feat(web): make produced-file overflow discoverable

packages/client/connection/README.i18n.yaml

@@ -2,5 +2,5 @@
 # side as of the last confirmed-consistent state. Both languages carry equal authority;
 # after editing either side, bring the other along and re-record with:
 #   pnpm run verify-translation-pairing --write packages/client/connection/README.md
-README.md: 85ff46052ba2f032ee6a95b16c396d45e766d3ba
-README.zh.md: 89cbb19a984d88e09b7af0890f57ecd15d46d3a5
+README.md: a82bb55ab65df2732ad16248d2cc9aa15b60e94d
+README.zh.md: d4c19db8e74e3562ec55b5ef60675aef79b82008

packages/client/connection/README.md

@@ -2,7 +2,7 @@
 
 English | [中文](README.zh.md)
 
-Wire consumer layer: the client plugin's apply mounts `ctx.connection` (shared api client + current-page loopback state + single-consumer stream-loop starter); the export face carries the wire contract types, the `AbstractApiClient` abstraction, and the loop's sink/config types. The browser carrier uses HTTP POST for unary and respond operations and opens one downlink-only WebSocket each for `events.mux` and `events.host`; the in-process carrier satisfies the same two-stream abstraction. The Host half owns the single `/api` route and its Fetch bridge; a registered TypeRT interceptor claims its Remote endpoints before the API Proxy fallback. Loopback hostname classification stays package-internal: the `/api` Host fence and WebSocket upgrades use it directly, while other client plugins consume the derived `ctx.connection.isLoopback` state. The node half's `/api` route pins the privileged method set (`host.pickDirectory`, `host.openPath`, and the whole configuration plane — `settings.describe`/`openDocument`/`update`/`replace`/`mutate` and `credentials.describe`/`set`/`unset`; reads and native actions included, since describing returns the exposed configuration, opening acts on the Host desktop, and probing an arbitrary reference reports where a credential comes from — and the agent-preset authoring plane, `agentPreset.read`/`copy`/`openDocument`/`remove`, since a composition names the plugins a session runs, so reading one is reconnaissance, and copy/remove/openDocument manage the roster and drive the host desktop (authoring is copy-only, so none of them accepts composition text or a path); `agentPreset.list` and `agentPreset.select` stay out — the roster carries only ids and trust, and choosing a preset grants nothing `session.create`'s own `agentPreset` did not, over a default that already carries bash) to loopback by passing the trust fence with an empty trust list — a declared `trustedHosts` authority reaches every other method, while these stay loopback-local until a real authentication layer exists. The platform carriers and ConnectionController loop are package-internal; apply selects and drives them. The downlink boundary is documented in the [WebSocket downlink carrier Agent Note](../../../.agents/notes/implemented/architecture/2026-08-04-websocket-downlink-carrier.md).
+Wire consumer layer: the client plugin's apply mounts `ctx.connection` (shared api client + current-page loopback state + observable generation-scoped `hostDescription` + single-consumer stream-loop starter); the export face carries the wire contract types, the `AbstractApiClient` abstraction, and the loop's sink/config types. Each successful readiness handshake publishes the exact `host.describe` value before `onConnected`; generation loss and explicit stop clear it, so native-capability consumers never retain a disconnected answer. The browser carrier uses HTTP POST for unary and respond operations and opens one downlink-only WebSocket each for `events.mux` and `events.host`; the in-process carrier satisfies the same two-stream abstraction. The Host half owns the single `/api` route and its Fetch bridge; a registered TypeRT interceptor claims its Remote endpoints before the API Proxy fallback. Loopback hostname classification stays package-internal: the `/api` Host fence and WebSocket upgrades use it directly, while other client plugins consume the derived `ctx.connection.isLoopback` state. The node half's `/api` route pins the privileged method set (`host.pickDirectory`, `host.openPath`, and the whole configuration plane — `settings.describe`/`openDocument`/`update`/`replace`/`mutate` and `credentials.describe`/`set`/`unset`; reads and native actions included, since describing returns the exposed configuration, opening acts on the Host desktop, and probing an arbitrary reference reports where a credential comes from — and the agent-preset authoring plane, `agentPreset.read`/`copy`/`openDocument`/`remove`, since a composition names the plugins a session runs, so reading one is reconnaissance, and copy/remove/openDocument manage the roster and drive the host desktop (authoring is copy-only, so none of them accepts composition text or a path); `agentPreset.list` and `agentPreset.select` stay out — the roster carries only ids and trust, and choosing a preset grants nothing `session.create`'s own `agentPreset` did not, over a default that already carries bash) to loopback by passing the trust fence with an empty trust list — a declared `trustedHosts` authority reaches every other method, while these stay loopback-local until a real authentication layer exists. The platform carriers and ConnectionController loop are package-internal; apply selects and drives them. The downlink boundary is documented in the [WebSocket downlink carrier Agent Note](../../../.agents/notes/implemented/architecture/2026-08-04-websocket-downlink-carrier.md).
 
 ## /api browser-trust fence
 

packages/client/connection/README.zh.md

@@ -2,7 +2,7 @@
 
 [English](README.md) | 中文
 
-协议消费层：客户端插件的 apply 会挂载 `ctx.connection`（共享 API 客户端 + 当前页面的 loopback 状态 + 单消费方流循环启动器）；导出表层携带协议约定类型、`AbstractApiClient` 抽象，以及循环的 sink／配置类型。浏览器载体以 HTTP POST 发送 unary／respond，并为 `events.mux` 与 `events.host` 各开一条只下行的 WebSocket；进程内载体满足同一双流抽象。Host half 持有唯一 `/api` route 及其 Fetch bridge；已注册的 TypeRT interceptor 会先认领自己的 Remote endpoint，未认领请求再回退 API Proxy。Loopback hostname 判定逻辑留在包内部：`/api` Host fence 与 WebSocket upgrade 会直接使用它，其他客户端插件则消费派生的 `ctx.connection.isLoopback` 状态。node 半侧的 `/api` 路由让特权方法集（`host.pickDirectory`、`host.openPath`，以及整个配置面——`settings.describe`/`openDocument`/`update`/`replace`/`mutate` 与 `credentials.describe`/`set`/`unset`；读取与原生操作也在内，因为 describe 会返回已暴露的配置、打开操作会作用于 Host 桌面，而探测任意引用会报出某条凭据来自何处——以及 agent preset 的创作面 `agentPreset.read`/`copy`/`openDocument`/`remove`，因为组装指明了一个会话所运行的插件，读取它是侦察，而 copy/remove/openDocument 管理名单并驱动宿主桌面（创作只有复制一种写入，因此这些方法都不接收组装文本或路径）；`agentPreset.list` 与 `agentPreset.select` 不在其中——名单只携带 id 与信任级别，而选择一个 preset 并不比 `session.create` 自带的 `agentPreset` 多给任何能力，何况默认 preset 本就带着 bash）以空信任表过信任 fence，从而钉在回环——已声明的 `trustedHosts` 授权可达其余全部方法，而这些方法在真正的认证层出现之前仍只限回环本机。平台载体与 ConnectionController 循环属于包内部；apply 负责选择并驱动它们。下行边界见 [WebSocket 下行载体 Agent Note](../../../.agents/notes/implemented/architecture/2026-08-04-websocket-downlink-carrier.md)。
+协议消费层：客户端插件的 apply 会挂载 `ctx.connection`（共享 API 客户端 + 当前页面的 loopback 状态 + 可观察且按 generation 生效的 `hostDescription` + 单消费方流循环启动器）；导出表层携带协议约定类型、`AbstractApiClient` 抽象，以及循环的 sink／配置类型。每次就绪握手成功后，都会在 `onConnected` 之前发布完整的 `host.describe` 值；generation 失效或显式 stop 会清空它，因此原生能力消费者不会保留已经断线的判断。浏览器载体以 HTTP POST 发送 unary／respond，并为 `events.mux` 与 `events.host` 各开一条只下行的 WebSocket；进程内载体满足同一双流抽象。Host half 持有唯一 `/api` route 及其 Fetch bridge；已注册的 TypeRT interceptor 会先认领自己的 Remote endpoint，未认领请求再回退 API Proxy。Loopback hostname 判定逻辑留在包内部：`/api` Host fence 与 WebSocket upgrade 会直接使用它，其他客户端插件则消费派生的 `ctx.connection.isLoopback` 状态。node 半侧的 `/api` 路由让特权方法集（`host.pickDirectory`、`host.openPath`，以及整个配置面——`settings.describe`/`openDocument`/`update`/`replace`/`mutate` 与 `credentials.describe`/`set`/`unset`；读取与原生操作也在内，因为 describe 会返回已暴露的配置、打开操作会作用于 Host 桌面，而探测任意引用会报出某条凭据来自何处——以及 agent preset 的创作面 `agentPreset.read`/`copy`/`openDocument`/`remove`，因为组装指明了一个会话所运行的插件，读取它是侦察，而 copy/remove/openDocument 管理名单并驱动宿主桌面（创作只有复制一种写入，因此这些方法都不接收组装文本或路径）；`agentPreset.list` 与 `agentPreset.select` 不在其中——名单只携带 id 与信任级别，而选择一个 preset 并不比 `session.create` 自带的 `agentPreset` 多给任何能力，何况默认 preset 本就带着 bash）以空信任表过信任 fence，从而钉在回环——已声明的 `trustedHosts` 授权可达其余全部方法，而这些方法在真正的认证层出现之前仍只限回环本机。平台载体与 ConnectionController 循环属于包内部；apply 负责选择并驱动它们。下行边界见 [WebSocket 下行载体 Agent Note](../../../.agents/notes/implemented/architecture/2026-08-04-websocket-downlink-carrier.md)。
 
 ## /api 浏览器信任栅栏
 

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

@@ -1,4 +1,4 @@
-import type { IApiClient, HostFrame, MuxFrame, RpcRequest } from './api.ts'
+import type { HostDescription, IApiClient, HostFrame, MuxFrame, RpcRequest } from './api.ts'
 
 /** Reconnect/backoff tunables (deployment-varying — no hardcoded tunables; these become the
  *  future `ctx.connection` plugin's Config). All fields optional; defaults below. */
@@ -45,7 +45,7 @@ export interface ConnectionSinks {
   onMuxEnvelope?: (envelope: RpcRequest<MuxFrame>) => void
   onHostEnvelope?: (envelope: RpcRequest<HostFrame>) => void
   /** After each connection generation is established (both streams open + describe succeeded), first connect included. */
-  onConnected?: () => void
+  onConnected?: (description: HostDescription) => void
   /** Coarse state transitions (deduplicated: fires only on change). The initial pre-connect
    *  span reports nothing — the UI treats "no state yet" as connecting, not as an outage. */
   onStateChange?: (state: ConnectionState) => void
@@ -99,6 +99,11 @@ export class ConnectionController {
     return this.running
   }
 
+  /** Re-read both mutable liveness guards after a potentially reentrant sink. */
+  private isGenerationActive(controller: AbortController): boolean {
+    return this.isRunning() && !controller.signal.aborted
+  }
+
   private async loop(): Promise<void> {
     while (this.running) {
       const gen = ++this.generation
@@ -143,7 +148,11 @@ export class ConnectionController {
         if (ac.signal.aborted) throw new Error('generation aborted during readiness handshake')
         this.attempt = 0
         this.emitState('connected')
-        this.callSink(this.sinks.onConnected)
+        // A state sink may synchronously stop this controller. Do not publish
+        // a description for a generation that no longer exists afterward.
+        if (this.isGenerationActive(ac)) {
+          this.callSink(() => { this.sinks.onConnected?.(descriptionResult.value) })
+        }
       } catch {
         // Transport failure: treat as generation failure, fall through to the shared backoff.
         if (!ac.signal.aborted) ac.abort()

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

@@ -2305,7 +2305,9 @@ function createFixtureWorld(options: FixtureOptions): FixtureWorld {
       interrupt: request => Promise.resolve(ok(request, { accepted: true as const })),
     },
     host: {
-      describe: request => ok(request, { version: '0.0.0-fixture', cwd: '/tmp/fixture', attachedSessions }),
+      describe: request => ok(request, {
+        version: '0.0.0-fixture', cwd: '/tmp/fixture', attachedSessions, canOpenPath: true,
+      }),
       // Deterministic native pick: the keyless lanes drive the full
       // pick-then-adopt path without an OS chooser (design-mock content,
       // same tree the browse primitives serve).

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

@@ -4,7 +4,7 @@
  * controller with its sinks.
  */
 import type { Context } from '@deepseek-ai/cordis'
-import type { IApiClient } from './api.ts'
+import type { HostDescription, IApiClient } from './api.ts'
 import { ConnectionController, type ConnectionConfig, type ConnectionSinks, type ConnectionState } from './connection.ts'
 import { FixtureApiClient } from './fixture.ts'
 import { WebApiClient } from './web-api-client.ts'
@@ -41,6 +41,13 @@ export {
 export type { ConnectionConfig, ConnectionSinks, ConnectionState }
 export type { ClientConnectionRpc } from '../rpc.ts'
 
+/** Observable Host description published by each completed connection handshake. */
+export interface HostDescriptionSource {
+  /** Latest connected-generation description; absent before connect and while reconnecting. */
+  getSnapshot(): HostDescription | undefined
+  /** Subscribe to description replacement and connection loss. */
+  subscribe(listener: () => void): () => void
+}
 
 /** Required services (none — this is the wire root). */
 export const inject: string[] = []
@@ -55,6 +62,8 @@ export interface ConnectionHandle {
   readonly api: IApiClient
   /** Whether the current page authority is loopback; non-browser contexts default to true. */
   readonly isLoopback: boolean
+  /** Generation-scoped Host facts, including native path-open capability. */
+  readonly hostDescription: HostDescriptionSource
   /** Generic logical RPC channels over the same Connection transport. */
   readonly rpc: ClientConnectionRpc
   /**
@@ -79,16 +88,56 @@ export function apply(ctx: Context): void {
   const api: IApiClient = fixtureClient ?? new WebApiClient()
   const rpc = fixtureClient?.rpc ?? createWebConnectionRpc()
   let started = false
+  let description: HostDescription | undefined
+  const descriptionListeners = new Set<() => void>()
+  const publishDescription = (next: HostDescription | undefined): void => {
+    if (Object.is(description, next)) return
+    description = next
+    for (const listener of [...descriptionListeners]) {
+      try {
+        listener()
+      } catch (error) {
+        console.error('[web-runtime] host-description listener threw:', error)
+      }
+    }
+  }
   const handle: ConnectionHandle = {
     api,
     isLoopback: pageLocation === undefined || isLoopbackHostname(pageLocation.hostname),
+    hostDescription: {
+      getSnapshot: () => description,
+      subscribe: (listener) => {
+        descriptionListeners.add(listener)
+        return () => { descriptionListeners.delete(listener) }
+      },
+    },
     rpc,
     start(sinks, config) {
       if (started) throw new Error('connection: the stream loop is already owned by another consumer')
       started = true
-      const controller = new ConnectionController(api, sinks, config ?? {})
+      const controller = new ConnectionController(api, {
+        ...sinks,
+        onConnected: (next) => {
+          publishDescription(next)
+          // A description subscriber may synchronously stop the loop. In that
+          // case publishDescription(undefined) has already retracted this
+          // generation, so do not leak its stale connected notification to
+          // the consumer sink afterward.
+          if (!Object.is(description, next)) return
+          sinks.onConnected?.(next)
+        },
+        onStateChange: (state) => {
+          if (state === 'reconnecting') publishDescription(undefined)
+          sinks.onStateChange?.(state)
+        },
+      }, config ?? {})
       controller.start()
-      return { stop: () => { controller.stop() } }
+      return {
+        stop: () => {
+          controller.stop()
+          publishDescription(undefined)
+        },
+      }
     },
   }
   ctx.provide('connection', handle)

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

@@ -87,10 +87,68 @@ describe('connection client apply', () => {
   it('start() hands out one loop, rejects a second consumer, and stop() aborts the streams', async () => {
     ;(globalThis as Win).location = { hostname: 'localhost', search: '?fixture' }
     const handle = await mount()
+    const descriptions: Array<boolean | undefined> = []
+    const stopDescription = handle.hostDescription.subscribe(() => {
+      descriptions.push(handle.hostDescription.getSnapshot()?.canOpenPath)
+    })
+    expect(handle.hostDescription.getSnapshot()).toBeUndefined()
     // config omitted: the `config ?? {}` default arm is part of the surface.
     const loop = handle.start({})
     expect(() => handle.start({})).toThrow(/already owned by another consumer/)
+    await vi.waitFor(() => {
+      expect(handle.hostDescription.getSnapshot()?.canOpenPath).toBe(true)
+    })
     loop.stop() // teardown must not throw; the fixture streams abort quietly
+    expect(handle.hostDescription.getSnapshot()).toBeUndefined()
+    expect(descriptions).toEqual([true, undefined])
+    stopDescription()
+  })
+
+  it('isolates description subscribers so later listeners and the consumer sink still run', async () => {
+    ;(globalThis as Win).location = { hostname: 'localhost', search: '?fixture' }
+    const handle = await mount()
+    const errorSpy = vi.spyOn(console, 'error').mockImplementation(() => undefined)
+    const seen: boolean[] = []
+    const stopThrowing = handle.hostDescription.subscribe(() => { throw new Error('subscriber bug') })
+    const stopRecording = handle.hostDescription.subscribe(() => {
+      const value = handle.hostDescription.getSnapshot()?.canOpenPath
+      if (value !== undefined) seen.push(value)
+    })
+    let connected = 0
+    const loop = handle.start({ onConnected: () => { connected++ } })
+    try {
+      await vi.waitFor(() => { expect(connected).toBe(1) })
+      expect(seen).toEqual([true])
+      expect(errorSpy).toHaveBeenCalledOnce()
+    } finally {
+      stopThrowing()
+      stopRecording()
+      loop.stop()
+      errorSpy.mockRestore()
+    }
+  })
+
+  it('does not announce a generation synchronously stopped by a description subscriber', async () => {
+    ;(globalThis as Win).location = { hostname: 'localhost', search: '?fixture' }
+    const handle = await mount()
+    const owner: { loop?: ReturnType<ConnectionHandle['start']> } = {}
+    let sawDescription = false
+    const stopDescription = handle.hostDescription.subscribe(() => {
+      if (handle.hostDescription.getSnapshot() === undefined) return
+      sawDescription = true
+      owner.loop?.stop()
+    })
+    const connected = vi.fn()
+    const loop = handle.start({ onConnected: connected })
+    owner.loop = loop
+    try {
+      await vi.waitFor(() => { expect(sawDescription).toBe(true) })
+      expect(handle.hostDescription.getSnapshot()).toBeUndefined()
+      expect(connected).not.toHaveBeenCalled()
+    } finally {
+      stopDescription()
+      loop.stop()
+    }
   })
 
   it('WebApiClient keeps unary calls and respond on globalThis.fetch', async () => {

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

@@ -23,10 +23,14 @@ describe('connection lifecycle', () => {
   it('announces connected after describe + both streams open, then pumps frames to sinks', async () => {
     const api = new FakeApiClient()
     const muxSeen: string[] = []
+    const descriptions: boolean[] = []
     let connected = 0
     const controller = new ConnectionController(api, {
       onMuxEnvelope: envelope => muxSeen.push(envelope.payload.type),
-      onConnected: () => { connected++ },
+      onConnected: (description) => {
+        connected++
+        descriptions.push(description.canOpenPath)
+      },
     }, FAST)
     controller.start()
     try {
@@ -34,6 +38,7 @@ describe('connection lifecycle', () => {
       api.pushMux(subscribedFrame())
       await vi.waitFor(() => { expect(muxSeen).toEqual(['session/subscribed']) })
       expect(api.callsOf('host.describe')).toHaveLength(1)
+      expect(descriptions).toEqual([true])
     } finally {
       controller.stop()
     }
@@ -75,7 +80,7 @@ describe('connection lifecycle', () => {
     try {
       await vi.waitFor(() => { expect(describeCalls).toBe(2) }) // retried after backoff
       expect(connected).toBe(0) // never announced during the failed generation
-      gate.resolve(ok({ version: '0', cwd: '/f', attachedSessions: 0 }))
+      gate.resolve(ok({ version: '0', cwd: '/f', attachedSessions: 0, canOpenPath: true }))
       await vi.waitFor(() => { expect(connected).toBe(1) })
     } finally {
       controller.stop()
@@ -97,7 +102,7 @@ describe('connection lifecycle', () => {
           },
         })
       }
-      return Promise.resolve(ok({ version: '0', cwd: '/f', attachedSessions: 0 }))
+      return Promise.resolve(ok({ version: '0', cwd: '/f', attachedSessions: 0, canOpenPath: true }))
     }
     let connected = 0
     const warnSpy = vi.spyOn(console, 'warn').mockImplementation(() => undefined)
@@ -210,6 +215,24 @@ describe('connection lifecycle', () => {
     }
   })
 
+  it('does not announce a generation stopped synchronously by its connected state sink', async () => {
+    const api = new FakeApiClient()
+    const states: ConnectionState[] = []
+    let connected = 0
+    const controller = new ConnectionController(api, {
+      onConnected: () => { connected++ },
+      onStateChange: (state) => {
+        states.push(state)
+        if (state === 'connected') controller.stop()
+      },
+    }, FAST)
+
+    controller.start()
+    await vi.waitFor(() => { expect(states).toEqual(['connected']) })
+    await vi.waitFor(() => { expect(api.openMuxCount).toBe(0) })
+    expect(connected).toBe(0)
+  })
+
   it('deduplicates consecutive reconnecting emissions across two straight failures', async () => {
     const api = new FakeApiClient()
     const gate = deferred<Awaited<ReturnType<FakeApiClient['onDescribe']>>>()
@@ -228,7 +251,7 @@ describe('connection lifecycle', () => {
     controller.start()
     try {
       await vi.waitFor(() => { expect(describeCalls).toBe(3) })
-      gate.resolve(ok({ version: '0', cwd: '/f', attachedSessions: 0 }))
+      gate.resolve(ok({ version: '0', cwd: '/f', attachedSessions: 0, canOpenPath: true }))
       await vi.waitFor(() => { expect(connected).toBe(1) })
       expect(states).toEqual(['reconnecting', 'connected']) // two failures, one reconnecting emission
     } finally {

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

@@ -71,8 +71,15 @@ export class FakeApiClient implements IApiClient {
     () => Promise.resolve(ok({ attachment: { attachmentId: 'a' as never, mediaType: 'image/png', bytes: 1, width: 1, height: 1 }, data: 'AA==' }))
   onUpdateQueue: (payload: unknown) => Promise<RpcResponse<{ accepted: true }>> = () => Promise.resolve(ok({ accepted: true as const }))
   onCancel: (payload: unknown) => Promise<RpcResponse<{ accepted: true }>> = () => Promise.resolve(ok({ accepted: true as const }))
-  onDescribe: (payload: unknown) => Promise<RpcResponse<{ version: string; cwd: string; attachedSessions: number }>> =
-    () => Promise.resolve(ok({ version: '0-fake', cwd: '/f', attachedSessions: 0 }))
+  onDescribe: (payload: unknown) => Promise<RpcResponse<{
+    version: string
+    cwd: string
+    attachedSessions: number
+    canOpenPath: boolean
+  }>> =
+    () => Promise.resolve(ok({
+      version: '0-fake', cwd: '/f', attachedSessions: 0, canOpenPath: true,
+    }))
   onPickDirectory: (payload: unknown) => Promise<RpcResponse<{ path: string | null }>> =
     () => Promise.resolve(ok({ path: null }))
   onOpenPath: (payload: unknown) => Promise<RpcResponse<{ opened: true }>> =

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

@@ -31,6 +31,10 @@ async function mount(): Promise<Bench> {
   const handle: ConnectionHandle = {
     api,
     isLoopback: true,
+    hostDescription: {
+      getSnapshot: () => undefined,
+      subscribe: () => () => {},
+    },
     rpc: {
       call: () => Promise.reject(new Error('unexpected generic RPC call')),
     },
@@ -86,7 +90,7 @@ describe('runtime client apply', () => {
     expect(workspaces.list.getSnapshot().items[0]?.workspaceId).toBe('w-new')
     // Mux sink and onConnected route without throwing (manager semantics own the behavior).
     bench.sinks?.onMuxEnvelope?.({ rpcId: 'r2' as never, payload: { type: 'stream/error', message: 'x' } as never })
-    bench.sinks?.onConnected?.()
+    bench.sinks?.onConnected?.({ version: '0', cwd: '/f', attachedSessions: 0, canOpenPath: true })
   })
 
   it('selects the recent Workspace once when the first baselines have no current session', async () => {
@@ -99,7 +103,7 @@ describe('runtime client apply', () => {
     }))
     bench.api.onList = () => Promise.resolve(ok({ items: [] }))
 
-    bench.sinks?.onConnected?.()
+    bench.sinks?.onConnected?.({ version: '0', cwd: '/f', attachedSessions: 0, canOpenPath: true })
     await flushMicrotasks()
 
     const sessions = bench.ctx.get('sessions') as SessionsService

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

@@ -90,8 +90,15 @@ export class FakeApiClient implements IApiClient {
   onUpdateQueue: (payload: unknown) => Promise<RpcResponse<{ accepted: true }>> = () => Promise.resolve(ok({ accepted: true as const }))
   onCancel: (payload: unknown) => Promise<RpcResponse<{ accepted: true }>> = () => Promise.resolve(ok({ accepted: true as const }))
 
-  onDescribe: (payload: unknown) => Promise<RpcResponse<{ version: string; cwd: string; attachedSessions: number }>> =
-    () => Promise.resolve(ok({ version: '0-fake', cwd: '/f', attachedSessions: 0 }))
+  onDescribe: (payload: unknown) => Promise<RpcResponse<{
+    version: string
+    cwd: string
+    attachedSessions: number
+    canOpenPath: boolean
+  }>> =
+    () => Promise.resolve(ok({
+      version: '0-fake', cwd: '/f', attachedSessions: 0, canOpenPath: true,
+    }))
   onPickDirectory: (payload: unknown) => Promise<RpcResponse<{ path: string | null }>> =
     () => Promise.resolve(ok({ path: null }))
   onOpenPath: (payload: unknown) => Promise<RpcResponse<{ opened: true }>> =

packages/client/runtime/tests/wire-events.spec.ts

@@ -24,6 +24,10 @@ async function mount(): Promise<Bench> {
   const handle: ConnectionHandle = {
     api,
     isLoopback: true,
+    hostDescription: {
+      getSnapshot: () => undefined,
+      subscribe: () => () => {},
+    },
     rpc: {
       call: () => Promise.reject(new Error('unexpected generic RPC call')),
     },
@@ -83,8 +87,9 @@ describe('wire event bridge', () => {
     const bench = await mount()
     let resets = 0
     bench.ctx.on('connection/reset', () => { resets++ })
-    bench.sinks?.onConnected?.()
-    bench.sinks?.onConnected?.() // second generation after a reconnect
+    const description = { version: '0', cwd: '/f', attachedSessions: 0, canOpenPath: true }
+    bench.sinks?.onConnected?.(description)
+    bench.sinks?.onConnected?.(description) // second generation after a reconnect
     expect(resets).toBe(2)
   })
 })

packages/client/ui-deliverables/README.i18n.yaml

@@ -2,5 +2,5 @@
 # side as of the last confirmed-consistent state. Both languages carry equal authority;
 # after editing either side, bring the other along and re-record with:
 #   pnpm run verify-translation-pairing --write packages/client/ui-deliverables/README.md
-README.md: 7d03e5faedda3ba8c9cc4cab6ca134d98dc7ec13
-README.zh.md: dfbbc7a39aa94aab438119a4f23ffb02da2daa3d
+README.md: 9cfcde9510c5d6814d5b42fd58a0520ea37b8679
+README.zh.md: 94dba9bb38725ddb3ef39d55a5f8a185a5008d18

packages/client/ui-deliverables/README.md

@@ -6,7 +6,7 @@ Produced-files feature owner: registers the deliverables row a finished turn end
 
 `deliverablesDefinition` folds each Turn's successful mutation calls into engine-published `DeliverablesTurnData`; `producedForClosing` reads that data with the closing Assistant seq. The vocabulary is the mutation tools' own follow-along `locations`, never the closing prose: a produced file is listed whether or not the model remembered to name it. A mutation is recognized by render intent, not tool name — a diff card, or a generic card whose `kind` is `edit` (the shape `str_replace_editor`'s insert presents) — so a new mutation tool joins by declaring what it does. Reads, deletes, and failed calls contribute nothing; a path appears once per Turn in first-seen order. The Conversation Location index owns Turn membership, so a Turn that mutates and then ends without content text cannot spill into the next Turn's row.
 
-`ProducedFiles` renders the row between the closing message's body and its IconActions footer: a quiet label, up to six chips (basename text, full path as the `title`), and an explicit remainder count past the cap. Each chip opens through the owner-supplied `openFile` — the same Host opener the tool rows use, with the chat view resolving relative paths against the session cwd. Design rationale: the [workspace file links Agent Note](../../../.agents/notes/implemented/feature/2026-07-31-web-workspace-file-links.md).
+`ProducedFiles` renders the row between the closing message's body and its IconActions footer: a quiet label and one measured file lane. It shows the largest leading prefix that fits (up to six chips; basename text, full path as the `title`) while reserving the exact localized `+ N files` width, so the remainder stays visible without wrapping or horizontal scrolling. Each chip opens through the owner-supplied `openFile` — the same Host opener the tool rows use, with the chat view resolving relative paths against the session cwd. When files are hidden, a second-line **Show in folder** action opens the session workspace through that same owner path only while the page is loopback and the current Host handshake reports `canOpenPath`; direct remote Web and headless/container Linux Hosts omit the action by default. Design rationale: the [workspace file links Agent Note](../../../.agents/notes/implemented/feature/2026-07-31-web-workspace-file-links.md).
 
 The closing prose carries the same vocabulary. This plugin provides the `chatFileMentions` service the chat view consults per closing message: `producedFileMentions` resolves an inline-code token by exact path, or by being exactly the basename of exactly one produced path — a basename two paths share stays inert rather than guessing, so a mention link can never open the wrong file or 404. A resolved mention keeps its code chip and takes the markdown sheet's link language — link-blue at rest, underlined on hover, exactly like URL-promoted inline code — with the full path as its `title`; mentions never render inside anchors or streaming text. Decision record: the [inline file mentions Agent Note](../../../.agents/notes/implemented/feature/2026-08-07-web-inline-file-mentions.md).
 
@@ -21,3 +21,4 @@ None; this package neither assembles nor sends provider requests.
 ## Known Limitations and Deferred Work
 
 - **Mention matching is exact path or unique basename only.** A suffix mention (`out/index.html` written as `index.html` resolves; `deep/out/index.html` written as `out/index.html` does not) stays inert; widening the matcher is deferred until a real closing-message shape needs it.
+- **Native folder handoff targets the Host desktop.** A browser reached through a non-loopback authority omits the action, as does a deployment reporting no native opener. SSH forwarding that makes a remote Host look loopback-local must set the gateway's `nativeOpen: false`; so must a headless macOS/Windows Host, a WSL deployment without working Windows interop, or any Linux desktop whose display/opener probe is a false positive. Identifying the operator-visible desktop remains deployment policy.

packages/client/ui-deliverables/README.zh.md

@@ -6,7 +6,7 @@
 
 `deliverablesDefinition` 把每个 Turn 中成功的修改调用折叠进引擎发布的 `DeliverablesTurnData`；`producedForClosing` 结合收尾 Assistant 的 seq 读取这份数据。依据的是修改工具自身附带的 `locations`，而不是收尾正文：无论模型是否记得点名，产出文件都会被列出。修改操作按渲染意图而非工具名识别：diff 卡片，或 `kind` 为 `edit` 的通用卡片（即 `str_replace_editor` 的 insert 操作所呈现的形态）；因此新的修改工具只需声明自身行为即可加入。读取、删除和失败的调用不贡献任何条目；同一路径在一个 Turn 内按首见顺序只出现一次。Conversation Location 索引拥有 Turn 成员关系，因此一个 Turn 即使先修改文件、随后没有正文内容就结束，也不会溢进下一个 Turn 的行里。
 
-`ProducedFiles` 在收尾消息正文与其 IconActions 之间渲染该行：一个低调的标签、至多六个标签项（文本为文件名，完整路径作为 `title`），超出上限则显示一个明确的剩余计数。每个标签项经由属主提供的 `openFile` 打开——与工具行相同的 Host 打开器，chat 视图会把相对路径按会话 cwd 解析。设计原理：[workspace 文件链接 Agent Note](../../../.agents/notes/implemented/feature/2026-07-31-web-workspace-file-links.md)。
+`ProducedFiles` 在收尾消息正文与其 IconActions 之间渲染该行：一个低调的标签和一条经过测量的单行文件 lane。它展示能够放下的最大前缀（至多六个标签项；文本为文件名，完整路径作为 `title`），并为本地化后的精确 `+ N 个文件` 宽度预留空间，因此剩余计数始终可见，既不换行也不横向滚动。每个标签项经由属主提供的 `openFile` 打开——与工具行相同的 Host 打开器，chat 视图会把相对路径按会话 cwd 解析。存在隐藏文件时，第二行的**在文件夹中显示**也经由同一属主路径打开会话 workspace；它只在页面使用 loopback 且当前 Host 握手报告 `canOpenPath` 时出现，直接远程 Web 与 headless／容器 Linux Host 默认均省略该操作。设计原理：[workspace 文件链接 Agent Note](../../../.agents/notes/implemented/feature/2026-07-31-web-workspace-file-links.md)。
 
 收尾正文承载同一份词表。本插件提供供 chat 视图按收尾消息查询的 `chatFileMentions` 服务：`producedFileMentions` 按精确路径解析行内代码 token，或当 token 恰好是且仅是一条产出路径的 basename 时解析——两条路径共享同一 basename 时，文本保持不可点击而不作猜测，因此提及链接永远不会打开错误的文件或 404。解析成功的提及保留代码标签，并采用 Markdown 样式表的链接样式：静止时为链接蓝色，悬停时显示下划线，与 URL 提升的行内代码完全一致——完整路径作为其 `title`；提及绝不会渲染在链接内部或流式文本中。决策记录：[行内文件提及 Agent Note](../../../.agents/notes/implemented/feature/2026-08-07-web-inline-file-mentions.md)。
 
@@ -21,3 +21,4 @@
 ## 已知限制与暂缓事项
 
 - **提及匹配只认精确路径或唯一 basename。**后缀式提及（`out/index.html` 写作 `index.html` 可解析；`deep/out/index.html` 写作 `out/index.html` 则不行）保持不可点击；等真实的收尾消息形态产生需求后再放宽匹配规则。
+- **原生文件夹交接以 Host 桌面为目标。**经非 loopback 权威访问的浏览器会省略该操作，报告没有原生打开器的部署也一样。若 SSH 转发让远端 Host 看似处于本机 loopback，部署必须为网关设置 `nativeOpen: false`；无界面的 macOS／Windows Host、Windows interop 不可用的 WSL，或 display／opener 探测误报的 Linux 桌面也必须这样配置。识别操作者实际可见的桌面仍属于部署策略。

packages/client/ui-deliverables/package.json

@@ -32,6 +32,7 @@
   "dsh": {
     "client": {
       "inject": [
+        "@deepseek-ai/dsh-client-connection",
         "@deepseek-ai/dsh-client-locale",
         "@deepseek-ai/dsh-client-runtime",
         "@deepseek-ai/dsh-client-ui-conversation"
@@ -48,6 +49,7 @@
     "react": "^18.2.0"
   },
   "peerDependencies": {
+    "@deepseek-ai/dsh-client-connection": "workspace:^",
     "@deepseek-ai/dsh-client-locale": "workspace:^",
     "@deepseek-ai/dsh-client-runtime": "workspace:^",
     "@deepseek-ai/dsh-client-ui-conversation": "workspace:^",
@@ -56,6 +58,7 @@
     "@deepseek-ai/cordis": "workspace:^"
   },
   "devDependencies": {
+    "@deepseek-ai/dsh-client-connection": "workspace:^",
     "@deepseek-ai/dsh-client-locale": "workspace:^",
     "@deepseek-ai/dsh-client-runtime": "workspace:^",
     "@deepseek-ai/dsh-client-test-runtime": "workspace:^",

packages/client/ui-deliverables/src/client/ProducedFiles.module.css

@@ -1,24 +1,39 @@
-/* Turn-tail produced-files row: a quiet label followed by wrapping file chips.
-   Sits between the assistant body and its IconActions footer, so it reads as
-   part of the answer rather than as another tool row. */
+/* Turn-tail produced-files summary: one measured chip lane plus an optional
+   native-folder action below it. */
 
 .root {
-  display: flex;
-  flex-wrap: wrap;
+  position: relative;
+  display: grid;
+  grid-template-columns: max-content minmax(0, 1fr);
   align-items: center;
-  gap: 8px;
+  column-gap: 8px;
+  row-gap: 6px;
   margin-top: 16px;
   font-size: 13px;
   line-height: 22px;
 }
 
 .label {
+  grid-column: 1;
+  grid-row: 1;
   color: var(--dsw-alias-label-tertiary);
 }
 
+.row {
+  grid-column: 2;
+  grid-row: 1;
+  display: flex;
+  flex-wrap: nowrap;
+  align-items: center;
+  gap: 8px;
+  min-width: 0;
+  overflow: hidden;
+}
+
 /* One produced file. A link by behavior (it opens the file), a chip by shape:
-   full paths are long and several may wrap onto one row. */
+   full paths are long, while the measured lane stays on one row. */
 .file {
+  flex: 0 0 auto;
   max-width: 320px;
   overflow: hidden;
   text-overflow: ellipsis;
@@ -38,7 +53,53 @@
   text-decoration: underline;
 }
 
+.file:focus-visible,
+.showFolder:focus-visible {
+  outline: none;
+  box-shadow: inset 0 0 0 2px var(--dsw-alias-border-l3);
+}
+
 /* Overflow count: the row never silently drops files it did not show. */
 .more {
+  flex: 0 0 auto;
+  white-space: nowrap;
   color: var(--dsw-alias-label-tertiary);
 }
+
+.showFolder {
+  grid-column: 2;
+  grid-row: 2;
+  justify-self: start;
+  margin: 0;
+  padding: 0 2px;
+  border: none;
+  border-radius: 4px;
+  background: transparent;
+  color: var(--dsw-alias-label-tertiary);
+  font: inherit;
+  line-height: 20px;
+  cursor: pointer;
+}
+
+.showFolder:hover {
+  color: var(--dsw-alias-label-secondary);
+  text-decoration: underline;
+}
+
+/* Exact browser-native probes for every candidate shown count. They share the
+   visible styles but never affect layout, accessibility, or scroll width. */
+.measure {
+  position: absolute;
+  width: 0;
+  height: 0;
+  overflow: hidden;
+  visibility: hidden;
+  pointer-events: none;
+  contain: strict;
+}
+
+.probe {
+  position: absolute;
+  inset: 0 auto auto 0;
+  width: max-content;
+}

packages/client/ui-deliverables/src/client/ProducedFiles.tsx

@@ -4,46 +4,146 @@
 // through the same openFile the tool rows use — the Host's own opener, on the
 // Host machine.
 
+import { useLayoutEffect, useRef, useState } from 'react'
 import type { PropsLocale } from '@deepseek-ai/dsh-client-ui-slots'
 import type { TurnTailOwnerProps } from '@deepseek-ai/dsh-client-ui-conversation/client'
 import { basename } from './turn-deliverables.ts'
 import type { NS } from './locales.ts'
 import css from './ProducedFiles.module.css'
 
-/** Files past this stay counted but unlisted: a refactor turn must not bury the answer. */
-const SHOWN = 6
+/** At most six chips compete for the one-line summary; every other path stays counted. */
+const SHOWN_LIMIT = 6
+
+/**
+ * Select the largest prefix whose measured chips and exact remainder fit.
+ * @param available - usable width of the one-line file lane.
+ * @param gap - computed flex gap between adjacent visible items.
+ * @param chipWidths - measured widths for the candidate file chips.
+ * @param moreWidthsByShown - exact localized remainder width for each shown count.
+ * @returns Number of leading chips to render.
+ */
+export function fitProducedFiles(
+  available: number,
+  gap: number,
+  chipWidths: readonly number[],
+  moreWidthsByShown: readonly (number | undefined)[],
+): number {
+  if (available <= 0) return chipWidths.length
+  const prefix = [0]
+  for (const width of chipWidths) prefix.push((prefix.at(-1) ?? 0) + width)
+  for (let shown = chipWidths.length; shown >= 0; shown -= 1) {
+    const more = moreWidthsByShown[shown]
+    const items = shown + (more === undefined ? 0 : 1)
+    const needed = (prefix[shown] ?? 0) + (more ?? 0) + Math.max(0, items - 1) * gap
+    if (needed <= available) return shown
+  }
+  return 0
+}
 
 /** Matched paths plus the opener and locale seats needed to present them. */
 export type ProducedFilesProps = Pick<TurnTailOwnerProps, 'openFile'> & {
   matched: readonly string[]
+  /** True only when this loopback deployment exposes a user-visible native opener. */
+  canOpenPath: boolean
 } & PropsLocale<typeof NS>
 
+/** Slot-owned props before the connection capability is injected. */
+export type ProducedFilesSeatProps = Omit<ProducedFilesProps, 'canOpenPath'>
+
+function moreLabel(t: ProducedFilesProps['t'], count: number): string {
+  return count === 1 ? t('produced.moreOne') : t('produced.more', { count: String(count) })
+}
+
 /**
  * Render one turn's produced files as openable chips.
  * @param props - selector-matched paths, the chat view's file opener, and the locale seat.
  * @returns The produced-files row.
  */
-export function ProducedFiles({ matched: paths, openFile, t }: ProducedFilesProps) {
-  const shown = paths.slice(0, SHOWN)
+export function ProducedFiles({ matched: paths, openFile, canOpenPath, t }: ProducedFilesProps) {
+  const limit = Math.min(paths.length, SHOWN_LIMIT)
+  const [shownCount, setShownCount] = useState(limit)
+  const rowRef = useRef<HTMLDivElement>(null)
+  const chipProbes = useRef<Array<HTMLButtonElement | null>>([])
+  const moreProbes = useRef<Array<HTMLSpanElement | null>>([])
+
+  useLayoutEffect(() => {
+    const row = rowRef.current
+    if (row === null) return
+    const measure = (): void => {
+      const styles = getComputedStyle(row)
+      const gap = Number.parseFloat(styles.columnGap || styles.gap) || 0
+      const chips = chipProbes.current.slice(0, limit)
+        .map(probe => probe?.getBoundingClientRect().width ?? 0)
+      const more = Array.from({ length: limit + 1 }, (_, candidate) =>
+        paths.length === candidate
+          ? undefined
+          : moreProbes.current[candidate]?.getBoundingClientRect().width)
+      setShownCount(fitProducedFiles(row.clientWidth, gap, chips, more))
+    }
+    measure()
+    if (typeof ResizeObserver === 'undefined') return
+    const observer = new ResizeObserver(measure)
+    observer.observe(row)
+    for (const probe of [...chipProbes.current, ...moreProbes.current]) {
+      if (probe !== null) observer.observe(probe)
+    }
+    return () => { observer.disconnect() }
+  }, [limit, paths, t])
+
+  const visibleCount = Math.min(shownCount, limit)
+  const shown = paths.slice(0, visibleCount)
   const hidden = paths.length - shown.length
   return (
     <div className={css.root}>
       <span className={css.label}>{t('produced.label')}</span>
-      {shown.map(path => (
-        <button
-          key={path}
-          type="button"
-          className={css.file}
-          // The full path is the disambiguator when two turns produce files
-          // that share a basename; the chip itself stays short.
-          title={path}
-          aria-label={t('produced.open', { name: path })}
-          onClick={() => { openFile(path) }}
-        >
-          {basename(path)}
+      <div ref={rowRef} className={css.row} data-produced-files-row>
+        {shown.map(path => (
+          <button
+            key={path}
+            type="button"
+            className={css.file}
+            // The full path is the disambiguator when two turns produce files
+            // that share a basename; the chip itself stays short.
+            title={path}
+            aria-label={t('produced.open', { name: path })}
+            onClick={() => { openFile(path) }}
+          >
+            {basename(path)}
+          </button>
+        ))}
+        {hidden > 0 && <span className={css.more}>{moreLabel(t, hidden)}</span>}
+      </div>
+      {hidden > 0 && canOpenPath && (
+        <button type="button" className={css.showFolder} onClick={() => { openFile('.') }}>
+          {t('produced.showInFolder')}
         </button>
-      ))}
-      {hidden > 0 && <span className={css.more}>{t('produced.more', { count: String(hidden) })}</span>}
+      )}
+      <div className={css.measure} aria-hidden="true">
+        {paths.slice(0, limit).map((path, index) => (
+          <button
+            key={path}
+            ref={(node) => { chipProbes.current[index] = node }}
+            type="button"
+            tabIndex={-1}
+            className={`${css.file} ${css.probe}`}
+          >
+            {basename(path)}
+          </button>
+        ))}
+        {Array.from({ length: limit + 1 }, (_, candidate) => {
+          const remaining = paths.length - candidate
+          if (remaining === 0) return null
+          return (
+            <span
+              key={candidate}
+              ref={(node) => { moreProbes.current[candidate] = node }}
+              className={`${css.more} ${css.probe}`}
+            >
+              {moreLabel(t, remaining)}
+            </span>
+          )
+        })}
+      </div>
     </div>
   )
 }

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

@@ -7,10 +7,14 @@
  * composing this plugin out of cordis.yml removes both surfaces entirely;
  * the owning view renders an empty chain and inert prose at zero cost.
  */
+import { createElement, useSyncExternalStore } from 'react'
+import type { ConnectionHandle } from '@deepseek-ai/dsh-client-connection/client'
 import type { ClientContext } from '@deepseek-ai/dsh-client-runtime/client'
 import type { ChatFileMentions } from '@deepseek-ai/dsh-client-ui-conversation/client'
 import type {} from '@deepseek-ai/dsh-client-locale/client'
-import { ProducedFiles } from './ProducedFiles.tsx'
+import {
+  ProducedFiles, type ProducedFilesSeatProps,
+} from './ProducedFiles.tsx'
 import { en, NS, zh, type DeliverablesKey } from './locales.ts'
 import {
   deliverablesDefinition, producedFileMentions, selectProducedFiles,
@@ -27,13 +31,24 @@ export { ProducedFiles, type ProducedFilesProps } from './ProducedFiles.tsx'
 export { producedForClosing } from './turn-deliverables.ts'
 
 /** Required services for the tail-slot registration and its dictionaries. */
-export const inject = ['slots', 'locale', 'conversationEvents']
+export const inject = ['slots', 'locale', 'conversationEvents', 'connection']
 
 /**
  * Client plugin body: register the dictionaries and the turn-tail entry.
  * @param ctx - client root context.
  */
 export function apply(ctx: ClientContext): void {
+  const connection = ctx.get('connection') as ConnectionHandle
+  const ProducedFilesSeat = (props: ProducedFilesSeatProps): ReturnType<typeof createElement> => {
+    const description = useSyncExternalStore(
+      listener => connection.hostDescription.subscribe(listener),
+      () => connection.hostDescription.getSnapshot(),
+    )
+    return createElement(ProducedFiles, {
+      ...props,
+      canOpenPath: connection.isLoopback && description?.canOpenPath === true,
+    })
+  }
   ctx.conversationEvents.register(deliverablesDefinition)
   ctx.effect(() => ctx.locale.register(NS, { zh, en }), 'ui-deliverables: dictionaries')
   ctx.slots.inject(
@@ -42,7 +57,7 @@ export function apply(ctx: ClientContext): void {
       name: 'conversation.chat.turnTail',
       select: selectProducedFiles,
       locale: NS,
-    }, ProducedFiles),
+    }, ProducedFilesSeat),
   )
   // The prose side of the same vocabulary: the chat view reaches this face
   // via ctx.get, so its absence — this plugin composed out — is the off state.

packages/client/ui-deliverables/src/client/locales.ts

@@ -6,15 +6,19 @@ export const NS = 'deliverables'
 /** Simplified Chinese dictionary (the key-set source of truth). */
 export const zh = {
   'produced.label': '产物',
-  'produced.more': '还有 {count} 个',
+  'produced.moreOne': '+ 1 个文件',
+  'produced.more': '+ {count} 个文件',
   'produced.open': '打开 {name}',
+  'produced.showInFolder': '在文件夹中显示',
 }
 
 /** English dictionary (same key set). */
 export const en: Record<DeliverablesKey, string> = {
   'produced.label': 'Produced',
-  'produced.more': '{count} more',
+  'produced.moreOne': '+ 1 file',
+  'produced.more': '+ {count} files',
   'produced.open': 'Open {name}',
+  'produced.showInFolder': 'Show in folder',
 }
 
 /** Union of this namespace's dictionary keys. */

packages/client/ui-deliverables/tests/produced-files.spec.tsx

@@ -6,7 +6,8 @@
  * (HMR safety) against the real SlotsService.
  */
 import { Context } from '@deepseek-ai/cordis'
-import { cleanup, fireEvent, render } from '@testing-library/react'
+import type { ComponentType } from 'react'
+import { act, cleanup, fireEvent, render, within } from '@testing-library/react'
 import { afterEach, describe, expect, it, vi } from 'vitest'
 import {
   ConversationEventRegistry, ConversationNodeAssembler, SlotsService,
@@ -19,7 +20,7 @@ import type {
 import { apply as applyLocale } from '@deepseek-ai/dsh-client-locale/client'
 import type { ChatFileMentions, TurnTailOwnerProps } from '@deepseek-ai/dsh-client-ui-conversation/client'
 import { makeTranslate } from '@deepseek-ai/dsh-client-test-runtime'
-import { ProducedFiles } from '../src/client/ProducedFiles.tsx'
+import { fitProducedFiles, ProducedFiles, type ProducedFilesSeatProps } from '../src/client/ProducedFiles.tsx'
 import {
   basename, deliverablesDefinition, producedFileMentions, producedForClosing, selectProducedFiles,
   type DeliverablesTurnData,
@@ -27,9 +28,20 @@ import {
 import { apply, inject } from '../src/client/index.ts'
 import { apply as applyNode } from '../src/index.ts'
 import { apply as applyInvariant } from '../src/invariant.ts'
-import { zh } from '../src/client/locales.ts'
+import { en, zh } from '../src/client/locales.ts'
 
-afterEach(cleanup)
+const originalClientWidth = Object.getOwnPropertyDescriptor(HTMLElement.prototype, 'clientWidth')
+
+afterEach(() => {
+  cleanup()
+  vi.restoreAllMocks()
+  vi.unstubAllGlobals()
+  if (originalClientWidth === undefined) {
+    delete (HTMLElement.prototype as { clientWidth?: number }).clientWidth
+  } else {
+    Object.defineProperty(HTMLElement.prototype, 'clientWidth', originalClientWidth)
+  }
+})
 
 class TestTurnDataStore implements ConversationLocationDataStore<ConversationTurnDataMap> {
   private readonly values = new Map<string, unknown>()
@@ -269,21 +281,104 @@ describe('produced-file Turn data', () => {
 describe('ProducedFiles row', () => {
   const t = makeTranslate(zh)
 
-  it('renders capped chips with the full path reachable and opens one on click', () => {
-    // Seven files: six chips plus an explicit remainder — the row bounds what
-    // it shows and says so rather than dropping the rest silently.
+  it('selects the largest prefix using the exact remainder width', () => {
+    expect(fitProducedFiles(230, 8, [70, 60, 60], [55, 55, 55, 55])).toBe(2)
+    expect(fitProducedFiles(145, 8, [70, 60, 60], [55, 55, 55, 55])).toBe(1)
+    expect(fitProducedFiles(300, 8, [70, 60, 60], [55, 55, 55, 55])).toBe(3)
+    // A zero-width lane is a pre-layout test/hidden state, not evidence that
+    // every chip overflowed; keep the bounded initial prefix until measured.
+    expect(fitProducedFiles(0, 8, [70, 60], [60, 50, undefined])).toBe(2)
+    // Candidate-specific suffix widths matter at the 10 -> 9 digit boundary.
+    expect(fitProducedFiles(126, 8, [60], [70, 50])).toBe(1)
+    expect(fitProducedFiles(20, 8, [60], [70, 50])).toBe(0)
+  })
+
+  it('keeps one measured line, updates on resize, and opens a file or the workspace folder', () => {
     const paths = ['deep/a.html', 'b.css', 'c.ts', 'd.ts', 'e.ts', 'f.ts', 'g.ts']
     const openFile = vi.fn<(path: string) => void>()
-    const view = render(<ProducedFiles matched={paths} openFile={openFile} t={t} />)
+    let available = 226
+    let resize: ResizeObserverCallback | undefined
+    const disconnect = vi.fn()
+    vi.stubGlobal('ResizeObserver', class {
+      constructor(callback: ResizeObserverCallback) { resize = callback }
+      observe(): void {}
+      disconnect(): void { disconnect() }
+    })
+    Object.defineProperty(HTMLElement.prototype, 'clientWidth', {
+      configurable: true,
+      get(this: HTMLElement) { return this.hasAttribute('data-produced-files-row') ? available : 0 },
+    })
+    const rect = (width: number): DOMRect => ({
+      x: 0, y: 0, width, height: 22, top: 0, right: width, bottom: 22, left: 0,
+      toJSON: () => ({}),
+    })
+    const bounds = vi.spyOn(HTMLElement.prototype, 'getBoundingClientRect')
+      .mockImplementation(function getProbeRect(this: HTMLElement) {
+        if (this.closest('[aria-hidden="true"]') === null) return rect(0)
+        if (this.tagName !== 'BUTTON') return rect(60)
+        return rect(this.textContent === 'a.html' || this.textContent === 'b.css' ? 50 : 100)
+      })
+
+    const view = render(
+      <ProducedFiles matched={paths} openFile={openFile} canOpenPath t={t} />,
+    )
     expect(view.getByText('产物')).toBeTruthy()
-    // Chips carry the basename; the full path stays reachable as the title.
+    const row = view.container.querySelector('[data-produced-files-row]')
+    if (!(row instanceof HTMLElement)) throw new Error('produced row missing')
+    // The third probe is 100px: two chips plus the remainder fit, three do not.
+    expect(within(row).getAllByRole('button')).toHaveLength(2)
+    expect(within(row).getByText('+ 5 个文件')).toBeTruthy()
     const chip = view.getByRole('button', { name: '打开 deep/a.html' })
     expect(chip.textContent).toBe('a.html')
     expect(chip.getAttribute('title')).toBe('deep/a.html')
     expect(view.queryByRole('button', { name: '打开 g.ts' })).toBeNull()
-    expect(view.getByText('还有 1 个')).toBeTruthy()
     fireEvent.click(chip)
     expect(openFile).toHaveBeenCalledWith('deep/a.html')
+
+    const showFolder = view.getByRole('button', { name: '在文件夹中显示' })
+    fireEvent.click(showFolder)
+    expect(openFile).toHaveBeenLastCalledWith('.')
+
+    available = 150
+    act(() => { resize?.([], {} as ResizeObserver) })
+    expect(within(row).getAllByRole('button')).toHaveLength(1)
+    expect(within(row).getByText('+ 6 个文件')).toBeTruthy()
+
+    view.unmount()
+    expect(disconnect).toHaveBeenCalledOnce()
+    bounds.mockRestore()
+  })
+
+  it('keeps the folder action absent without overflow or a local native opener', () => {
+    const openFile = vi.fn<(path: string) => void>()
+    const noOverflow = render(
+      <ProducedFiles matched={['a.md']} openFile={openFile} canOpenPath t={t} />,
+    )
+    expect(noOverflow.queryByRole('button', { name: '在文件夹中显示' })).toBeNull()
+    noOverflow.unmount()
+    const headless = render(
+      <ProducedFiles
+        matched={['a.md', 'b.md', 'c.md', 'd.md', 'e.md', 'f.md', 'g.md']}
+        openFile={openFile}
+        canOpenPath={false}
+        t={t}
+      />,
+    )
+    expect(headless.queryByRole('button', { name: '在文件夹中显示' })).toBeNull()
+  })
+
+  it('uses singular English copy when exactly one file is hidden', () => {
+    const view = render(
+      <ProducedFiles
+        matched={['a.md', 'b.md', 'c.md', 'd.md', 'e.md', 'f.md', 'g.md']}
+        openFile={() => {}}
+        canOpenPath={false}
+        t={makeTranslate(en)}
+      />,
+    )
+    const row = view.container.querySelector('[data-produced-files-row]')
+    if (!(row instanceof HTMLElement)) throw new Error('produced row missing')
+    expect(within(row).getByText('+ 1 file')).toBeTruthy()
   })
 })
 
@@ -340,13 +435,56 @@ describe('plugin registration', () => {
       name: 'root',
       children: { 'conversation.chat.turnTail': { kind: 'chain', scope: 'session' } },
     } as never, () => null)
-    ctx.provide('connection', { api: { settings: {} }, isLoopback: false } as never)
+    const hostDescription = (canOpenPath: boolean) => ({
+      version: 'test', cwd: '/workspace', attachedSessions: 1, canOpenPath,
+    })
+    let description: ReturnType<typeof hostDescription> | undefined = hostDescription(true)
+    const descriptionListeners = new Set<() => void>()
+    const connection = {
+      api: { settings: {} },
+      isLoopback: false,
+      hostDescription: {
+        getSnapshot: () => description,
+        subscribe: (listener: () => void) => {
+          descriptionListeners.add(listener)
+          return () => { descriptionListeners.delete(listener) }
+        },
+      },
+    }
+    ctx.provide('connection', connection as never)
     await ctx.plugin({ inject: ['slots'], apply: applyLocale }).await()
 
     const fiber = ctx.plugin({ inject: [...inject], apply })
     await fiber.await()
     expect(ctx.slots.entries('conversation.chat.turnTail')).toHaveLength(1)
 
+    // The native action needs both independent facts. A Host capability does
+    // not authorize a remote page; loopback without a capable Host does not
+    // render a dead action; reconnect/disconnect retracts the capability.
+    const Entry = ctx.slots.entries('conversation.chat.turnTail')[0]!.component as ComponentType<ProducedFilesSeatProps>
+    const entryProps: ProducedFilesSeatProps = {
+      matched: ['a.md', 'b.md', 'c.md', 'd.md', 'e.md', 'f.md', 'g.md'],
+      openFile: () => {},
+      t: makeTranslate(zh),
+    }
+    const surface = render(<Entry {...entryProps} />)
+    expect(surface.queryByRole('button', { name: '在文件夹中显示' })).toBeNull()
+    connection.isLoopback = true
+    description = hostDescription(false)
+    surface.rerender(<Entry {...entryProps} />)
+    expect(surface.queryByRole('button', { name: '在文件夹中显示' })).toBeNull()
+    act(() => {
+      description = hostDescription(true)
+      for (const listener of descriptionListeners) listener()
+    })
+    expect(surface.getByRole('button', { name: '在文件夹中显示' })).toBeTruthy()
+    act(() => {
+      description = undefined
+      for (const listener of descriptionListeners) listener()
+    })
+    expect(surface.queryByRole('button', { name: '在文件夹中显示' })).toBeNull()
+    surface.unmount()
+
     // The prose face is live while the plugin is: a produced turn yields a
     // resolver whose matches open through the owner-supplied opener.
     const opened: string[] = []