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
2026-07-28 11:41:40 +08:00
parent a1835c3228 2a46685414
commit 004f598917
1499 changed files with 48621 additions and 21956 deletions
--- a/packages/host/apiproxy/src/api-proxy.ts
+++ b/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({
--- a/packages/host/apiproxy/src/api/events.schema.ts
+++ b/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>
--- a/packages/host/apiproxy/src/api/events.ts
+++ b/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
--- a/packages/host/apiproxy/src/api/host.schema.ts
+++ b/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'>>>
--- a/packages/host/apiproxy/src/api/host.ts
+++ b/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 }>>
 }
--- a/packages/host/apiproxy/src/api/index.ts
+++ b/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'
--- a/packages/host/apiproxy/src/api/rpc-map.ts
+++ b/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']
--- a/packages/host/apiproxy/src/api/rpc.schema.ts
+++ b/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() }) }),
--- a/packages/host/apiproxy/src/api/rpc.ts
+++ b/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 }
--- a/packages/host/apiproxy/src/api/sessions.schema.ts
+++ b/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() })

--- a/packages/host/apiproxy/src/api/sessions.ts
+++ b/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[] }>):
--- a/packages/host/apiproxy/src/api/workspace.schema.ts
+++ b/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,
--- a/packages/host/apiproxy/src/api/workspace.ts
+++ b/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
--- a/packages/host/apiproxy/src/fetch/client.ts
+++ b/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),
  }

--- a/packages/host/apiproxy/src/fetch/handler.ts
+++ b/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) },
--- a/packages/host/apiproxy/src/native-directory-picker.ts
+++ b/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}`)
+}