Merge remote-tracking branch 'origin/master' into worktree/web-multimodal-image-input

# Conflicts:
#	docs/architecture.i18n.yaml
#	docs/architecture.md
#	docs/architecture.zh.md
#	docs/config-catalog.md
#	docs/core-data-structures/core.i18n.yaml
#	docs/core-data-structures/llm-streaming.i18n.yaml
#	docs/module-graph.md
#	examples/acp-agent/tests/snapshots/cordis-inspect-jsdoc/session.jsonl
#	packages/README.i18n.yaml
#	packages/client/connection/src/client/fixture.ts
#	packages/client/connection/src/index.ts
#	packages/client/runtime/README.i18n.yaml
#	packages/client/runtime/README.md
#	packages/client/runtime/README.zh.md
#	packages/client/runtime/src/client/sessions/conversation.ts
#	packages/client/ui-conversation/README.i18n.yaml
#	packages/client/ui-conversation/src/client/apply.ts
#	packages/client/ui-conversation/src/client/chat/ChatView.tsx
#	packages/client/ui-conversation/src/client/chat/MessageItem.tsx
#	packages/client/ui-conversation/src/client/contract/slots.ts
#	packages/client/ui-trajectory/tests/views.spec.tsx
#	packages/compact/compact-basic/README.i18n.yaml
#	packages/cordis/tool-cordis/src/api-catalog.ts
#	packages/host/apiproxy/src/api-proxy.ts
#	packages/host/apiproxy/src/api/index.ts
#	packages/host/apiproxy/src/api/sessions.ts
#	packages/host/apiproxy/src/index.ts
#	packages/host/apiproxy/tests/fetch-carrier.spec.ts
#	packages/llm/llm-deepseek/src/adapter.ts
#	packages/llm/llm-deepseek/tests/adapter.spec.ts
#	packages/llm/llm-deepseek/tests/serialize.spec.ts
#	packages/llm/llm-pi-ai/README.i18n.yaml
#	packages/llm/llm-pi-ai/src/adapter.ts
#	packages/llm/llm-pi-ai/src/index.ts
#	packages/llm/llm-pi-ai/tests/adapter.spec.ts
#	packages/llm/llm/src/types.ts
#	packages/ui/tui/README.i18n.yaml
#	packages/ui/tui/src/index.ts
#	packages/ui/tui/tests/tui.spec.ts

packages/host/apiproxy/README.i18n.yaml

@@ -1,6 +1,6 @@
 # Bilingual-pair consistency record (docs/i18n/README.md): the git blob hash of each
 # 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
-README.md: 43ad70fa8b865b0b80496bbb67013f24e9e3a33f
-README.zh.md: cc95a7512fb872add816bf0456a93dfcf7b84c10
+#   pnpm run verify-translation-pairing --write packages/host/apiproxy/README.md
+README.md: d6db9a9541b0727b61dbe501f7234564ffef139e
+README.zh.md: 4175c8fdb98aad2882718a2c95cd9e45825d787d

packages/host/apiproxy/README.md

@@ -12,7 +12,13 @@ The layering/protocol decisions are recorded in the [GUI layering and RPC protoc
 
 The mux stream projects the latest log-backed title as a validated `session/title` control frame after each attached-session subscription baseline and immediately after the corresponding live raw title event. This projection does not add titles to `session.list`; cold sessions remain metadata-only there until opening or resuming attaches their logs.
 
-Workspace and Session lists are separate reconnect baselines. `workspace.create` creates a unique name or adopts an existing directory, `session.create` accepts an optional preallocated Session id, and `host/workspace-changed` plus `host/session-added` carry committed increments in either arrival order. `SessionSummary.blank` and the `host/session-added` frame carry the derived zero-events bit: clients hide blank sessions and reuse them per workspace, flip blank on the first `host/session-status(running:true)`, and treat `session.list` as the reconnect authority; cold summaries are never blank because lazy persistence keeps never-appended sessions out of `list()`.
+Session model routing is a session-domain contract. `session.models` returns the selected provider/model/reasoning target with provider-grouped advisory models, exact-route reasoning metadata, and provider-local lookup failures. `session.selectModel` validates the optional adapter-owned reasoning effort and replaces the complete target selected for the next prompt-assembly boundary. Catalog membership is not validation: an adapter may resolve an unlisted model, while an unavailable route or unsupported effort returns `model-unavailable`.
+
+Workspace and Session lists are separate reconnect baselines. `workspace.create` creates a unique name or adopts an existing directory, `workspace.delete` removes only the Workspace registration, `session.create` accepts an optional preallocated Session id, and `host/workspace-changed`, `host/workspace-removed`, plus `host/session-added` carry committed increments in either arrival order. Registration deletion preserves the directory and session logs; its Sessions remain in `session.list` and become Ungrouped. `SessionSummary.blank` and the `host/session-added` frame carry the derived zero-events bit: clients hide blank sessions and reuse them per workspace, flip blank on the first `host/session-status(running:true)`, and treat `session.list` as the reconnect authority; cold summaries are never blank because lazy persistence keeps never-appended sessions out of `list()`.
+
+`host.pickDirectory` opens one native directory picker and returns its selected path, or `null` when the user cancels. Its host implementation invokes platform tools without a shell: `osascript` on macOS, an STA PowerShell `FolderBrowserDialog` on Windows, and Zenity with a KDialog fallback on Linux. The picker function is injectable for tests. This user-paced method is the sole unary call exempt from the default 30-second timeout; caller and connection aborts still propagate to the native process. The browser carrier separately restricts this privileged method to loopback, same-origin requests.
+
+`session.history` pages on message boundaries, and its tail page (no `beforeSeq`) carries two session-level extras the page window cannot supply: the in-flight partial's chunk events, and `todos` — the latest `todo/write` whole-list projection over the full log. Older pages omit `todos` because the projection is session-level, not per-page; a tail response that omits it means the whole log holds no `todo/write`, so clients read the absent field as the empty plan rather than as unchanged state.
 
 The `command.*` and `skill.*` domains expose the host command registry and skill catalog to clients. Every method addresses one session's agent by `sessionId` (a served session always has an Agent; `command.*` resumes cold sessions through the same path as `session.*`, while `skill.list` resolves the project root from the session header without touching the Agent registry). `command.execute` runs a slash-command line host-side and returns a detached result; the carrier's request signal cancels the running handler. `host/commands-changed` is the catalog invalidation frame: clients refetch `command.list` instead of diffing.
 
@@ -33,3 +39,4 @@ None; this package neither assembles nor sends a provider request.
 - **`respond` routing is shipped, but pending-interaction state is host-side work** — the wire shape (POST `/api/respond`, `RpcReceipt`) is final; the pending table that makes late/duplicate answers meaningful lives in `src/api-proxy.ts` and is still minimal (questions only, no approvals).
 - **Reserved seams stay out of `RpcMethodMap`** — `session.fork`, `prompt.mode: 'inject'`, `task.list`, `host.listModels`, and a describe `hostInstanceId` are documented reservations; an unknown method fails loud at envelope parse rather than getting a not-implemented code.
 - **No protocol version field** — client and host ship together; `host.describe` gains a version negotiation field only when an independently released client exists.
+- **Linux native picker requires desktop tooling** — `host.pickDirectory` reports an actionable error when neither Zenity nor KDialog is installed; it does not fall back to a custom or typed-path browser.

packages/host/apiproxy/README.zh.md

@@ -12,7 +12,13 @@
 
 mux 流会在每个已附加会话的订阅基线之后，以及对应的实时原始标题事件之后，立即把基于日志的最新标题投影为经过校验的 `session/title` 控制帧。该投影不会把标题加入 `session.list`；冷会话在其中仍只有元数据，直到打开或恢复操作附加其日志。
 
-Workspace 列表与 Session 列表是相互独立的重连基线。`workspace.create` 会创建唯一名称或接纳现有目录，`session.create` 接受可选的预分配 Session id，`host/workspace-changed` 与 `host/session-added` 则以任意到达顺序携带已提交的增量。`SessionSummary.blank` 与 `host/session-added` 帧携带派生的零事件位：客户端隐藏空白会话并按 workspace 复用它们，在首个 `host/session-status(running:true)` 时翻转 blank，并以 `session.list` 作为重连权威；冷会话摘要永远不是空白——惰性持久化让从未追加过事件的会话根本不出现在 `list()` 中。
+会话模型路由属于会话领域契约。`session.models` 返回选中的提供方／模型／推理（reasoning）目标，以及按提供方分组的建议性模型、精确路由推理元数据和逐提供方查询失败记录。`session.selectModel` 校验由适配器持有的可选推理强度，并替换将在下一提示词组装边界使用的完整目标。目录成员关系不构成校验：适配器可以解析未列出的模型，而不可用路由或不受支持的推理强度会返回 `model-unavailable`。
+
+Workspace 列表与 Session 列表是相互独立的重连基线。`workspace.create` 会创建唯一名称或接纳现有目录，`workspace.delete` 只移除 Workspace 注册记录，`session.create` 接受可选的预分配 Session id，`host/workspace-changed`、`host/workspace-removed` 与 `host/session-added` 则以任意到达顺序携带已提交的增量。删除注册记录会保留目录和会话日志；相关 Session 仍留在 `session.list` 中，并进入 Ungrouped。`SessionSummary.blank` 与 `host/session-added` 帧携带派生的零事件位：客户端隐藏空白会话并按 workspace 复用它们，在首个 `host/session-status(running:true)` 时翻转 blank，并以 `session.list` 作为重连权威；冷会话摘要永远不是空白：惰性持久化让从未追加过事件的会话根本不出现在 `list()` 中。
+
+`host.pickDirectory` 会打开一个原生目录选择器并返回选中的路径；用户取消时返回 `null`。宿主实现不经 shell 调用平台工具：macOS 使用 `osascript`，Windows 使用以 STA 模式运行的 PowerShell `FolderBrowserDialog`，Linux 使用 Zenity，并以 KDialog 作为回退。选择器函数可在测试中注入。该方法需等待用户完成操作，是唯一不受默认 30 秒超时限制的一元调用；调用方发出的中止信号和连接中止仍会传播至原生进程。浏览器载体另行将这一特权方法限制为仅接受来自回环地址的同源请求。
+
+`session.history` 按消息边界分页，其尾页（不带 `beforeSeq`）额外携带两项页窗口本身无法提供的会话级数据：进行中局部消息的 chunk 事件，以及 `todos`——整份日志上最后一次 `todo/write` 的整表投影。较早的页面不带 `todos`，因为该投影是会话级而非分页级的；尾页响应缺少该字段意味着整份日志中没有任何 `todo/write`，因此客户端要把缺失字段读作空计划，而不是读作「状态未变」。
 
 `command.*` 与 `skill.*` 领域向客户端暴露宿主命令注册表和技能目录。每个方法都通过 `sessionId` 寻址一个会话的 Agent（被服务的会话必有 Agent；`command.*` 经由与 `session.*` 相同的路径恢复冷会话，而 `skill.list` 从会话头解析项目根目录，不触碰 Agent 注册表）。`command.execute` 在宿主侧运行一条斜杠命令行并返回脱耦结果；载体的请求信号可取消正在运行的处理器。`host/commands-changed` 是目录失效帧：客户端重新拉取 `command.list` 而不是做差分。
 
@@ -33,3 +39,4 @@ Workspace 列表与 Session 列表是相互独立的重连基线。`workspace.cr
 - **`respond` 路由已经发布，但待处理交互状态仍属宿主侧工作**：协议形状（POST `/api/respond`、`RpcReceipt`）已经定型；使延迟或重复回答具有明确语义的待处理表位于 `src/api-proxy.ts`，目前仍很精简（只支持问题，不支持审批）。
 - **预留 seam 不进入 `RpcMethodMap`**：`session.fork`、`prompt.mode: 'inject'`、`task.list`、`host.listModels` 和描述字段 `hostInstanceId` 都是已记录的预留项；未知方法会在信封解析时直接失败，而不会返回「尚未实现」错误码。
 - **没有协议版本字段**：客户端与宿主一同发布；只有出现独立发布的客户端后，`host.describe` 才会增加版本协商字段。
+- **Linux 原生选择器依赖桌面工具**：Zenity 和 KDialog 均未安装时，`host.pickDirectory` 会给出包含解决建议的错误提示；它不会回退到自定义目录浏览器，也不会要求用户手动输入路径。

packages/host/apiproxy/src/api-proxy.ts

@@ -7,11 +7,15 @@ import { randomUUID } from 'node:crypto'
 import { mkdir, stat } from 'node:fs/promises'
 import { join } from 'node:path'
 import type { Context } from 'cordis'
-import type { Agent, AgentMessage, AgentMessageId, AgentStatus } from '@deepseek-ai/dsh-agent'
+import { installAgentLlmTarget } from '@deepseek-ai/dsh-agent'
+import type {
+  Agent, AgentLlmTarget, AgentLlmTargetRef, AgentMessage, AgentMessageId, AgentStatus,
+} from '@deepseek-ai/dsh-agent'
 import { AttachmentError } from '@deepseek-ai/dsh-attachment-local'
 import type { ImageAttachmentRef } from '@deepseek-ai/dsh-attachment-local'
+import { errorChain, ReasoningEffortId } from '@deepseek-ai/dsh-llm'
 import type { ContentBlock, MessageSource } from '@deepseek-ai/dsh-llm'
-import type { JsonValue, Session, SessionEvent, SessionHeader, SessionId } from '@deepseek-ai/dsh-session'
+import type { JsonValue, Session, SessionEvent, SessionHeader, SessionId, TodoItem } from '@deepseek-ai/dsh-session'
 import type { SessionPersistence } from '@deepseek-ai/dsh-session-persistence'
 import { foldSessionTitle } from '@deepseek-ai/dsh-session-title'
 import type { Workspace, WorkspaceRecord } from '@deepseek-ai/dsh-workspace'
@@ -22,7 +26,8 @@ import {
 // Type-only: brings the `ctx.tools` Context merge into this program (viewFor reads presenters).
 import type {} from '@deepseek-ai/dsh-tools'
 import type {
-  ApiProxy, HistoryEntry, HostFrame, MuxFrame, PromptContentPart, QuestionResponsePayload, SessionSummary, ToolEventView,
+  ApiProxy, HistoryEntry, HostFrame, ModelCatalogFailure, ModelProviderGroup, ModelReasoning,
+  MuxFrame, PromptContentPart, QuestionResponsePayload, SessionSummary, ToolEventView,
   WorkspaceId, WorkspaceView,
 } from './api/index.ts'
 // Type-only edges: resolve `ctx.get('commands')`, the `commands/change` event, and `ctx.get('skills')`.
@@ -35,6 +40,7 @@ import type {
   AskUserQuestionAnswer, AskUserQuestionItem, AskUserQuestionRequest,
 } from '@deepseek-ai/dsh-user-interaction'
 import { UserInteractionError } from '@deepseek-ai/dsh-user-interaction'
+import { pickNativeDirectory } from './native-directory-picker.ts'
 
 /** Page size when history is called without maxMessages. */
 const DEFAULT_MAX_MESSAGES = 50
@@ -54,6 +60,9 @@ function decodeBase64(data: string): Uint8Array {
 }
 
 async function durablePromptContent(ctx: Context, content: readonly PromptContentPart[]): Promise<ContentBlock[]> {
+  if (content.every(part => part.type === 'text')) {
+    return content.map(part => ({ type: 'text', text: part.text }))
+  }
   const limits = ctx.attachments.imageLimits
   const prepared = content.map(part => part.type === 'text'
     ? part
@@ -271,6 +280,8 @@ export interface ApiProxyDefaults {
   cwd: string
   /** Parent directory for name-created workspaces. */
   workspaceRoot: string
+  /** Native single-directory picker; injectable for carrier tests. */
+  pickDirectory?: (signal: AbortSignal) => Promise<string | null>
 }
 
 /** The tool/call payload fields the presenter path reads. */
@@ -360,6 +371,15 @@ function backscanArgs(events: readonly SessionEvent[], callId: string): { name:
   return undefined
 }
 
+/** Current todo projection: the latest `todo/write` over the full log (whole-list replace ⇒ last write wins); undefined when none. */
+function backscanTodos(events: readonly SessionEvent[]): TodoItem[] | undefined {
+  for (let i = events.length - 1; i >= 0; i--) {
+    const event = events[i]
+    if (event !== undefined && event.type === 'todo/write') return event.data.todos
+  }
+  return undefined
+}
+
 /**
  * Thrown by the cold-resume path when the id names no servable session
  * (absent from the store, or a pre-project legacy log without a cwd).
@@ -425,6 +445,8 @@ function changedWorkspaceView(workspaceId: string, value: unknown): WorkspaceVie
  */
 export function createApiProxy(ctx: Context, defaults: ApiProxyDefaults): ApiProxy {
   const agentOptions = { provider: defaults.provider, model: defaults.model }
+  type WebLlmTargetRef = AgentLlmTargetRef & { current: AgentLlmTarget }
+  const targets = new WeakMap<Agent, WebLlmTargetRef>()
   /** Implicit resume of cold sessions, deduplicating concurrent calls (follows the jsonrpc sessionCreations precedent). */
   const resumes = new Map<SessionId, Promise<Agent>>()
   /** Client-chosen identity creation/resume, deduplicated across concurrent retries. */
@@ -434,6 +456,40 @@ export function createApiProxy(ctx: Context, defaults: ApiProxyDefaults): ApiPro
   const pendingQuestions = new Map<RpcId, PendingQuestion>()
   const muxQueues = new Set<FrameQueue<RpcRequest<MuxFrame>>>()
 
+  /**
+   * Install or return the session-local target that prompt assembly snapshots.
+   * Seed order: latest logged request/header, else the host default routing.
+   * There is no create-time per-session override tier on this wire — if one
+   * returns (a create-options contribution), it must fold in between the two.
+   */
+  function targetFor(agent: Agent): WebLlmTargetRef {
+    const installed = targets.get(agent)
+    if (installed !== undefined) return installed
+    const logged = agent.session.requestHeader()?.config
+    const target: WebLlmTargetRef = {
+      current: logged === undefined
+        ? { provider: defaults.provider, model: defaults.model }
+        : {
+          provider: logged.provider,
+          model: logged.model,
+          ...logged.reasoningEffort === undefined
+            ? {}
+            : { reasoningEffort: logged.reasoningEffort },
+        },
+      assembled: undefined,
+    }
+    installAgentLlmTarget(agent.ctx, target)
+    targets.set(agent, target)
+    return target
+  }
+
+  /** Pre-publication setup used by both fresh and resumed Web agents. */
+  function installTarget(agentCtx: Context): void {
+    const agent = agentCtx.agent
+    if (agent === undefined) throw new Error('api-proxy: agent setup has no scoped agent')
+    targetFor(agent)
+  }
+
   /** Send one transient frame to every connected mux consumer. */
   function broadcast(payload: MuxFrame): void {
     const envelope = frame(payload)
@@ -447,7 +503,7 @@ export function createApiProxy(ctx: Context, defaults: ApiProxyDefaults): ApiPro
    * `agent/inbox/dequeue` OR `agent/inbox/discard` (the inbox contract), so
    * the mirror needs no consumption heuristics or sweeps beyond disposal.
    */
-  const queuedMirror = new Map<SessionId, Map<AgentMessageId, AgentMessage>>()
+  const queuedMirror = new Map<SessionId, Map<AgentMessageId, { message: AgentMessage; steering: boolean }>>()
   ctx.effect(() => {
     const retire = (agent: Agent, id: AgentMessageId): void => {
       const entries = queuedMirror.get(agent.id)
@@ -456,11 +512,21 @@ export function createApiProxy(ctx: Context, defaults: ApiProxyDefaults): ApiPro
       if (entries.size === 0) queuedMirror.delete(agent.id)
     }
     const disposers = [
-      ctx.on('agent/inbox/enqueue', (agent: Agent, message: AgentMessage) => {
+      ctx.on('agent/inbox/enqueue', (agent: Agent, message: AgentMessage, placement) => {
         let entries = queuedMirror.get(agent.id)
-        if (entries === undefined) queuedMirror.set(agent.id, entries = new Map<AgentMessageId, AgentMessage>())
-        entries.set(message.id, message)
-        broadcast({ type: 'session/queued', sessionId: agent.id, content: message.content, source: message.source, steering: message.steering })
+        if (entries === undefined) {
+          entries = new Map<AgentMessageId, { message: AgentMessage; steering: boolean }>()
+          queuedMirror.set(agent.id, entries)
+        }
+        const steering = placement === 'steering'
+        entries.set(message.id, { message, steering })
+        broadcast({
+          type: 'session/queued',
+          sessionId: agent.id,
+          content: message.content,
+          source: message.source,
+          steering,
+        })
       }),
       ctx.on('agent/inbox/dequeue', (agent: Agent, message: AgentMessage) => {
         retire(agent, message.id)
@@ -547,7 +613,11 @@ export function createApiProxy(ctx: Context, defaults: ApiProxyDefaults): ApiPro
       resume = (async () => {
         try {
           await assertServable(sessionId)
-          const handle = await ctx.agents.resume({ resumeSessionId: sessionId, agentOptions })
+          const handle = await ctx.agents.resume({
+            resumeSessionId: sessionId,
+            agentOptions,
+            setup: installTarget,
+          })
           return handle.agent
         } finally {
           resumes.delete(sessionId)
@@ -582,7 +652,11 @@ export function createApiProxy(ctx: Context, defaults: ApiProxyDefaults): ApiPro
           if (stored.cwd !== cwd) {
             throw new SessionCwdConflict(sessionId, cwd, stored.cwd)
           }
-          return (await ctx.agents.resume({ resumeSessionId: sessionId, agentOptions })).agent
+          return (await ctx.agents.resume({
+            resumeSessionId: sessionId,
+            agentOptions,
+            setup: installTarget,
+          })).agent
         }
 
         try {
@@ -590,7 +664,12 @@ export function createApiProxy(ctx: Context, defaults: ApiProxyDefaults): ApiPro
         } catch (error: unknown) {
           throw new Error(`failed to ensure project directory "${cwd}": ${String(error)}`, { cause: error })
         }
-        return (await ctx.agents.create({ sessionId, agentOptions, meta: { cwd } })).agent
+        return (await ctx.agents.create({
+          sessionId,
+          agentOptions,
+          meta: { cwd },
+          setup: installTarget,
+        })).agent
       })().catch((error: unknown) => {
         // Another Host entry path may have published the same identity while
         // this operation crossed an asynchronous persistence/filesystem step.
@@ -719,7 +798,112 @@ export function createApiProxy(ctx: Context, defaults: ApiProxyDefaults): ApiPro
           const view = viewFor(ctx, event, callId => backscanArgs(page.events, callId))
           return { event, ...view === undefined ? {} : { view } }
         })
-        return ok(request, { events: entries, hasMore: page.hasMore })
+        // Tail page carries the session-level todo projection over the FULL
+        // log (the page window may not contain the last todo/write; a paged
+        // client cannot reconstruct session-level state from it).
+        const todos = beforeSeq === undefined ? backscanTodos(found.agent.session.events) : undefined
+        return ok(request, { events: entries, hasMore: page.hasMore, ...todos === undefined ? {} : { todos } })
+      },
+
+      async models(request) {
+        const { sessionId } = request.payload
+        const found = await agentFor(sessionId)
+        if ('error' in found) return err(request, found.error)
+        const current = targetFor(found.agent).current
+        const catalog = await Promise.all(ctx.llm.listProviders().map(async (provider) => {
+          try {
+            const advertised = await ctx.llm.listModels(provider.id)
+            const models = [...advertised]
+            if (
+              provider.id === current.provider
+              && !models.some(model => model.id === current.model)
+            ) {
+              models.push({
+                provider: provider.id,
+                id: current.model,
+                name: current.model,
+              })
+            }
+            const entries = await Promise.all(models.map(async (model) => {
+              const resolved = await ctx.llm.resolveModelInfo(provider.id, model.id)
+              const reasoning: ModelReasoning | undefined = resolved.reasoning === undefined
+                ? undefined
+                : {
+                  efforts: resolved.reasoning.efforts.map(effort => ({
+                    id: effort.id,
+                    name: effort.name,
+                    ...effort.description === undefined
+                      ? {}
+                      : { description: effort.description },
+                  })),
+                  ...resolved.reasoning.defaultEffort === undefined
+                    ? {}
+                    : { defaultEffort: resolved.reasoning.defaultEffort },
+                }
+              return {
+                id: model.id,
+                name: model.name,
+                ...model.description === undefined ? {} : { description: model.description },
+                ...provider.id === current.provider
+                  && model.id === current.model
+                  && !advertised.some(candidate => candidate.id === current.model)
+                  ? { unlisted: true as const }
+                  : {},
+                ...reasoning === undefined ? {} : { reasoning },
+              }
+            }))
+            const group: ModelProviderGroup = {
+              id: provider.id,
+              name: provider.name,
+              models: entries,
+            }
+            return { kind: 'group' as const, group }
+          } catch (error: unknown) {
+            const failure: ModelCatalogFailure = {
+              id: provider.id,
+              name: provider.name,
+              message: error instanceof Error ? error.message : String(error),
+            }
+            return { kind: 'failure' as const, failure }
+          }
+        }))
+        const groups = catalog.flatMap(item => item.kind === 'group' ? [item.group] : [])
+        const failures = catalog.flatMap(item => item.kind === 'failure' ? [item.failure] : [])
+        return ok(request, {
+          current: { ...current },
+          groups: groups.filter(group => group.models.length > 0),
+          failures,
+        })
+      },
+
+      async selectModel(request) {
+        const { sessionId, provider, model, reasoningEffort } = request.payload
+        const found = await agentFor(sessionId)
+        if ('error' in found) return err(request, found.error)
+        try {
+          const resolved = await ctx.llm.resolveCallConfig({
+            provider,
+            model,
+            ...reasoningEffort === undefined
+              ? {}
+              : { reasoningEffort: ReasoningEffortId(reasoningEffort) },
+          })
+          const selected: AgentLlmTarget = {
+            provider: resolved.provider,
+            model: resolved.model,
+            ...resolved.reasoningEffort === undefined
+              ? {}
+              : { reasoningEffort: resolved.reasoningEffort },
+          }
+          targetFor(found.agent).current = selected
+          return ok(request, { selected: { ...selected } })
+        } catch (error: unknown) {
+          return err(request, {
+            code: 'model-unavailable',
+            message: error instanceof Error ? error.message : String(error),
+            details: { provider, model },
+          })
+        }
       },
 
       async prompt(request) {
@@ -731,11 +915,11 @@ export function createApiProxy(ctx: Context, defaults: ApiProxyDefaults): ApiPro
         const source: MessageSource = { kind: 'user', rpcId: request.rpcId }
         try {
           if (content.some(part => part.type === 'image')) {
-            const routed = agent.session.requestHeader()?.config
-            const provider = routed?.provider ?? agent.options.provider ?? defaults.provider
-            const model = routed?.model ?? agent.options.model ?? defaults.model
-            const activeModel = (await ctx.llm.listModels(provider)).find(candidate => candidate.id === model)
-            if (activeModel?.inputModalities !== undefined && !activeModel.inputModalities.includes('image')) {
+            const target = targetFor(agent).current
+            const provider = target.provider
+            const model = target.model
+            const activeModel = await ctx.llm.resolveModelInfo(provider, model)
+            if (activeModel.inputModalities !== undefined && !activeModel.inputModalities.includes('image')) {
               return err(request, {
                 code: 'attachment-error',
                 message: `Model "${model}" does not support image input.`,
@@ -744,8 +928,8 @@ export function createApiProxy(ctx: Context, defaults: ApiProxyDefaults): ApiPro
             }
           }
           const durable = await durablePromptContent(ctx, content)
-          if (mode === 'steer') agent.steer(durable, { source })
-          else agent.followup(durable, { source })
+          if (mode === 'steer') agent.steer({ content: durable, source })
+          else agent.followup({ content: durable, source })
         } catch (error: unknown) {
           if (error instanceof AttachmentError) {
             return err(request, {
@@ -804,7 +988,7 @@ export function createApiProxy(ctx: Context, defaults: ApiProxyDefaults): ApiPro
             details: { sessionId },
           }))
         }
-        agent.cancel()
+        agent.cancel({ kind: 'user' })
         return Promise.resolve(ok(request, { accepted: true as const }))
       },
     },
@@ -896,6 +1080,15 @@ export function createApiProxy(ctx: Context, defaults: ApiProxyDefaults): ApiPro
         return ok(request, { workspace: workspaceView(workspace) })
       },
 
+      async delete(request) {
+        const { workspaceId } = request.payload
+        const operation = workspaceCreationChain.then(() =>
+          ctx.workspace.delete(brandWorkspaceId(workspaceId)))
+        workspaceCreationChain = operation.then(() => undefined, () => undefined)
+        if (!await operation) return workspaceNotFound(request, workspaceId)
+        return ok(request, { deleted: true as const })
+      },
+
       async insertSessionBefore(request) {
         const { payload } = request
         const workspace = ctx.workspace.get(brandWorkspaceId(payload.workspaceId))
@@ -940,6 +1133,26 @@ export function createApiProxy(ctx: Context, defaults: ApiProxyDefaults): ApiPro
           attachedSessions: ctx.agents.list().length,
         })
       },
+
+      async pickDirectory(request, signal) {
+        try {
+          const path = await (defaults.pickDirectory ?? pickNativeDirectory)(signal)
+          return ok(request, { path })
+        } catch (error: unknown) {
+          if (signal.aborted) {
+            return err(request, {
+              code: 'cancelled',
+              message: 'directory picker was aborted',
+              details: {},
+            })
+          }
+          return err(request, {
+            code: 'internal',
+            message: `directory picker failed: ${error instanceof Error ? error.message : String(error)}`,
+            details: {},
+          })
+        }
+      },
     },
 
     commands: {
@@ -1045,7 +1258,13 @@ export function createApiProxy(ctx: Context, defaults: ApiProxyDefaults): ApiPro
         // queue view from these alone.
         for (const [sessionId, entries] of queuedMirror) {
           for (const entry of entries.values()) {
-            queue.push(frame({ type: 'session/queued', sessionId, content: entry.content, source: entry.source, steering: entry.steering }))
+            queue.push(frame({
+              type: 'session/queued',
+              sessionId,
+              content: entry.message.content,
+              source: entry.message.source,
+              steering: entry.steering,
+            }))
           }
         }
         // Per-session open-call table for result-view pairing. Bounded by the
@@ -1109,15 +1328,15 @@ export function createApiProxy(ctx: Context, defaults: ApiProxyDefaults): ApiPro
             queue.push(frame({ type: 'host/session-removed', sessionId: session.id }))
           }),
           ctx.on('agent/status', (agent: Agent, status: AgentStatus) => {
-            if (status === 'disposed') return
             queue.push(frame({ type: 'host/session-status', sessionId: agent.id, running: status === 'running' }))
           }),
-          ctx.on('agent/error', (agent: Agent, _turn: number, _step: number, error: Error) => {
-            queue.push(frame({ type: 'host/agent-error', sessionId: agent.id, message: String(error) }))
+          ctx.on('agent/error', (agent: Agent, _turn: number, _step: number, error: unknown) => {
+            queue.push(frame({ type: 'host/agent-error', sessionId: agent.id, message: errorChain(error) }))
           }),
           ctx.on('domain/changed', (change) => {
-            if (change.domain !== 'workspace' || change.operation !== 'put') return
+            if (change.domain !== 'workspace') return
             if (change.table === '') {
+              if (change.operation !== 'put') return
               const state = workspaceDomainState.parse(change.value)
               for (const workspaceId of state.workspaceIds) {
                 if (committedWorkspaceIds.has(workspaceId)) continue
@@ -1130,7 +1349,16 @@ export function createApiProxy(ctx: Context, defaults: ApiProxyDefaults): ApiPro
               }
               return
             }
-            if (change.table !== 'workspaces' || !committedWorkspaceIds.has(change.key)) return
+            if (change.table !== 'workspaces') return
+            if (change.operation === 'deleted') {
+              if (!committedWorkspaceIds.delete(change.key)) return
+              queue.push(frame({
+                type: 'host/workspace-removed',
+                workspaceId: change.key as WorkspaceId,
+              }))
+              return
+            }
+            if (!committedWorkspaceIds.has(change.key)) return
             // Existing-entity table writes are complete attach/touch commits.
             // A new entity's first put waits for the global registry write above.
             queue.push(frame({

packages/host/apiproxy/src/api/events.schema.ts

@@ -11,7 +11,7 @@ import type { Wire } from './rpc.schema.ts'
 import { rpcErrorSchema, rpcIdSchema } from './rpc.schema.ts'
 import { approvalRequestIdSchema } from './approvals.schema.ts'
 import { contentBlockSchema, sessionEventSchema, sessionIdSchema, toolEventViewSchema } from './sessions.schema.ts'
-import { workspaceViewSchema } from './workspace.schema.ts'
+import { workspaceIdSchema, workspaceViewSchema } from './workspace.schema.ts'
 
 /** Question shape validated strictly against core dsh-user-interaction. */
 export const askUserQuestionItemSchema = z.object({
@@ -47,6 +47,7 @@ export const hostFrameSchema = z.discriminatedUnion('type', [
   z.object({ type: z.literal('host/session-status'), sessionId: sessionIdSchema, running: z.boolean() }),
   z.object({ type: z.literal('host/agent-error'), sessionId: sessionIdSchema, message: z.string() }),
   z.object({ type: z.literal('host/workspace-changed'), workspace: workspaceViewSchema }),
+  z.object({ type: z.literal('host/workspace-removed'), workspaceId: workspaceIdSchema }),
   z.object({ type: z.literal('host/commands-changed') }),
   z.object({ type: z.literal('stream/error'), error: rpcErrorSchema }),
 ]) as unknown as z.ZodType<HostFrame>

packages/host/apiproxy/src/api/events.ts

@@ -63,14 +63,16 @@ export type MuxFrame =
   | { type: 'question/requested'; sessionId: SessionId; questions: AskUserQuestionItem[] }
   | { type: 'question/resolved'; sessionId: SessionId; questionRpcId: RpcId; outcome: 'answered' | 'cancelled' }
   /**
-   * A message entered the addressed agent's inbox (`agent/queued` passthrough:
-   * a queued message is not model-visible, so there is no session event to
-   * ride — this transient frame is the only wire signal). On stream open the
+   * A message entered the addressed agent's inbox. A queued message is not
+   * model-visible, so there is no session event to carry it; this transient
+   * frame is the only wire signal. On stream open the
    * host replays the current queue snapshot for every attached session (same
    * refresh-recovery baseline as pending questions); queue clearing on cancel
    * has no dedicated frame — clients fold it from the status flip.
-   * source carries the prompt's rpcId when the message came over this wire
-   * (the client's provisional-echo reconciliation key).
+   * `steering` is the host's acceptance-time queue classification and remains
+   * authoritative in reconnect snapshots. `source` carries the prompt's rpcId
+   * when the message came over this wire (the client's provisional-echo
+   * reconciliation key).
    */
   | { type: 'session/queued'; sessionId: SessionId; content: ContentBlock[]; source: MessageSource; steering: boolean }
   | { type: 'stream/error'; error: RpcError }
@@ -85,7 +87,9 @@ export type MuxFrame =
  * agent-error is the only outlet for live failures with no turn position;
  * workspace-changed pushes the full new snapshot after every durable
  * workspace mutation (create/attach/order change — the client upserts, while
- * `workspace.list` provides the reconnect baseline).
+ * `workspace.list` provides the reconnect baseline); workspace-removed is the
+ * committed registration-deletion increment and never implies directory or
+ * session-log deletion.
  */
 export type HostFrame =
   | { type: 'host/session-added'; sessionId: SessionId; blank: boolean; parentSessionId?: SessionId; cwd?: string }
@@ -93,6 +97,7 @@ export type HostFrame =
   | { type: 'host/session-status'; sessionId: SessionId; running: boolean }
   | { type: 'host/agent-error'; sessionId: SessionId; message: string }
   | { type: 'host/workspace-changed'; workspace: WorkspaceView }
+  | { type: 'host/workspace-removed'; workspaceId: WorkspaceView['workspaceId'] }
   /**
    * The command registry changed (`commands/change` passthrough). Pure
    * invalidation signal, no payload: clients refetch `command.list` in the

packages/host/apiproxy/src/api/host.schema.ts

@@ -37,3 +37,11 @@ export const hostDescribeValueSchema = z.object({
   }).optional(),
   attachedSessions: z.number().int().nonnegative(),
 }) satisfies z.ZodType<Wire<ResponseValue<'host.describe'>>>
+
+/** host.pickDirectory request payload (empty object literal). */
+export const hostPickDirectoryRequestSchema = z.object({}) satisfies z.ZodType<Wire<RequestPayload<'host.pickDirectory'>>>
+
+/** host.pickDirectory response value; null means the user cancelled. */
+export const hostPickDirectoryValueSchema = z.object({
+  path: z.string().nullable(),
+}) satisfies z.ZodType<Wire<ResponseValue<'host.pickDirectory'>>>

packages/host/apiproxy/src/api/host.ts

@@ -28,4 +28,10 @@ export interface HostApi {
     imageLimits?: ImageAttachmentLimits
     attachedSessions: number
   }>>
+
+  /** Open the operating system's single-directory picker; cancellation returns null. */
+  pickDirectory(
+    request: RpcRequest<{}>,
+    signal: AbortSignal,
+  ): Promise<RpcResponse<{ path: string | null }>>
 }

packages/host/apiproxy/src/api/index.ts

@@ -25,7 +25,10 @@ export interface ApiProxy {
 }
 
 // ---- Domain interfaces and payload entities ----
-export type { HistoryEntry, PromptContentPart, SessionsApi, SessionSummary } from './sessions.ts'
+export type {
+  HistoryEntry, ModelCatalogFailure, ModelCatalogModel, ModelProviderGroup, ModelReasoning,
+  ModelReasoningEffort, ModelTarget, PromptContentPart, SessionModels, SessionsApi, SessionSummary,
+} from './sessions.ts'
 export type { HostApi } from './host.ts'
 export type { WorkspaceApi, WorkspaceId, WorkspaceView } from './workspace.ts'
 export type { CommandsApi, CommandDescriptor, CommandExecuteResult } from './commands.ts'

packages/host/apiproxy/src/api/rpc-map.ts

@@ -20,13 +20,17 @@ export interface RpcMethodMap {
   'session.list': SessionsApi['list']
   'session.create': SessionsApi['create']
   'session.history': SessionsApi['history']
+  'session.models': SessionsApi['models']
+  'session.selectModel': SessionsApi['selectModel']
   'session.prompt': SessionsApi['prompt']
   'session.attachment': SessionsApi['attachment']
   'session.cancel': SessionsApi['cancel']
   'host.describe': HostApi['describe']
+  'host.pickDirectory': HostApi['pickDirectory']
   'workspace.list': WorkspaceApi['list']
   'workspace.create': WorkspaceApi['create']
   'workspace.rename': WorkspaceApi['rename']
+  'workspace.delete': WorkspaceApi['delete']
   'workspace.insertSessionBefore': WorkspaceApi['insertSessionBefore']
   'command.list': CommandsApi['list']
   'command.execute': CommandsApi['execute']

packages/host/apiproxy/src/api/rpc.schema.ts

@@ -35,6 +35,7 @@ export const rpcErrorSchema: z.ZodType<RpcError> = z.discriminatedUnion('code',
   z.object({ code: z.literal('bad-request'), message: z.string(), details: z.object({ issues: z.array(z.custom<ZodIssue>()) }) }),
   z.object({ code: z.literal('cancelled'), message: z.string(), details: z.object({}) }),
   z.object({ code: z.literal('session-not-found'), message: z.string(), details: z.object({ sessionId: z.string() }) }),
+  z.object({ code: z.literal('model-unavailable'), message: z.string(), details: z.object({ provider: z.string(), model: z.string() }) }),
   z.object({ code: z.literal('session-conflict'), message: z.string(), details: z.object({ sessionId: z.string(), requestedCwd: z.string(), existingCwd: z.string().optional() }) }),
   z.object({ code: z.literal('workspace-attach-failed'), message: z.string(), details: z.object({ sessionId: z.string(), workspaceId: z.string() }) }),
   z.object({ code: z.literal('workspace-not-found'), message: z.string(), details: z.object({ workspaceId: z.string() }) }),

packages/host/apiproxy/src/api/rpc.ts

@@ -32,6 +32,7 @@ export interface RpcErrorDetailsMap {
   'bad-request': { issues: ZodIssue[] }
   'cancelled': {}
   'session-not-found': { sessionId: SessionId }
+  'model-unavailable': { provider: string; model: string }
   'session-conflict': { sessionId: SessionId; requestedCwd: string; existingCwd?: string }
   'workspace-attach-failed': { sessionId: SessionId; workspaceId: string }
   'workspace-not-found': { workspaceId: string }

packages/host/apiproxy/src/api/sessions.schema.ts

@@ -9,7 +9,10 @@ import { z } from 'zod'
 import type { SessionEvent, SessionId } from '@deepseek-ai/dsh-session/types'
 import type { RequestPayload, ResponseValue } from './rpc-map.ts'
 import type { Wire } from './rpc.schema.ts'
-import type { HistoryEntry, SessionSummary } from './sessions.ts'
+import type {
+  HistoryEntry, ModelCatalogFailure, ModelCatalogModel, ModelProviderGroup, ModelReasoning,
+  ModelReasoningEffort, ModelTarget, SessionSummary,
+} from './sessions.ts'
 import type { ToolEventView } from './events.ts'
 import type { AttachmentIdType, ImageAttachmentRef } from '@deepseek-ai/dsh-attachment'
 import type { WorkspaceId } from './workspace.ts'
@@ -77,6 +80,49 @@ export const sessionHistoryRequestSchema = z.object({
   maxMessages: z.number().int().positive().optional(),
 }) satisfies z.ZodType<Wire<RequestPayload<'session.history'>>>
 
+/** Complete provider/model target. */
+export const modelTargetSchema = z.object({
+  provider: z.string().min(1),
+  model: z.string().min(1),
+  reasoningEffort: z.string().min(1).optional(),
+}) satisfies z.ZodType<Wire<ModelTarget>>
+
+/** One adapter-owned reasoning effort. */
+export const modelReasoningEffortSchema = z.object({
+  id: z.string().min(1),
+  name: z.string().min(1),
+  description: z.string().optional(),
+}) satisfies z.ZodType<Wire<ModelReasoningEffort>>
+
+/** Exact-model reasoning metadata. */
+export const modelReasoningSchema = z.object({
+  efforts: z.array(modelReasoningEffortSchema).min(1),
+  defaultEffort: z.string().min(1).optional(),
+}) satisfies z.ZodType<Wire<ModelReasoning>>
+
+/** One advisory model entry inside a provider group. */
+export const modelCatalogModelSchema = z.object({
+  id: z.string().min(1),
+  name: z.string().min(1),
+  description: z.string().optional(),
+  unlisted: z.literal(true).optional(),
+  reasoning: modelReasoningSchema.optional(),
+}) satisfies z.ZodType<Wire<ModelCatalogModel>>
+
+/** One successfully loaded provider group. */
+export const modelProviderGroupSchema = z.object({
+  id: z.string().min(1),
+  name: z.string().min(1),
+  models: z.array(modelCatalogModelSchema),
+}) satisfies z.ZodType<Wire<ModelProviderGroup>>
+
+/** One provider-local catalog failure. */
+export const modelCatalogFailureSchema = z.object({
+  id: z.string().min(1),
+  name: z.string().min(1),
+  message: z.string(),
+}) satisfies z.ZodType<Wire<ModelCatalogFailure>>
+
 /**
  * ToolEventView passthrough: lock only the `for` discriminant and the presence
  * of a card-tagged `view` object. The view interior is a host-computed product
@@ -94,12 +140,44 @@ export const historyEntrySchema = z.object({
   view: toolEventViewSchema.optional(),
 }) satisfies z.ZodType<Wire<HistoryEntry>>
 
+/** One todo item of the tail page's session-level projection (the todo/write payload shape). */
+export const todoItemSchema = z.object({
+  content: z.string(),
+  status: z.union([z.literal('pending'), z.literal('in_progress'), z.literal('completed')]),
+})
+
 /** session.history response value. */
 export const sessionHistoryValueSchema = z.object({
   events: z.array(historyEntrySchema),
   hasMore: z.boolean(),
+  todos: z.array(todoItemSchema).optional(),
 }) satisfies z.ZodType<Wire<ResponseValue<'session.history'>>>
 
+/** session.models request payload. */
+export const sessionModelsRequestSchema = z.object({
+  sessionId: sessionIdSchema,
+}) satisfies z.ZodType<Wire<RequestPayload<'session.models'>>>
+
+/** session.models response value. */
+export const sessionModelsValueSchema = z.object({
+  current: modelTargetSchema,
+  groups: z.array(modelProviderGroupSchema),
+  failures: z.array(modelCatalogFailureSchema),
+}) satisfies z.ZodType<Wire<ResponseValue<'session.models'>>>
+
+/** session.selectModel request payload. */
+export const sessionSelectModelRequestSchema = z.object({
+  sessionId: sessionIdSchema,
+  provider: z.string().min(1),
+  model: z.string().min(1),
+  reasoningEffort: z.string().min(1).optional(),
+}) satisfies z.ZodType<Wire<RequestPayload<'session.selectModel'>>>
+
+/** session.selectModel response value. */
+export const sessionSelectModelValueSchema = z.object({
+  selected: modelTargetSchema,
+}) satisfies z.ZodType<Wire<ResponseValue<'session.selectModel'>>>
+
 /** ContentBlock passthrough: core is merge-extensible — the type discriminant envelope is strict, the rest stays wide. */
 export const contentBlockSchema = z.looseObject({ type: z.string() })
 

packages/host/apiproxy/src/api/sessions.ts

@@ -5,7 +5,7 @@
  */
 
 import type { AttachmentIdType, ImageAttachmentRef, ImageMediaType } from '@deepseek-ai/dsh-attachment'
-import type { SessionEvent, SessionId } from '@deepseek-ai/dsh-session/types'
+import type { SessionEvent, SessionId, TodoItem } from '@deepseek-ai/dsh-session/types'
 import type { RpcId, RpcRequest, RpcResponse } from './rpc.ts'
 import type { ToolEventView } from './events.ts'
 import type { WorkspaceId } from './workspace.ts'
@@ -32,6 +32,78 @@ export interface HistoryEntry {
   view?: ToolEventView
 }
 
+/** Complete model target selected for one session. */
+export interface ModelTarget {
+  /** Registered provider route. */
+  provider: string
+  /** Provider-owned model id. */
+  model: string
+  /** Adapter-owned reasoning effort; absence preserves adapter/provider default behavior. */
+  reasoningEffort?: string
+}
+
+/** One adapter-owned reasoning effort displayed for an exact model route. */
+export interface ModelReasoningEffort {
+  /** Opaque value submitted back to the owning adapter. */
+  id: string
+  /** Adapter-supplied display name. */
+  name: string
+  /** Optional adapter-supplied description. */
+  description?: string
+}
+
+/** Selectable reasoning metadata for one exact model route. */
+export interface ModelReasoning {
+  /** Efforts in adapter-preferred display order. */
+  efforts: ModelReasoningEffort[]
+  /** Adapter-configured default; absence preserves the provider default. */
+  defaultEffort?: string
+}
+
+/** One model displayed inside its provider group. */
+export interface ModelCatalogModel {
+  /** Provider-owned model id. */
+  id: string
+  /** Provider-supplied display name. */
+  name: string
+  /** Optional provider-supplied description. */
+  description?: string
+  /** The current model was inserted because the advisory catalog omitted it. */
+  unlisted?: true
+  /** Exact-route reasoning metadata when the adapter exposes it. */
+  reasoning?: ModelReasoning
+}
+
+/** One provider and the models it advertised successfully. */
+export interface ModelProviderGroup {
+  /** Provider route id used for requests. */
+  id: string
+  /** Provider display name. */
+  name: string
+  /** Models in provider-preferred order. */
+  models: ModelCatalogModel[]
+}
+
+/** A provider whose asynchronous catalog lookup failed. */
+export interface ModelCatalogFailure {
+  /** Provider route id. */
+  id: string
+  /** Provider display name. */
+  name: string
+  /** Lookup failure diagnostic. */
+  message: string
+}
+
+/** Detached model-directory snapshot for one session. */
+export interface SessionModels {
+  /** Target selected for the session's next assembled step. */
+  current: ModelTarget
+  /** Successfully loaded provider groups. */
+  groups: ModelProviderGroup[]
+  /** Provider-local failures; successful groups remain usable. */
+  failures: ModelCatalogFailure[]
+}
+
 /** Session list entry (v1 builds no index: list does readdir+stat). */
 export interface SessionSummary {
   sessionId: SessionId
@@ -82,9 +154,29 @@ export interface SessionsApi {
    * Each entry pairs the raw SessionEvent with the host-computed view (tool events whose
    * presenter produced one, evaluated against the registry at pagination time); the client
    * rebuilds the surface from the events with the shared fold.
+   * The tail page (beforeSeq absent) also carries `todos` — the session's current todo
+   * projection (latest `todo/write` over the FULL log, independent of the page window) —
+   * so a paged client restores the plan without walking history; absent when the session
+   * never wrote one. Older pages omit it (the projection is session-level, not per-page).
    */
   history(request: RpcRequest<{ sessionId: SessionId; beforeSeq?: number; maxMessages?: number }>):
-  Promise<RpcResponse<{ events: HistoryEntry[]; hasMore: boolean }>>
+  Promise<RpcResponse<{ events: HistoryEntry[]; hasMore: boolean; todos?: TodoItem[] }>>
+
+  /** Reads a fresh advisory model directory for this session. Provider lookups run independently. */
+  models(request: RpcRequest<{ sessionId: SessionId }>): Promise<RpcResponse<SessionModels>>
+
+  /**
+   * Selects the complete target for this session. Exact model metadata
+   * validates an optional reasoning effort, while catalog membership remains
+   * advisory.
+   */
+  selectModel(request: RpcRequest<{
+    sessionId: SessionId
+    provider: string
+    model: string
+    reasoningEffort?: string
+  }>):
+  Promise<RpcResponse<{ selected: ModelTarget }>>
 
   /** Sends text plus temporary base64 image uploads; the host persists images before calling the agent. */
   prompt(request: RpcRequest<{ sessionId: SessionId; mode: 'queue' | 'steer'; content: PromptContentPart[] }>):

packages/host/apiproxy/src/api/workspace.schema.ts

@@ -59,6 +59,16 @@ export const workspaceRenameValueSchema = z.object({
   workspace: workspaceViewSchema,
 }) satisfies z.ZodType<Wire<ResponseValue<'workspace.rename'>>>
 
+/** workspace.delete request payload. */
+export const workspaceDeleteRequestSchema = z.object({
+  workspaceId: workspaceIdSchema,
+}) satisfies z.ZodType<Wire<RequestPayload<'workspace.delete'>>>
+
+/** workspace.delete response value. */
+export const workspaceDeleteValueSchema = z.object({
+  deleted: z.literal(true),
+}) satisfies z.ZodType<Wire<ResponseValue<'workspace.delete'>>>
+
 /** workspace.insertSessionBefore request payload (anchor omitted = append to end). */
 export const workspaceInsertSessionBeforeRequestSchema = z.object({
   workspaceId: workspaceIdSchema,

packages/host/apiproxy/src/api/workspace.ts

@@ -65,6 +65,14 @@ export interface WorkspaceApi {
   rename(request: RpcRequest<{ workspaceId: WorkspaceId; title: string }>):
   Promise<RpcResponse<{ workspace: WorkspaceView }>>
 
+  /**
+   * Removes one Workspace registration. The directory, every user file, and
+   * every session log remain untouched; those Sessions consequently become
+   * ungrouped. An unknown id fails with `workspace-not-found`.
+   */
+  delete(request: RpcRequest<{ workspaceId: WorkspaceId }>):
+  Promise<RpcResponse<{ deleted: true }>>
+
   /**
    * Moves an accounted session within its workspace's manual order,
    * DOM-insertBefore-like: with `beforeSessionId` the session is inserted

packages/host/apiproxy/src/fetch/client.ts

@@ -13,17 +13,20 @@ import { RpcId } from '../api/rpc.ts'
 import type { Wire } from '../api/rpc.schema.ts'
 import { rpcReceiptSchema, serverRequestSchema, serverResponseSchema } from '../api/rpc.schema.ts'
 import { hostFrameSchema, muxFrameSchema } from '../api/events.schema.ts'
-import { hostDescribeValueSchema } from '../api/host.schema.ts'
+import { hostDescribeValueSchema, hostPickDirectoryValueSchema } from '../api/host.schema.ts'
 import {
   sessionCancelValueSchema,
   sessionAttachmentValueSchema,
   sessionCreateValueSchema,
   sessionHistoryValueSchema,
   sessionListValueSchema,
+  sessionModelsValueSchema,
   sessionPromptValueSchema,
+  sessionSelectModelValueSchema,
 } from '../api/sessions.schema.ts'
 import {
   workspaceCreateValueSchema,
+  workspaceDeleteValueSchema,
   workspaceInsertSessionBeforeValueSchema,
   workspaceListValueSchema,
   workspaceRenameValueSchema,
@@ -51,17 +54,21 @@ export interface IApiClient {
     list(payload: RequestPayload<'session.list'>, signal?: AbortSignal): Promise<RpcResponse<ResponseValue<'session.list'>>>
     create(payload: RequestPayload<'session.create'>, signal?: AbortSignal): Promise<RpcResponse<ResponseValue<'session.create'>>>
     history(payload: RequestPayload<'session.history'>, signal?: AbortSignal): Promise<RpcResponse<ResponseValue<'session.history'>>>
+    models(payload: RequestPayload<'session.models'>, signal?: AbortSignal): Promise<RpcResponse<ResponseValue<'session.models'>>>
+    selectModel(payload: RequestPayload<'session.selectModel'>, signal?: AbortSignal): Promise<RpcResponse<ResponseValue<'session.selectModel'>>>
     prompt(payload: RequestPayload<'session.prompt'>, signal?: AbortSignal): Promise<RpcResponse<ResponseValue<'session.prompt'>>>
     attachment(payload: RequestPayload<'session.attachment'>, signal?: AbortSignal): Promise<RpcResponse<ResponseValue<'session.attachment'>>>
     cancel(payload: RequestPayload<'session.cancel'>, signal?: AbortSignal): Promise<RpcResponse<ResponseValue<'session.cancel'>>>
   }
   host: {
     describe(payload: RequestPayload<'host.describe'>, signal?: AbortSignal): Promise<RpcResponse<ResponseValue<'host.describe'>>>
+    pickDirectory(payload: RequestPayload<'host.pickDirectory'>, signal?: AbortSignal): Promise<RpcResponse<ResponseValue<'host.pickDirectory'>>>
   }
   workspace: {
     list(payload: RequestPayload<'workspace.list'>, signal?: AbortSignal): Promise<RpcResponse<ResponseValue<'workspace.list'>>>
     create(payload: RequestPayload<'workspace.create'>, signal?: AbortSignal): Promise<RpcResponse<ResponseValue<'workspace.create'>>>
     rename(payload: RequestPayload<'workspace.rename'>, signal?: AbortSignal): Promise<RpcResponse<ResponseValue<'workspace.rename'>>>
+    delete(payload: RequestPayload<'workspace.delete'>, signal?: AbortSignal): Promise<RpcResponse<ResponseValue<'workspace.delete'>>>
     insertSessionBefore(payload: RequestPayload<'workspace.insertSessionBefore'>, signal?: AbortSignal): Promise<RpcResponse<ResponseValue<'workspace.insertSessionBefore'>>>
   }
   commands: {
@@ -87,13 +94,17 @@ const UNARY_VALUE_SCHEMAS: { [K in keyof RpcMethodMap]: z.ZodType<Wire<ResponseV
   'session.list': sessionListValueSchema,
   'session.create': sessionCreateValueSchema,
   'session.history': sessionHistoryValueSchema,
+  'session.models': sessionModelsValueSchema,
+  'session.selectModel': sessionSelectModelValueSchema,
   'session.prompt': sessionPromptValueSchema,
   'session.attachment': sessionAttachmentValueSchema,
   'session.cancel': sessionCancelValueSchema,
   'host.describe': hostDescribeValueSchema,
+  'host.pickDirectory': hostPickDirectoryValueSchema,
   'workspace.list': workspaceListValueSchema,
   'workspace.create': workspaceCreateValueSchema,
   'workspace.rename': workspaceRenameValueSchema,
+  'workspace.delete': workspaceDeleteValueSchema,
   'workspace.insertSessionBefore': workspaceInsertSessionBeforeValueSchema,
   'command.list': commandListValueSchema,
   'command.execute': commandExecuteValueSchema,
@@ -177,13 +188,22 @@ export abstract class AbstractApiClient implements IApiClient {
    * Shared POST leg of both C→S carriers (callUnary/respond): JSON body,
    * timeout merged with the caller's optional external signal, non-2xx → transport throw.
    */
-  private async postJson(path: string, body: ClientRequest | ClientResponse, signal: AbortSignal | undefined): Promise<Response> {
-    const timeout = AbortSignal.timeout(this.timeoutMs)
+  private async postJson(
+    path: string,
+    body: ClientRequest | ClientResponse,
+    signal: AbortSignal | undefined,
+    useDefaultTimeout = true,
+  ): Promise<Response> {
+    const requestSignal = useDefaultTimeout
+      ? signal === undefined
+        ? AbortSignal.timeout(this.timeoutMs)
+        : AbortSignal.any([AbortSignal.timeout(this.timeoutMs), signal])
+      : signal
     const response = await this.doFetch(new URL(path, this.resolveBase()), {
       method: 'POST',
       headers: { 'content-type': 'application/json' },
       body: JSON.stringify(body),
-      signal: signal === undefined ? timeout : AbortSignal.any([timeout, signal]),
+      ...requestSignal === undefined ? {} : { signal: requestSignal },
     })
     if (!response.ok) throw new Error(`transport failure for ${path}: HTTP ${response.status}`)
     return response
@@ -198,10 +218,11 @@ export abstract class AbstractApiClient implements IApiClient {
     method: K,
     payload: RequestPayload<K>,
     signal?: AbortSignal,
+    useDefaultTimeout = true,
   ): Promise<RpcResponse<ResponseValue<K>>> {
     const message: ClientRequest = { type: 'client-request', rpcId: this.mintRpcId(), method, payload }
     this.onEnvelope(message)
-    const response = await this.postJson(`/api/${method}`, message, signal)
+    const response = await this.postJson(`/api/${method}`, message, signal, useDefaultTimeout)
     const full = serverResponseSchema.parse(await response.json())
     this.onEnvelope(full)
     if (full.rpcId !== message.rpcId) throw new Error(`rpcId mismatch for ${method}: sent ${message.rpcId}, got ${full.rpcId}`)
@@ -276,6 +297,8 @@ export abstract class AbstractApiClient implements IApiClient {
     list: (payload, signal) => this.callUnary('session.list', payload, signal),
     create: (payload, signal) => this.callUnary('session.create', payload, signal),
     history: (payload, signal) => this.callUnary('session.history', payload, signal),
+    models: (payload, signal) => this.callUnary('session.models', payload, signal),
+    selectModel: (payload, signal) => this.callUnary('session.selectModel', payload, signal),
     prompt: (payload, signal) => this.callUnary('session.prompt', payload, signal),
     attachment: (payload, signal) => this.callUnary('session.attachment', payload, signal),
     cancel: (payload, signal) => this.callUnary('session.cancel', payload, signal),
@@ -283,12 +306,16 @@ export abstract class AbstractApiClient implements IApiClient {
 
   readonly host: IApiClient['host'] = {
     describe: (payload, signal) => this.callUnary('host.describe', payload, signal),
+    // A native system dialog is user-paced and may legitimately stay open
+    // longer than the normal unary deadline. Caller/connection aborts remain.
+    pickDirectory: (payload, signal) => this.callUnary('host.pickDirectory', payload, signal, false),
   }
 
   readonly workspace: IApiClient['workspace'] = {
     list: (payload, signal) => this.callUnary('workspace.list', payload, signal),
     create: (payload, signal) => this.callUnary('workspace.create', payload, signal),
     rename: (payload, signal) => this.callUnary('workspace.rename', payload, signal),
+    delete: (payload, signal) => this.callUnary('workspace.delete', payload, signal),
     insertSessionBefore: (payload, signal) => this.callUnary('workspace.insertSessionBefore', payload, signal),
   }
 

packages/host/apiproxy/src/fetch/handler.ts

@@ -20,11 +20,14 @@ import {
   sessionCreateRequestSchema,
   sessionHistoryRequestSchema,
   sessionListRequestSchema,
+  sessionModelsRequestSchema,
   sessionPromptRequestSchema,
+  sessionSelectModelRequestSchema,
 } from '../api/sessions.schema.ts'
-import { hostDescribeRequestSchema } from '../api/host.schema.ts'
+import { hostDescribeRequestSchema, hostPickDirectoryRequestSchema } from '../api/host.schema.ts'
 import {
   workspaceCreateRequestSchema,
+  workspaceDeleteRequestSchema,
   workspaceInsertSessionBeforeRequestSchema,
   workspaceListRequestSchema,
   workspaceRenameRequestSchema,
@@ -52,13 +55,17 @@ const UNARY_ROUTES: UnaryRoutes = {
   'session.list': { schema: sessionListRequestSchema, invoke: (api, r) => api.sessions.list(r) },
   'session.create': { schema: sessionCreateRequestSchema, invoke: (api, r) => api.sessions.create(r) },
   'session.history': { schema: sessionHistoryRequestSchema, invoke: (api, r) => api.sessions.history(r) },
+  'session.models': { schema: sessionModelsRequestSchema, invoke: (api, r) => api.sessions.models(r) },
+  'session.selectModel': { schema: sessionSelectModelRequestSchema, invoke: (api, r) => api.sessions.selectModel(r) },
   'session.prompt': { schema: sessionPromptRequestSchema, invoke: (api, r) => api.sessions.prompt(r) },
   'session.attachment': { schema: sessionAttachmentRequestSchema, invoke: (api, r) => api.sessions.attachment(r) },
   'session.cancel': { schema: sessionCancelRequestSchema, invoke: (api, r) => api.sessions.cancel(r) },
   'host.describe': { schema: hostDescribeRequestSchema, invoke: (api, r) => api.host.describe(r) },
+  'host.pickDirectory': { schema: hostPickDirectoryRequestSchema, invoke: (api, r, signal) => api.host.pickDirectory(r, signal) },
   'workspace.list': { schema: workspaceListRequestSchema, invoke: (api, r) => api.workspace.list(r) },
   'workspace.create': { schema: workspaceCreateRequestSchema, invoke: (api, r) => api.workspace.create(r) },
   'workspace.rename': { schema: workspaceRenameRequestSchema, invoke: (api, r) => api.workspace.rename(r) },
+  'workspace.delete': { schema: workspaceDeleteRequestSchema, invoke: (api, r) => api.workspace.delete(r) },
   'workspace.insertSessionBefore': { schema: workspaceInsertSessionBeforeRequestSchema, invoke: (api, r) => api.workspace.insertSessionBefore(r) },
   'command.list': { schema: commandListRequestSchema, invoke: (api, r) => api.commands.list(r) },
   'command.execute': { schema: commandExecuteRequestSchema, invoke: (api, r, signal) => api.commands.execute(r, signal) },

packages/host/apiproxy/src/native-directory-picker.ts

@@ -0,0 +1,136 @@
+/** Cross-platform native single-directory picker used by the local GUI carrier. */
+
+import { execFile } from 'node:child_process'
+
+/** Testable command boundary; native implementations never invoke a shell. */
+export type DirectoryPickerRunner = (
+  command: string,
+  args: readonly string[],
+  signal: AbortSignal,
+) => Promise<{ stdout: string; stderr: string }>
+
+/** Injectable platform facts for deterministic adapter tests. */
+export interface DirectoryPickerInternals {
+  platform?: NodeJS.Platform
+  run?: DirectoryPickerRunner
+}
+
+const runCommand: DirectoryPickerRunner = (command, args, signal) =>
+  new Promise((resolve, reject) => {
+    execFile(
+      command,
+      [...args],
+      { encoding: 'utf8', signal, windowsHide: true },
+      (error, stdout, stderr) => {
+        if (error !== null) {
+          const failure = Object.assign(new Error(error.message, { cause: error }), {
+            code: error.code,
+            stdout,
+            stderr,
+          })
+          reject(failure)
+          return
+        }
+        resolve({ stdout, stderr })
+      },
+    )
+  })
+
+function outputPath(stdout: string): string | null {
+  const path = stdout.replace(/[\r\n]+$/, '')
+  return path === '' ? null : path
+}
+
+function errorCode(error: unknown): string | number | undefined {
+  if (typeof error !== 'object' || error === null || !('code' in error)) return undefined
+  const code = (error as { code?: unknown }).code
+  return typeof code === 'string' || typeof code === 'number' ? code : undefined
+}
+
+function errorStderr(error: unknown): string {
+  if (typeof error !== 'object' || error === null || !('stderr' in error)) return ''
+  const stderr = (error as { stderr?: unknown }).stderr
+  return typeof stderr === 'string' ? stderr : ''
+}
+
+function isMissingCommand(error: unknown): boolean {
+  return errorCode(error) === 'ENOENT'
+}
+
+function rethrowIfAborted(signal: AbortSignal, error: unknown): void {
+  if (signal.aborted) throw error
+}
+
+/**
+ * Open the platform directory picker.
+ * @param signal - caller/connection lifetime; abort terminates the native command.
+ * @param internals - platform and runner seam for deterministic tests.
+ * @returns the selected path, or null when the user cancels.
+ */
+export async function pickNativeDirectory(
+  signal: AbortSignal,
+  internals: DirectoryPickerInternals = {},
+): Promise<string | null> {
+  const platform = internals.platform ?? process.platform
+  const run = internals.run ?? runCommand
+
+  if (platform === 'darwin') {
+    try {
+      const result = await run('osascript', [
+        '-e', 'set selectedFolder to choose folder with prompt "Select Workspace Directory"',
+        '-e', 'POSIX path of selectedFolder',
+      ], signal)
+      return outputPath(result.stdout)
+    } catch (error: unknown) {
+      if (!signal.aborted && errorCode(error) === 1
+        && /(?:User canceled|-128)/i.test(errorStderr(error))) return null
+      throw error
+    }
+  }
+
+  if (platform === 'win32') {
+    const script = [
+      "$ErrorActionPreference = 'Stop'",
+      'Add-Type -AssemblyName System.Windows.Forms',
+      '$dialog = New-Object System.Windows.Forms.FolderBrowserDialog',
+      "$dialog.Description = 'Select Workspace Directory'",
+      '$dialog.ShowNewFolderButton = $true',
+      '$result = $dialog.ShowDialog()',
+      'if ($result -eq [System.Windows.Forms.DialogResult]::OK) {',
+      '  [Console]::OutputEncoding = [System.Text.Encoding]::UTF8',
+      '  [Console]::WriteLine($dialog.SelectedPath)',
+      '}',
+    ].join('; ')
+    const result = await run('powershell.exe', ['-NoProfile', '-STA', '-Command', script], signal)
+    return outputPath(result.stdout)
+  }
+
+  if (platform === 'linux') {
+    try {
+      const result = await run('zenity', [
+        '--file-selection', '--directory', '--title=Select Workspace Directory',
+      ], signal)
+      return outputPath(result.stdout)
+    } catch (error: unknown) {
+      rethrowIfAborted(signal, error)
+      if (errorCode(error) === 1) return null
+      if (!isMissingCommand(error)) throw error
+    }
+
+    try {
+      const result = await run('kdialog', [
+        '--getexistingdirectory', '.', '--title', 'Select Workspace Directory',
+      ], signal)
+      return outputPath(result.stdout)
+    } catch (error: unknown) {
+      rethrowIfAborted(signal, error)
+      if (errorCode(error) === 1) return null
+      if (isMissingCommand(error)) {
+        throw new Error('no supported native directory picker found (install zenity or kdialog)')
+      }
+      throw error
+    }
+  }
+
+  throw new Error(`native directory picker is unsupported on ${platform}`)
+}

packages/host/apiproxy/tests/api-proxy-cold.spec.ts

@@ -1,8 +1,9 @@
 /**
  * Cold-session and degenerate-composition paths of the host ApiProxy:
  * sessions.list merging persisted-but-unattached summaries (mtime source,
- * createdAt fallbacks, lineage projection) and the resume error split when
- * the composition has no persistence gate and no agent factory.
+ * createdAt fallbacks, lineage projection), the resume error split when
+ * the composition has no persistence gate and no agent factory, and the
+ * agent-busy mapping of a synchronous prompt rejection.
  */
 
 import { mkdtempSync, writeFileSync, utimesSync } from 'node:fs'
@@ -12,6 +13,7 @@ import { describe, expect, it } from 'vitest'
 import { Context } from 'cordis'
 import SessionStore from '@deepseek-ai/dsh-session'
 import AgentRegistry from '@deepseek-ai/dsh-agent'
+import type { Agent } from '@deepseek-ai/dsh-agent'
 import UserInteractionService from '@deepseek-ai/dsh-user-interaction'
 import type { SessionHeader, SessionId } from '@deepseek-ai/dsh-session'
 import type { RpcRequest } from '@deepseek-ai/dsh-host-apiproxy/api/rpc'
@@ -98,3 +100,38 @@ describe('degenerate composition (no persistence, no factory)', () => {
     }
   })
 })
+
+describe('sessions.prompt synchronous rejection', () => {
+  it('maps a synchronous send throw (disposed/invalid input) to agent-busy with the reason attached', async () => {
+    const ctx = new Context()
+    await ctx.plugin(SessionStore)
+    await ctx.plugin(AgentRegistry)
+    await ctx.plugin(UserInteractionService)
+    const session = ctx.sessions.create(sid('session-throwing'))
+    // A live structural stub whose delivery verbs throw synchronously, the
+    // shape a disposed loop presents at this seam.
+    ctx.agents.register({
+      id: session.id,
+      session,
+      status: 'idle',
+      ctx,
+      followup: () => { throw new Error('agent "session-throwing" lifecycle disposed') },
+      steer: () => { throw new Error('agent "session-throwing" lifecycle disposed') },
+    } as unknown as Agent)
+    const api = createApiProxy(ctx, { provider: 'p', model: 'm', cwd: '/tmp', workspaceRoot: '/tmp' })
+
+    for (const mode of ['queue', 'steer'] as const) {
+      const response = await api.sessions.prompt(request({
+        sessionId: session.id, mode, content: [{ type: 'text' as const, text: 'x' }],
+      }))
+      expect(response.result.ok).toBe(false)
+      if (!response.result.ok) {
+        expect(response.result.error.code).toBe('agent-busy')
+        expect(response.result.error.message).toBe('prompt rejected')
+        expect(response.result.error.details).toEqual({
+          reason: 'Error: agent "session-throwing" lifecycle disposed',
+        })
+      }
+    }
+  })
+})

packages/host/apiproxy/tests/api-proxy-commands.spec.ts

@@ -238,14 +238,11 @@ describe('host/commands-changed frame', () => {
 })
 
 /** Build one frozen inbox message for the live `agent/inbox/*` events. */
-function inboxMessage(id: string, text: string, steering: boolean, rpcId?: string): AgentMessage {
+function inboxMessage(id: string, text: string, rpcId?: string): AgentMessage {
   return Object.freeze({
     id: AgentMessageId(id),
     content: [{ type: 'text' as const, text }],
     source: rpcId === undefined ? { kind: 'user' as const } : { kind: 'user' as const, rpcId: RpcId(rpcId) },
-    contexts: [],
-    steering,
-    wakeup: true,
   })
 }
 
@@ -259,10 +256,10 @@ describe('session/queued frames', () => {
     // subscribed baseline + 2 queued frames
     const liveCollected = collect<MuxFrame>(liveStream, 3, live)
 
-    const queued = inboxMessage('m-1', 'queued prompt', false)
-    const steering = inboxMessage('m-2', 'queued prompt', true)
-    ctx.emit('agent/inbox/enqueue', agent, queued)
-    ctx.emit('agent/inbox/enqueue', agent, steering)
+    const queued = inboxMessage('m-1', 'queued prompt')
+    const steering = inboxMessage('m-2', 'queued prompt')
+    ctx.emit('agent/inbox/enqueue', agent, queued, 'queued')
+    ctx.emit('agent/inbox/enqueue', agent, steering, 'steering')
 
     const liveFrames = (await liveCollected).filter(f => f.type === 'session/queued')
     expect(liveFrames).toEqual([
@@ -274,17 +271,17 @@ describe('session/queued frames', () => {
     const replay = new AbortController()
     const replayFrames = await collect<MuxFrame>(
       api.events.mux({ rpcId: RpcId('t-mux-replay'), payload: {} }, replay.signal), 3, replay)
-    expect(replayFrames.filter(f => f.type === 'session/queued')).toHaveLength(2)
+    expect(replayFrames.filter(f => f.type === 'session/queued')).toEqual(liveFrames)
   })
 
   it('retires mirror entries on their terminal dequeue', async () => {
     const ctx = await harness()
     const api = createApiProxy(ctx, DEFAULTS)
     const agent = stubAgent(ctx)
-    const queued = inboxMessage('m-3', 'x', false)
-    const steering = inboxMessage('m-4', 'x', true, 'r-1')
-    ctx.emit('agent/inbox/enqueue', agent, queued)
-    ctx.emit('agent/inbox/enqueue', agent, steering)
+    const queued = inboxMessage('m-3', 'x')
+    const steering = inboxMessage('m-4', 'x', 'r-1')
+    ctx.emit('agent/inbox/enqueue', agent, queued, 'queued')
+    ctx.emit('agent/inbox/enqueue', agent, steering, 'steering')
     ctx.emit('agent/inbox/dequeue', agent, queued)
     ctx.emit('agent/inbox/dequeue', agent, steering)
 
@@ -298,10 +295,10 @@ describe('session/queued frames', () => {
     const ctx = await harness()
     const api = createApiProxy(ctx, DEFAULTS)
     const agent = stubAgent(ctx)
-    const doomed = inboxMessage('m-5', 'doomed', false)
-    const survivor = inboxMessage('m-6', 'survivor', false)
-    ctx.emit('agent/inbox/enqueue', agent, doomed)
-    ctx.emit('agent/inbox/enqueue', agent, survivor)
+    const doomed = inboxMessage('m-5', 'doomed')
+    const survivor = inboxMessage('m-6', 'survivor')
+    ctx.emit('agent/inbox/enqueue', agent, doomed, 'queued')
+    ctx.emit('agent/inbox/enqueue', agent, survivor, 'queued')
     ctx.emit('agent/inbox/discard', agent, [doomed])
 
     const abort = new AbortController()

packages/host/apiproxy/tests/api-proxy-models.spec.ts

@@ -0,0 +1,233 @@
+/**
+ * Web session model-directory and selection behavior: dynamic provider grouping,
+ * provider-local catalog failures, logged-target restoration, advisory unlisted
+ * models, and the prompt-assembly boundary for a running selection change.
+ */
+
+import { describe, expect, it } from 'vitest'
+import { Context } from 'cordis'
+import AgentRegistry, { agentEvents } from '@deepseek-ai/dsh-agent'
+import type { Agent } from '@deepseek-ai/dsh-agent'
+import LlmService, { LlmAdapter, ReasoningEffortId } from '@deepseek-ai/dsh-llm'
+import type {
+  GenerateOptions, LlmCallConfig, LlmModelInfo, LlmModelReasoningInfo, LlmProviderInfo,
+  LlmResolvedModelInfo, StreamChunk,
+} from '@deepseek-ai/dsh-llm'
+import SessionStore from '@deepseek-ai/dsh-session'
+import type { SessionId } from '@deepseek-ai/dsh-session'
+import SystemPrompt from '@deepseek-ai/dsh-system-prompt'
+import UserInteractionService from '@deepseek-ai/dsh-user-interaction'
+import type { RpcRequest } from '@deepseek-ai/dsh-host-apiproxy/api/rpc'
+import { RpcId } from '@deepseek-ai/dsh-host-apiproxy/api/rpc'
+import { createApiProxy } from '../src/api-proxy.ts'
+
+let nextRpc = 1
+function request<P>(payload: P): RpcRequest<P> {
+  return { rpcId: RpcId(`models-${String(nextRpc++)}`), payload }
+}
+
+class CatalogAdapter extends LlmAdapter {
+  constructor(
+    private readonly name: string,
+    private readonly models: readonly LlmModelInfo[] | Error,
+    private readonly reasoning?: LlmModelReasoningInfo,
+    private readonly exactError?: Error,
+  ) {
+    super()
+  }
+
+  override providerInfo(provider: string): LlmProviderInfo {
+    return { id: provider, name: this.name }
+  }
+
+  override listModels(): Promise<readonly LlmModelInfo[]> {
+    return this.models instanceof Error
+      ? Promise.reject(this.models)
+      : Promise.resolve(this.models)
+  }
+
+  override resolveModel(provider: string, model: string): Promise<LlmResolvedModelInfo> {
+    if (this.exactError !== undefined) return Promise.reject(this.exactError)
+    return Promise.resolve({
+      provider,
+      id: model,
+      name: model,
+      ...this.reasoning === undefined ? {} : { reasoning: this.reasoning },
+    })
+  }
+
+  override async *stream(_options: GenerateOptions): AsyncIterable<StreamChunk> {
+    // Catalog tests never enter provider streaming.
+  }
+}
+
+const REASONING: LlmModelReasoningInfo = {
+  efforts: [
+    { id: ReasoningEffortId('off'), name: 'Off' },
+    { id: ReasoningEffortId('high'), name: 'High' },
+    { id: ReasoningEffortId('max'), name: 'Max' },
+  ],
+  defaultEffort: ReasoningEffortId('high'),
+}
+
+async function harness(logged?: {
+  provider: string
+  model: string
+  reasoningEffort?: ReasoningEffortId
+}): Promise<{
+  ctx: Context
+  agent: Agent
+  sessionId: SessionId
+}> {
+  const ctx = new Context()
+  await ctx.plugin(SessionStore)
+  await ctx.plugin(SystemPrompt, { persona: '' })
+  await ctx.plugin(LlmService)
+  await ctx.plugin(UserInteractionService)
+  await ctx.plugin(AgentRegistry)
+  ctx.llm.registerAdapter(['deepseek'], new CatalogAdapter('DeepSeek', [
+    { provider: 'deepseek', id: 'deepseek-chat', name: 'DeepSeek Chat' },
+    { provider: 'deepseek', id: 'deepseek-reasoner', name: 'DeepSeek Reasoner', description: 'Reasoning model' },
+  ], REASONING))
+  ctx.llm.registerAdapter(['broken'], new CatalogAdapter('Broken Provider', new Error('catalog offline')))
+  ctx.llm.registerAdapter(['metadata-broken'], new CatalogAdapter('Metadata Broken', [
+    { provider: 'metadata-broken', id: 'listed', name: 'Listed' },
+  ], undefined, new Error('reasoning metadata offline')))
+  ctx.llm.registerAdapter(['empty'], new CatalogAdapter('Empty Provider', []))
+  ctx.llm.registerAdapter(['duplicate'], new CatalogAdapter('Duplicate Provider', [
+    { provider: 'duplicate', id: 'same', name: 'Same' },
+    { provider: 'duplicate', id: 'same', name: 'Same Again' },
+  ]))
+  const session = ctx.sessions.create()
+  if (logged !== undefined) {
+    session.append('request/header', { header: { config: logged }, reason: 'initial' })
+  }
+  const agent = {
+    id: session.id,
+    session,
+    status: 'running',
+    ctx,
+  } as Agent
+  ctx.agents.register(agent)
+  return { ctx, agent, sessionId: session.id }
+}
+
+function expectValue<T>(response: { result: { ok: true; value: T } | { ok: false } }): T {
+  if (!response.result.ok) throw new Error('expected successful response')
+  return response.result.value
+}
+
+describe('Web session model selection', () => {
+  it('groups successful providers, isolates failures, and preserves an unlisted current model', async () => {
+    const { ctx, sessionId } = await harness({
+      provider: 'deepseek',
+      model: 'private-preview',
+      reasoningEffort: ReasoningEffortId('max'),
+    })
+    const api = createApiProxy(ctx, { provider: 'deepseek', model: 'deepseek-chat', cwd: '/tmp', workspaceRoot: '/tmp' })
+
+    const catalog = expectValue(await api.sessions.models(request({ sessionId })))
+    expect(catalog.current).toEqual({
+      provider: 'deepseek',
+      model: 'private-preview',
+      reasoningEffort: 'max',
+    })
+    expect(catalog.groups).toEqual([{
+      id: 'deepseek',
+      name: 'DeepSeek',
+      models: [
+        { id: 'deepseek-chat', name: 'DeepSeek Chat', reasoning: REASONING },
+        {
+          id: 'deepseek-reasoner',
+          name: 'DeepSeek Reasoner',
+          description: 'Reasoning model',
+          reasoning: REASONING,
+        },
+        {
+          id: 'private-preview',
+          name: 'private-preview',
+          unlisted: true,
+          reasoning: REASONING,
+        },
+      ],
+    }])
+    expect(catalog.failures).toEqual([
+      { id: 'broken', name: 'Broken Provider', message: 'catalog offline' },
+      { id: 'metadata-broken', name: 'Metadata Broken', message: 'reasoning metadata offline' },
+      {
+        id: 'duplicate',
+        name: 'Duplicate Provider',
+        message: 'adapter returned invalid or duplicate model metadata for provider "duplicate"',
+      },
+    ])
+    await ctx.fiber.dispose()
+  })
+
+  it('accepts an advisory-unlisted model, rejects an unavailable provider, and switches only after the next assembly', async () => {
+    const { ctx, agent, sessionId } = await harness()
+    const api = createApiProxy(ctx, { provider: 'deepseek', model: 'deepseek-chat', cwd: '/tmp', workspaceRoot: '/tmp' })
+    const seed: LlmCallConfig = { provider: 'seed', model: 'seed', temperature: 0.2 }
+    const signal = new AbortController().signal
+
+    expect(expectValue(await api.sessions.models(request({ sessionId }))).current)
+      .toEqual({ provider: 'deepseek', model: 'deepseek-chat' })
+    expect((await ctx.systemPrompt.assemble()).variables)
+      .toMatchObject({ provider: 'deepseek', model: 'deepseek-chat' })
+
+    const selected = expectValue(await api.sessions.selectModel(request({
+      sessionId,
+      provider: 'deepseek',
+      model: 'private-preview',
+      reasoningEffort: 'max',
+    })))
+    expect(selected.selected).toEqual({
+      provider: 'deepseek',
+      model: 'private-preview',
+      reasoningEffort: 'max',
+    })
+    await expect(agentEvents(ctx, agent).waterfall(
+      'agent/request', 1, 0, signal, () => Promise.resolve(seed),
+    )).resolves.toMatchObject({ provider: 'deepseek', model: 'deepseek-chat' })
+
+    expect((await ctx.systemPrompt.assemble()).variables)
+      .toMatchObject({ provider: 'deepseek', model: 'private-preview' })
+    await expect(agentEvents(ctx, agent).waterfall(
+      'agent/request', 1, 1, signal, () => Promise.resolve(seed),
+    )).resolves.toMatchObject({
+      provider: 'deepseek',
+      model: 'private-preview',
+      reasoningEffort: 'max',
+    })
+
+    const unsupported = await api.sessions.selectModel(request({
+      sessionId,
+      provider: 'deepseek',
+      model: 'private-preview',
+      reasoningEffort: 'medium',
+    }))
+    expect(unsupported.result).toMatchObject({
+      ok: false,
+      error: {
+        code: 'model-unavailable',
+        message: 'provider "deepseek" model "private-preview" does not support reasoning effort "medium"',
+      },
+    })
+
+    const rejected = await api.sessions.selectModel(request({
+      sessionId,
+      provider: 'missing',
+      model: 'model',
+    }))
+    expect(rejected.result).toEqual({
+      ok: false,
+      error: {
+        code: 'model-unavailable',
+        message: 'no adapter registered for provider "missing"',
+        details: { provider: 'missing', model: 'model' },
+      },
+    })
+    expect(expectValue(await api.sessions.models(request({ sessionId }))).current)
+      .toEqual({ provider: 'deepseek', model: 'private-preview', reasoningEffort: 'max' })
+    await ctx.fiber.dispose()
+  })
+})

packages/host/apiproxy/tests/api-proxy-view.spec.ts

@@ -154,6 +154,39 @@ describe('mux live view computation', () => {
     expect('view' in (byKey.get('tool/result:h-plain') ?? {})).toBe(false)
   })
 
+  it('tail page carries the full-log todo projection; older pages and todo-less sessions omit it', async () => {
+    const { ctx } = await harness()
+    const api = createApiProxy(ctx, { provider: 'p', model: 'm', cwd: '/tmp', workspaceRoot: '/tmp' })
+    const session = ctx.sessions.create()
+    ctx.agents.register({ id: session.id, session, status: 'idle', ctx } as Agent)
+    // Superseded write early in the log, latest write later; enough messages to page.
+    session.append('todo/write', { todos: [{ content: 'old', status: 'pending' }] })
+    for (let turn = 0; turn < 6; turn++) {
+      session.append('turn/start', { turn, trigger: { kind: 'message', source: { kind: 'user' } } })
+      session.append('user/message', { content: [{ type: 'text', text: `q${turn}` }], source: { kind: 'user' } }, { surfaceOp: 'append' })
+      session.append('assistant/message', { turn, step: 0, content: [{ type: 'text', text: `a${turn}` }], provenance: { provider: 'p', model: 'm' } }, { surfaceOp: 'append' })
+      session.append('turn/end', { turn, reason: { kind: 'completed' } })
+    }
+    session.append('todo/write', { todos: [{ content: 'current', status: 'in_progress' }] })
+
+    // Tail page limited to 2 messages: the latest todo/write may or may not sit
+    // in the window — the projection must come from the FULL log either way.
+    const tail = await api.sessions.history({ rpcId: RpcId('t-todos'), payload: { sessionId: session.id, maxMessages: 2 } })
+    if (!tail.result.ok) throw new Error('history failed')
+    expect(tail.result.value.todos).toEqual([{ content: 'current', status: 'in_progress' }])
+    // An older page omits the projection (session-level, tail-page-only).
+    const boundary = tail.result.value.events[0]?.event.seq ?? 0
+    const older = await api.sessions.history({ rpcId: RpcId('t-todos-2'), payload: { sessionId: session.id, beforeSeq: boundary, maxMessages: 2 } })
+    if (!older.result.ok) throw new Error('older failed')
+    expect('todos' in older.result.value).toBe(false)
+    // A session with no todo/write anywhere omits the field.
+    const bare = ctx.sessions.create()
+    ctx.agents.register({ id: bare.id, session: bare, status: 'idle', ctx } as Agent)
+    const bareTail = await api.sessions.history({ rpcId: RpcId('t-todos-3'), payload: { sessionId: bare.id } })
+    if (!bareTail.result.ok) throw new Error('bare failed')
+    expect('todos' in bareTail.result.value).toBe(false)
+  })
+
   it('drops a disposed session from the live open-call table (result after dispose gets no view)', async () => {
     const { ctx } = await harness()
     const api = createApiProxy(ctx, { provider: 'p', model: 'm', cwd: '/tmp', workspaceRoot: '/tmp' })

packages/host/apiproxy/tests/api-proxy-workspace.spec.ts

@@ -43,9 +43,9 @@ function stubAgent(session: Session): Agent {
     options: {},
     session,
     status: 'idle',
+    acceptsNextStep: false,
     ctx: new Context(),
     followup: () => AgentMessageId('stub'),
-    queue: () => AgentMessageId('stub'),
     steer: () => AgentMessageId('stub'),
     inject: () => AgentMessageId('stub'),
     send: () => AgentMessageId('stub'),
@@ -57,6 +57,7 @@ function stubAgent(session: Session): Agent {
 /** Compose the API over real Session, Agent, Storage, Domain, and Workspace services. */
 async function harness(
   workspaceRoot = realpathSync(mkdtempSync(join(tmpdir(), 'dsh-apiproxy-workspace-'))),
+  pickDirectory?: (signal: AbortSignal) => Promise<string | null>,
 ) {
   const ctx = new Context()
   await ctx.plugin(SessionStore)
@@ -96,10 +97,33 @@ async function harness(
     model: 'test-model',
     cwd: workspaceRoot,
     workspaceRoot,
+    ...pickDirectory === undefined ? {} : { pickDirectory },
   })
   return { api, ctx, storageDomain, workspaceRoot }
 }
 
+describe('host.pickDirectory', () => {
+  it('returns a selected path or explicit cancellation from the injected native boundary', async () => {
+    const selected = await harness(undefined, async () => '/tmp/project')
+    expect((await selected.api.host.pickDirectory(request({}), new AbortController().signal)).result)
+      .toEqual({ ok: true, value: { path: '/tmp/project' } })
+
+    const cancelled = await harness(undefined, async () => null)
+    expect((await cancelled.api.host.pickDirectory(request({}), new AbortController().signal)).result)
+      .toEqual({ ok: true, value: { path: null } })
+  })
+
+  it('propagates abort into the native boundary as a cancelled RPC error', async () => {
+    const { api } = await harness(undefined, signal => new Promise((_resolve, reject) => {
+      signal.addEventListener('abort', () => { reject(new Error('aborted')) }, { once: true })
+    }))
+    const abort = new AbortController()
+    const pending = api.host.pickDirectory(request({}), abort.signal)
+    abort.abort()
+    expect((await pending).result).toMatchObject({ ok: false, error: { code: 'cancelled' } })
+  })
+})
+
 describe('workspace.create', () => {
   it('serializes concurrent names and rejects the duplicate', async () => {
     const { api, workspaceRoot } = await harness()
@@ -131,6 +155,13 @@ describe('workspace.create', () => {
     expect(first).toMatchObject({ created: true, workspace: { path: existing, title: 'existing' } })
     expect(repeated).toMatchObject({ created: false, workspace: { workspaceId: first.workspace.workspaceId } })
 
+    expectOk(await api.workspace.rename(request({
+      workspaceId: first.workspace.workspaceId,
+      title: 'renamed-existing',
+    })))
+    const reopened = expectOk(await api.workspace.create(request({ path: existing })))
+    expect(reopened.workspace.title).toBe('renamed-existing')
+
     const missing = join(workspaceRoot, 'missing')
     const missingResult = await api.workspace.create(request({ path: missing }))
     expect(missingResult.result).toMatchObject({ ok: false, error: { code: 'workspace-invalid-path' } })
@@ -141,6 +172,20 @@ describe('workspace.create', () => {
       expect(invalid.result).toMatchObject({ ok: false, error: { code: 'workspace-invalid-path' } })
     }
   })
+
+  it('rejects different paths that derive the same Workspace title', async () => {
+    const { api, workspaceRoot } = await harness()
+    const first = join(workspaceRoot, 'one', 'project')
+    const second = join(workspaceRoot, 'two', 'project')
+    mkdirSync(first, { recursive: true })
+    mkdirSync(second, { recursive: true })
+    expectOk(await api.workspace.create(request({ path: first })))
+    const conflict = await api.workspace.create(request({ path: second }))
+    expect(conflict.result).toMatchObject({
+      ok: false,
+      error: { code: 'workspace-name-conflict', details: { name: 'project' } },
+    })
+  })
 })
 
 describe('session creation and Workspace membership', () => {
@@ -244,4 +289,37 @@ describe('Host Workspace increments', () => {
     abort.abort()
     expect(await next).toMatchObject({ done: true })
   })
+
+  it('deletes the registration, keeps its session and folder, and streams one removal', async () => {
+    const { api, ctx } = await harness()
+    const workspace = expectOk(await api.workspace.create(request({ name: 'delete-me' }))).workspace
+    const sessionId = SessionId('session-kept-after-workspace-delete')
+    expectOk(await api.sessions.create(request({ workspaceId: workspace.workspaceId, sessionId })))
+
+    const abort = new AbortController()
+    const stream: AsyncIterator<RpcRequest<HostFrame>> =
+      api.events.host(request({}), abort.signal)[Symbol.asyncIterator]()
+    const removed = nextHostFrame(stream)
+    expectOk(await api.workspace.delete(request({ workspaceId: workspace.workspaceId })))
+    expect(await removed).toMatchObject({
+      payload: { type: 'host/workspace-removed', workspaceId: workspace.workspaceId },
+    })
+    expect(expectOk(await api.workspace.list(request({}))).items).toEqual([])
+    expect(expectOk(await api.sessions.list(request({}))).items.map(item => item.sessionId)).toContain(sessionId)
+    expect(ctx.agents.get(sessionId)).toBeDefined()
+    expect(existsSync(workspace.path)).toBe(true)
+
+    const missing = await api.workspace.delete(request({ workspaceId: workspace.workspaceId }))
+    expect(missing.result).toMatchObject({
+      ok: false,
+      error: { code: 'workspace-not-found', details: { workspaceId: workspace.workspaceId } },
+    })
+
+    const reregistered = expectOk(await api.workspace.create(request({ path: workspace.path }))).workspace
+    expect(reregistered.workspaceId).not.toBe(workspace.workspaceId)
+    expect(reregistered.path).toBe(workspace.path)
+    expect(reregistered.sessionIds).toEqual([])
+    expect(expectOk(await api.sessions.list(request({}))).items.map(item => item.sessionId)).toContain(sessionId)
+    abort.abort()
+  })
 })

packages/host/apiproxy/tests/client-handler.spec.ts

@@ -30,7 +30,19 @@ function scriptedApi(overrides: {
     sessions: {
       list: r => ok(r, { items: [] }),
       create: r => ok(r, { sessionId: sid('s-new') }),
-      history: r => ok(r, { events: [], hasMore: false }),
+      history: r => ok(r, {
+        events: [],
+        hasMore: false,
+        modelTarget: { provider: 'deepseek', model: 'deepseek-v4-flash' },
+      }),
+      models: r => ok(r, {
+        current: { provider: 'deepseek', model: 'deepseek-v4-flash' },
+        groups: [],
+        failures: [],
+      }),
+      selectModel: r => ok(r, {
+        selected: { provider: r.payload.provider, model: r.payload.model },
+      }),
       prompt: r => ok(r, { accepted: true as const }),
       attachment: r => ok(r, {
         attachment: { attachmentId: 'a' as never, mediaType: 'image/png', bytes: 1, width: 1, height: 1 },
@@ -39,11 +51,16 @@ function scriptedApi(overrides: {
       cancel: r => ok(r, { accepted: true as const }),
       ...overrides.sessions,
     },
-    host: { describe: r => ok(r, { version: '0-test', cwd: '/t', attachedSessions: 0 }), ...overrides.host },
+    host: {
+      describe: r => ok(r, { version: '0-test', cwd: '/t', attachedSessions: 0 }),
+      pickDirectory: r => ok(r, { path: null }),
+      ...overrides.host,
+    },
     workspace: {
       list: r => ok(r, { items: [] }),
       create: r => ok(r, { workspace: { workspaceId: 'w1' as never, path: '/t', title: 't', sessionIds: [], createdAt: '0', updatedAt: '0' }, created: true }),
       rename: r => ok(r, { workspace: { workspaceId: 'w1' as never, path: '/t', title: 't', sessionIds: [], createdAt: '0', updatedAt: '0' } }),
+      delete: r => ok(r, { deleted: true as const }),
       insertSessionBefore: r => ok(r, { workspace: { workspaceId: 'w1' as never, path: '/t', title: 't', sessionIds: [], createdAt: '0', updatedAt: '0' } }),
     },
     commands: {
@@ -80,13 +97,15 @@ describe('unary round trip', () => {
     expect(response.result).toEqual({ ok: true, value: { items: [{ sessionId: 's1', updatedAt: 7, running: false, blank: false }] } })
   })
 
-  it('routes workspace rename and insertSessionBefore through the wire', async () => {
+  it('routes workspace rename, delete, and insertSessionBefore through the wire', async () => {
     const api = scriptedApi()
     const c = client(api)
     const renamed = await c.workspace.rename({ workspaceId: 'w1' as never, title: 'next' })
     expect(renamed.result.ok).toBe(true)
     const blankTitle = await c.workspace.rename({ workspaceId: 'w1' as never, title: '   ' })
     expect(blankTitle.result).toMatchObject({ ok: false, error: { code: 'bad-request' } })
+    const deleted = await c.workspace.delete({ workspaceId: 'w1' as never })
+    expect(deleted.result).toEqual({ ok: true, value: { deleted: true } })
     const anchored = await c.workspace.insertSessionBefore({ workspaceId: 'w1' as never, sessionId: sid('s1'), beforeSessionId: sid('s2') })
     expect(anchored.result.ok).toBe(true)
     const appended = await c.workspace.insertSessionBefore({ workspaceId: 'w1' as never, sessionId: sid('s1') })

packages/host/apiproxy/tests/fetch-carrier.spec.ts

@@ -37,11 +37,47 @@ function fakeApi(overrides: Partial<{
         return { rpcId: request.rpcId, result: { ok: true, value: { sessionId: 's-new' as never } } }
       },
       async history(request) {
+        if (request.payload.sessionId === ('with-todos' as never)) {
+          return {
+            rpcId: request.rpcId,
+            result: { ok: true, value: { events: [], hasMore: false, todos: [{ content: 'current', status: 'in_progress' as const }] } },
+          }
+        }
         return {
           rpcId: request.rpcId,
           result: { ok: false, error: { code: 'session-not-found', message: 'nope', details: { sessionId: request.payload.sessionId } } },
         }
       },
+      async models(request) {
+        return {
+          rpcId: request.rpcId,
+          result: {
+            ok: true,
+            value: {
+              current: { provider: 'deepseek', model: 'deepseek-v4-flash' },
+              groups: [],
+              failures: [],
+            },
+          },
+        }
+      },
+      async selectModel(request) {
+        return {
+          rpcId: request.rpcId,
+          result: {
+            ok: true,
+            value: {
+              selected: {
+                provider: request.payload.provider,
+                model: request.payload.model,
+                ...request.payload.reasoningEffort === undefined
+                  ? {}
+                  : { reasoningEffort: request.payload.reasoningEffort },
+              },
+            },
+          },
+        }
+      },
       async prompt(request) {
         return { rpcId: request.rpcId, result: { ok: true, value: { accepted: true as const } } }
       },
@@ -65,6 +101,9 @@ function fakeApi(overrides: Partial<{
           },
         }
       },
+      async pickDirectory(request) {
+        return { rpcId: request.rpcId, result: { ok: true, value: { path: null } } }
+      },
     },
     workspace: {
       async list(request) {
@@ -82,6 +121,9 @@ function fakeApi(overrides: Partial<{
           result: { ok: true, value: { workspace: { workspaceId: 'w1' as never, path: '/w', title: 'w', sessionIds: [], createdAt: 't', updatedAt: 't' } } },
         }
       },
+      async delete(request) {
+        return { rpcId: request.rpcId, result: { ok: true, value: { deleted: true as const } } }
+      },
       async insertSessionBefore(request) {
         return {
           rpcId: request.rpcId,
@@ -123,8 +165,8 @@ function fakeApi(overrides: Partial<{
   }
 }
 
-function client(api: ApiProxy = fakeApi()): InProcessApiClient {
-  return new InProcessApiClient(toFetchHandler(api))
+function client(api: ApiProxy = fakeApi(), timeoutMs?: number): InProcessApiClient {
+  return new InProcessApiClient(toFetchHandler(api), timeoutMs)
 }
 
 async function collect<F>(stream: AsyncIterable<RpcRequest<F>>): Promise<RpcRequest<F>[]> {
@@ -140,6 +182,12 @@ describe('unary round trip (handler ⇄ client, no network)', () => {
     expect(response.rpcId).toMatch(/[0-9a-f-]{36}/)
   })
 
+  it('carries the tail-page todos projection through the wire schema (Zod must not strip it)', async () => {
+    const response = await client().sessions.history({ sessionId: 'with-todos' as never })
+    expect(response.result.ok).toBe(true)
+    if (response.result.ok) expect(response.result.value.todos).toEqual([{ content: 'current', status: 'in_progress' }])
+  })
+
   it('carries a business error as 200 + error result', async () => {
     const response = await client().sessions.history({ sessionId: 'missing' as never })
     expect(response.result.ok).toBe(false)
@@ -149,6 +197,23 @@ describe('unary round trip (handler ⇄ client, no network)', () => {
   it('covers create/prompt/cancel/describe passthrough', async () => {
     const c = client()
     expect((await c.sessions.create({})).result.ok).toBe(true)
+    expect((await c.sessions.models({ sessionId: 's' as never })).result.ok).toBe(true)
+    const selected = await c.sessions.selectModel({
+      sessionId: 's' as never,
+      provider: 'deepseek',
+      model: 'deepseek-v4-flash',
+      reasoningEffort: 'max',
+    })
+    expect(selected.result).toMatchObject({
+      ok: true,
+      value: {
+        selected: {
+          provider: 'deepseek',
+          model: 'deepseek-v4-flash',
+          reasoningEffort: 'max',
+        },
+      },
+    })
     expect((await c.sessions.prompt({ sessionId: 's' as never, mode: 'queue', content: [{ type: 'text', text: 'x' }] })).result.ok).toBe(true)
     expect((await c.sessions.attachment({ sessionId: 's' as never, attachmentId: 'a' as never })).result.ok).toBe(true)
     expect((await c.sessions.cancel({ sessionId: 's' as never })).result.ok).toBe(true)
@@ -189,6 +254,16 @@ describe('unary round trip (handler ⇄ client, no network)', () => {
     })
   })
 
+  it('round-trips the native picker without the default unary timeout', async () => {
+    const api = fakeApi()
+    api.host.pickDirectory = async (request) => {
+      await new Promise(resolve => setTimeout(resolve, 15))
+      return { rpcId: request.rpcId, result: { ok: true, value: { path: '/tmp/project' } } }
+    }
+    const response = await client(api, 1).host.pickDirectory({})
+    expect(response.result).toEqual({ ok: true, value: { path: '/tmp/project' } })
+  })
+
   it('round-trips command.list / command.execute / skill.list through the wire form', async () => {
     const c = client()
     const list = await c.commands.list({ sessionId: 's' as never })
@@ -214,6 +289,30 @@ describe('unary round trip (handler ⇄ client, no network)', () => {
     expect(parsed.rpcId).toBe('r-sig')
     expect(parsed.result.error?.code).toBe('cancelled')
   })
+
+  it('propagates the carrier Request signal into host.pickDirectory', async () => {
+    const api = fakeApi()
+    api.host.pickDirectory = async (request, signal) => {
+      if (!signal.aborted) {
+        await new Promise<void>((resolve) => {
+          signal.addEventListener('abort', () => { resolve() }, { once: true })
+        })
+      }
+      return {
+        rpcId: request.rpcId,
+        result: { ok: false, error: { code: 'cancelled', message: 'aborted', details: {} } },
+      }
+    }
+    const handler = toFetchHandler(api)
+    const controller = new AbortController()
+    const body = JSON.stringify({ type: 'client-request', rpcId: 'r-picker', method: 'host.pickDirectory', payload: {} })
+    const pending = handler.fetch(new Request('http://x/api/host.pickDirectory', {
+      method: 'POST', body, signal: controller.signal,
+    }))
+    controller.abort()
+    const parsed = await (await pending).json() as { result: { error?: { code: string } } }
+    expect(parsed.result.error?.code).toBe('cancelled')
+  })
 })
 
 describe('handler carrier-layer statuses', () => {

packages/host/apiproxy/tests/native-directory-picker.spec.ts

@@ -0,0 +1,139 @@
+type ExecFileCallback = (
+  error: (Error & { code?: string | number }) | null,
+  stdout: string,
+  stderr: string,
+) => void
+type ExecFileMock = (
+  command: string,
+  args: readonly string[],
+  options: { encoding: string; signal: AbortSignal; windowsHide: boolean },
+  callback: ExecFileCallback,
+) => void
+
+const { execFileMock } = vi.hoisted(() => ({ execFileMock: vi.fn<ExecFileMock>() }))
+
+vi.mock('node:child_process', () => ({ execFile: execFileMock }))
+
+import { describe, expect, it, vi } from 'vitest'
+import { pickNativeDirectory, type DirectoryPickerRunner } from '../src/native-directory-picker.ts'
+
+function failure(code: string | number, stderr = ''): Error {
+  return Object.assign(new Error(`command failed: ${String(code)}`), { code, stderr })
+}
+
+const signal = () => new AbortController().signal
+
+describe('native directory picker', () => {
+  it('uses the macOS folder chooser and maps user cancellation to null', async () => {
+    const run = vi.fn<DirectoryPickerRunner>(async () => ({ stdout: '/Users/test/project/\n', stderr: '' }))
+    await expect(pickNativeDirectory(signal(), { platform: 'darwin', run })).resolves.toBe('/Users/test/project/')
+    expect(run).toHaveBeenCalledWith('osascript', expect.arrayContaining(['POSIX path of selectedFolder']), expect.any(AbortSignal))
+
+    run.mockRejectedValueOnce(failure(1, 'execution error: User canceled. (-128)'))
+    await expect(pickNativeDirectory(signal(), { platform: 'darwin', run })).resolves.toBeNull()
+
+    run.mockRejectedValueOnce(failure(2, 'permission denied'))
+    await expect(pickNativeDirectory(signal(), { platform: 'darwin', run })).rejects.toThrow('command failed')
+  })
+
+  it.each([
+    ['a primitive error', 'failed'],
+    ['an invalid code type', { code: true }],
+    ['a missing stderr property', { code: 1 }],
+    ['a non-string stderr property', { code: 1, stderr: 42 }],
+  ])('does not mistake %s for macOS cancellation', async (_label, reason) => {
+    const run = vi.fn<DirectoryPickerRunner>(async () => { throw reason })
+    await expect(pickNativeDirectory(signal(), { platform: 'darwin', run })).rejects.toBe(reason)
+  })
+
+  it('uses the Windows STA folder dialog and maps empty output to cancellation', async () => {
+    const run = vi.fn<DirectoryPickerRunner>(async () => ({ stdout: 'C:\\work\\project\r\n', stderr: '' }))
+    await expect(pickNativeDirectory(signal(), { platform: 'win32', run })).resolves.toBe('C:\\work\\project')
+    expect(run).toHaveBeenCalledWith(
+      'powershell.exe',
+      expect.arrayContaining(['-NoProfile', '-STA', '-Command']),
+      expect.any(AbortSignal),
+    )
+    expect(run.mock.calls[0]?.[1].at(-1)).toContain("$ErrorActionPreference = 'Stop'")
+    run.mockResolvedValueOnce({ stdout: '', stderr: '' })
+    await expect(pickNativeDirectory(signal(), { platform: 'win32', run })).resolves.toBeNull()
+    run.mockRejectedValueOnce(failure(1, 'Add-Type failed'))
+    await expect(pickNativeDirectory(signal(), { platform: 'win32', run })).rejects.toThrow('command failed')
+  })
+
+  it('runs the default command adapter without a shell and preserves command failures', async () => {
+    execFileMock.mockImplementationOnce((_command, _args, _options, callback) => {
+      callback(null, 'C:\\work\\default\r\n', '')
+    })
+    await expect(pickNativeDirectory(signal(), { platform: 'win32' })).resolves.toBe('C:\\work\\default')
+    const [command, args, options] = execFileMock.mock.calls[0]!
+    expect(command).toBe('powershell.exe')
+    expect(args).toEqual(expect.arrayContaining(['-NoProfile', '-STA', '-Command']))
+    expect(options.encoding).toBe('utf8')
+    expect(options.windowsHide).toBe(true)
+    expect(options.signal).toBeInstanceOf(AbortSignal)
+
+    const commandError = Object.assign(new Error('powershell failed'), { code: 7 })
+    execFileMock.mockImplementationOnce((_command, _args, _options, callback) => {
+      callback(commandError, 'partial output', 'failure details')
+    })
+    await expect(pickNativeDirectory(signal(), { platform: 'win32' })).rejects.toMatchObject({
+      message: 'powershell failed', cause: commandError, code: 7,
+      stdout: 'partial output', stderr: 'failure details',
+    })
+  })
+
+  it('uses the current process platform when no platform override is supplied', async () => {
+    const run = vi.fn<DirectoryPickerRunner>(async () => ({ stdout: '/default/platform\n', stderr: '' }))
+    await expect(pickNativeDirectory(signal(), { run })).resolves.toBe('/default/platform')
+  })
+
+  it('uses Zenity on Linux and falls back to KDialog only when Zenity is missing', async () => {
+    const run = vi.fn<DirectoryPickerRunner>()
+      .mockRejectedValueOnce(failure('ENOENT'))
+      .mockResolvedValueOnce({ stdout: '/home/test/project\n', stderr: '' })
+    await expect(pickNativeDirectory(signal(), { platform: 'linux', run })).resolves.toBe('/home/test/project')
+    expect(run.mock.calls.map(call => call[0])).toEqual(['zenity', 'kdialog'])
+
+    const zenity = vi.fn<DirectoryPickerRunner>(async () => ({ stdout: '/home/test/direct\n', stderr: '' }))
+    await expect(pickNativeDirectory(signal(), { platform: 'linux', run: zenity }))
+      .resolves.toBe('/home/test/direct')
+    expect(zenity).toHaveBeenCalledOnce()
+  })
+
+  it('maps Linux cancellation to null and reports a missing desktop picker', async () => {
+    const cancelled = vi.fn<DirectoryPickerRunner>(async () => { throw failure(1) })
+    await expect(pickNativeDirectory(signal(), { platform: 'linux', run: cancelled })).resolves.toBeNull()
+
+    const missing = vi.fn<DirectoryPickerRunner>(async () => { throw failure('ENOENT') })
+    await expect(pickNativeDirectory(signal(), { platform: 'linux', run: missing }))
+      .rejects.toThrow('install zenity or kdialog')
+
+    const kdialogCancelled = vi.fn<DirectoryPickerRunner>()
+      .mockRejectedValueOnce(failure('ENOENT'))
+      .mockRejectedValueOnce(failure(1))
+    await expect(pickNativeDirectory(signal(), { platform: 'linux', run: kdialogCancelled }))
+      .resolves.toBeNull()
+
+    const zenityFailed = vi.fn<DirectoryPickerRunner>(async () => { throw failure(2) })
+    await expect(pickNativeDirectory(signal(), { platform: 'linux', run: zenityFailed }))
+      .rejects.toThrow('command failed')
+
+    const kdialogFailed = vi.fn<DirectoryPickerRunner>()
+      .mockRejectedValueOnce(failure('ENOENT'))
+      .mockRejectedValueOnce(failure(2))
+    await expect(pickNativeDirectory(signal(), { platform: 'linux', run: kdialogFailed }))
+      .rejects.toThrow('command failed')
+  })
+
+  it('does not convert caller aborts into user cancellation', async () => {
+    const abort = new AbortController()
+    abort.abort(new Error('closed'))
+    const run = vi.fn<DirectoryPickerRunner>(async () => { throw failure('ABORT_ERR') })
+    await expect(pickNativeDirectory(abort.signal, { platform: 'linux', run })).rejects.toThrow('command failed')
+  })
+
+  it('reports unsupported platforms', async () => {
+    await expect(pickNativeDirectory(signal(), { platform: 'aix' })).rejects.toThrow('unsupported on aix')
+  })
+})

packages/host/apiproxy/tests/rpc-schemas.spec.ts

@@ -9,12 +9,14 @@ import {
   promptContentPartSchema, sessionAttachmentRequestSchema, sessionAttachmentValueSchema,
   sessionCancelRequestSchema, sessionCancelValueSchema, sessionCreateRequestSchema,
   sessionCreateValueSchema, sessionEventSchema, sessionHistoryRequestSchema, sessionHistoryValueSchema,
-  sessionIdSchema, sessionListRequestSchema, sessionListValueSchema, sessionPromptRequestSchema,
-  sessionPromptValueSchema, sessionSummarySchema,
+  sessionIdSchema, sessionListRequestSchema, sessionListValueSchema, sessionModelsRequestSchema,
+  sessionModelsValueSchema, sessionPromptRequestSchema, sessionPromptValueSchema,
+  sessionSelectModelRequestSchema, sessionSelectModelValueSchema, sessionSummarySchema,
 } from '../src/api/sessions.schema.ts'
 import { hostDescribeRequestSchema, hostDescribeValueSchema } from '../src/api/host.schema.ts'
 import {
   workspaceCreateRequestSchema, workspaceCreateValueSchema, workspaceIdSchema,
+  workspaceDeleteRequestSchema, workspaceDeleteValueSchema,
   workspaceInsertSessionBeforeRequestSchema, workspaceInsertSessionBeforeValueSchema,
   workspaceListRequestSchema, workspaceListValueSchema,
   workspaceRenameRequestSchema, workspaceRenameValueSchema, workspaceViewSchema,
@@ -56,6 +58,11 @@ describe('rpcErrorSchema', () => {
     expect(rpcErrorSchema.parse({ code: 'workspace-invalid-path', message: 'm', details: { path: '/x' } }).code).toBe('workspace-invalid-path')
     expect(rpcErrorSchema.parse({ code: 'workspace-name-conflict', message: 'm', details: { name: 'x' } }).code).toBe('workspace-name-conflict')
     expect(rpcErrorSchema.parse({ code: 'workspace-move-invalid', message: 'm', details: { workspaceId: 'w', sessionId: 's' } }).code).toBe('workspace-move-invalid')
+    expect(rpcErrorSchema.parse({
+      code: 'model-unavailable',
+      message: 'm',
+      details: { provider: 'p', model: 'm' },
+    }).code).toBe('model-unavailable')
     expect(rpcErrorSchema.parse({ code: 'agent-busy', message: 'm', details: { reason: 'r' } }).code).toBe('agent-busy')
     expect(rpcErrorSchema.parse({ code: 'attachment-error', message: 'm', details: { reason: 'r' } }).code).toBe('attachment-error')
     expect(rpcErrorSchema.parse({ code: 'internal', message: 'm', details: {} }).code).toBe('internal')
@@ -130,7 +137,62 @@ describe('sessions domain schemas', () => {
     expect(sessionCreateValueSchema.parse({ sessionId: 's1' }).sessionId).toBe('s1')
     expect(sessionHistoryRequestSchema.parse({ sessionId: 's1', beforeSeq: 3, maxMessages: 5 }).beforeSeq).toBe(3)
     expect(() => sessionHistoryRequestSchema.parse({ sessionId: 's1', maxMessages: 0 })).toThrow()
-    expect(sessionHistoryValueSchema.parse({ events: [], hasMore: false }).hasMore).toBe(false)
+    expect(sessionHistoryValueSchema.parse({
+      events: [],
+      hasMore: false,
+      modelTarget: { provider: 'deepseek', model: 'deepseek-v4-flash' },
+    }).hasMore).toBe(false)
+    expect(sessionModelsRequestSchema.parse({ sessionId: 's1' }).sessionId).toBe('s1')
+    expect(sessionModelsValueSchema.parse({
+      current: { provider: 'deepseek', model: 'deepseek-v4-flash', reasoningEffort: 'max' },
+      groups: [{
+        id: 'deepseek',
+        name: 'DeepSeek',
+        models: [{
+          id: 'deepseek-v4-flash',
+          name: 'DeepSeek V4 Flash',
+          description: 'fast',
+          unlisted: true,
+          reasoning: {
+            efforts: [
+              { id: 'off', name: 'Off' },
+              { id: 'max', name: 'Max', description: 'Largest budget' },
+            ],
+            defaultEffort: 'off',
+          },
+        }],
+      }],
+      failures: [{ id: 'broken', name: 'Broken', message: 'offline' }],
+    }).groups[0]?.models[0]?.id).toBe('deepseek-v4-flash')
+    expect(sessionSelectModelRequestSchema.parse({
+      sessionId: 's1',
+      provider: 'deepseek',
+      model: 'deepseek-v4-pro',
+      reasoningEffort: 'max',
+    }).reasoningEffort).toBe('max')
+    expect(sessionSelectModelValueSchema.parse({
+      selected: { provider: 'deepseek', model: 'deepseek-v4-pro', reasoningEffort: 'max' },
+    }).selected.reasoningEffort).toBe('max')
+    expect(() => sessionSelectModelRequestSchema.parse({
+      sessionId: 's1',
+      provider: '',
+      model: 'm',
+    })).toThrow()
+    expect(() => sessionSelectModelRequestSchema.parse({
+      sessionId: 's1',
+      provider: 'deepseek',
+      model: 'm',
+      reasoningEffort: '',
+    })).toThrow()
+    expect(() => sessionModelsValueSchema.parse({
+      current: { provider: 'deepseek', model: 'm' },
+      groups: [{
+        id: 'deepseek',
+        name: 'DeepSeek',
+        models: [{ id: 'm', name: 'M', reasoning: { efforts: [] } }],
+      }],
+      failures: [],
+    })).toThrow()
     const prompt = sessionPromptRequestSchema.parse({ sessionId: 's1', mode: 'queue', content: [{ type: 'text', text: 'hi' }] })
     expect(prompt.mode).toBe('queue')
     expect(() => sessionPromptRequestSchema.parse({ sessionId: 's1', mode: 'inject', content: [] })).toThrow()
@@ -213,6 +275,13 @@ describe('workspace domain schemas', () => {
     expect(workspaceRenameValueSchema.parse({ workspace: view }).workspace.workspaceId).toBe('w1')
   })
 
+  it('validates workspace deletion payload and receipt', () => {
+    expect(workspaceDeleteRequestSchema.parse({ workspaceId: 'w1' }).workspaceId).toBe('w1')
+    expect(() => workspaceDeleteRequestSchema.parse({})).toThrow()
+    expect(workspaceDeleteValueSchema.parse({ deleted: true })).toEqual({ deleted: true })
+    expect(() => workspaceDeleteValueSchema.parse({ deleted: false })).toThrow()
+  })
+
   it('insertSessionBefore accepts an anchored and an anchorless move', () => {
     expect(workspaceInsertSessionBeforeRequestSchema.parse({ workspaceId: 'w1', sessionId: 's1', beforeSessionId: 's2' }).beforeSessionId).toBe('s2')
     expect(workspaceInsertSessionBeforeRequestSchema.parse({ workspaceId: 'w1', sessionId: 's1' }).beforeSessionId).toBeUndefined()
@@ -297,8 +366,8 @@ describe('events frame schemas', () => {
   })
 
   it('rejects a queued frame missing its members', () => {
-    expect(() => muxFrameSchema.parse({ type: 'session/queued', sessionId: 's', content: [{ type: 'text' }], source: { kind: 'user' } })).toThrow()
-    expect(() => muxFrameSchema.parse({ type: 'session/queued', sessionId: 's', content: 'x', source: { kind: 'user' }, steering: false })).toThrow()
+    expect(() => muxFrameSchema.parse({ type: 'session/queued', sessionId: 's', content: 'x', source: { kind: 'user' } })).toThrow()
+    expect(() => muxFrameSchema.parse({ type: 'session/queued', sessionId: 's', content: [], source: { kind: 'user' } })).toThrow()
     expect(() => muxFrameSchema.parse({ type: 'session/queued', sessionId: 's', content: [], source: {}, steering: false })).toThrow()
   })
 
@@ -309,6 +378,11 @@ describe('events frame schemas', () => {
       { type: 'host/session-removed', sessionId: 's' },
       { type: 'host/session-status', sessionId: 's', running: true },
       { type: 'host/agent-error', sessionId: 's', message: 'boom' },
+      { type: 'host/workspace-changed', workspace: {
+        workspaceId: 'w', path: '/w', title: 'w', sessionIds: [],
+        createdAt: '0', updatedAt: '0',
+      } },
+      { type: 'host/workspace-removed', workspaceId: 'w' },
       { type: 'host/commands-changed' },
       { type: 'stream/error', error: { code: 'internal', message: 'm', details: {} } },
     ]