve) => { wake = resolve })
+      }
+    } finally {
+      signal.removeEventListener('abort', handleAbort)
+      socket.removeEventListener('open', handleOpen)
+      socket.removeEventListener('message', handleMessage)
+      socket.removeEventListener('close', handleClose)
+      handleAbort()
+    }
+  }
 }
--- a/packages/client/connection/src/index.ts
+++ b/packages/client/connection/src/index.ts
@@ -2,13 +2,14 @@
 import type { Context } from 'cordis'
 import z from 'schemastery'
 // Activates the httpServer Context merge used below.
-import type { WebRoute } from '@deepseek-ai/dsh-host-webserver'
+import type { WebRoute, WebUpgradeRoute } from '@deepseek-ai/dsh-host-webserver'
 import { toFetchHandler } from '@deepseek-ai/dsh-host-apiproxy'
-import { API_PATH } from './api-path.ts'
+import { API_PATH, HOST_EVENTS_PATH, MUX_EVENTS_PATH } from './api-path.ts'
 import { bridge } from './http-bridge.ts'
 import { assertTrustedAuthority, isTrustedApiRequest } from './api-request-trust.ts'
+import { rejectWebSocketUpgrade, WebSocketDownlinks } from './websocket-downlink.ts'

-export { API_PATH } from './api-path.ts'
+export { API_PATH, HOST_EVENTS_PATH, MUX_EVENTS_PATH } from './api-path.ts'

 /** Stable Cordis plugin name. */
 export const name = 'client-connection'
@@ -33,10 +34,40 @@ export const Config: z<ConnectionConfig> = z.object({
  trustedHosts: z.array(String).default([]),
 })

+/**
+ * Methods gated to loopback even on a trusted-host deployment. Native dialogs
+ * act on the host machine; the settings and credential domains mutate the
+ * user's configuration and secret store, and READING them is equally
+ * privileged — `settings.describe` returns every exposed namespace's
+ * configuration and `credentials.describe` reports whether an arbitrary
+ * environment-variable name is configured and where from, which is
+ * reconnaissance no anonymous caller should have. `trustedHosts` is a
+ * DNS-rebinding fence, explicitly not authentication, so the whole
+ * configuration plane stays loopback-same-origin until a real authentication
+ * layer exists. The model catalog (`llm.providers`, `llm.models`) is
+ * deliberately NOT here: it carries provider ids, display names, and model
+ * lists — no endpoints, keys, or key state — and a LAN client's model picker
+ * legitimately needs it.
+ */
+const PRIVILEGED_METHODS = new Set([
+  'host.pickDirectory',
+  'host.openPath',
+  'settings.describe',
+  'settings.openDocument',
+  'settings.update',
+  'settings.replace',
+  'settings.mutate',
+  'credentials.describe',
+  'credentials.set',
+  'credentials.unset',
+])
+
 /**
 * Mounts the API gateway under the browser transport prefix. Every request on
 * the prefix passes the browser-trust fence first (DNS-rebinding and
- * cross-site defense — [api-request-trust](./api-request-trust.ts)).
+ * cross-site defense — [api-request-trust](./api-request-trust.ts));
+ * privileged methods additionally pass it with an empty trust list, which
+ * pins them to loopback.
 * @param ctx - Host plugin context.
 * @param config - resolved plugin config (schema defaults applied).
 */
@@ -47,17 +78,48 @@ export function apply(ctx: Context, config?: ConnectionConfig): void {
  // silently authorizing its hostname prefix at request time.
  for (const entry of trustedHosts) assertTrustedAuthority(entry)
  const apiHandler = toFetchHandler(ctx.apiProxy)
+  const downlinks = new WebSocketDownlinks(ctx.apiProxy)
  const route: WebRoute = {
    kind: 'prefix',
    path: API_PATH,
    handler: async (req, res) => {
-      if (!isTrustedApiRequest(req, trustedHosts)) {
+      const pathname = new URL(req.url ?? '/', 'http://dsh.internal').pathname
+      const method = pathname.startsWith(`${API_PATH}/`)
+        ? pathname.slice(API_PATH.length + 1)
+        : undefined
+      const allowed = method !== undefined && PRIVILEGED_METHODS.has(method)
+        ? isTrustedApiRequest(req, [])
+        : isTrustedApiRequest(req, trustedHosts)
+      if (!allowed) {
        res.writeHead(403)
        res.end('forbidden')
        return
      }
+      if (req.method === 'GET' && (pathname === MUX_EVENTS_PATH || pathname === HOST_EVENTS_PATH)) {
+        res.writeHead(426, { connection: 'Upgrade', upgrade: 'websocket' })
+        res.end('upgrade required')
+        return
+      }
      await bridge(req, res, apiHandler)
    },
  }
  ctx.effect(() => ctx.httpServer.register(route), 'client-connection: /api route')
+  const registerDownlink = (
+    path: string,
+    handle: WebUpgradeRoute['handler'],
+  ): void => {
+    ctx.effect(() => ctx.httpServer.registerUpgrade({
+      path,
+      handler: (req, socket, head) => {
+        if (!isTrustedApiRequest(req, trustedHosts)) {
+          rejectWebSocketUpgrade(socket)
+          return
+        }
+        return handle(req, socket, head)
+      },
+    }), `client-connection: ${path} WebSocket`)
+  }
+  ctx.effect(() => () => downlinks.close(), 'client-connection: WebSocket downlinks')
+  registerDownlink(MUX_EVENTS_PATH, (req, socket, head) => { downlinks.handleMux(req, socket, head) })
+  registerDownlink(HOST_EVENTS_PATH, (req, socket, head) => { downlinks.handleHost(req, socket, head) })
 }
--- a/packages/client/connection/src/loopback-hostname.ts
+++ b/packages/client/connection/src/loopback-hostname.ts
@@ -0,0 +1,18 @@
+/**
+ * Browser-safe, zero-dependency loopback classification shared by the `/api`
+ * Host fence and the package's `ctx.connection` state. The predicate stays
+ * package-internal; client plugins consume the derived state through Cordis.
+ */
+
+/**
+ * Whether a normalized URL hostname names the local loopback authority.
+ * @param hostname - WHATWG URL hostname (IPv6 literals retain brackets).
+ * @returns true for localhost, IPv6 loopback, or any IPv4 address in 127/8.
+ */
+export function isLoopbackHostname(hostname: string): boolean {
+  if (hostname === 'localhost' || hostname === '[::1]') return true
+  const parts = hostname.split('.')
+  return parts.length === 4
+    && parts[0] === '127'
+    && parts.every(part => /^\d{1,3}$/.test(part) && Number(part) <= 255)
+}
--- a/packages/client/connection/src/websocket-downlink.ts
+++ b/packages/client/connection/src/websocket-downlink.ts
@@ -0,0 +1,153 @@
+/** Host-side WebSocket carrier for the two server-to-browser event streams. */
+
+import { randomUUID } from 'node:crypto'
+import type { IncomingMessage } from 'node:http'
+import type { Duplex } from 'node:stream'
+import WebSocket, { WebSocketServer } from 'ws'
+import type {
+  ApiProxy, HostFrame, MuxFrame, RpcRequest, ServerRequest,
+} from '@deepseek-ai/dsh-host-apiproxy/api'
+import { RpcId } from '@deepseek-ai/dsh-host-apiproxy/api'
+
+type Frame = MuxFrame | HostFrame
+
+function serverRequest(frame: RpcRequest<Frame>): ServerRequest {
+  return {
+    type: 'server-request',
+    rpcId: frame.rpcId,
+    method: frame.payload.type,
+    payload: frame.payload,
+  }
+}
+
+function send(socket: WebSocket, frame: RpcRequest<Frame>): Promise<void> {
+  return new Promise((resolve, reject) => {
+    if (socket.readyState !== WebSocket.OPEN) {
+      reject(new Error('websocket downlink closed before frame delivery'))
+      return
+    }
+    socket.send(JSON.stringify(serverRequest(frame)), (error) => {
+      if (error) reject(error)
+      else resolve()
+    })
+  })
+}
+
+function failureFrame(error: unknown): RpcRequest<Frame> {
+  return {
+    rpcId: RpcId(randomUUID()),
+    payload: {
+      type: 'stream/error',
+      error: { code: 'internal', message: String(error), details: {} },
+    },
+  }
+}
+
+/**
+ * Owns WebSocket negotiation and frame pumping for the connection plugin's
+ * two downlinks. Client messages are a protocol violation: upstream traffic
+ * remains on HTTP.
+ */
+export class WebSocketDownlinks {
+  private readonly server = new WebSocketServer({ noServer: true })
+  private readonly pumps = new Set<Promise<void>>()
+
+  /** @param api - host API supplying the typed event streams. */
+  constructor(private readonly api: ApiProxy) {}
+
+  /**
+   * Upgrade one socket and pump the mux stream until either side closes.
+   * @param req - HTTP upgrade request.
+   * @param socket - Raw socket transferred by the HTTP server.
+   * @param head - Bytes already read after the upgrade headers.
+   */
+  handleMux(req: IncomingMessage, socket: Duplex, head: Buffer): void {
+    this.upgrade(req, socket, head, signal => this.api.events.mux({
+      rpcId: RpcId(randomUUID()),
+      payload: {},
+    }, signal))
+  }
+
+  /**
+   * Upgrade one socket and pump the host stream until either side closes.
+   * @param req - HTTP upgrade request.
+   * @param socket - Raw socket transferred by the HTTP server.
+   * @param head - Bytes already read after the upgrade headers.
+   */
+  handleHost(req: IncomingMessage, socket: Duplex, head: Buffer): void {
+    this.upgrade(req, socket, head, signal => this.api.events.host({
+      rpcId: RpcId(randomUUID()),
+      payload: {},
+    }, signal))
+  }
+
+  /**
+   * Terminate owned sockets and await the no-server acceptor plus frame pumps.
+   * @returns A promise resolving after every socket and source iterator stops.
+   */
+  async close(): Promise<void> {
+    for (const socket of this.server.clients) socket.terminate()
+    await new Promise<void>((resolve, reject) => {
+      this.server.close((error) => {
+        if (error === undefined) resolve()
+        else reject(error)
+      })
+    })
+    await Promise.all(this.pumps)
+  }
+
+  private upgrade<F extends Frame>(
+    req: IncomingMessage,
+    socket: Duplex,
+    head: Buffer,
+    open: (signal: AbortSignal) => AsyncIterable<RpcRequest<F>>,
+  ): void {
+    this.server.handleUpgrade(req, socket, head, (websocket) => {
+      const abort = new AbortController()
+      websocket.once('close', () => { abort.abort() })
+      websocket.once('error', () => { abort.abort() })
+      websocket.once('message', () => {
+        websocket.close(1008, 'downlink only')
+      })
+      const pump = this.pump(websocket, open(abort.signal), abort)
+      this.pumps.add(pump)
+      void pump.then(() => { this.pumps.delete(pump) })
+    })
+  }
+
+  private async pump<F extends Frame>(
+    socket: WebSocket,
+    frames: AsyncIterable<RpcRequest<F>>,
+    abort: AbortController,
+  ): Promise<void> {
+    try {
+      for await (const frame of frames) await send(socket, frame)
+    } catch (error) {
+      if (!abort.signal.aborted) {
+        try {
+          await send(socket, failureFrame(error))
+        } catch {
+          // Socket loss won the race; no downstream remains to receive the failure frame.
+        }
+      }
+    } finally {
+      abort.abort()
+      if (socket.readyState === WebSocket.OPEN) socket.close()
+    }
+  }
+}
+
+/**
+ * Reject an untrusted upgrade before protocol negotiation.
+ * @param socket - Raw HTTP socket that remains owned by the caller.
+ */
+export function rejectWebSocketUpgrade(socket: Duplex): void {
+  socket.end([
+    'HTTP/1.1 403 Forbidden',
+    'Connection: close',
+    'Content-Type: text/plain; charset=utf-8',
+    'Content-Length: 9',
+    '',
+    'forbidden',
+  ].join('\r\n'))
+}
--- a/packages/client/connection/tests/client-apply.spec.ts
+++ b/packages/client/connection/tests/client-apply.spec.ts
@@ -3,15 +3,55 @@
 * selection off the page URL, and the single-consumer stream-loop ownership.
 */
 import { Context } from 'cordis'
-import { afterEach, describe, expect, it } from 'vitest'
+import { afterEach, describe, expect, it, vi } from 'vitest'
 import { apply, type ConnectionHandle } from '../src/client/index.ts'
+import type { RpcMessage } from '../src/client/api.ts'
+import { RpcId } from '../src/client/api.ts'
 import { FixtureApiClient } from '../src/client/fixture.ts'
 import { WebApiClient } from '../src/client/web-api-client.ts'

-type Win = { location?: { search: string } }
+type Win = { location?: { hostname: string; search: string; origin?: string } }
+type WebSocketGlobal = { WebSocket?: typeof WebSocket }
+
+const originalWebSocket = globalThis.WebSocket
+const sockets: FakeWebSocket[] = []
+
+class FakeWebSocket extends EventTarget {
+  static readonly CONNECTING = 0
+  static readonly OPEN = 1
+  static readonly CLOSING = 2
+  static readonly CLOSED = 3
+
+  readonly url: string
+  readyState = FakeWebSocket.CONNECTING
+
+  constructor(url: string | URL) {
+    super()
+    this.url = String(url)
+    sockets.push(this)
+    queueMicrotask(() => {
+      if (this.readyState !== FakeWebSocket.CONNECTING) return
+      this.readyState = FakeWebSocket.OPEN
+      this.dispatchEvent(new Event('open'))
+    })
+  }
+
+  close(): void {
+    if (this.readyState === FakeWebSocket.CLOSED) return
+    this.readyState = FakeWebSocket.CLOSED
+    this.dispatchEvent(new Event('close'))
+  }
+
+  receive(data: unknown): void {
+    this.dispatchEvent(new MessageEvent('message', { data }))
+  }
+}

 afterEach(() => {
  delete (globalThis as Win).location
+  sockets.length = 0
+  if (originalWebSocket === undefined) delete (globalThis as WebSocketGlobal).WebSocket
+  else globalThis.WebSocket = originalWebSocket
 })

 async function mount(): Promise<ConnectionHandle> {
@@ -24,20 +64,28 @@ async function mount(): Promise<ConnectionHandle> {

 describe('connection client apply', () => {
  it('mounts ctx.connection with the real client when no ?fixture switch is present', async () => {
-    ;(globalThis as Win).location = { search: '' }
+    ;(globalThis as Win).location = { hostname: 'localhost', search: '' }
    const handle = await mount()
    expect(handle.api).toBeInstanceOf(WebApiClient)
+    expect(handle.isLoopback).toBe(true)
  })

  it('selects the fixture client under ?fixture (and with no location at all stays real)', async () => {
-    ;(globalThis as Win).location = { search: '?fixture' }
+    ;(globalThis as Win).location = { hostname: '127.0.0.1', search: '?fixture' }
    expect((await mount()).api).toBeInstanceOf(FixtureApiClient)
    delete (globalThis as Win).location
-    expect((await mount()).api).toBeInstanceOf(WebApiClient)
+    const handle = await mount()
+    expect(handle.api).toBeInstanceOf(WebApiClient)
+    expect(handle.isLoopback).toBe(true)
+  })
+
+  it('reports non-loopback page authority through the connection handle', async () => {
+    ;(globalThis as Win).location = { hostname: '192.0.2.20', search: '' }
+    expect((await mount()).isLoopback).toBe(false)
  })

  it('start() hands out one loop, rejects a second consumer, and stop() aborts the streams', async () => {
-    ;(globalThis as Win).location = { search: '?fixture' }
+    ;(globalThis as Win).location = { hostname: 'localhost', search: '?fixture' }
    const handle = await mount()
    // config omitted: the `config ?? {}` default arm is part of the surface.
    const loop = handle.start({})
@@ -45,8 +93,8 @@ describe('connection client apply', () => {
    loop.stop() // teardown must not throw; the fixture streams abort quietly
  })

-  it('WebApiClient carries requests over globalThis.fetch', async () => {
-    ;(globalThis as Win).location = { search: '' }
+  it('WebApiClient keeps unary calls and respond on globalThis.fetch', async () => {
+    ;(globalThis as Win).location = { hostname: 'localhost', search: '' }
    const handle = await mount()
    const original = globalThis.fetch
    const seen: string[] = []
@@ -57,9 +105,102 @@ describe('connection client apply', () => {
    try {
      // Schema rejection is fine — the transport hop is the assertion.
      await (handle.api as WebApiClient).host.describe({}).catch(() => undefined)
+      await handle.api.respond({
+        type: 'client-response',
+        rpcId: RpcId('response-over-http'),
+        result: { ok: true, value: {} },
+      }).catch(() => undefined)
    } finally {
      globalThis.fetch = original
    }
-    expect(seen.some(u => u.includes('/api/'))).toBe(true)
+    expect(seen.some(u => u.includes('/api/host.describe'))).toBe(true)
+    expect(seen.some(u => u.includes('/api/respond'))).toBe(true)
+  })
+
+  it('opens one WebSocket per downlink, parses frames, and aborts both without using fetch', async () => {
+    ;(globalThis as Win).location = {
+      hostname: 'localhost', search: '', origin: 'http://localhost:3080',
+    }
+    ;(globalThis as WebSocketGlobal).WebSocket = FakeWebSocket as unknown as typeof WebSocket
+    const fetch = vi.spyOn(globalThis, 'fetch')
+    const client = (await mount()).api as WebApiClient
+    const envelopes: RpcMessage[][] = []
+    client.subscribeEnvelopes((batch) => { envelopes.push([...batch]) })
+    const opened: string[] = []
+    const muxAbort = new AbortController()
+    const hostAbort = new AbortController()
+    const mux = client.events.mux({}, muxAbort.signal, () => { opened.push('mux') })[Symbol.asyncIterator]()
+    const host = client.events.host({}, hostAbort.signal, () => { opened.push('host') })[Symbol.asyncIterator]()
+    const muxFrame = mux.next()
+    const hostFrame = host.next()
+    await vi.waitFor(() => { expect(sockets).toHaveLength(2) })
+    expect(sockets.map(socket => socket.url)).toEqual([
+      'ws://localhost:3080/api/events.mux',
+      'ws://localhost:3080/api/events.host',
+    ])
+    await vi.waitFor(() => { expect(opened).toEqual(['mux', 'host']) })
+
+    const errors = vi.spyOn(console, 'error').mockImplementation(() => {})
+    sockets[0]!.receive(new Uint8Array([1, 2, 3]))
+    sockets[1]!.receive(JSON.stringify({ type: 'server-request', rpcId: 'bad', method: 'host/session-status', payload: {} }))
+    sockets[0]!.receive(JSON.stringify({
+      type: 'server-request',
+      rpcId: 'mux-browser',
+      method: 'session/subscribed',
+      payload: { type: 'session/subscribed', sessionId: 'session-browser', lastSeq: 8 },
+    }))
+    sockets[1]!.receive(JSON.stringify({
+      type: 'server-request',
+      rpcId: 'host-browser',
+      method: 'host/commands-changed',
+      payload: { type: 'host/commands-changed' },
+    }))
+    expect(await muxFrame).toMatchObject({
+      value: { rpcId: 'mux-browser', payload: { type: 'session/subscribed', lastSeq: 8 } },
+    })
+    expect(await hostFrame).toMatchObject({
+      value: { rpcId: 'host-browser', payload: { type: 'host/commands-changed' } },
+    })
+    expect(errors).toHaveBeenCalledTimes(2)
+    await vi.waitFor(() => { expect(envelopes.flat()).toHaveLength(2) })
+    expect(fetch).not.toHaveBeenCalled()
+
+    const muxEnd = mux.next()
+    const hostEnd = host.next()
+    muxAbort.abort()
+    hostAbort.abort()
+    await expect(muxEnd).resolves.toMatchObject({ done: true })
+    await expect(hostEnd).resolves.toMatchObject({ done: true })
+    expect(sockets.every(socket => socket.readyState === FakeWebSocket.CLOSED)).toBe(true)
+    errors.mockRestore()
+    fetch.mockRestore()
+  })
+
+  it('maps an HTTPS page origin to a secure WebSocket URL', async () => {
+    ;(globalThis as Win).location = {
+      hostname: 'harness.example', search: '', origin: 'https://harness.example',
+    }
+    ;(globalThis as WebSocketGlobal).WebSocket = FakeWebSocket as unknown as typeof WebSocket
+    const client = (await mount()).api
+    const abort = new AbortController()
+    const iterator = client.events.mux({}, abort.signal)[Symbol.asyncIterator]()
+    const pending = iterator.next()
+    await vi.waitFor(() => { expect(sockets[0]?.url).toBe('wss://harness.example/api/events.mux') })
+    abort.abort()
+    await expect(pending).resolves.toMatchObject({ done: true })
+  })
+
+  it('closes a WebSocket immediately when its signal was already aborted', async () => {
+    ;(globalThis as Win).location = {
+      hostname: 'localhost', search: '', origin: 'http://localhost:3080',
+    }
+    ;(globalThis as WebSocketGlobal).WebSocket = FakeWebSocket as unknown as typeof WebSocket
+    const client = (await mount()).api
+    const abort = new AbortController()
+    abort.abort()
+    const iterator = client.events.mux({}, abort.signal)[Symbol.asyncIterator]()
+    await expect(iterator.next()).resolves.toMatchObject({ done: true })
+    expect(sockets).toHaveLength(1)
+    expect(sockets[0]?.readyState).toBe(FakeWebSocket.CLOSED)
  })
 })
--- a/packages/client/connection/tests/fake-api.ts
+++ b/packages/client/connection/tests/fake-api.ts
@@ -4,7 +4,7 @@
 import type { CommandId } from '@deepseek-ai/dsh-commands/brand'
 import type {
  CommandDescriptor, HostFrame, IApiClient, ModelTarget, MuxFrame,
-  RpcRequest, RpcResponse, SessionId, SessionModels, SkillEntry,
+  RpcRequest, RpcResponse, SessionId, SessionModels, SessionSearchItem, SkillEntry,
 } from '../src/client/api.ts'
 import { RpcId } from '../src/client/api.ts'

@@ -44,17 +44,21 @@ export class FakeApiClient implements IApiClient {

  // Programmable slots (defaults answer OK-empty); reassign per case.
  onList: (payload: unknown) => Promise<RpcResponse<{ items: never[] }>> = () => Promise.resolve(ok({ items: [] }))
+  onSearch: (payload: unknown) => Promise<RpcResponse<{ items: SessionSearchItem[]; hasMore: boolean }>> =
+    () => Promise.resolve(ok({ items: [], hasMore: false }))
  onCreate: (payload: unknown) => Promise<RpcResponse<{ sessionId: SessionId }>> = () => Promise.resolve(ok({ sessionId: 'fk-new' as SessionId }))
+  onRename: (payload: unknown) => Promise<RpcResponse<{ title: string; seq: number }>> = () => Promise.resolve(ok({ title: 'fk-renamed', seq: 0 }))
+  onFork: (payload: unknown) => Promise<RpcResponse<{ sessionId: SessionId }>> = () => Promise.resolve(ok({ sessionId: 'fk-fork' as SessionId }))
  onHistory: (payload: { sessionId: SessionId; beforeSeq?: number; maxMessages?: number })
  => Promise<RpcResponse<{ events: never[]; hasMore: boolean; modelTarget: ModelTarget }>> =
    () => Promise.resolve(ok({
      events: [],
      hasMore: false,
-      modelTarget: { provider: 'deepseek', model: 'deepseek-chat' },
+      modelTarget: { provider: 'deepseek-official', model: 'deepseek-chat' },
    }))

  onModels: (payload: unknown) => Promise<RpcResponse<SessionModels>> = () => Promise.resolve(ok({
-    current: { provider: 'deepseek', model: 'deepseek-chat' },
+    current: { provider: 'deepseek-official', model: 'deepseek-chat' },
    groups: [],
    failures: [],
  }))
@@ -62,6 +66,7 @@ export class FakeApiClient implements IApiClient {
  => Promise<RpcResponse<{ selected: ModelTarget }>> =
    payload => Promise.resolve(ok({ selected: { provider: payload.provider, model: payload.model } }))
  onPrompt: (payload: unknown) => Promise<RpcResponse<{ accepted: true }>> = () => Promise.resolve(ok({ accepted: true as const }))
+  onUpdateQueue: (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 }))
@@ -84,22 +89,44 @@ export class FakeApiClient implements IApiClient {

  private readonly muxConns: StreamConn<MuxFrame>[] = []
  private readonly hostConns: StreamConn<HostFrame>[] = []
+  lastSearchSignal: AbortSignal | undefined

  // Parameter annotations below are local structural types on purpose: the CI
  // lint lane runs without built artifacts, where IApiClient's wire types
  // (apiproxy subpath) resolve to any and inferred params trip no-unsafe-argument.
  readonly sessions: IApiClient['sessions'] = {
    list: (payload: unknown) => this.record('session.list', payload, this.onList(payload)),
+    search: (payload: unknown, signal?: AbortSignal) => {
+      this.lastSearchSignal = signal
+      return this.record('session.search', payload, this.onSearch(payload))
+    },
    create: (payload: unknown) => this.record('session.create', payload, this.onCreate(payload)),
    history: (payload: { sessionId: SessionId; beforeSeq?: number; maxMessages?: number }) =>
      this.record('session.history', payload, this.onHistory(payload)),
    models: (payload: unknown) => this.record('session.models', payload, this.onModels(payload)),
    selectModel: (payload: ModelTarget & { sessionId: SessionId }) =>
      this.record('session.selectModel', payload, this.onSelectModel(payload)),
+    rename: (payload: unknown) => this.record('session.rename', payload, this.onRename(payload)),
+    fork: (payload: unknown) => this.record('session.fork', payload, this.onFork(payload)),
    prompt: (payload: unknown) => this.record('session.prompt', payload, this.onPrompt(payload)),
+    updateQueue: (payload: unknown) => this.record('session.updateQueue', payload, this.onUpdateQueue(payload)),
    cancel: (payload: unknown) => this.record('session.cancel', payload, this.onCancel(payload)),
  }

+  readonly subagents: IApiClient['subagents'] = {
+    list: (payload: unknown) => this.record('subagent.list', payload, Promise.resolve(ok({
+      entries: [],
+      parentAvailable: true,
+    }))),
+    history: (payload: unknown) => this.record('subagent.history', payload, Promise.resolve(ok({
+      events: [],
+      hasMore: false,
+    }))),
+    prompt: (payload: unknown) => this.record('subagent.prompt', payload, Promise.resolve(ok({
+      messageId: 'fake-message' as never,
+    }))),
+  }
+
  readonly host: IApiClient['host'] = {
    describe: payload => this.record('host.describe', payload, this.onDescribe(payload)),
    pickDirectory: payload => this.record('host.pickDirectory', payload, this.onPickDirectory(payload)),
@@ -109,7 +136,7 @@ export class FakeApiClient implements IApiClient {
  }

  readonly workspace: IApiClient['workspace'] = {
-    list: (payload: unknown) => this.record('workspace.list', payload, Promise.resolve(ok({ items: [] }))),
+    list: (payload: unknown) => this.record('workspace.list', payload, Promise.resolve(ok({ items: [], archivedSessionIds: [] }))),
    create: (payload: unknown) => this.record('workspace.create', payload, Promise.resolve(ok({
      workspace: { workspaceId: 'fk-ws' as never, path: '/f/ws', title: 'ws', sessionIds: [], createdAt: '0', updatedAt: '0' },
      created: true,
@@ -121,6 +148,9 @@ export class FakeApiClient implements IApiClient {
    insertSessionBefore: (payload: unknown) => this.record('workspace.insertSessionBefore', payload, Promise.resolve(ok({
      workspace: { workspaceId: 'fk-ws' as never, path: '/f/ws', title: 'ws', sessionIds: [], createdAt: '0', updatedAt: '0' },
    }))),
+    archiveSession: (payload: unknown) => this.record('workspace.archiveSession', payload, Promise.resolve(ok({
+      archivedSessionIds: [(payload as { sessionId: SessionId }).sessionId],
+    }))),
  }

  // Payloads stay `unknown` (lint-lane note above); response rows are the real
@@ -150,6 +180,25 @@ export class FakeApiClient implements IApiClient {
    clear: payload => this.record('goal.clear', payload, Promise.resolve(ok({ cleared: true as const }))),
  }

+  readonly settings: IApiClient['settings'] = {
+    describe: payload => this.record('settings.describe', payload, Promise.resolve(ok({ writable: true, hasDocument: false, namespaces: [] }))),
+    openDocument: payload => this.record('settings.openDocument', payload, Promise.resolve(ok({ opened: true as const }))),
+    update: payload => this.record('settings.update', payload, Promise.resolve(ok({ ns: 'fake', schema: {}, value: {}, applies: 'live' as const, secrets: [], revision: 0 }))),
+    replace: payload => this.record('settings.replace', payload, Promise.resolve(ok({ ns: 'fake', schema: {}, value: {}, applies: 'live' as const, secrets: [], revision: 0 }))),
+    mutate: payload => this.record('settings.mutate', payload, Promise.resolve(ok({ ns: 'fake', schema: {}, value: {}, applies: 'live' as const, secrets: [], revision: 0 }))),
+  }
+
+  readonly credentials: IApiClient['credentials'] = {
+    describe: payload => this.record('credentials.describe', payload, Promise.resolve(ok({ credentials: {} }))),
+    set: payload => this.record('credentials.set', payload, Promise.resolve(ok({}))),
+    unset: payload => this.record('credentials.unset', payload, Promise.resolve(ok({}))),
+  }
+
+  readonly llm: IApiClient['llm'] = {
+    providers: payload => this.record('llm.providers', payload, Promise.resolve(ok({ providers: [] }))),
+    models: payload => this.record('llm.models', payload, Promise.resolve(ok({ groups: [], failures: [] }))),
+  }
+
  /** When true, streams never fire onOpen (misbehaving-carrier material for the handshake timeout guard). */
  suppressStreamOpen = false

--- a/packages/client/connection/tests/fixture.spec.ts
+++ b/packages/client/connection/tests/fixture.spec.ts
@@ -19,6 +19,20 @@ interface TimingHooks {
  failNextHistory(): void
  appendUser(id: string, msg: string): void
  appendTitle(id: string, title: string): void
+  startReasoningChunkStorm(id: string, chunkCount: number, chunksPerInterval: number, intervalMs: number): string
+  reasoningChunkStormState(): {
+    sessionId: string
+    chunkCount: number
+    chunksPerInterval: number
+    intervalMs: number
+    emitted: number
+    marker: string
+    emitting: boolean
+  } | null
+  beginModelRetry(id: string): void
+  scheduleModelRetry(id: string, retry?: number, delayMs?: number): void
+  cancelModelRetryDuringBackoff(id: string, delayMs?: number): void
+  completeModelRetry(id: string): void
  appendSilent(id: string, msg: string): void
  breakStreams(): void
 }
@@ -48,6 +62,59 @@ describe('createFixtureApi', () => {
    expect(response.result.value.items[1]?.parentSessionId).toBe('fx-alpha') // lineage material
  })

+  it('searches current message text with literal unicode61-style token phrases', async () => {
+    const api = createFixtureApi()
+    const signal = new AbortController().signal
+    const phrase = await api.sessions.search(req({ query: 'FIXTURE 历史消息' }), signal)
+    expect(phrase.result).toMatchObject({
+      ok: true,
+      value: {
+        items: [{ sessionId: 'fx-alpha' }],
+        hasMore: false,
+      },
+    })
+    if (!phrase.result.ok) throw new Error('search failed')
+    expect(phrase.result.value.items[0]?.snippet).toContain('fixture 历史消息')
+
+    timing().appendUser(
+      'fx-alpha',
+      `${'leading context '.repeat(20)}late café token${' trailing context'.repeat(20)}`,
+    )
+    const late = await api.sessions.search(req({ query: 'LATE CAFE TOKEN' }), signal)
+    if (!late.result.ok) throw new Error('late search failed')
+    const lateSnippet = late.result.value.items[0]?.snippet ?? ''
+    expect(lateSnippet).toContain('late café token')
+    expect(lateSnippet.startsWith('…')).toBe(true)
+    expect(lateSnippet.endsWith('…')).toBe(true)
+    expect(Array.from(lateSnippet).length).toBeLessThanOrEqual(120)
+
+    timing().appendUser('fx-alpha', 'Greek final sigma: ος')
+    const finalSigma = await api.sessions.search(req({ query: 'ΟΣ' }), signal)
+    if (!finalSigma.result.ok) throw new Error('final sigma search failed')
+    expect(finalSigma.result.value.items[0]?.snippet).toContain('ος')
+
+    const substring = await api.sessions.search(req({ query: 'ixtur' }), signal)
+    expect(substring.result).toEqual({
+      ok: true,
+      value: { items: [], hasMore: false },
+    })
+    const punctuationOnly = await api.sessions.search(req({ query: '*' }), signal)
+    expect(punctuationOnly.result).toEqual({
+      ok: true,
+      value: { items: [], hasMore: false },
+    })
+    const reasoningOnly = await api.sessions.search(req({ query: '思考过程' }), signal)
+    expect(reasoningOnly.result).toEqual({
+      ok: true,
+      value: { items: [], hasMore: false },
+    })
+
+    const aborted = new AbortController()
+    aborted.abort()
+    await expect(api.sessions.search(req({ query: 'fixture' }), aborted.signal))
+      .resolves.toMatchObject({ result: { ok: false, error: { code: 'cancelled' } } })
+  })
+
  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 }))
@@ -84,6 +151,19 @@ describe('createFixtureApi', () => {
        },
        plan: { active: false, pending: false },
        goal: null,
+        tokenUsage: {
+          uncachedInputTokens: 0,
+          outputTokens: 0,
+          cacheReadTokens: 0,
+          cacheWriteTokens: 0,
+        },
+        // No request ran, so neither pressure nor capacity is known yet.
+        contextPressure: {},
+        contextBreakdown: {
+          systemTokens: 0,
+          toolsTokens: 0,
+          messageTokens: 0,
+        },
      } },
    })
  })
@@ -119,6 +199,36 @@ describe('createFixtureApi', () => {
    expect(JSON.stringify(after.result.value.events)).toContain('openai/gpt-5')
  })

+  it('serves configured DeepSeek readiness and keeps credential values write-only', async () => {
+    const api = createFixtureApi()
+    const settings = await api.settings.describe(req({}))
+    if (!settings.result.ok) throw new Error('settings describe failed')
+    expect(settings.result.value.namespaces).toMatchObject([{
+      ns: 'llm-deepseek',
+      value: { apiKeyEnv: 'DEEPSEEK_API_KEY' },
+      secrets: [{ path: ['apiKey'], set: false }],
+    }])
+
+    const initial = await api.credentials.describe(req({ refs: ['DEEPSEEK_API_KEY', 'TEST_API_KEY'] }))
+    if (!initial.result.ok) throw new Error('credential describe failed')
+    expect(initial.result.value.credentials).toEqual({
+      DEEPSEEK_API_KEY: { configured: true, source: 'file', writable: true },
+      TEST_API_KEY: { configured: false, writable: true },
+    })
+    await api.credentials.set(req({ ref: 'TEST_API_KEY', value: 'write-only-fixture-secret' }))
+    const configured = await api.credentials.describe(req({ refs: ['TEST_API_KEY'] }))
+    if (!configured.result.ok) throw new Error('credential describe failed')
+    expect(configured.result.value.credentials.TEST_API_KEY).toEqual({
+      configured: true,
+      source: 'file',
+      writable: true,
+    })
+    await api.credentials.unset(req({ ref: 'TEST_API_KEY' }))
+    const cleared = await api.credentials.describe(req({ refs: ['TEST_API_KEY'] }))
+    if (!cleared.result.ok) throw new Error('credential describe failed')
+    expect(cleared.result.value.credentials.TEST_API_KEY).toEqual({ configured: false, writable: true })
+  })
+
  it('emits the todo/write snapshot at the real tool boundary: between tool/call and tool/result, timestamps monotonic', async () => {
    const api = createFixtureApi()
    const tail = await api.sessions.history(req({ sessionId: sid('fx-alpha'), maxMessages: 10 }))
@@ -188,6 +298,21 @@ describe('createFixtureApi', () => {
    expect(types).toContain('assistant/chunk')
    expect(types).toContain('assistant/message')
    expect(types.at(-1)).toBe('turn/end')
+    // Capacity is durable log state, not a transient frame: the prompt path
+    // records request/context and the projection carries it to the client.
+    expect(types).toContain('request/context')
+    expect(frames.some(frame =>
+      frame.type === 'session/projection'
+      && frame.key === 'tokenUsage'
+      && (frame.value as { outputTokens?: number }).outputTokens === 8)).toBe(true)
+    expect(frames.some(frame =>
+      frame.type === 'session/projection'
+      && frame.key === 'contextPressure'
+      && (frame.value as { contextWindow?: number }).contextWindow === 128_000)).toBe(true)
+    expect(frames.some(frame =>
+      frame.type === 'session/projection'
+      && frame.key === 'contextBreakdown'
+      && (frame.value as { messageTokens?: number }).messageTokens! > 0)).toBe(true)
    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.
@@ -195,7 +320,7 @@ describe('createFixtureApi', () => {
    expect(idleCancel.result).toMatchObject({ ok: true })
  })

-  it('steer during a replay inserts a steering message and the replay continues to completion', async () => {
+  it('steer during a replay lands a user/message inside the current turn and the replay continues', async () => {
    const api = createFixtureApi()
    const created = await api.sessions.create(req({}))
    if (!created.result.ok) throw new Error('create failed')
@@ -208,7 +333,7 @@ describe('createFixtureApi', () => {
    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(JSON.stringify(frames)).toContain('插话')
    expect(types.at(-1)).toBe('turn/end') // steer did not restart the turn
  })

@@ -219,7 +344,7 @@ describe('createFixtureApi', () => {
      const envelopes: RpcRequest<MuxFrame>[] = []
      for await (const envelope of api.events.mux(req({}), abort.signal)) {
        envelopes.push(envelope)
-        if (envelopes.length >= 8) abort.abort()
+        if (envelopes.length >= 11) abort.abort()
      }
      return envelopes
    }
@@ -227,16 +352,23 @@ describe('createFixtureApi', () => {
    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)
-    // Projection baseline frames follow the subscribed frame (title + todos + permissions + plan + goal units).
+    // Projection baseline frames follow subscribed (domain units + token usage).
    expect(first[1]?.payload).toMatchObject({ type: 'session/projection', sessionId: 'fx-alpha', key: 'title', value: 'Fixture 历史会话' })
    expect(first[2]?.payload).toMatchObject({ type: 'session/projection', sessionId: 'fx-alpha', key: 'todos' })
    expect(first[3]?.payload).toMatchObject({ type: 'session/projection', sessionId: 'fx-alpha', key: 'permissions' })
    expect(first[4]?.payload).toMatchObject({ type: 'session/projection', sessionId: 'fx-alpha', key: 'plan', value: { active: false, pending: false } })
    expect(first[5]?.payload).toMatchObject({ type: 'session/projection', sessionId: 'fx-alpha', key: 'goal', value: null })
-    expect(first[6]?.payload).toMatchObject({ type: 'approval/requested', toolName: 'dangerous_tool' })
-    expect(second[6]?.rpcId).toBe(first[6]?.rpcId) // stable rpcId across replays (host replay semantics)
-    expect(first[7]?.payload).toMatchObject({ type: 'question/requested', sessionId: 'fx-alpha' })
-    expect(second[7]?.rpcId).toBe(first[7]?.rpcId)
+    expect(first[6]?.payload).toMatchObject({ type: 'session/projection', sessionId: 'fx-alpha', key: 'tokenUsage' })
+    expect(first[7]?.payload).toMatchObject({ type: 'session/projection', sessionId: 'fx-alpha', key: 'contextPressure' })
+    expect(first[8]?.payload).toMatchObject({
+      type: 'session/projection', sessionId: 'fx-alpha', key: 'contextBreakdown',
+      value: { systemTokens: 0, toolsTokens: 0 },
+    })
+    expect((first[8]?.payload as { value: { messageTokens: number } }).value.messageTokens).toBeGreaterThan(0)
+    expect(first[9]?.payload).toMatchObject({ type: 'approval/requested', toolName: 'dangerous_tool' })
+    expect(second[9]?.rpcId).toBe(first[9]?.rpcId) // stable rpcId across replays (host replay semantics)
+    expect(first[10]?.payload).toMatchObject({ type: 'question/requested', sessionId: 'fx-alpha' })
+    expect(second[10]?.rpcId).toBe(first[10]?.rpcId)
  })

  it('steer with no replay in flight falls through to a fresh queued turn; non-text blocks stringify empty', async () => {
@@ -254,7 +386,7 @@ describe('createFixtureApi', () => {
    }))
    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
+    expect(types[0]).toBe('turn/start') // idle steer degraded to a queued turn, not an in-turn insert
  })

  it('gamma interval flip emits host/session-status and a running log-less session subscribes at lastSeq -1', async () => {
@@ -464,6 +596,47 @@ describe('createFixtureApi', () => {
    expect(seen.map(f => f.type)).toEqual(['host/workspace-changed', 'host/workspace-changed'])
  })

+  it('session.rename covers not-found, blank title, and the accepted append + title frame', async () => {
+    const api = createFixtureApi()
+    const abort = new AbortController()
+    const framesPromise = (async () => {
+      const frames: MuxFrame[] = []
+      for await (const envelope of api.events.mux(req({}), abort.signal)) {
+        frames.push(envelope.payload)
+        if (frames.some(f => f.type === 'session/projection' && f.key === 'title' && f.value === '重命名')) abort.abort()
+      }
+      return frames
+    })()
+    await new Promise(resolve => setTimeout(resolve, 10))
+
+    const missing = await api.sessions.rename(req({ sessionId: sid('fx-void'), title: 'x' }))
+    expect(missing.result).toMatchObject({ ok: false, error: { code: 'session-not-found', details: { sessionId: 'fx-void' } } })
+
+    const blank = await api.sessions.rename(req({ sessionId: sid('fx-alpha'), title: '   ' }))
+    expect(blank.result).toMatchObject({ ok: false, error: { code: 'title-invalid', details: { sessionId: 'fx-alpha' } } })
+
+    const renamed = await api.sessions.rename(req({ sessionId: sid('fx-alpha'), title: '  重命名  ' }))
+    if (!renamed.result.ok) throw new Error('rename failed')
+    expect(renamed.result.value.title).toBe('重命名')
+    const acceptedSeq = renamed.result.value.seq
+    // The response seq addresses the appended title event (the client plane
+    // has no session/title in its event union — titles ride the projection —
+    // so the event is located by seq and its payload checked structurally).
+    const history = await api.sessions.history(req({ sessionId: sid('fx-alpha'), maxMessages: 100 }))
+    if (!history.result.ok) throw new Error('history failed')
+    const appended = history.result.value.events.find(entry => entry.event.seq === acceptedSeq)
+    expect(appended?.event).toMatchObject({
+      type: 'session/title',
+      data: { title: '重命名', messageSeqs: [], source: { kind: 'user' } },
+    })
+    // Beyond the subscribe-time baseline replay, the append emitted exactly
+    // one title projection frame carrying the new value at the response seq.
+    const frames = await framesPromise
+    const titleFrames = frames.filter(f => f.type === 'session/projection' && f.key === 'title' && f.sessionId === sid('fx-alpha') && f.value === '重命名')
+    expect(titleFrames).toHaveLength(1)
+    expect(titleFrames[0]).toMatchObject({ seq: acceptedSeq })
+  })
+
  it('workspace.insertSessionBefore moves, appends, no-ops, and rejects invalid ids', async () => {
    const api = createFixtureApi()
    const wsid = 'fx-ws-fixture' as WorkspaceId
@@ -690,8 +863,18 @@ describe('createFixtureApi', () => {
    hooks.appendSilent('fx-alpha', '静默丢帧')
    hooks.appendUser('fx-alpha', '正常直播')
    hooks.appendTitle('fx-alpha', 'Fixture 修订标题')
+    hooks.beginModelRetry('fx-alpha')
+    hooks.scheduleModelRetry('fx-alpha')
+    hooks.completeModelRetry('fx-alpha')
+    hooks.beginModelRetry('fx-alpha')
+    hooks.cancelModelRetryDuringBackoff('fx-alpha')
    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' && (f.event as { type: string }).type === 'llm/retry')).toBe(true)
+      expect(seen.some(f => f.type === 'session/event' && JSON.stringify(f.event.data).includes('重试后的完整回复'))).toBe(true)
+      expect(seen.some(f => f.type === 'session/event'
+        && f.event.type === 'turn/end'
+        && f.event.data.reason.kind === 'aborted')).toBe(true)
      expect(seen.some(f => f.type === 'session/projection' && f.key === 'title' && f.value === 'Fixture 修订标题')).toBe(true)
    })
    expect(seen.some(f => f.type === 'session/event' && JSON.stringify(f.event.data).includes('静默丢帧'))).toBe(false)
@@ -714,6 +897,50 @@ describe('createFixtureApi', () => {
    expect(abort.signal.aborted).toBe(false)
    expect(habort.signal.aborted).toBe(false)
  })
+
+  it('paces the opt-in reasoning stress hook from an external interval', async () => {
+    vi.useFakeTimers()
+    vi.setSystemTime(0)
+    const api = createFixtureApi()
+    const hooks = timing()
+    expect(hooks.reasoningChunkStormState()).toBeNull()
+    expect(() => hooks.startReasoningChunkStorm('fx-alpha', 0, 1, 16)).toThrow(/chunk count/)
+    expect(() => hooks.startReasoningChunkStorm('fx-alpha', 1, 0, 16)).toThrow(/chunks per interval/)
+    expect(() => hooks.startReasoningChunkStorm('fx-alpha', 1, 1, 0)).toThrow(/reasoning interval/)
+    const abort = new AbortController()
+    try {
+      const streamed = collect(api.events.mux(req({}), abort.signal), abort, frames => frames.some(frame => (
+        frame.type === 'session/event'
+        && frame.event.type === 'assistant/chunk'
+        && frame.event.data.chunk.type === 'reasoning-delta'
+        && frame.event.data.chunk.text.includes('REASONING_STRESS_COMPLETE')
+      )))
+      const marker = hooks.startReasoningChunkStorm('fx-alpha', 3, 2, 16)
+      expect(() => hooks.startReasoningChunkStorm('fx-alpha', 1, 1, 16)).toThrow(/already running/)
+      expect(hooks.reasoningChunkStormState()).toMatchObject({ emitted: 0, emitting: true, marker })
+
+      await vi.advanceTimersByTimeAsync(0)
+      expect(hooks.reasoningChunkStormState()).toMatchObject({ emitted: 2, emitting: true })
+      await vi.advanceTimersByTimeAsync(16)
+      expect(hooks.reasoningChunkStormState()).toEqual({
+        sessionId: 'fx-alpha', chunkCount: 3, chunksPerInterval: 2, intervalMs: 16,
+        emitted: 3, marker, emitting: false,
+      })
+
+      const frames = await streamed
+      const deltas = frames.flatMap(frame => (
+        frame.type === 'session/event'
+        && frame.event.type === 'assistant/chunk'
+        && frame.event.data.chunk.type === 'reasoning-delta'
+          ? [frame.event.data.chunk.text]
+          : []
+      ))
+      expect(deltas).toEqual(['推理', '推理', `\n${marker}`])
+    } finally {
+      abort.abort()
+      vi.useRealTimers()
+    }
+  })
 })

 describe('FixtureApiClient (protocol-level fake carrier)', () => {
@@ -748,6 +975,10 @@ describe('FixtureApiClient (protocol-level fake carrier)', () => {

  it('covers the whole unary dispatch table', async () => {
    const client = new FixtureApiClient()
+    expect((await client.sessions.search(
+      { query: 'fixture' },
+      new AbortController().signal,
+    )).result.ok).toBe(true)
    const created = await client.sessions.create({})
    if (!created.result.ok) throw new Error('create failed')
    const id = created.result.value.sessionId
@@ -791,6 +1022,21 @@ describe('FixtureApiClient (protocol-level fake carrier)', () => {
    // complete → complete is an invalid transition.
    expect((await client.goals.complete({ sessionId: id, ref })).result.ok).toBe(false)
    expect((await client.goals.clear({ sessionId: id, ref })).result).toEqual({ ok: true, value: { cleared: true } })
+
+    const goalHistory = await client.sessions.history({ sessionId: id })
+    if (!goalHistory.result.ok) throw new Error('goal history failed')
+    const goalEvents = goalHistory.result.value.events.map(entry => entry.event as unknown as {
+      type: string
+      data: {
+        operation?: string
+        source?: { kind?: string; round?: number }
+      }
+    })
+    const goalChanges = goalEvents.filter(event => event.type === 'goal/change')
+    expect(goalChanges.map(event => event.data.operation))
+      .toEqual(['create', 'edit', 'pause', 'resume', 'complete', 'clear'])
+    expect(goalEvents.some(event => event.type === 'user/message'
+      && event.data.source?.kind === 'goal' && event.data.source.round === 0)).toBe(false)
  })

  it('maps empty, prompt-reject, and workspace-first query scenarios', async () => {
--- a/packages/client/connection/tests/loopback-hostname.spec.ts
+++ b/packages/client/connection/tests/loopback-hostname.spec.ts
@@ -0,0 +1,18 @@
+/** Shared loopback-hostname semantics for the Host fence and browser UI. */
+
+import { describe, expect, it } from 'vitest'
+import { isLoopbackHostname } from '../src/loopback-hostname.ts'
+
+describe('isLoopbackHostname', () => {
+  it('accepts localhost, IPv6 loopback, and the whole IPv4 127/8 block', () => {
+    for (const hostname of ['localhost', '[::1]', '127.0.0.1', '127.8.9.10', '127.255.255.255']) {
+      expect(isLoopbackHostname(hostname)).toBe(true)
+    }
+  })
+
+  it('refuses malformed and non-loopback hostnames', () => {
+    for (const hostname of ['remote.localhost', '::1', '128.0.0.1', '127.0.0', '127.0.0.256', '127.0.0.-1']) {
+      expect(isLoopbackHostname(hostname)).toBe(false)
+    }
+  })
+})
--- a/packages/client/connection/tests/node-half.spec.ts
+++ b/packages/client/connection/tests/node-half.spec.ts
@@ -1,29 +1,38 @@
 /** Node half: registers the /api prefix route bridging to the api gateway. */
-import { EventEmitter } from 'node:events'
-import { Readable } from 'node:stream'
+import { EventEmitter, once } from 'node:events'
+import { createServer, request as httpRequest } from 'node:http'
+import { PassThrough, Readable } from 'node:stream'
 import { Context } from 'cordis'
 import { describe, expect, it } from 'vitest'
+import type { AddressInfo } from 'node:net'
 import type { IncomingMessage, ServerResponse } from 'node:http'
 import type { ApiProxy } from '@deepseek-ai/dsh-host-apiproxy/api'
-import type { HttpServerService, WebRoute } from '@deepseek-ai/dsh-host-webserver'
-import { API_PATH, apply, inject } from '../src/index.ts'
+import type { HttpServerService, WebRoute, WebUpgradeRoute } from '@deepseek-ai/dsh-host-webserver'
+import { API_PATH, apply, HOST_EVENTS_PATH, inject, MUX_EVENTS_PATH } from '../src/index.ts'

-/** Structural httpServer fake: the plugin only touches register(). */
-function fakeHttpServer(routes: WebRoute[]): Pick<HttpServerService, 'register' | 'tapIndex' | 'port'> {
+/** Structural httpServer fake recording both route registries. */
+function fakeHttpServer(
+  routes: WebRoute[],
+  upgrades: WebUpgradeRoute[],
+): Pick<HttpServerService, 'register' | 'registerUpgrade' | 'tapIndex' | 'port'> {
  return {
    register(route) {
      routes.push(route)
      return () => { routes.splice(routes.indexOf(route), 1) }
    },
+    registerUpgrade(route) {
+      upgrades.push(route)
+      return () => { upgrades.splice(upgrades.indexOf(route), 1) }
+    },
    tapIndex: () => () => {},
    port: 0,
  }
 }

 /** Bodyless GET carrying the given headers (enough for the trust fence + bridge). */
-function fakeRequest(headers: Record<string, string>): IncomingMessage {
+function fakeRequest(headers: Record<string, string>, url = `${API_PATH}/session.list`): IncomingMessage {
  const request = Readable.from([]) as unknown as IncomingMessage
-  Object.assign(request, { url: `${API_PATH}/session.list`, method: 'GET', headers })
+  Object.assign(request, { url, method: 'GET', headers })
  return request
 }

@@ -43,47 +52,67 @@ function fakeResponse(): { response: ServerResponse; state: { status?: number; b
  return { response, state }
 }

-async function mounted(config?: { trustedHosts?: string[] }): Promise<{ routes: WebRoute[]; dispose: () => Promise<void> }> {
+async function mounted(config?: { trustedHosts?: string[] }): Promise<{
+  routes: WebRoute[]
+  upgrades: WebUpgradeRoute[]
+  dispose: () => Promise<void>
+}> {
  const ctx = new Context()
  const routes: WebRoute[] = []
-  ctx.provide('httpServer', fakeHttpServer(routes) as HttpServerService)
+  const upgrades: WebUpgradeRoute[] = []
+  ctx.provide('httpServer', fakeHttpServer(routes, upgrades) as HttpServerService)
  ctx.provide('apiProxy', {} as unknown as ApiProxy)
  const fiber = ctx.plugin({ inject: [...inject], apply }, config)
  await fiber.await()
-  return { routes, dispose: () => fiber.dispose() }
+  return { routes, upgrades, dispose: () => fiber.dispose() }
 }

 describe('connection node half', () => {
  it('fails the load on a trustedHosts entry that is not a bare authority', async () => {
    const routes: WebRoute[] = []
+    const upgrades: WebUpgradeRoute[] = []
    const ctx = new Context()
-    ctx.provide('httpServer', fakeHttpServer(routes) as HttpServerService)
+    ctx.provide('httpServer', fakeHttpServer(routes, upgrades) as HttpServerService)
    ctx.provide('apiProxy', {} as unknown as ApiProxy)
-    // The apply throw also escapes cordis as a late rejection — the shape the
-    // boot's installFailLoud is contracted to catch. Capture it so the run
-    // stays clean, same pattern as the webserver bind-failure test.
-    const rejections: unknown[] = []
-    const onUnhandled = (err: unknown): void => { rejections.push(err) }
-    process.on('unhandledRejection', onUnhandled)
-    try {
-      const fiber = ctx.plugin({ inject: [...inject], apply }, { trustedHosts: ['harness.internal/path'] })
-      await expect(fiber.await()).rejects.toThrow(/not a bare host\[:port\] authority/)
-      expect(routes).toHaveLength(0)
-      for (let i = 0; i < 100 && rejections.length === 0; i++) {
-        await new Promise(resolve => setTimeout(resolve, 10))
-      }
-      expect(rejections.map(String).join('\n')).toContain('not a bare host[:port] authority')
-    } finally {
-      process.off('unhandledRejection', onUnhandled)
-    }
+    const fiber = ctx.plugin({ inject: [...inject], apply }, { trustedHosts: ['harness.internal/path'] })
+    await expect(fiber).rejects.toThrow(/not a bare host\[:port\] authority/)
+    expect(routes).toHaveLength(0)
+    expect(upgrades).toHaveLength(0)
  })

-  it('registers the /api prefix route and removes it with the fiber', async () => {
-    const { routes, dispose } = await mounted()
+  it('registers one HTTP route plus one upgrade route per downlink and removes all three with the fiber', async () => {
+    const { routes, upgrades, dispose } = await mounted()
    expect(routes).toHaveLength(1)
    expect(routes[0]).toMatchObject({ kind: 'prefix', path: API_PATH })
+    expect(upgrades.map(route => route.path)).toEqual([MUX_EVENTS_PATH, HOST_EVENTS_PATH])
    await dispose()
    expect(routes).toHaveLength(0)
+    expect(upgrades).toHaveLength(0)
+  })
+
+  it('requires WebSocket upgrade for network GETs to either event path', async () => {
+    const { routes, dispose } = await mounted()
+    for (const path of [MUX_EVENTS_PATH, HOST_EVENTS_PATH]) {
+      const { response, state } = fakeResponse()
+      await routes[0]!.handler(fakeRequest({ host: '127.0.0.1:3080' }, path), response)
+      expect(state.status).toBe(426)
+      expect(state.body).toBe('upgrade required')
+    }
+    await dispose()
+  })
+
+  it('rejects an untrusted WebSocket upgrade before protocol negotiation', async () => {
+    const { upgrades, dispose } = await mounted()
+    const socket = new PassThrough()
+    const chunks: Buffer[] = []
+    socket.on('data', (chunk: Buffer) => { chunks.push(chunk) })
+    const ended = once(socket, 'end')
+    await upgrades[0]!.handler(fakeRequest({
+      host: 'harness.example', origin: 'http://harness.example', 'sec-fetch-site': 'same-origin',
+    }, MUX_EVENTS_PATH), socket, Buffer.alloc(0))
+    await ended
+    expect(Buffer.concat(chunks).toString()).toContain('HTTP/1.1 403 Forbidden')
+    await dispose()
  })

  it('refuses an untrusted Host on any /api path before the bridge runs', async () => {
@@ -97,6 +126,31 @@ describe('connection node half', () => {
    await dispose()
  })

+  it('pins privileged methods to loopback even for a declared trusted authority', async () => {
+    const { routes, dispose } = await mounted({ trustedHosts: ['harness.example'] })
+    // The privileged set: native dialogs plus the whole settings/credential
+    // configuration plane, reads included. The same declared authority reaches
+    // ordinary reads (carrier-level 404 from the empty proxy proves the fence
+    // passed), but each privileged method stays loopback-only and 403s.
+    for (const method of [
+      'host.pickDirectory', 'host.openPath',
+      'settings.describe', 'settings.openDocument', 'settings.update', 'settings.replace', 'settings.mutate',
+      'credentials.describe', 'credentials.set', 'credentials.unset',
+    ]) {
+      const denied = fakeResponse()
+      await routes[0]!.handler(
+        fakeRequest({ host: 'harness.example' }, `${API_PATH}/${method}`),
+        denied.response,
+      )
+      expect(denied.state.status).toBe(403)
+      expect(denied.state.body).toBe('forbidden')
+    }
+    const read = fakeResponse()
+    await routes[0]!.handler(fakeRequest({ host: 'harness.example' }), read.response)
+    expect(read.state.status).not.toBe(403)
+    await dispose()
+  })
+
  it('passes loopback and declared-authority requests through to the bridge', async () => {
    const { routes, dispose } = await mounted({ trustedHosts: ['harness.example:3080', '192.168.1.5'] })
    // Loopback, no browser markers (curl shape): the fence passes; the carrier
@@ -118,3 +172,69 @@ describe('connection node half', () => {
    await dispose()
  })
 })
+
+describe('connection node half over a real HTTP server', () => {
+  /** Serve the registered prefix route from a real server and return its port. */
+  async function serve(routes: WebRoute[]): Promise<{ port: number; close: () => Promise<void> }> {
+    const server = createServer((request, response) => {
+      void routes[0]!.handler(request, response)
+    })
+    await new Promise<void>(resolve => server.listen(0, '127.0.0.1', resolve))
+    const address = server.address() as AddressInfo
+    return {
+      port: address.port,
+      close: () => new Promise<void>((resolve, reject) => {
+        server.close((error) => {
+          if (error === undefined || error === null) resolve()
+          else reject(error)
+        })
+      }),
+    }
+  }
+
+  /** One real request; `host` spoofs the authority the way a LAN client's browser would send it. */
+  function call(port: number, method: string, host: string): Promise<number> {
+    return new Promise((resolve, reject) => {
+      const request = httpRequest(
+        { host: '127.0.0.1', port, path: `${API_PATH}/${method}`, method: 'GET', headers: { host } },
+        (response) => {
+          response.resume()
+          response.on('end', () => { resolve(response.statusCode ?? 0) })
+        },
+      )
+      request.on('error', reject)
+      request.end()
+    })
+  }
+
+  it('answers a declared LAN authority with 403 on every configuration method, over real HTTP', async () => {
+    // The fence's input is a real IncomingMessage parsed by Node from the
+    // wire, not a hand-assembled object: the Host header a LAN browser sends
+    // is exactly what decides loopback-only here, so the boundary is asserted
+    // against the parse the server actually performs.
+    const { routes, dispose } = await mounted({ trustedHosts: ['harness.example'] })
+    const { port, close } = await serve(routes)
+    try {
+      // Reads are as privileged as writes: describe returns the exposed
+      // configuration, and credentials.describe probes arbitrary env-var names.
+      for (const method of [
+        'settings.describe', 'settings.openDocument', 'settings.update', 'settings.replace', 'settings.mutate',
+        'credentials.describe', 'credentials.set', 'credentials.unset',
+        'host.pickDirectory', 'host.openPath',
+      ]) {
+        expect([method, await call(port, method, 'harness.example')]).toEqual([method, 403])
+      }
+      // The model catalog stays reachable for the same authority: a LAN
+      // client's model picker needs it, and it carries no key or endpoint
+      // state (404 is the empty proxy's carrier answer — the fence passed).
+      for (const method of ['llm.providers', 'llm.models']) {
+        expect([method, await call(port, method, 'harness.example')]).toEqual([method, 404])
+      }
+      // Loopback reaches everything, configuration included.
+      expect(await call(port, 'settings.describe', `127.0.0.1:${String(port)}`)).toBe(404)
+    } finally {
+      await close()
+      await dispose()
+    }
+  })
+})
--- a/packages/client/connection/tests/websocket-downlink.spec.ts
+++ b/packages/client/connection/tests/websocket-downlink.spec.ts
@@ -0,0 +1,308 @@
+import { once } from 'node:events'
+import { createServer } from 'node:http'
+import type { AddressInfo } from 'node:net'
+import { afterEach, describe, expect, it, vi } from 'vitest'
+import WebSocket from 'ws'
+import type {
+  ApiProxy, HostFrame, MuxFrame, RpcRequest, ServerRequest,
+} from '@deepseek-ai/dsh-host-apiproxy/api'
+import { RpcId } from '@deepseek-ai/dsh-host-apiproxy/api'
+import { HOST_EVENTS_PATH, MUX_EVENTS_PATH } from '../src/api-path.ts'
+import { WebSocketDownlinks } from '../src/websocket-downlink.ts'
+
+type MuxSource = (signal: AbortSignal) => AsyncIterable<RpcRequest<MuxFrame>>
+type HostSource = (signal: AbortSignal) => AsyncIterable<RpcRequest<HostFrame>>
+
+const running: (() => Promise<void>)[] = []
+
+afterEach(async () => {
+  await Promise.all(running.splice(0).map(close => close()))
+})
+
+function untilAbort(signal: AbortSignal): Promise<void> {
+  if (signal.aborted) return Promise.resolve()
+  return new Promise((resolve) => {
+    signal.addEventListener('abort', () => { resolve() }, { once: true })
+  })
+}
+
+async function * idle<F>(signal: AbortSignal): AsyncGenerator<RpcRequest<F>> {
+  await untilAbort(signal)
+}
+
+function api(mux: MuxSource, host: HostSource): ApiProxy {
+  return {
+    events: {
+      mux: (_request, signal) => mux(signal),
+      host: (_request, signal) => host(signal),
+    },
+  } as ApiProxy
+}
+
+async function serve(downlinks: WebSocketDownlinks): Promise<{
+  origin: string
+  close: () => Promise<void>
+}> {
+  const server = createServer()
+  server.on('upgrade', (request, socket, head) => {
+    const pathname = new URL(request.url ?? '/', 'http://dsh.internal').pathname
+    if (pathname === MUX_EVENTS_PATH) downlinks.handleMux(request, socket, head)
+    else if (pathname === HOST_EVENTS_PATH) downlinks.handleHost(request, socket, head)
+    else socket.destroy()
+  })
+  await new Promise<void>(resolve => server.listen(0, '127.0.0.1', resolve))
+  const port = (server.address() as AddressInfo).port
+  return {
+    origin: `ws://127.0.0.1:${String(port)}`,
+    close: async () => {
+      await downlinks.close()
+      await new Promise<void>(resolve => server.close(() => { resolve() }))
+    },
+  }
+}
+
+function read(socket: WebSocket): Promise<ServerRequest> {
+  return once(socket, 'message').then(([data]) => JSON.parse(String(data)) as ServerRequest)
+}
+
+async function acceptedSocket(downlinks: WebSocketDownlinks): Promise<WebSocket> {
+  const server = (downlinks as unknown as { server: { clients: Set<WebSocket> } }).server
+  let accepted: WebSocket | undefined
+  await vi.waitFor(() => {
+    accepted = server.clients.values().next().value
+    expect(accepted).toBeDefined()
+  })
+  return accepted as WebSocket
+}
+
+describe('WebSocket downlinks', () => {
+  it('carries mux and host over independent downstream sockets and cancels each source on close', async () => {
+    let muxAborted = false
+    let hostAborted = false
+    const downlinks = new WebSocketDownlinks(api(
+      async function * (signal) {
+        try {
+          yield {
+            rpcId: RpcId('mux-1'),
+            payload: { type: 'session/subscribed', sessionId: 'session-1' as never, lastSeq: 4 },
+          }
+          await untilAbort(signal)
+        } finally {
+          muxAborted = true
+        }
+      },
+      async function * (signal) {
+        try {
+          yield { rpcId: RpcId('host-1'), payload: { type: 'host/commands-changed' } }
+          await untilAbort(signal)
+        } finally {
+          hostAborted = true
+        }
+      },
+    ))
+    const host = await serve(downlinks)
+    running.push(host.close)
+
+    const mux = new WebSocket(`${host.origin}${MUX_EVENTS_PATH}`)
+    const hostSocket = new WebSocket(`${host.origin}${HOST_EVENTS_PATH}`)
+    const muxFrame = read(mux)
+    const hostFrame = read(hostSocket)
+    expect(await muxFrame).toEqual({
+      type: 'server-request',
+      rpcId: 'mux-1',
+      method: 'session/subscribed',
+      payload: { type: 'session/subscribed', sessionId: 'session-1', lastSeq: 4 },
+    })
+    expect(await hostFrame).toEqual({
+      type: 'server-request',
+      rpcId: 'host-1',
+      method: 'host/commands-changed',
+      payload: { type: 'host/commands-changed' },
+    })
+
+    const muxClosed = once(mux, 'close')
+    const hostClosed = once(hostSocket, 'close')
+    mux.close()
+    hostSocket.close()
+    await Promise.all([muxClosed, hostClosed])
+    await vi.waitFor(() => {
+      expect(muxAborted).toBe(true)
+      expect(hostAborted).toBe(true)
+    })
+  })
+
+  it('rejects client messages because upstream remains HTTP', async () => {
+    let aborted = false
+    const downlinks = new WebSocketDownlinks(api(
+      async function * (signal) {
+        try {
+          await untilAbort(signal)
+        } finally {
+          aborted = true
+        }
+      },
+      idle,
+    ))
+    const host = await serve(downlinks)
+    running.push(host.close)
+    const socket = new WebSocket(`${host.origin}${MUX_EVENTS_PATH}`)
+    await once(socket, 'open')
+    const closed = once(socket, 'close')
+    socket.send('upstream payload')
+    const [code, reason] = await closed as [number, Buffer]
+    expect(code).toBe(1008)
+    expect(String(reason)).toBe('downlink only')
+    await vi.waitFor(() => { expect(aborted).toBe(true) })
+  })
+
+  it('sends stream/error before closing when a source fails', async () => {
+    const downlinks = new WebSocketDownlinks(api(
+      async function * () {
+        throw new Error('mux source failed')
+      },
+      idle,
+    ))
+    const host = await serve(downlinks)
+    running.push(host.close)
+    const socket = new WebSocket(`${host.origin}${MUX_EVENTS_PATH}`)
+    const failure = read(socket)
+    const closed = once(socket, 'close')
+    expect((await failure).payload).toEqual({
+      type: 'stream/error',
+      error: { code: 'internal', message: 'Error: mux source failed', details: {} },
+    })
+    await closed
+  })
+
+  it('aborts the source when an accepted socket reports a transport error', async () => {
+    let aborted = false
+    const downlinks = new WebSocketDownlinks(api(
+      async function * (signal) {
+        try {
+          await untilAbort(signal)
+        } finally {
+          aborted = true
+        }
+      },
+      idle,
+    ))
+    const host = await serve(downlinks)
+    running.push(host.close)
+    const socket = new WebSocket(`${host.origin}${MUX_EVENTS_PATH}`)
+    await once(socket, 'open')
+    const accepted = await acceptedSocket(downlinks)
+    const closed = once(socket, 'close')
+    accepted.emit('error', new Error('transport failed'))
+    await closed
+    expect(aborted).toBe(true)
+  })
+
+  it('drops a source frame that races after the client has closed', async () => {
+    let release!: () => void
+    const gate = new Promise<void>((resolve) => { release = resolve })
+    let finish!: () => void
+    const finished = new Promise<void>((resolve) => { finish = resolve })
+    let sourceSignal: AbortSignal | undefined
+    const downlinks = new WebSocketDownlinks(api(
+      async function * (signal) {
+        sourceSignal = signal
+        try {
+          await gate
+          yield {
+            rpcId: RpcId('late'),
+            payload: { type: 'session/subscribed', sessionId: 'session-late' as never, lastSeq: 0 },
+          }
+        } finally {
+          finish()
+        }
+      },
+      idle,
+    ))
+    const host = await serve(downlinks)
+    running.push(host.close)
+    const socket = new WebSocket(`${host.origin}${MUX_EVENTS_PATH}`)
+    await once(socket, 'open')
+    const closed = once(socket, 'close')
+    socket.close()
+    await closed
+    await vi.waitFor(() => { expect(sourceSignal?.aborted).toBe(true) })
+    release()
+    await finished
+  })
+
+  it('contains socket send callback failures and closes the downlink', async () => {
+    let release!: () => void
+    const gate = new Promise<void>((resolve) => { release = resolve })
+    const downlinks = new WebSocketDownlinks(api(
+      async function * () {
+        await gate
+        yield {
+          rpcId: RpcId('send-failure'),
+          payload: { type: 'session/subscribed', sessionId: 'session-send' as never, lastSeq: 0 },
+        }
+      },
+      idle,
+    ))
+    const host = await serve(downlinks)
+    running.push(host.close)
+    const socket = new WebSocket(`${host.origin}${MUX_EVENTS_PATH}`)
+    await once(socket, 'open')
+    const accepted = await acceptedSocket(downlinks)
+    const send = vi.spyOn(accepted, 'send').mockImplementation(((
+      _data: unknown,
+      optionsOrCallback?: unknown,
+      callback?: (error?: Error) => void,
+    ) => {
+      const done = typeof optionsOrCallback === 'function'
+        ? optionsOrCallback as (error?: Error) => void
+        : callback
+      done?.(new Error('socket send failed'))
+    }) as WebSocket['send'])
+    const closed = once(socket, 'close')
+    release()
+    await closed
+    expect(send).toHaveBeenCalledTimes(2)
+    send.mockRestore()
+  })
+
+  it('rejects when its acceptor has already closed', async () => {
+    const downlinks = new WebSocketDownlinks(api(idle, idle))
+    await downlinks.close()
+    await expect(downlinks.close()).rejects.toThrow('The server is not running')
+  })
+
+  it('waits for source cleanup before teardown resolves', async () => {
+    let cleanupStarted!: () => void
+    const started = new Promise<void>((resolve) => { cleanupStarted = resolve })
+    let releaseCleanup!: () => void
+    const cleanupGate = new Promise<void>((resolve) => { releaseCleanup = resolve })
+    let cleaned = false
+    const downlinks = new WebSocketDownlinks(api(
+      async function * (signal) {
+        try {
+          await untilAbort(signal)
+        } finally {
+          cleanupStarted()
+          await cleanupGate
+          cleaned = true
+        }
+      },
+      idle,
+    ))
+    const host = await serve(downlinks)
+    const socket = new WebSocket(`${host.origin}${MUX_EVENTS_PATH}`)
+    await once(socket, 'open')
+    let closed = false
+    const closing = host.close().then(() => { closed = true })
+    try {
+      await started
+      expect(closed).toBe(false)
+      releaseCleanup()
+      await closing
+      expect(cleaned).toBe(true)
+    } finally {
+      releaseCleanup()
+      await closing
+    }
+  })
+})