feat(web): add subagent conversation transport

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

@@ -132,6 +132,19 @@ export class FakeApiClient implements IApiClient {
     cancel: (payload: unknown) => this.record('session.cancel', payload, this.onCancel(payload)),
   }
 
+  onSubagentList: (payload: unknown) => Promise<RpcResponse<{ entries: never[]; parentAvailable: boolean }>>
+    = () => Promise.resolve(ok({ entries: [], parentAvailable: true }))
+  onSubagentHistory: (payload: unknown) => Promise<RpcResponse<{ events: never[]; hasMore: boolean }>>
+    = () => Promise.resolve(ok({ events: [], hasMore: false }))
+  onSubagentPrompt: (payload: unknown) => Promise<RpcResponse<{ messageId: never }>>
+    = () => Promise.resolve(ok({ messageId: 'fake-message' as never }))
+
+  readonly subagents: IApiClient['subagents'] = {
+    list: (payload: unknown) => this.record('subagent.list', payload, this.onSubagentList(payload)),
+    history: (payload: unknown) => this.record('subagent.history', payload, this.onSubagentHistory(payload)),
+    prompt: (payload: unknown) => this.record('subagent.prompt', payload, this.onSubagentPrompt(payload)),
+  }
+
   readonly host: IApiClient['host'] = {
     describe: (payload: unknown) => this.record('host.describe', payload, this.onDescribe(payload)),
     pickDirectory: (payload: unknown) => this.record('host.pickDirectory', payload, this.onPickDirectory(payload)),

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

@@ -272,6 +272,87 @@ describe('host frame routing', () => {
   })
 })
 
+describe('subagent catalogs', () => {
+  it('selects only a catalog-discovered child and keeps its durable address across status frames', async () => {
+    const api = new FakeApiClient()
+    api.onList = () => Promise.resolve(ok({ items: [
+      summary(S1),
+    ] as never[] }))
+    api.onSubagentList = () => Promise.resolve(ok({
+      entries: [{ kind: 'child', id: S2, label: 'worker', activity: 'running' }] as never[],
+      parentAvailable: true,
+    }))
+    const manager = new SessionManager(api)
+    await manager.refreshList()
+    await manager.refreshSubagents(S1)
+    manager.selectSubagent({ parentSessionId: S1, childSessionId: S2 })
+
+    expect(manager.getListSnapshot().currentAddress).toEqual({
+      parentSessionId: S1, childSessionId: S2,
+    })
+    expect(manager.get(S2).getSnapshot().subagent).toEqual({
+      address: { parentSessionId: S1, childSessionId: S2 },
+      parentAvailable: true,
+    })
+    const listCalls = api.callsOf('subagent.list').length
+    manager.handleHostEnvelope({
+      rpcId: 'child-complete' as never,
+      payload: { type: 'host/session-status', sessionId: S2, running: false },
+    })
+    expect(manager.getListSnapshot().subagentsByParent[S1]?.entries[0]).toMatchObject({
+      kind: 'child', id: S2, activity: 'inactive',
+    })
+    expect(api.callsOf('subagent.list')).toHaveLength(listCalls)
+
+    manager.handleHostEnvelope({
+      rpcId: 'child-detached' as never,
+      payload: { type: 'host/session-removed', sessionId: S2 },
+    })
+    expect(manager.get(S2).getSnapshot()).toMatchObject({
+      removed: false,
+      subagent: { address: { parentSessionId: S1, childSessionId: S2 } },
+    })
+  })
+
+  it('refetches debounced membership only while the parent catalog is open', async () => {
+    vi.useFakeTimers()
+    try {
+      const api = new FakeApiClient()
+      const manager = new SessionManager(api)
+      await manager.refreshSubagents(S1)
+      manager.setSubagentCatalogOpen(S1, true)
+      await Promise.resolve()
+      const baseline = api.callsOf('subagent.list').length
+      manager.handleHostEnvelope({
+        rpcId: 'child-added' as never,
+        payload: {
+          type: 'host/session-added', sessionId: S2, parentSessionId: S1, blank: false,
+        },
+      })
+      manager.handleHostEnvelope({
+        rpcId: 'child-added-again' as never,
+        payload: {
+          type: 'host/session-added', sessionId: 'fk-m3' as SessionId, parentSessionId: S1, blank: false,
+        },
+      })
+      await vi.advanceTimersByTimeAsync(50)
+      expect(api.callsOf('subagent.list')).toHaveLength(baseline + 1)
+
+      manager.setSubagentCatalogOpen(S1, false)
+      manager.handleHostEnvelope({
+        rpcId: 'child-added-closed' as never,
+        payload: {
+          type: 'host/session-added', sessionId: 'fk-m4' as SessionId, parentSessionId: S1, blank: false,
+        },
+      })
+      await vi.advanceTimersByTimeAsync(50)
+      expect(api.callsOf('subagent.list')).toHaveLength(baseline + 1)
+    } finally {
+      vi.useRealTimers()
+    }
+  })
+})
+
 describe('remaining branches', () => {
   it('refreshList folds a transport throw into the error state', async () => {
     const api = new FakeApiClient()
@@ -435,6 +516,19 @@ describe('connected generation', () => {
       expect(api.callsOf('session.history').length).toBe(historyCallsBefore + 1)
     })
   })
+
+  it('reloads the durable parent address for a restored child selection', async () => {
+    const api = new FakeApiClient()
+    const address = { parentSessionId: S1, childSessionId: S2 }
+    const manager = new SessionManager(api, S2, address)
+
+    manager.handleConnected()
+
+    await vi.waitFor(() => {
+      expect(api.callsOf('subagent.list')).toContainEqual({ parentSessionId: S1 })
+    })
+    expect(manager.getListSnapshot().currentAddress).toEqual(address)
+  })
 })
 
 describe('waiting-approval list bit', () => {

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

@@ -18,6 +18,7 @@ const at = (seq: number, e: Record<string, unknown>): SessionEvent =>
   ({ seq, time: 1_700_000_000_000 + seq, ...e }) as unknown as SessionEvent
 
 const SID = 'fk-s1' as SessionId
+const PARENT = 'fk-parent' as SessionId
 
 function makeSession(api = new FakeApiClient()): { api: FakeApiClient; session: Session } {
   return { api, session: new Session(SID, api) }
@@ -580,6 +581,33 @@ describe('paging', () => {
 })
 
 describe('prompt and cancel errors', () => {
+  it('routes an addressed child through non-activating history and continuation prompt only', async () => {
+    const api = new FakeApiClient()
+    const session = new Session(SID, api, {
+      address: { parentSessionId: PARENT, childSessionId: SID },
+      parentAvailable: true,
+    })
+    await session.open()
+    const prompted = await session.prompt([{ type: 'text', text: '继续' }], 'queue')
+    const cancelled = await session.cancel()
+
+    expect(prompted).toEqual({ ok: true, value: { accepted: true } })
+    expect(cancelled).toMatchObject({ ok: false, error: { code: 'subagent-not-delivered' } })
+    expect(api.callsOf('subagent.history')).toEqual([
+      { parentSessionId: PARENT, childSessionId: SID, maxMessages: 50 },
+    ])
+    expect(api.callsOf('subagent.prompt')).toEqual([
+      { parentSessionId: PARENT, childSessionId: SID, content: [{ type: 'text', text: '继续' }] },
+    ])
+    expect(api.callsOf('session.history')).toEqual([])
+    expect(api.callsOf('session.prompt')).toEqual([])
+    expect(api.callsOf('session.cancel')).toEqual([])
+    expect(session.getSnapshot().subagent).toEqual({
+      address: { parentSessionId: PARENT, childSessionId: SID },
+      parentAvailable: true,
+    })
+  })
+
   it('sends content through session.prompt; composerPhase steps blank → engaging synchronously at send entry', async () => {
     const { api, session } = makeSession()
     // The blank → engaging edge fires before the RPC settles: the first-send