Merge remote-tracking branch 'origin/master' into worktree/composer-scroll-sync

2026-07-31 14:26:51 +08:00
parent dec1950b6a 4c9056edb9
commit 22d6b1ed81
70 changed files with 982 additions and 148 deletions
--- a/packages/client/connection/src/client/fixture.ts
+++ b/packages/client/connection/src/client/fixture.ts
@@ -969,6 +969,9 @@ export function createFixtureApi(options: FixtureOptions = {}): ApiProxy {
    updatedAt: fixtureEpoch,
  }]
  let nextWorkspace = 1
+  // Registry-global archive set mirroring the host: archived sessions keep
+  // their workspace accounting slot and only grouping surfaces hide them.
+  const archivedSessionIds: SessionId[] = []

  // In-memory browse tree behind the fixture's `browse` picker capability —
  // deterministic content mirroring the design mock so assembled Web tests
@@ -1623,7 +1626,10 @@ export function createFixtureApi(options: FixtureOptions = {}): ApiProxy {
      openPath: request => ok(request, { opened: true as const }),
    },
    workspace: {
-      list: request => ok(request, { items: workspaces.map(w => ({ ...w })) }),
+      list: request => ok(request, {
+        items: workspaces.map(w => ({ ...w })),
+        archivedSessionIds: [...archivedSessionIds],
+      }),
      create: (request) => {
        const { path, name } = request.payload
        const target = path ?? `/tmp/fixture-workspaces/${name ?? ''}`
@@ -1709,6 +1715,16 @@ export function createFixtureApi(options: FixtureOptions = {}): ApiProxy {
        }
        return ok(request, { workspace: { ...workspace } })
      },
+      archiveSession: (request) => {
+        const missing = requireSession(request)
+        if (missing !== undefined) return missing
+        const { sessionId } = request.payload
+        if (!archivedSessionIds.includes(sessionId)) {
+          archivedSessionIds.push(sessionId)
+          emitHost({ type: 'host/archived-sessions-changed', archivedSessionIds: [...archivedSessionIds] })
+        }
+        return ok(request, { archivedSessionIds: [...archivedSessionIds] })
+      },
    },
    commands: {
      // The catalog mirrors one session's effective view (every fixture
@@ -2089,6 +2105,7 @@ export class FixtureApiClient extends AbstractApiClient {
      case 'workspace.rename': return this.api.workspace.rename(request)
      case 'workspace.delete': return this.api.workspace.delete(request)
      case 'workspace.insertSessionBefore': return this.api.workspace.insertSessionBefore(request)
+      case 'workspace.archiveSession': return this.api.workspace.archiveSession(request)
      case 'command.list': return this.api.commands.list(request)
      case 'command.execute': return this.api.commands.execute(request, signal)
      case 'skill.list': return this.api.skills.list(request)
--- a/packages/client/connection/tests/fake-api.ts
+++ b/packages/client/connection/tests/fake-api.ts
@@ -122,7 +122,7 @@ export class FakeApiClient implements IApiClient {
  }

  readonly workspace: IApiClient['workspace'] = {
-    list: (payload: unknown) => this.record('workspace.list', payload, Promise.resolve(ok({ items: [] }))),
+    list: (payload: unknown) => this.record('workspace.list', payload, Promise.resolve(ok({ items: [], archivedSessionIds: [] }))),
    create: (payload: unknown) => this.record('workspace.create', payload, Promise.resolve(ok({
      workspace: { workspaceId: 'fk-ws' as never, path: '/f/ws', title: 'ws', sessionIds: [], createdAt: '0', updatedAt: '0' },
      created: true,
@@ -134,6 +134,9 @@ export class FakeApiClient implements IApiClient {
    insertSessionBefore: (payload: unknown) => this.record('workspace.insertSessionBefore', payload, Promise.resolve(ok({
      workspace: { workspaceId: 'fk-ws' as never, path: '/f/ws', title: 'ws', sessionIds: [], createdAt: '0', updatedAt: '0' },
    }))),
+    archiveSession: (payload: unknown) => this.record('workspace.archiveSession', payload, Promise.resolve(ok({
+      archivedSessionIds: [(payload as { sessionId: SessionId }).sessionId],
+    }))),
  }

  // Payloads stay `unknown` (lint-lane note above); response rows are the real
--- a/packages/client/locale/tests/language-row.spec.tsx
+++ b/packages/client/locale/tests/language-row.spec.tsx
@@ -21,7 +21,7 @@ function emptySessions() {
 }
 function emptyWorkspaces() {
  const store = createSnapshotStore<WorkspaceListState>({
-    items: [], state: 'idle', phase: 'ready', error: null,
+    items: [], archivedSessionIds: [], state: 'idle', phase: 'ready', error: null,
    baselinesReady: true, recentWorkspaceId: undefined,
  })
  return bindSnapshotSelector(store)
--- a/packages/client/runtime/README.i18n.yaml
+++ b/packages/client/runtime/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/runtime/README.md
-README.md: 9f2b165f1a98dcecfa3ab82386da9b094cfd2f54
-README.zh.md: 3ed047e65d3bddc14c3b6b84f327bbeebf805d4b
+README.md: 022dc6f82ea7aa1490144449ea61a84a512906a2
+README.zh.md: 4d0f74f573a5e03b05755cfcfea930e69ef386e2
--- a/packages/client/runtime/README.md
+++ b/packages/client/runtime/README.md
@@ -10,6 +10,8 @@ Workspace and Session lists have independent monotone `pending` → `ready` base

 `WorkspacesService.delete(workspaceId)` removes the registration from the client projection after the successful unary response; the matching `host/workspace-removed` frame is idempotent and synchronizes other tabs. Session state and the current Session selection are independent, so accounted Sessions immediately project under Ungrouped after their Workspace disappears.

+`WorkspaceListState.archivedSessionIds` mirrors the Host's registry-global archive set (a `readonly SessionId[]` in Host order, replaced only when membership changes; consumers needing O(1) lookups build a transient Set). It is full-snapshot state: the `workspace.list` baseline, the `archiveSession` unary echo, and the `host/archived-sessions-changed` frame each install the complete set. `WorkspacesService.archiveSession(sessionId)` archives over the wire; the projection sweep clears the current selection into the New Session view state whenever it lands in the archive set — one rule covering the local echo, another tab's frame, and a reconnect baseline restoring a selection archived while this client was away. A set installed while a `workspace.list` request is in flight also supersedes that stale baseline's set. Grouping surfaces hide members everywhere while the session rows stay in the list store.
+
 SlotsService gives the renderer separate bare observables for `useSessions` and `useWorkspaces`; web-react creates the hooks. Workspace business state does not enter `SessionListState` or an entry store.

 `SessionsService.search(query, signal)` is a stateless one-shot action over the `session.search` RPC. It returns ranked session/snippet pairs without putting query, loading, or error state into the shared Session list, so each UI owner controls debounce, cancellation, stale-response suppression, and fallback presentation. `searchResultLimit` re-exposes `SESSION_SEARCH_RESULT_LIMIT` — the bound the response schema itself enforces — as injected presentation data, so client plugins do not duplicate it. It is a protocol constant rather than per-connection state, so the connection handle does not carry it.
--- a/packages/client/runtime/README.zh.md
+++ b/packages/client/runtime/README.zh.md
@@ -10,6 +10,8 @@ Workspace 和 Session 列表各自具有单调的 `pending` → `ready` 基线

 `WorkspacesService.delete(workspaceId)` 在一元响应成功后从客户端投影中移除注册记录；对应的 `host/workspace-removed` 帧具有幂等性，并负责同步其他标签页。Session 状态与当前 Session selection 相互独立，因此 Workspace 消失后，其已纳入客户端投影的 Session 会立即投影到 Ungrouped 下。

+`WorkspaceListState.archivedSessionIds` 镜像 Host 的注册表级全局归档集合（一个按 Host 顺序的 `readonly SessionId[]`，仅在成员变化时才替换；需要 O(1) 查询的消费方自建临时 Set）。它是全快照状态：`workspace.list` 基线、`archiveSession` 一元回声和 `host/archived-sessions-changed` 帧各自安装完整集合。`WorkspacesService.archiveSession(sessionId)` 通过 wire 归档；投影层在当前 selection 落入归档集合时统一清空为 New Session 视图状态——一条规则同时覆盖本地回声、其他标签页的帧、以及重连基线恢复出一个离线期间被归档的 selection。在 `workspace.list` 请求进行中安装的集合还会取代该过期基线携带的集合。各分组视图在所有位置隐藏集合成员，而会话行本身仍留在列表 store 中。
+
 SlotsService 分别为 renderer 提供 `useSessions` 与 `useWorkspaces` 的裸 observable；web-react 创建钩子。Workspace 业务状态不会进入 `SessionListState` 或配置项 store。

 `SessionsService.search(query, signal)` 是基于 `session.search` RPC 的无状态单次操作。它返回经过排序的会话／snippet 对，但不会将查询条件、加载状态或错误状态写入共享 Session 列表，因此每个 UI 所有者都自行负责防抖、取消、抑制陈旧响应和回退呈现。`searchResultLimit` 将 `SESSION_SEARCH_RESULT_LIMIT`——即响应 schema 自身强制执行的上限——作为注入的呈现数据重新公开，使客户端插件无需复制该值。它是协议常量而非逐连接状态，因此连接 handle 不携带它。
--- a/packages/client/runtime/src/client/contract/workspaces.ts
+++ b/packages/client/runtime/src/client/contract/workspaces.ts
@@ -76,4 +76,11 @@ export interface IWorkspaces {
   * @returns the updated Workspace view.
   */
  insertSessionBefore(workspaceId: WorkspaceId, sessionId: SessionId, beforeSessionId?: SessionId): Promise<WorkspaceView>
+  /**
+   * Archive a session into the registry-global set (hidden from grouping
+   * surfaces; session log and accounting slot remain). Archiving the current
+   * session clears the selection into the New Session view state.
+   * @param sessionId - session to archive.
+   */
+  archiveSession(sessionId: SessionId): Promise<void>
 }
--- a/packages/client/runtime/src/client/workspaces/manager.ts
+++ b/packages/client/runtime/src/client/workspaces/manager.ts
@@ -14,6 +14,14 @@ export type WorkspaceListPhase = 'pending' | 'ready'
 /** Immutable workspace-list snapshot. */
 export interface WorkspaceListSnapshot {
  items: readonly WorkspaceView[]
+  /**
+   * Registry-global archive set in Host order (hidden from grouping
+   * surfaces; accounting slots retained). A plain array, not a Set: public
+   * snapshot state stays in the store engine's plain-data vocabulary
+   * (immer drafts reject Sets without the MapSet plugin); membership
+   * lookups build their own transient Set where they need one.
+   */
+  archivedSessionIds: readonly SessionId[]
  state: 'idle' | 'loading' | 'error'
  phase: WorkspaceListPhase
  error: RpcError | null
@@ -28,11 +36,21 @@ export class WorkspaceManager {
  private items: Workspace[] = []
  private itemViewsSource: readonly Workspace[] | null = null
  private itemViewsCache: readonly WorkspaceView[] = []
+  // Full-snapshot state (list response / unary response / changed frame all
+  // carry the complete set), so deltas never merge — installs replace.
+  private archivedSessionIds: readonly SessionId[] = []
  private state: WorkspaceListSnapshot['state'] = 'idle'
  private phase: WorkspaceListPhase = 'pending'
  private error: RpcError | null = null
  private inflight: Promise<void> | null = null
  private refreshFrames: WorkspaceDelta[] | null = null
+  /**
+   * True once a frame or unary echo installed the archive set while a list
+   * request was in flight: that install is newer than the pending baseline,
+   * so the baseline's (older) set must not roll it back — the archive
+   * mirror of replaying refreshFrames over the item baseline.
+   */
+  private archivedSupersedesRefresh = false
  /**
   * Ids this process has seen removed, kept for the connection's lifetime so
   * a late changed frame or a stale baseline row cannot resurrect a deleted
@@ -77,6 +95,7 @@ export class WorkspaceManager {
          items = items.filter(workspace => !this.removedIds.has(workspace.workspaceId))
          for (const delta of frames) items = applyWorkspaceDelta(items, delta)
          this.installViews(items)
+          if (!this.archivedSupersedesRefresh) this.installArchived(result.value.archivedSessionIds)
          this.state = 'idle'
          this.phase = 'ready'
        } else {
@@ -90,6 +109,7 @@ export class WorkspaceManager {
        this.error = folded.ok ? null : folded.error
      } finally {
        this.refreshFrames = null
+        this.archivedSupersedesRefresh = false
        this.inflight = null
        this.notifier.markDirty()
      }
@@ -158,6 +178,18 @@ export class WorkspaceManager {
    return result
  }

+  /**
+   * Archive one session in the registry-global set, then install the
+   * returned full set without waiting for the changed frame.
+   * @param sessionId - session to archive.
+   * @returns the wire result.
+   */
+  async archiveSession(sessionId: SessionId): Promise<RpcResult<{ archivedSessionIds: SessionId[] }>> {
+    const { result } = await this.api.workspace.archiveSession({ sessionId })
+    if (result.ok) this.installArchived(result.value.archivedSessionIds)
+    return result
+  }
+
  /**
   * Host-frame entry. Non-workspace frames are ignored so the runtime can
   * fan one host stream out to both object managers.
@@ -166,6 +198,9 @@ export class WorkspaceManager {
  handleHostEnvelope(envelope: RpcRequest<HostFrame>): void {
    if (envelope.payload.type === 'host/workspace-changed') this.upsert(envelope.payload.workspace)
    else if (envelope.payload.type === 'host/workspace-removed') this.remove(envelope.payload.workspaceId)
+    else if (envelope.payload.type === 'host/archived-sessions-changed') {
+      this.installArchived(envelope.payload.archivedSessionIds)
+    }
  }

  /** Re-pull the baseline after each connection generation. */
@@ -194,12 +229,26 @@ export class WorkspaceManager {
  private buildSnapshot(): WorkspaceListSnapshot {
    return {
      items: this.itemViews(),
+      archivedSessionIds: this.archivedSessionIds,
      state: this.state,
      phase: this.phase,
      error: this.error,
    }
  }

+  /**
+   * Replace the archive set when membership actually changed (array identity
+   * backs Object.is short-circuits). Host snapshots are append-ordered, so
+   * positional comparison is exact, not merely heuristic.
+   */
+  private installArchived(archivedSessionIds: readonly SessionId[]): void {
+    if (this.refreshFrames !== null) this.archivedSupersedesRefresh = true
+    if (archivedSessionIds.length === this.archivedSessionIds.length
+      && archivedSessionIds.every((id, index) => id === this.archivedSessionIds[index])) return
+    this.archivedSessionIds = [...archivedSessionIds]
+    this.notifier.markDirty()
+  }
+
  /** Upsert one Host view, optionally retaining the local object that materialized it. */
  private upsert(view: WorkspaceView, identity?: Workspace): void {
    if (this.removedIds.has(view.workspaceId)) return
--- a/packages/client/runtime/src/client/workspaces/service.ts
+++ b/packages/client/runtime/src/client/workspaces/service.ts
@@ -14,6 +14,14 @@ import { WorkspaceManager, type WorkspaceListPhase } from './manager.ts'
 /** Workspace list plus the two-baseline readiness and default-target projection. */
 export interface WorkspaceListState {
  items: readonly WorkspaceView[]
+  /**
+   * Registry-global archive set in Host order: grouping surfaces hide these
+   * sessions everywhere (workspace groups and the ungrouped bucket) while
+   * their session logs and workspace accounting slots remain. A plain array
+   * (store-engine vocabulary; immer drafts reject Sets) — membership lookups
+   * build their own transient Set.
+   */
+  archivedSessionIds: readonly SessionId[]
  state: 'idle' | 'loading' | 'error'
  phase: WorkspaceListPhase
  error: RpcError | null
@@ -58,7 +66,7 @@ export class WorkspacesService implements IWorkspaces {
  constructor(ctx: Context, private readonly api: IApiClient, private readonly sessions: SessionsPort) {
    this.manager = new WorkspaceManager(api)
    this.list = createSnapshotStore<WorkspaceListState>({
-      items: [], state: 'idle', phase: 'pending', error: null,
+      items: [], archivedSessionIds: [], state: 'idle', phase: 'pending', error: null,
      baselinesReady: false, recentWorkspaceId: undefined,
    })
    this.manager.subscribe(() => { this.project() })
@@ -88,10 +96,14 @@ export class WorkspacesService implements IWorkspaces {
    if (inflight !== undefined) return inflight
    // Reuse: blank && same canonical cwd (workspace.path is the host realpath
    // canon; summary cwd is the session header passthrough of the same canon).
+    // An archived blank is never reused: reuse would open a session no
+    // grouping surface can show, so New Session mints a fresh one instead.
+    const archived = this.list.getSnapshot().archivedSessionIds
    const sessions = this.sessions.list.getSnapshot()
    for (const id of sessions.ids) {
      const summary = sessions.byId[id]
-      if (summary !== undefined && summary.blank && summary.cwd === workspace.path) return summary.id
+      if (summary !== undefined && summary.blank && summary.cwd === workspace.path
+        && !archived.includes(summary.id)) return summary.id
    }
    const attempt = this.sessions.create({ workspaceId })
      .finally(() => { this.connecting.delete(workspaceId) })
@@ -249,6 +261,17 @@ export class WorkspacesService implements IWorkspaces {
    if (!result.ok) throw new Error(`workspace delete failed: ${result.error.code}: ${result.error.message}`)
  }

+  /**
+   * Archive a session into the registry-global set. Clearing an archived
+   * current selection is the projection sweep's job (one rule for the local
+   * echo and a remote tab's frame alike).
+   * @param sessionId - session to archive.
+   */
+  async archiveSession(sessionId: SessionId): Promise<void> {
+    const result = await this.manager.archiveSession(sessionId)
+    if (!result.ok) throw new Error(`session archive failed: ${result.error.code}: ${result.error.message}`)
+  }
+
  /**
   * Move a session within its Workspace's manual order (DOM-insertBefore-like).
   * @param workspaceId - owning workspace.
@@ -291,8 +314,17 @@ export class WorkspacesService implements IWorkspaces {
    const workspace = this.manager.getSnapshot()
    const sessions = this.sessions.list.getSnapshot()
    const baselinesReady = workspace.phase === 'ready' && sessions.phase === 'ready'
+    // An archived current selection clears into the New Session view state —
+    // a hidden row must not stay open behind the list. Sweeping here covers
+    // every install path with one rule: the local unary echo, another tab's
+    // changed frame, and a reconnect baseline restoring a persisted
+    // selection that was archived while this client was away.
+    if (sessions.current !== undefined && workspace.archivedSessionIds.includes(sessions.current)) {
+      this.sessions.clear()
+    }
    this.list.set({
      items: workspace.items,
+      archivedSessionIds: workspace.archivedSessionIds,
      state: workspace.state,
      phase: workspace.phase,
      error: workspace.error,
--- a/packages/client/runtime/tests/fake-api.ts
+++ b/packages/client/runtime/tests/fake-api.ts
@@ -140,7 +140,10 @@ export class FakeApiClient implements IApiClient {
    openPath: (payload: unknown) => this.record('host.openPath', payload, this.onOpenPath(payload)),
  }

-  onWorkspaceList: (payload: unknown) => Promise<RpcResponse<{ items: never[] }>> = () => Promise.resolve(ok({ items: [] }))
+  // The archive-set field defaults at the binding below so list stubs keep
+  // the pre-archive `{ items }` shape; a stub carrying the field wins.
+  onWorkspaceList: (payload: unknown) => Promise<RpcResponse<{ items: never[]; archivedSessionIds?: never[] }>> =
+    () => Promise.resolve(ok({ items: [] }))
  onWorkspaceCreate: (payload: unknown) => Promise<RpcResponse<{ workspace: WorkspaceView; created: boolean }>> =
    () => Promise.resolve(ok({ workspace: fakeWorkspace('fk-ws'), created: true }))

@@ -153,13 +156,22 @@ export class FakeApiClient implements IApiClient {
  onWorkspaceInsertSessionBefore: (payload: unknown) => Promise<RpcResponse<{ workspace: WorkspaceView }>> =
    () => Promise.resolve(ok({ workspace: fakeWorkspace('fk-ws') }))

+  onWorkspaceArchiveSession: (payload: unknown) => Promise<RpcResponse<{ archivedSessionIds: SessionId[] }>> =
+    payload => Promise.resolve(ok({ archivedSessionIds: [(payload as { sessionId: SessionId }).sessionId] }))
+
  readonly workspace: IApiClient['workspace'] = {
-    list: (payload: unknown) => this.record('workspace.list', payload, this.onWorkspaceList(payload)),
+    list: (payload: unknown) => this.record('workspace.list', payload, this.onWorkspaceList(payload).then(response => (
+      response.result.ok
+        ? { ...response, result: { ok: true as const, value: { archivedSessionIds: [] as never[], ...response.result.value } } }
+        : response
+    )) as ReturnType<IApiClient['workspace']['list']>),
    create: (payload: unknown) => this.record('workspace.create', payload, this.onWorkspaceCreate(payload)),
    rename: (payload: unknown) => this.record('workspace.rename', payload, this.onWorkspaceRename(payload)),
    delete: (payload: unknown) => this.record('workspace.delete', payload, this.onWorkspaceDelete(payload)),
    insertSessionBefore: (payload: unknown) =>
      this.record('workspace.insertSessionBefore', payload, this.onWorkspaceInsertSessionBefore(payload)),
+    archiveSession: (payload: unknown) =>
+      this.record('workspace.archiveSession', payload, this.onWorkspaceArchiveSession(payload)),
  }

  // Payloads stay `unknown` (lint-lane note above); response rows are the real
--- a/packages/client/runtime/tests/workspaces-service.spec.ts
+++ b/packages/client/runtime/tests/workspaces-service.spec.ts
@@ -183,6 +183,12 @@ describe('WorkspacesService', () => {

    // Unknown workspace fails loud instead of silently creating in nowhere.
    await expect(workspaces.connectWorkspace(wid('ghost'))).rejects.toThrow(/unknown workspace ghost/)
+
+    // An archived blank is never reused: no surface can show it, so New
+    // Session mints a fresh one for alpha instead.
+    await workspaces.archiveSession(sid('s-blank'))
+    api.onCreate = () => Promise.resolve(ok({ sessionId: sid('s-fresh-2') }))
+    await expect(workspaces.connectWorkspace(wid('alpha'))).resolves.toBe('s-fresh-2')
  })

  it('a rejected first prompt keeps the blank session eligible for connectWorkspace reuse', async () => {
@@ -285,6 +291,84 @@ describe('WorkspacesService', () => {
    }))
    await expect(workspaces.delete(wid('ghost'))).rejects.toThrow(/workspace-not-found: gone/)
  })
+
+  it('archives a session, projects the set from the response, list, and frame, and clears only the current one', async () => {
+    const ctx = new Context()
+    const api = new FakeApiClient()
+    const sessions = new SessionsService(ctx, api)
+    const workspaces = new WorkspacesService(ctx, api, sessions)
+    api.onList = () => Promise.resolve(ok({
+      items: [
+        { sessionId: sid('s-open'), updatedAt: 2, running: false, blank: false },
+        { sessionId: sid('s-idle'), updatedAt: 1, running: false, blank: false },
+      ],
+    }) as never)
+    await sessions.refresh()
+    sessions.open(sid('s-open'))
+
+    // Archiving a non-current session installs the unary echo and keeps the selection.
+    await expect(workspaces.archiveSession(sid('s-idle'))).resolves.toBeUndefined()
+    expect(api.callsOf('workspace.archiveSession')).toEqual([{ sessionId: 's-idle' }])
+    expect(workspaces.list.getSnapshot().archivedSessionIds).toEqual(['s-idle'])
+    expect(sessions.list.getSnapshot().current).toBe('s-open')
+
+    // Archiving the current session clears it into the New Session view state.
+    api.onWorkspaceArchiveSession = () => Promise.resolve(ok({ archivedSessionIds: [sid('s-idle'), sid('s-open')] }))
+    await workspaces.archiveSession(sid('s-open'))
+    expect(workspaces.list.getSnapshot().archivedSessionIds).toEqual(['s-idle', 's-open'])
+    expect(sessions.list.getSnapshot().current).toBeUndefined()
+
+    // A Host failure leaves the set and the selection untouched.
+    api.onWorkspaceArchiveSession = () => Promise.resolve(err({
+      code: 'session-not-found', message: 'no session ghost', details: { sessionId: sid('ghost') },
+    }))
+    await expect(workspaces.archiveSession(sid('ghost'))).rejects.toThrow(/session-not-found/)
+    expect(workspaces.list.getSnapshot().archivedSessionIds).toEqual(['s-idle', 's-open'])
+
+    // The changed frame and the list baseline both re-install the full set.
+    workspaces.handleHostEnvelope({
+      rpcId: 'frame' as never,
+      payload: { type: 'host/archived-sessions-changed', archivedSessionIds: [sid('s-idle')] },
+    } as never)
+    // Frame installs ride the notifier's microtask batch before projecting.
+    await new Promise(resolve => setTimeout(resolve, 0))
+    expect(workspaces.list.getSnapshot().archivedSessionIds).toEqual(['s-idle'])
+    api.onWorkspaceList = () => Promise.resolve(ok({ items: [], archivedSessionIds: [sid('s-open')] }) as never)
+    await workspaces.refresh()
+    expect(workspaces.list.getSnapshot().archivedSessionIds).toEqual(['s-open'])
+  })
+
+  it('clears a current archived by a remote frame and shields the set from a stale in-flight baseline', async () => {
+    const ctx = new Context()
+    const api = new FakeApiClient()
+    const sessions = new SessionsService(ctx, api)
+    const workspaces = new WorkspacesService(ctx, api, sessions)
+    api.onList = () => Promise.resolve(ok({
+      items: [{ sessionId: sid('s-open'), updatedAt: 1, running: false, blank: false }],
+    }) as never)
+    await sessions.refresh()
+    sessions.open(sid('s-open'))
+
+    // A stale baseline is in flight (older, empty set) when another tab's
+    // archive frame lands: the frame clears the current selection and its
+    // set survives the baseline's later resolution.
+    const gate = deferred<Awaited<ReturnType<FakeApiClient['onWorkspaceList']>>>()
+    api.onWorkspaceList = () => gate.promise
+    const hydration = workspaces.refresh()
+    workspaces.handleHostEnvelope({
+      rpcId: 'frame' as never,
+      payload: { type: 'host/archived-sessions-changed', archivedSessionIds: [sid('s-open')] },
+    } as never)
+    await new Promise(resolve => setTimeout(resolve, 0))
+    expect(sessions.list.getSnapshot().current).toBeUndefined()
+    gate.resolve(ok({ items: [], archivedSessionIds: [] }))
+    await hydration
+    expect(workspaces.list.getSnapshot().archivedSessionIds).toEqual(['s-open'])
+    // The next (fresh) baseline is authoritative again.
+    api.onWorkspaceList = () => Promise.resolve(ok({ items: [], archivedSessionIds: [] }) as never)
+    await workspaces.refresh()
+    expect(workspaces.list.getSnapshot().archivedSessionIds).toEqual([])
+  })
 })

 describe('startInitialSelection', () => {
--- a/packages/client/test-runtime/src/fixtures.ts
+++ b/packages/client/test-runtime/src/fixtures.ts
@@ -73,6 +73,7 @@ export function conversationSnapshot(sessionId: SessionId): ConversationSnapshot
 export function workspaceListState(): WorkspaceListState {
  return {
    items: [],
+    archivedSessionIds: [],
    state: 'idle',
    phase: 'ready',
    error: null,
--- a/packages/client/test-runtime/src/workspaces.ts
+++ b/packages/client/test-runtime/src/workspaces.ts
@@ -186,4 +186,21 @@ export class TestWorkspaces implements IWorkspaces {
    if (stub !== undefined) return await (stub(workspaceId, sessionId, beforeSessionId) as Promise<WorkspaceView>)
    return { workspaceId, title: '', path: '', sessionIds: [sessionId] } as unknown as WorkspaceView
  }
+
+  /**
+   * Archive a session (recorded). The default mirrors the production face's
+   * observable effect: the id joins the list state's archive set.
+   * @param sessionId - session to archive.
+   */
+  async archiveSession(sessionId: SessionId): Promise<void> {
+    this.calls.push({ method: 'archiveSession', args: [sessionId] })
+    const stub = this.stubs.get('archiveSession')
+    if (stub !== undefined) {
+      await (stub(sessionId) as Promise<void>)
+      return
+    }
+    await this.update((draft) => {
+      draft.archivedSessionIds = [...draft.archivedSessionIds, sessionId]
+    })
+  }
 }
--- a/packages/client/test-runtime/tests/runtime.spec.tsx
+++ b/packages/client/test-runtime/tests/runtime.spec.tsx
@@ -551,8 +551,12 @@ describe('workspaces action face', () => {
    await ws.openPath('/proj/file.ts')
    const moved = await ws.insertSessionBefore('w1' as WorkspaceId, 's1' as SessionId, 's2' as SessionId)
    expect(moved.sessionIds).toEqual(['s1'])
+    // Default archive mirrors the production effect: the id joins the list
+    // state's archive set (features render against the same snapshot).
+    await ws.archiveSession('s1' as SessionId)
+    expect(ws.list.getSnapshot().archivedSessionIds).toEqual(['s1'])
    expect(ws.calls.map(c => c.method)).toEqual(
-      ['create', 'create', 'pickDirectory', 'rename', 'delete', 'openPath', 'insertSessionBefore'])
+      ['create', 'create', 'pickDirectory', 'rename', 'delete', 'openPath', 'insertSessionBefore', 'archiveSession'])

    ws.stub('create', () => Promise.resolve({ workspaceId: 'ws-x', title: 'X', path: '/x', sessionIds: [] } as never))
    ws.stub('pickDirectory', () => Promise.resolve('/picked'))
@@ -560,12 +564,16 @@ describe('workspaces action face', () => {
    ws.stub('delete', () => Promise.resolve())
    ws.stub('openPath', () => Promise.resolve())
    ws.stub('insertSessionBefore', () => Promise.resolve({ workspaceId: 'w1', title: '', path: '', sessionIds: [] } as never))
+    ws.stub('archiveSession', () => Promise.resolve())
    expect((await ws.create({ name: 'y' })).title).toBe('X')
    await expect(ws.pickDirectory()).resolves.toBe('/picked')
    expect((await ws.rename('w1' as WorkspaceId, 'z')).title).toBe('S')
    await ws.delete('w1' as WorkspaceId)
    await ws.openPath('/other')
    expect((await ws.insertSessionBefore('w1' as WorkspaceId, 's1' as SessionId)).sessionIds).toEqual([])
+    // The stub replaces the default set mutation: the set stays as-is.
+    await ws.archiveSession('s2' as SessionId)
+    expect(ws.list.getSnapshot().archivedSessionIds).toEqual(['s1'])
    await runtime.dispose()
  })
 })
--- a/packages/client/ui-conversation/tests/chat-code-subcalls.spec.tsx
+++ b/packages/client/ui-conversation/tests/chat-code-subcalls.spec.tsx
@@ -128,7 +128,7 @@ async function bench(snapshot: ConversationSnapshot) {
  ctx.provide('sessions', sessionsFake)
  const workspaces = {
    list: createSnapshotStore<WorkspaceListState>({
-      items: [], state: 'idle', phase: 'ready', error: null,
+      items: [], archivedSessionIds: [], state: 'idle', phase: 'ready', error: null,
      baselinesReady: true, recentWorkspaceId: undefined,
    }),
    startSession: vi.fn(),
--- a/packages/client/ui-conversation/tests/chat-view.spec.tsx
+++ b/packages/client/ui-conversation/tests/chat-view.spec.tsx
@@ -94,7 +94,7 @@ function emptySessions() {

 function emptyWorkspaces() {
  const store = createSnapshotStore<WorkspaceListState>({
-    items: [], state: 'idle', phase: 'ready', error: null,
+    items: [], archivedSessionIds: [], state: 'idle', phase: 'ready', error: null,
    baselinesReady: true, recentWorkspaceId: undefined,
  })
  return bindSnapshotSelector(store)
--- a/packages/client/ui-conversation/tests/diff-card.spec.tsx
+++ b/packages/client/ui-conversation/tests/diff-card.spec.tsx
@@ -287,7 +287,7 @@ describe('DetailsPanel diff Output section', () => {
        phase: 'ready',
      })
    const workspaces = createSnapshotStore<WorkspaceListState>({
-      items: [], state: 'idle', phase: 'ready', error: null,
+      items: [], archivedSessionIds: [], state: 'idle', phase: 'ready', error: null,
      baselinesReady: true, recentWorkspaceId: undefined,
    })
    return render(
--- a/packages/client/ui-conversation/tests/gate-branch-tails.spec.tsx
+++ b/packages/client/ui-conversation/tests/gate-branch-tails.spec.tsx
@@ -74,7 +74,7 @@ describe('render branch tails', () => {
    const emptyList = createSnapshotStore<SessionListState>(
      { ids: [], byId: {}, current: undefined, phase: 'ready' })
    const emptyWorkspaces = createSnapshotStore<WorkspaceListState>({
-      items: [], state: 'idle', phase: 'ready', error: null,
+      items: [], archivedSessionIds: [], state: 'idle', phase: 'ready', error: null,
      baselinesReady: true, recentWorkspaceId: undefined,
    })
    const view = render(
@@ -111,7 +111,7 @@ describe('render branch tails', () => {
    const emptyList = createSnapshotStore<SessionListState>(
      { ids: [], byId: {}, current: undefined, phase: 'ready' })
    const emptyWorkspaces = createSnapshotStore<WorkspaceListState>({
-      items: [], state: 'idle', phase: 'ready', error: null,
+      items: [], archivedSessionIds: [], state: 'idle', phase: 'ready', error: null,
      baselinesReady: true, recentWorkspaceId: undefined,
    })
    const view = render(
--- a/packages/client/ui-conversation/tests/input-bar.spec.tsx
+++ b/packages/client/ui-conversation/tests/input-bar.spec.tsx
@@ -96,7 +96,7 @@ function bench(over?: BenchOptions) {
      ids: [], byId: {}, current: undefined, phase: 'ready',
    })),
    useWorkspaces: bindSnapshotSelector(createSnapshotStore({
-      items: [], state: 'idle', phase: 'ready', error: null,
+      items: [], archivedSessionIds: [], state: 'idle', phase: 'ready', error: null,
      baselinesReady: true, recentWorkspaceId: undefined,
    })),
    useProjection: ((key: string, selector?: (v: unknown) => unknown) =>
--- a/packages/client/ui-conversation/tests/input-matrix.spec.tsx
+++ b/packages/client/ui-conversation/tests/input-matrix.spec.tsx
@@ -39,7 +39,7 @@ function mountBar(shell: SessionInputShell, over?: { running?: boolean; disabled
      ids: [], byId: {}, current: undefined, phase: 'ready',
    })),
    useWorkspaces: bindSnapshotSelector(createSnapshotStore({
-      items: [], state: 'idle', phase: 'ready', error: null,
+      items: [], archivedSessionIds: [], state: 'idle', phase: 'ready', error: null,
      baselinesReady: true, recentWorkspaceId: undefined,
    })),
    useProjection: (() => undefined),
--- a/packages/client/ui-conversation/tests/input-scenarios.spec.tsx
+++ b/packages/client/ui-conversation/tests/input-scenarios.spec.tsx
@@ -125,7 +125,7 @@ async function scopedBench(register?: (slash: SlashService) => void) {
      ids: [], byId: {}, current: undefined, phase: 'ready',
    })),
    useWorkspaces: bindSnapshotSelector(createSnapshotStore({
-      items: [], state: 'idle', phase: 'ready', error: null,
+      items: [], archivedSessionIds: [], state: 'idle', phase: 'ready', error: null,
      baselinesReady: true, recentWorkspaceId: undefined,
    })),
    useProjection: (() => undefined),
--- a/packages/client/ui-conversation/tests/skeleton.spec.tsx
+++ b/packages/client/ui-conversation/tests/skeleton.spec.tsx
@@ -62,7 +62,7 @@ function workspace(id = 'w1'): WorkspaceView {
 }

 const workspaceState = (items: readonly WorkspaceView[]): WorkspaceListState => ({
-  items, state: 'idle', phase: 'ready', error: null,
+  items, archivedSessionIds: [], state: 'idle', phase: 'ready', error: null,
  baselinesReady: true, recentWorkspaceId: undefined,
 })

--- a/packages/client/ui-conversation/tests/terminal-card.spec.tsx
+++ b/packages/client/ui-conversation/tests/terminal-card.spec.tsx
@@ -429,7 +429,7 @@ describe('DetailsPanel Output section', () => {
        phase: 'ready',
      })
    const workspaces = createSnapshotStore<WorkspaceListState>({
-      items: [], state: 'idle', phase: 'ready', error: null,
+      items: [], archivedSessionIds: [], state: 'idle', phase: 'ready', error: null,
      baselinesReady: true, recentWorkspaceId: undefined,
    })
    return render(
@@ -607,7 +607,7 @@ describe('DetailsPanel Output section', () => {
        useSessions={bindSnapshotSelector(createSnapshotStore<SessionListState>(
          { ids: [], byId: {}, current: undefined, phase: 'ready' }))}
        useWorkspaces={bindSnapshotSelector(createSnapshotStore<WorkspaceListState>({
-          items: [], state: 'idle', phase: 'ready', error: null,
+          items: [], archivedSessionIds: [], state: 'idle', phase: 'ready', error: null,
          baselinesReady: true, recentWorkspaceId: undefined,
        }))}
        useInput={(() => { throw new Error('unused') })}
--- a/packages/client/ui-conversation/tests/web-card.spec.tsx
+++ b/packages/client/ui-conversation/tests/web-card.spec.tsx
@@ -190,7 +190,7 @@ describe('DetailsPanel web Output section', () => {
    if (selection !== null) chat.actions.select(selection)
    const sessions = createSnapshotStore<SessionListState>({ ids: [], byId: {}, current: undefined, phase: 'ready' })
    const workspaces = createSnapshotStore<WorkspaceListState>({
-      items: [], state: 'idle', phase: 'ready', error: null,
+      items: [], archivedSessionIds: [], state: 'idle', phase: 'ready', error: null,
      baselinesReady: true, recentWorkspaceId: undefined,
    })
    return render(
--- a/packages/client/ui-layout/tests/app-frame.spec.tsx
+++ b/packages/client/ui-layout/tests/app-frame.spec.tsx
@@ -77,7 +77,7 @@ function mountFrame() {
    return sel(sessionState)
  }) as never
  const workspaceState: WorkspaceListState = {
-    items: [], state: 'idle', phase: 'ready', error: null,
+    items: [], archivedSessionIds: [], state: 'idle', phase: 'ready', error: null,
    baselinesReady: baselinesReady.current, recentWorkspaceId: undefined,
  }
  const element = () => (
--- a/packages/client/ui-theme/tests/appearance-row.spec.tsx
+++ b/packages/client/ui-theme/tests/appearance-row.spec.tsx
@@ -27,7 +27,7 @@ function emptySessions() {
 }
 function emptyWorkspaces() {
  const store = createSnapshotStore<WorkspaceListState>({
-    items: [], state: 'idle', phase: 'ready', error: null,
+    items: [], archivedSessionIds: [], state: 'idle', phase: 'ready', error: null,
    baselinesReady: true, recentWorkspaceId: undefined,
  })
  return bindSnapshotSelector(store)
--- a/packages/client/ui-trajectory/tests/views.spec.tsx
+++ b/packages/client/ui-trajectory/tests/views.spec.tsx
@@ -113,7 +113,7 @@ function emptySessions() {

 function emptyWorkspaces() {
  const store = createSnapshotStore<WorkspaceListState>({
-    items: [], state: 'idle', phase: 'ready', error: null, baselinesReady: true,
+    items: [], archivedSessionIds: [], state: 'idle', phase: 'ready', error: null, baselinesReady: true,
    recentWorkspaceId: undefined,
  })
  return bindSnapshotSelector(store)
--- a/packages/client/ui-workspace/README.i18n.yaml
+++ b/packages/client/ui-workspace/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-workspace/README.md
-README.md: f71bfa09c795bd69e1f49c8f6dffffd5959dbe47
-README.zh.md: 80b53d85eb210b0e7a7ace1699d6bbfc9a836606
+README.md: cc73214a281c6950acf8846f0bae3214c8726934
+README.zh.md: c0b6472c7db74dbfd4b0afd19a258e0132a7c534
--- a/packages/client/ui-workspace/README.md
+++ b/packages/client/ui-workspace/README.md
@@ -6,7 +6,7 @@ Shared Workspace browser and picker plugin. `WorkspaceBrowser` fills the sidebar

 The browser renders grouped or flat Session rows from the global runtime hooks and owns the Workspace create/rename and in-Workspace reorder flows. A non-blank search query replaces either browsing mode with one flat result list: case-insensitive title and Workspace substring matches appear immediately, while a 250 ms debounced Host request adds ranked current-conversation content matches and snippets. The English search input and its defensive request path remove NUL, cap the query at the wire schema's 500 UTF-16 code units without splitting a surrogate pair, and preserve the existing debounce and cancellation behavior. Each new query aborts the preceding request; a failed content search leaves metadata matches visible with a warning. The list is capped at 20, asks the user to narrow broader queries, and opens the selected Session without clearing the query or jumping to a specific event.

-The picker lists real Host Workspace entities through the global `useWorkspaces` hook. Selecting a Workspace invokes the slot owner's `onPick` callback to retarget the frontend Session object. Each registration declares a **directory-flow child hole** (`single` kind: `conversation.hero.workspace.directoryFlow` / `sidebar.workspaces.directoryFlow`) that the composed picker package's client half fills with its picking interaction — the [`-native`](../../host/directory-picker-native/README.md) backend's renderless OS-chooser driver today, an in-app browsing dialog under a `-browse` composition. The flat **Open local folder...** action renders only while the surface's hole is occupied (occupancy read per menu render; an empty hole means the composition has no picking affordance — the seam's documented no-flow default). This package owns the trigger and the adoption: the occupant reports one picked path per open through the hole's owner conversation (`open`/`busy`/`onPicked`/`onCancel`/`onError`), and the owner adopts it through the object layer, selecting the committed Workspace only after its list projection has refreshed; cancellation is silent, and errors land in the retryable folder dialog whose **Choose again** reopens the flow. **Create a new workspace** retains the name dialog and disables names already present in that list, while the Host remains authoritative for concurrent or non-UI callers. The runtime Session and Workspace services own materialization. The Workspace row's Delete action opens a confirmation that states the retention boundary, blocks duplicate submission, and keeps failures open; success removes the group while its Sessions remain under Ungrouped. The Session row's Rename action opens the same browser-owned dialog pattern prefilled with the row's display title: no client-side conflict rule exists (the host normalizes and may reject with `title-invalid`, rendered in the dialog alert), and confirming an unchanged title is deliberately allowed — it pins the current automatic title against regeneration.
+The picker lists real Host Workspace entities through the global `useWorkspaces` hook. Selecting a Workspace invokes the slot owner's `onPick` callback to retarget the frontend Session object. Each registration declares a **directory-flow child hole** (`single` kind: `conversation.hero.workspace.directoryFlow` / `sidebar.workspaces.directoryFlow`) that the composed picker package's client half fills with its picking interaction — the [`-native`](../../host/directory-picker-native/README.md) backend's renderless OS-chooser driver today, an in-app browsing dialog under a `-browse` composition. The flat **Open local folder...** action renders only while the surface's hole is occupied (occupancy read per menu render; an empty hole means the composition has no picking affordance — the seam's documented no-flow default). This package owns the trigger and the adoption: the occupant reports one picked path per open through the hole's owner conversation (`open`/`busy`/`onPicked`/`onCancel`/`onError`), and the owner adopts it through the object layer, selecting the committed Workspace only after its list projection has refreshed; cancellation is silent, and errors land in the retryable folder dialog whose **Choose again** reopens the flow. **Create a new workspace** retains the name dialog and disables names already present in that list, while the Host remains authoritative for concurrent or non-UI callers. The runtime Session and Workspace services own materialization. The Workspace row's Delete action opens a confirmation that states the retention boundary, blocks duplicate submission, and keeps failures open; success removes the group while its Sessions remain under Ungrouped. The Session row's Rename action opens the same browser-owned dialog pattern prefilled with the row's display title: no client-side conflict rule exists (the host normalizes and may reject with `title-invalid`, rendered in the dialog alert), and confirming an unchanged title is deliberately allowed — it pins the current automatic title against regeneration. The Session row's Archive action commits without a confirmation dialog (non-destructive: the log and the workspace accounting slot remain) through `ctx.workspaces.archiveSession`; the row disappears from every grouping surface — workspace groups, Ungrouped, content search, and the flat list — when the archive-set echo lands, and failures are console diagnostics that leave the tree unchanged. A blank New Session row is a pure placeholder: it renders no row menu and no time label (nothing has happened in it yet), so rename, fork, and archive first apply once the first prompt lands.

 The Session row's Fork action forks at the source's last completed turn, increments the inherited persisted title on the client, and then opens the child; a trailing ASCII or fullwidth parenthesized number is incremented in the same style, while an unnumbered title gets ` (1)` appended. The source and child always appear as peer rows within a workspace group, with lineage retained only as session data. A fork or rename failure leaves the current selection unchanged; after a rename failure, the created child remains in the list.

@@ -23,5 +23,5 @@ None; this package neither assembles nor sends a provider request.
 ## Known Limitations and Deferred Work

 - **No fuzzy content search or event deep links** — the content backend uses literal token/phrase matching, and selecting a result opens the Session rather than the matching event.
- **No Session deletion control** — the Session menu's Delete row remains visual-only; Workspace registration deletion does not delete Sessions.
+- **No Session deletion or unarchive control** — archiving replaces the former Delete placeholder; archived sessions have no viewing or unarchive surface yet, and Workspace registration deletion does not delete Sessions.
 - **Native folder selection depends on the local Host carrier** — under the `-native` composition, fixture-only or remote browser deployments cannot open a local operating-system dialog; platform failures are shown in a retryable modal. Remote-capable picking is the `-browse` composition's in-app flow.
--- a/packages/client/ui-workspace/README.zh.md
+++ b/packages/client/ui-workspace/README.zh.md
@@ -6,7 +6,7 @@

 该浏览器通过全局运行时钩子将 Session 行渲染为分组或扁平形式，并负责 Workspace 创建／重命名和 Workspace 内的重排序流程。非空白查询会以单一扁平结果列表替代任一浏览模式：不区分大小写的标题和 Workspace 子串匹配项会立即显示，经 250 ms 防抖的 Host 请求则会加入经过排序的当前对话内容匹配项及其摘要片段。英文搜索输入框及其防御性请求路径会移除 NUL，将查询限制在传输 schema 规定的 500 个 UTF-16 code unit 内且不会拆分 surrogate pair，并保留现有的防抖与取消行为。每次新查询都会中止前一个请求；内容搜索失败时，元数据匹配项仍会显示，同时给出警告。列表最多显示 20 条结果，并会在查询过宽时提示用户缩小范围；打开所选 Session 时既不会清除查询，也不会跳转至特定事件。

-该选择器通过全局 `useWorkspaces` hook 列出真实的 Host Workspace 实体。选择 Workspace 会调用 slot owner 的 `onPick` 回调，重新定位前端 Session 对象。每个注册各自声明一个**目录流子洞**（`single` kind：`conversation.hero.workspace.directoryFlow`／`sidebar.workspaces.directoryFlow`），由组合的选择器包 client half 填入其选取交互——今天是 [`-native`](../../host/directory-picker-native/README.md) 后端的无渲染 OS 选择器驱动，`-browse` 组合下则是应用内浏览对话框。平铺显示的 **打开本地文件夹…** 操作仅在本表层的洞被占用时渲染（每次菜单渲染读取占用状态；洞为空意味着该组合没有选目录能力——seam 文档化的无流程默认行为）。本包持有触发与接纳：占用者经洞的 owner 会话（`open`/`busy`/`onPicked`/`onCancel`/`onError`）每次打开上报一个所选路径，owner 通过对象层接纳它，并等待 Workspace 列表投影刷新后才选中已提交的 Workspace；取消操作不会显示提示，错误落入可重试的文件夹对话框，其 **重新选择** 会重新打开流程。**创建新工作区** 操作保留名称对话框，并禁用列表中已有的名称，而 Host 对并发或非 UI 调用方仍具有最终决定权。运行时 Session 与 Workspace 服务负责物化。Workspace 行内的 Delete 操作会打开确认框，说明保留边界、阻止重复提交，并在失败时保持打开；成功后，该分组会被移除，其 Session 则留在 Ungrouped 下。Session 行内的 Rename 操作打开同款浏览器持有的对话框，并以该行的显示标题预填：客户端不设名称冲突规则（host 负责规范化，可能以 `title-invalid` 拒绝，错误渲染在对话框告警区）；确认未修改的标题是有意允许的——这正是把当前自动标题钉住、不再被重新生成覆盖的手势。
+该选择器通过全局 `useWorkspaces` hook 列出真实的 Host Workspace 实体。选择 Workspace 会调用 slot owner 的 `onPick` 回调，重新定位前端 Session 对象。每个注册各自声明一个**目录流子洞**（`single` kind：`conversation.hero.workspace.directoryFlow`／`sidebar.workspaces.directoryFlow`），由组合的选择器包 client half 填入其选取交互——今天是 [`-native`](../../host/directory-picker-native/README.md) 后端的无渲染 OS 选择器驱动，`-browse` 组合下则是应用内浏览对话框。平铺显示的 **打开本地文件夹…** 操作仅在本表层的洞被占用时渲染（每次菜单渲染读取占用状态；洞为空意味着该组合没有选目录能力——seam 文档化的无流程默认行为）。本包持有触发与接纳：占用者经洞的 owner 会话（`open`/`busy`/`onPicked`/`onCancel`/`onError`）每次打开上报一个所选路径，owner 通过对象层接纳它，并等待 Workspace 列表投影刷新后才选中已提交的 Workspace；取消操作不会显示提示，错误落入可重试的文件夹对话框，其 **重新选择** 会重新打开流程。**创建新工作区** 操作保留名称对话框，并禁用列表中已有的名称，而 Host 对并发或非 UI 调用方仍具有最终决定权。运行时 Session 与 Workspace 服务负责物化。Workspace 行内的 Delete 操作会打开确认框，说明保留边界、阻止重复提交，并在失败时保持打开；成功后，该分组会被移除，其 Session 则留在 Ungrouped 下。Session 行内的 Rename 操作打开同款浏览器持有的对话框，并以该行的显示标题预填：客户端不设名称冲突规则（host 负责规范化，可能以 `title-invalid` 拒绝，错误渲染在对话框告警区）；确认未修改的标题是有意允许的——这正是把当前自动标题钉住、不再被重新生成覆盖的手势。Session 行内的 Archive 操作不经确认对话框直接提交（非破坏性：日志和 workspace 记账席位保持不变），通过 `ctx.workspaces.archiveSession` 归档；归档集合回声落地后，该行从所有分组视图——workspace 分组、Ungrouped、内容搜索和平铺列表——中消失，失败只作为控制台诊断输出，树保持不变。blank「新会话」行是纯占位：不渲染行菜单和时间标签（其中还没有发生任何事），rename/fork/归档都从首条 prompt 落地后才可用。

 Session 行内的 Fork 操作在源会话最后一个已完成轮次处 fork，在 client 端递增继承的持久化标题后再打开子会话；尾部半角或全角括号编号会原样式递增，无编号标题追加 ` (1)`。源会话与子会话在 workspace 组内始终作为同级行展示，谱系只保留为 session 数据。Fork 或改名失败都不会改变当前选中项，改名失败时已创建的子会话仍会留在列表中。

@@ -23,5 +23,5 @@ Session 行内的 Fork 操作在源会话最后一个已完成轮次处 fork，
 ## 已知限制与暂缓事项

 - **没有模糊内容搜索或事件深链接**：内容后端采用字面 token／短语匹配，选择结果会打开 Session，而不是匹配的事件。
- **没有 Session 删除控件**：Session 菜单的 Delete 行仍仅提供视觉效果；删除 Workspace 注册记录不会删除 Session。
+- **没有 Session 删除与取消归档控件**：归档取代了原先的 Delete 占位；已归档会话尚无查看或取消归档入口；删除 Workspace 注册记录不会删除 Session。
 - **原生文件夹选择依赖本地 Host 载体**：在 `-native` 组合下，仅使用 fixture（测试前置数据）的部署或远程浏览器部署无法打开本地操作系统对话框；模态框会显示平台故障，并允许重试。可远程的选取是 `-browse` 组合的应用内流程。
--- a/packages/client/ui-workspace/src/client/WorkspaceBrowser.tsx
+++ b/packages/client/ui-workspace/src/client/WorkspaceBrowser.tsx
@@ -102,18 +102,22 @@ type SessionTreeProps = Pick<
  'useSessions' | 'startSession' | 'open' | 'forkSession' | 'insertSessionBefore' | 't'
 > & {
  workspaces: readonly WorkspaceView[]
+  /** Registry-global archive set (hidden rows). */
+  archivedSessionIds: readonly SessionNode['id'][]
  /** Open the browser-owned rename dialog for a real Workspace group. */
  onRenameRequest: (workspaceId: WorkspaceId, currentTitle: string) => void
  /** Open the browser-owned delete-confirmation dialog for a real Workspace group. */
  onDeleteRequest: (workspaceId: WorkspaceId, currentTitle: string) => void
  /** Open the browser-owned session rename dialog. */
  onSessionRename: (sessionId: SessionNode['id'], currentTitle: string) => void
+  /** Archive a session (row menu action; the row disappears on the state echo). */
+  onSessionArchive: (sessionId: SessionNode['id']) => void
 }

 /** The scrolling session tree; unmounting at collapse settle drops the sessions subscription and expansion state. */
 function SessionTree({
-  useSessions, startSession, open, forkSession, workspaces,
-  onRenameRequest, onDeleteRequest, onSessionRename, insertSessionBefore, t,
+  useSessions, startSession, open, forkSession, workspaces, archivedSessionIds,
+  onRenameRequest, onDeleteRequest, onSessionRename, onSessionArchive, insertSessionBefore, t,
 }: SessionTreeProps) {
  const list = useSessions(s => s)
  const current = list.current
@@ -129,8 +133,8 @@ function SessionTree({
    setExpandedProjects(l => (l.includes(currentGroup) ? l : [...l, currentGroup]))
  }, [current, currentGroup])
  const groups = useMemo(
-    () => deriveGroups(list, workspaces, { expandedProjects }),
-    [list, workspaces, expandedProjects],
+    () => deriveGroups(list, workspaces, archivedSessionIds, { expandedProjects }),
+    [list, workspaces, archivedSessionIds, expandedProjects],
  )
  const now = Date.now()

@@ -209,6 +213,7 @@ function SessionTree({
                  onOpen={open}
                  onRename={onSessionRename}
                  onFork={forkSession}
+                  onArchive={onSessionArchive}
                  drag={dragProps}
                  t={t}
                />
@@ -223,9 +228,11 @@ function SessionTree({
 }

 /** The flat "In one list" body: every session a top-level row, newest-first. */
-function FlatList({ useSessions, open, forkSession, onSessionRename, t }: Pick<SessionTreeProps, 'useSessions' | 'open' | 'forkSession' | 'onSessionRename' | 't'>) {
+function FlatList({ useSessions, open, forkSession, onSessionRename, onSessionArchive, archivedSessionIds, t }: Pick<
+  SessionTreeProps, 'useSessions' | 'open' | 'forkSession' | 'onSessionRename' | 'onSessionArchive' | 'archivedSessionIds' | 't'
+>) {
  const list = useSessions(s => s)
-  const rows = useMemo(() => deriveFlat(list), [list])
+  const rows = useMemo(() => deriveFlat(list, archivedSessionIds), [list, archivedSessionIds])
  const now = Date.now()
  return (
    <div className={clsx(css.treeBody, css.wide)}>
@@ -242,6 +249,7 @@ function FlatList({ useSessions, open, forkSession, onSessionRename, t }: Pick<S
            onOpen={open}
            onRename={onSessionRename}
            onFork={forkSession}
+            onArchive={onSessionArchive}
            t={t}
          />
        ))}
@@ -263,12 +271,14 @@ function SearchResults({
  useSessions,
  open,
  workspaces,
+  archivedSessionIds,
  query,
  remote,
  resultLimit,
  t,
 }: Pick<SessionTreeProps, 'useSessions' | 'open' | 't'> & {
  workspaces: readonly WorkspaceView[]
+  archivedSessionIds: readonly SessionNode['id'][]
  query: string
  remote: RemoteSearchState
  resultLimit: number
@@ -278,8 +288,8 @@ function SearchResults({
    ? remote
    : { query, status: 'loading' as const, items: [], hasMore: false }
  const results = useMemo(
-    () => deriveSearchResults(list, workspaces, query, currentRemote, resultLimit),
-    [list, workspaces, query, currentRemote, resultLimit],
+    () => deriveSearchResults(list, workspaces, query, archivedSessionIds, currentRemote, resultLimit),
+    [list, workspaces, query, archivedSessionIds, currentRemote, resultLimit],
  )
  const pending = currentRemote.status === 'loading'
  const failed = currentRemote.status === 'error'
@@ -337,6 +347,7 @@ export function WorkspaceBrowser({
  forkSession,
  renameWorkspace,
  deleteWorkspace,
+  archiveSession,
  insertSessionBefore,
  createWorkspace,
  searchSessions,
@@ -346,6 +357,7 @@ export function WorkspaceBrowser({
  t,
 }: WorkspaceBrowserProps) {
  const workspaces = useWorkspaces(state => state.items)
+  const archivedSessionIds = useWorkspaces(state => state.archivedSessionIds)
  const groupBy = useStore(s => s.groupBy)
  // The query outlives the tree and the input (both wide-only) so collapsing
  // does not silently drop an in-progress filter.
@@ -475,6 +487,16 @@ export function WorkspaceBrowser({
    setSessionRenameError(null)
  }

+  // Archive is dialog-free: not destructive (the log and the accounting slot
+  // remain), so the menu action commits directly; the row disappears when the
+  // archive-set echo lands. Failures are non-fatal console diagnostics, the
+  // same posture as reorder rejections.
+  const onSessionArchive = (sessionId: SessionNode['id']) => {
+    archiveSession(sessionId).catch((reason: unknown) => {
+      console.warn('session archive rejected:', reason)
+    })
+  }
+
  // Delete dialog is separate from the row so a successful removal can
  // unmount that row without tearing down the in-flight confirmation state.
  const [deleteTarget, setDeleteTarget] = useState<{ workspaceId: WorkspaceId; title: string } | null>(null)
@@ -597,6 +619,7 @@ export function WorkspaceBrowser({
              useSessions={useSessions}
              open={open}
              workspaces={workspaces}
+              archivedSessionIds={archivedSessionIds}
              query={normalizedQuery}
              remote={remoteSearch}
              resultLimit={searchResultLimit}
@@ -607,15 +630,18 @@ export function WorkspaceBrowser({
            ? (
              <FlatList
                useSessions={useSessions} open={open} forkSession={forkSession}
-                onSessionRename={onSessionRename} t={t}
+                onSessionRename={onSessionRename} onSessionArchive={onSessionArchive}
+                archivedSessionIds={archivedSessionIds} t={t}
              />
            )
            : (
              <SessionTree
                useSessions={useSessions}
                onSessionRename={onSessionRename}
+                onSessionArchive={onSessionArchive}
                forkSession={forkSession}
                workspaces={workspaces}
+                archivedSessionIds={archivedSessionIds}
                startSession={startSession}
                open={open}
                insertSessionBefore={insertSessionBefore}
--- a/packages/client/ui-workspace/src/client/contract/slots.ts
+++ b/packages/client/ui-workspace/src/client/contract/slots.ts
@@ -113,6 +113,12 @@ export type WorkspaceBrowserInjected = DirectoryPickingInjected & {
  renameWorkspace: (workspaceId: WorkspaceId, title: string) => Promise<void>
  /** Delete only a Host Workspace registration; directory and Session logs remain. */
  deleteWorkspace: (workspaceId: WorkspaceId) => Promise<void>
+  /**
+   * Archive a Session into the registry-global set: hidden from grouping
+   * surfaces, log and accounting slot retained. Archiving the current
+   * session clears the selection into the New Session view state.
+   */
+  archiveSession: (sessionId: SessionId) => Promise<void>
  /**
   * Reorder a session inside its Workspace account (DOM-insertBefore
   * semantics: omitted anchor appends to the end). The view refreshes from
--- a/packages/client/ui-workspace/src/client/index.ts
+++ b/packages/client/ui-workspace/src/client/index.ts
@@ -92,6 +92,7 @@ export function apply(ctx: ClientContext): void {
    },
    renameWorkspace: async (workspaceId, title) => { await ctx.workspaces.rename(workspaceId, title) },
    deleteWorkspace: async (workspaceId) => { await ctx.workspaces.delete(workspaceId) },
+    archiveSession: async (sessionId) => { await ctx.workspaces.archiveSession(sessionId) },
    insertSessionBefore: async (workspaceId, sessionId, beforeSessionId) => {
      await ctx.workspaces.insertSessionBefore(workspaceId, sessionId, beforeSessionId)
    },
--- a/packages/client/ui-workspace/src/client/locales.ts
+++ b/packages/client/ui-workspace/src/client/locales.ts
@@ -45,7 +45,7 @@ export const zh = {
  'delete.desc': '将把“{name}”从工作区列表中移除。文件夹与会话记录会保留，其会话将显示在“未分组”下。',
  'delete.pending': '正在删除工作区…',
  'menu.fork': '分叉会话',
-  'menu.deleteSession': '删除会话',
+  'menu.archiveSession': '归档会话',
  'sessions.count.one': '{n} 个会话',
  'sessions.count.other': '{n} 个会话',
  'actions.workspace.aria': '工作区“{name}”的操作',
@@ -108,7 +108,7 @@ export const en = {
  'delete.desc': 'This removes “{name}” from the workspace list. The folder and session logs will be kept. Its sessions will appear under Ungrouped.',
  'delete.pending': 'Deleting workspace…',
  'menu.fork': 'Fork session',
-  'menu.deleteSession': 'Delete session',
+  'menu.archiveSession': 'Archive session',
  'sessions.count.one': '{n} session',
  'sessions.count.other': '{n} sessions',
  'actions.workspace.aria': 'Workspace actions for {name}',
--- a/packages/client/ui-workspace/src/client/rows/Rows.tsx
+++ b/packages/client/ui-workspace/src/client/rows/Rows.tsx
@@ -2,14 +2,14 @@
 * Workspace browser tree row components (figma Cell set 14:3080): pure presentational —
 * all data and callbacks arrive via props. Hover swaps (folder->chevron,
 * time->ellipsis, action buttons) are CSS-only. Row ... menus are visual-only
- * except workspace Rename/Delete and session Rename/Fork; the session and
- * workspace hover cards are suppressed while a menu is open.
+ * except workspace Rename/Delete and session Rename/Fork/Archive; the session
+ * and workspace hover cards are suppressed while a menu is open.
 */
 import { useState } from 'react'
 import clsx from 'clsx'
 import {
-  HoverCard, IconBranchOutline16, IconEditOutline16, IconEllipsisOutline16,
-  IconFolderClose16, IconFolderOpen16, IconPlusOutline16,
+  HoverCard, IconBranchOutline16, IconDownloadOutline16, IconEditOutline16,
+  IconEllipsisOutline16, IconFolderClose16, IconFolderOpen16, IconPlusOutline16,
  IconTrashOutline16, IconTriangleRightFill14, Menu, StateDot,
 } from '@deepseek-ai/dsh-client-ui-primitives'
 import type { WorkspaceBrowserProps } from '../contract/slots.ts'
@@ -175,7 +175,9 @@ function SessionHoverContent({ node, now, t }: { node: SessionNode; now: number;
  return (
    <div className={css.hoverContent}>
      <div className={css.hoverTitle}>{displayTitle(node, t)}</div>
-      <div className={css.hoverTime}>{hoverTimeLabel(node.updatedAt, now, t)}</div>
+      {/* Same placeholder rule as the row's trailing cell: no timestamp
+          before the first prompt. */}
+      {!node.blank && <div className={css.hoverTime}>{hoverTimeLabel(node.updatedAt, now, t)}</div>}
      <div className={css.hoverStatus}>
        <StateDot state={node.running ? 'ongoing' : 'done'} />
        <span>{node.running ? t('status.running') : t('status.idle')}</span>
@@ -243,7 +245,7 @@ function rowHalf(e: { clientY: number; currentTarget: HTMLElement }): 'before' |
  return e.clientY < rect.top + rect.height / 2 ? 'before' : 'after'
 }

-export function SessionNodeItem({ node, currentId, now, onOpen, onRename, onFork, drag, t }: {
+export function SessionNodeItem({ node, currentId, now, onOpen, onRename, onFork, onArchive, drag, t }: {
  node: SessionNode
  currentId: string | undefined
  now: number
@@ -252,6 +254,8 @@ export function SessionNodeItem({ node, currentId, now, onOpen, onRename, onFork
  onRename: (id: SessionNode['id'], currentTitle: string) => void
  /** Fork a session at its last completed turn (row menu action). */
  onFork: (id: SessionNode['id']) => void
+  /** Archive this session (row menu action; commits without a dialog). */
+  onArchive: (id: SessionNode['id']) => void
  /** Present only on draggable rows (workspace-group sessions outside search). */
  drag?: RowDragProps | undefined
  t: RowTranslate
@@ -260,10 +264,13 @@ export function SessionNodeItem({ node, currentId, now, onOpen, onRename, onFork
  const title = displayTitle(node, t)
  const selected = node.id === currentId
  const [menuOpen, setMenuOpen] = useState(false)
+  // Archive replaces the former Delete placeholder: it hides the row through
+  // the registry-global archive set and never touches the session log, so it
+  // is not styled as destructive and needs no confirmation dialog.
  const sessionMenuItems = [
    { id: 'rename', label: t('rename'), icon: <IconEditOutline16 /> },
    { id: 'fork', label: t('menu.fork'), icon: <IconBranchOutline16 /> },
-    { id: 'delete', label: t('menu.deleteSession'), icon: <IconTrashOutline16 />, danger: true },
+    { id: 'archive', label: t('menu.archiveSession'), icon: <IconDownloadOutline16 /> },
  ]
  // Figma session cell: pad 8, status slot 16, then a 4px title gap.
  const ownRow = (
@@ -301,31 +308,38 @@ export function SessionNodeItem({ node, currentId, now, onOpen, onRename, onFork
    >
      <span className={css.slot}>{row.running && <StateDot state="ongoing" />}</span>
      <span className={css.title}>{title}</span>
-      <span className={css.time}>{timeLabel(row.updatedAt, now, t)}</span>
-      <span className={css.rowActions}>
-        <Menu
-          open={menuOpen}
-          onClose={() => { setMenuOpen(false) }}
-          items={sessionMenuItems}
-          onSelect={(id) => {
-            setMenuOpen(false)
-            if (id === 'rename') onRename(node.id, row.title)
-            if (id === 'fork') onFork(node.id) // delete stays visual-only.
-          }}
-          portal
-          closeOnPointerLeave
-          anchor={(
-            <button
-              type="button"
-              className={css.iconButton}
-              aria-label={t('actions.session.aria', { name: title })}
-              onClick={(e) => { e.stopPropagation(); setMenuOpen(v => !v) }}
-            >
-              <IconEllipsisOutline16 />
-            </button>
-          )}
-        />
-      </span>
+      {/* A blank New Session row is a provisional placeholder: nothing has
+          happened in it yet, so a "now" timestamp and the row verbs
+          (rename/fork/archive) would all act on content that does not
+          exist — both trailing cells stay off until the first prompt. */}
+      {!row.blank && <span className={css.time}>{timeLabel(row.updatedAt, now, t)}</span>}
+      {!row.blank && (
+        <span className={css.rowActions}>
+          <Menu
+            open={menuOpen}
+            onClose={() => { setMenuOpen(false) }}
+            items={sessionMenuItems}
+            onSelect={(id) => {
+              setMenuOpen(false)
+              if (id === 'rename') onRename(node.id, row.title)
+              if (id === 'fork') onFork(node.id)
+              if (id === 'archive') onArchive(node.id)
+            }}
+            portal
+            closeOnPointerLeave
+            anchor={(
+              <button
+                type="button"
+                className={css.iconButton}
+                aria-label={t('actions.session.aria', { name: title })}
+                onClick={(e) => { e.stopPropagation(); setMenuOpen(v => !v) }}
+              >
+                <IconEllipsisOutline16 />
+              </button>
+            )}
+          />
+        </span>
+      )}
    </div>
  )
  return (
--- a/packages/client/ui-workspace/src/client/tree.ts
+++ b/packages/client/ui-workspace/src/client/tree.ts
@@ -90,9 +90,13 @@ function byRecency(a: SessionSummary, b: SessionSummary): number {
  return a.id < b.id ? -1 : 1
 }

-/** Ordinary sessions are visible; among blank sessions, only the current one is visible. */
-function sessionVisible(session: SessionSummary, current: SessionId | undefined): boolean {
-  return !session.blank || session.id === current
+/**
+ * Ordinary sessions are visible; among blank sessions, only the current one
+ * is visible; archived sessions are visible nowhere (their accounting slots
+ * remain, so unarchiving restores position).
+ */
+function sessionVisible(session: SessionSummary, current: SessionId | undefined, archived: ReadonlySet<SessionId>): boolean {
+  return !archived.has(session.id) && (!session.blank || session.id === current)
 }

 /**
@@ -126,7 +130,11 @@ function buildGroup(
 * order, with members resolved from sessionIds in their stored order. Sessions
 * outside every Workspace trail in the recency-ordered Ungrouped bucket.
 */
-function groupByWorkspace(list: SessionListState, workspaces: readonly WorkspaceView[]): Group[] {
+function groupByWorkspace(
+  list: SessionListState,
+  workspaces: readonly WorkspaceView[],
+  archived: ReadonlySet<SessionId>,
+): Group[] {
  const groups: Group[] = []
  const accounted = new Set<SessionId>()
  for (const workspace of workspaces) {
@@ -135,7 +143,7 @@ function groupByWorkspace(list: SessionListState, workspaces: readonly Workspace
      const summary = list.byId[id]
      if (summary === undefined) continue // account may lead the list pull; the row appears when the summary lands
      accounted.add(id)
-      if (!sessionVisible(summary, list.current)) continue
+      if (!sessionVisible(summary, list.current, archived)) continue
      members.push(summary)
    }
    groups.push(buildGroup(
@@ -146,7 +154,7 @@ function groupByWorkspace(list: SessionListState, workspaces: readonly Workspace
  const stray = list.ids
    .map(id => list.byId[id])
    .filter((s): s is SessionSummary =>
-      s !== undefined && !accounted.has(s.id) && sessionVisible(s, list.current))
+      s !== undefined && !accounted.has(s.id) && sessionVisible(s, list.current, archived))
  if (stray.length > 0) {
    groups.push(buildGroup(UNGROUPED_KEY, undefined, undefined, undefined, UNGROUPED_LABEL, stray, 'recency'))
  }
@@ -168,25 +176,29 @@ function sessionNode(s: SessionSummary): SessionNode {
 *
 * Every group shows; sessions populate under expanded groups, preserving
 * Host account order. Blank sessions are excluded except for the selected
- * provisional New Session row. Content search lives outside this derivation
+ * provisional New Session row; archived sessions are excluded everywhere.
+ * Content search lives outside this derivation
 * (see {@link deriveSearchResults}).
 * @param list - sessions list snapshot (`current` feeds containsCurrent).
 * @param workspaces - real workspaces in stable Host order.
+ * @param archivedSessionIds - registry-global archive set.
 * @param view - local expansion arrays.
 * @returns group sections in render order.
 */
 export function deriveGroups(
  list: SessionListState,
  workspaces: readonly WorkspaceView[],
+  archivedSessionIds: readonly SessionId[],
  view: TreeView,
 ): GroupNode[] {
+  const archived = new Set(archivedSessionIds)
  const expandedProjects = new Set(view.expandedProjects)
  const currentGroup = list.current === undefined
    ? undefined
    : (workspaces.find(w => w.sessionIds.includes(list.current as SessionId))?.workspaceId as string | undefined)
        ?? UNGROUPED_KEY
  const groups: GroupNode[] = []
-  for (const g of groupByWorkspace(list, workspaces)) {
+  for (const g of groupByWorkspace(list, workspaces, archived)) {
    const expanded = expandedProjects.has(g.key)
    groups.push({
      key: g.key,
@@ -209,13 +221,15 @@ export function deriveGroups(
 * no parent/child adjacency. Content search lives outside this derivation
 * (see {@link deriveSearchResults}).
 * @param list - sessions list snapshot.
+ * @param archivedSessionIds - registry-global archive set.
 * @returns flat rows in render order.
 */
-export function deriveFlat(list: SessionListState): SessionNode[] {
+export function deriveFlat(list: SessionListState, archivedSessionIds: readonly SessionId[]): SessionNode[] {
+  const archived = new Set(archivedSessionIds)
  const rows: SessionSummary[] = []
  for (const id of list.ids) {
    const s = list.byId[id]
-    if (s === undefined || !sessionVisible(s, list.current)) continue
+    if (s === undefined || !sessionVisible(s, list.current, archived)) continue
    rows.push(s)
  }
  rows.sort(byRecency)
@@ -238,6 +252,7 @@ export interface RelativeTime {
 * @param list - session metadata authority.
 * @param workspaces - Workspace membership and display labels.
 * @param query - caller text; surrounding whitespace is ignored.
+ * @param archivedSessionIds - registry-global archive set (members never match).
 * @param content - ranked Host content-search page.
 * @param limit - protocol-owned maximum merged row count.
 * @returns bounded deduplicated flat rows and a refine-query hint bit.
@@ -246,11 +261,13 @@ export function deriveSearchResults(
  list: SessionListState,
  workspaces: readonly WorkspaceView[],
  query: string,
+  archivedSessionIds: readonly SessionId[],
  content: { items: readonly SessionSearchResultItem[]; hasMore: boolean },
  limit: number,
 ): SearchResultSet {
  const q = query.trim().toLowerCase()
  if (q === '') return { items: [], hasMore: false }
+  const archived = new Set(archivedSessionIds)

  const workspaceBySession = new Map<SessionId, string>()
  for (const workspace of workspaces) {
@@ -270,7 +287,7 @@ export function deriveSearchResults(
    const summary = list.byId[id]
    // Blank placeholders never match a query (their canonical title displays
    // localized, so matching it would tie search to one language).
-    if (summary === undefined || summary.blank || !sessionVisible(summary, list.current)) continue
+    if (summary === undefined || summary.blank || !sessionVisible(summary, list.current, archived)) continue
    if (
      sessionTitle(summary).toLowerCase().includes(q)
      || labelOf(summary).toLowerCase().includes(q)
@@ -290,7 +307,7 @@ export function deriveSearchResults(
  for (const summary of local) include(summary)
  for (const item of content.items) {
    const summary = list.byId[item.sessionId]
-    if (summary !== undefined && !summary.blank && sessionVisible(summary, list.current)) include(summary)
+    if (summary !== undefined && !summary.blank && sessionVisible(summary, list.current, archived)) include(summary)
  }

  return {
--- a/packages/client/ui-workspace/tests/rows.spec.tsx
+++ b/packages/client/ui-workspace/tests/rows.spec.tsx
@@ -88,7 +88,7 @@ describe('workspace browser rows', () => {
    const onOpen = vi.fn()
    render(
      <SessionNodeItem node={node} currentId={node.id} now={0} onOpen={onOpen}
-        onRename={vi.fn()} onFork={vi.fn()} t={t} />,
+        onRename={vi.fn()} onFork={vi.fn()} onArchive={vi.fn()} t={t} />,
    )

    const row = screen.getByRole('treeitem')
@@ -157,18 +157,43 @@ describe('workspace browser rows', () => {
    expect(screen.queryByRole('button', { name: /工作区/ })).toBeNull()
  })

-  it('session row menu opens without opening the session and dispatches rename and fork', () => {
+  it('blank New Session rows carry no menu, no time label, and no hover-card time', () => {
+    vi.useFakeTimers()
+    try {
+      const node: SessionNode = {
+        id: sid('s-blank'), title: 'ignored', blank: true, running: false, updatedAt: 0,
+      }
+      render(<SessionNodeItem node={node} currentId={node.id} now={0} onOpen={vi.fn()}
+        onRename={vi.fn()} onFork={vi.fn()} onArchive={vi.fn()} t={t} />)
+      // The placeholder has no content yet: no row verbs, no "now" stamp.
+      expect(screen.queryByRole('button', { name: /会话.*的操作/ })).toBeNull()
+      expect(screen.queryByText('刚刚')).toBeNull()
+      // The hover card keeps title + status but drops the timestamp line.
+      const wrapper = screen.getByRole('treeitem').parentElement as HTMLElement
+      fireEvent.pointerEnter(wrapper)
+      act(() => { vi.advanceTimersByTime(500) })
+      expect(screen.getAllByText('新会话').length).toBeGreaterThanOrEqual(2)
+      expect(screen.getByText('空闲')).toBeTruthy()
+      expect(screen.queryByText('刚刚')).toBeNull()
+    } finally {
+      vi.useRealTimers()
+    }
+  })
+
+  it('session row menu opens without opening the session and dispatches rename, fork, and archive', () => {
    const onOpen = vi.fn()
    const onRename = vi.fn()
    const onFork = vi.fn()
+    const onArchive = vi.fn()
    const node: SessionNode = {
      id: sid('s1'), title: 'One', blank: false, running: false, updatedAt: 0,
    }
    render(<SessionNodeItem node={node} currentId={undefined} now={0} onOpen={onOpen}
-      onRename={onRename} onFork={onFork} t={t} />)
+      onRename={onRename} onFork={onFork} onArchive={onArchive} t={t} />)
    fireEvent.click(screen.getByRole('button', { name: '会话“One”的操作' }))
    expect(onOpen).not.toHaveBeenCalled()
-    expect(screen.getByRole('menuitem', { name: '删除会话' }).className).toMatch(/danger/)
+    // Archive is not destructive (log and accounting slot remain): no danger styling.
+    expect(screen.getByRole('menuitem', { name: '归档会话' }).className).not.toMatch(/danger/)
    // Rename dispatches with the current display title (dialog prefill).
    fireEvent.click(screen.getByRole('menuitem', { name: '重命名' }))
    expect(screen.queryByRole('menu')).toBeNull()
@@ -177,10 +202,12 @@ describe('workspace browser rows', () => {
    fireEvent.click(screen.getByRole('button', { name: '会话“One”的操作' }))
    fireEvent.click(screen.getByRole('menuitem', { name: '分叉会话' }))
    expect(onFork).toHaveBeenCalledWith(node.id)
-    // Delete stays visual-only.
+    // Archive dispatches without opening the session.
    fireEvent.click(screen.getByRole('button', { name: '会话“One”的操作' }))
-    fireEvent.click(screen.getByRole('menuitem', { name: '删除会话' }))
+    fireEvent.click(screen.getByRole('menuitem', { name: '归档会话' }))
+    expect(onArchive).toHaveBeenCalledWith(node.id)
    expect(onRename).toHaveBeenCalledOnce()
+    expect(onOpen).not.toHaveBeenCalled()
    // Escape closes without selecting (Menu onClose path).
    fireEvent.click(screen.getByRole('button', { name: '会话“One”的操作' }))
    fireEvent.keyDown(document, { key: 'Escape' })
@@ -194,7 +221,7 @@ describe('workspace browser rows', () => {
        id: sid('s1'), title: 'Hovered', blank: false, running: true, updatedAt: 0,
      }
      render(<SessionNodeItem node={node} currentId={undefined} now={60_000} onOpen={vi.fn()}
-        onRename={vi.fn()} onFork={vi.fn()} t={t} />)
+        onRename={vi.fn()} onFork={vi.fn()} onArchive={vi.fn()} t={t} />)
      const wrapper = screen.getByRole('treeitem').parentElement as HTMLElement
      fireEvent.pointerEnter(wrapper)
      act(() => { vi.advanceTimersByTime(500) })
@@ -220,7 +247,7 @@ describe('workspace browser rows', () => {
        id: sid('s1'), title: 'Quiet', blank: false, running: false, updatedAt: 0,
      }
      render(<SessionNodeItem node={node} currentId={undefined} now={0} onOpen={vi.fn()}
-        onRename={vi.fn()} onFork={vi.fn()} t={t} />)
+        onRename={vi.fn()} onFork={vi.fn()} onArchive={vi.fn()} t={t} />)
      fireEvent.pointerEnter(screen.getByRole('treeitem').parentElement as HTMLElement)
      act(() => { vi.advanceTimersByTime(500) })
      expect(screen.getByText('空闲')).toBeTruthy()
@@ -237,7 +264,7 @@ describe('workspace browser rows', () => {
    const inactive = dragProps()
    const { rerender } = render(
      <SessionNodeItem node={node} currentId={undefined} now={0} onOpen={vi.fn()}
-        onRename={vi.fn()} onFork={vi.fn()} drag={inactive} t={t} />,
+        onRename={vi.fn()} onFork={vi.fn()} onArchive={vi.fn()} drag={inactive} t={t} />,
    )
    const row = screen.getByRole('treeitem')
    stubRect(row)
@@ -255,7 +282,7 @@ describe('workspace browser rows', () => {
    const active = dragProps({ active: true, marker: 'before' })
    rerender(
      <SessionNodeItem node={node} currentId={undefined} now={0} onOpen={vi.fn()}
-        onRename={vi.fn()} onFork={vi.fn()} drag={active} t={t} />,
+        onRename={vi.fn()} onFork={vi.fn()} onArchive={vi.fn()} drag={active} t={t} />,
    )
    stubRect(screen.getByRole('treeitem'))
    // Top half hovers/drops 'before'; bottom half 'after' (row mid = 117).
@@ -269,7 +296,7 @@ describe('workspace browser rows', () => {
    const after = dragProps({ active: true, marker: 'after' })
    rerender(
      <SessionNodeItem node={node} currentId={undefined} now={0} onOpen={vi.fn()}
-        onRename={vi.fn()} onFork={vi.fn()} drag={after} t={t} />,
+        onRename={vi.fn()} onFork={vi.fn()} onArchive={vi.fn()} drag={after} t={t} />,
    )
    expect(screen.getByRole('treeitem').className).toMatch(/dropAfter/)
  })
--- a/packages/client/ui-workspace/tests/tree.spec.ts
+++ b/packages/client/ui-workspace/tests/tree.spec.ts
@@ -26,19 +26,21 @@ const workspace = (id: string, sessionIds: string[], title = id): WorkspaceView
 const view = (expandedProjects: readonly string[] = []) => ({
  expandedProjects,
 })
+const noArchive: readonly SessionId[] = []
+const archived = (...ids: string[]): readonly SessionId[] => ids.map(sid)

 describe('deriveGroups', () => {
  it('keeps Host Workspace and sessionIds order without Client recency sorting', () => {
    const sessions = list(summary('newer', 20), summary('older', 10))
    const workspaces = [workspace('first', ['older', 'newer']), workspace('empty', [])]
-    const groups = deriveGroups(sessions, workspaces, view(['first']))
+    const groups = deriveGroups(sessions, workspaces, noArchive, view(['first']))
    expect(groups.map(group => group.key)).toEqual(['first', 'empty'])
    expect(groups[0]!.sessions.map(session => session.id)).toEqual([sid('older'), sid('newer')])
  })

  it('puts only real unaccounted Sessions in the trailing Ungrouped group', () => {
    const sessions = list(summary('owned', 1, '/projects/first'), summary('loose', 9, '/other'))
-    const groups = deriveGroups(sessions, [workspace('first', ['owned'])], view([UNGROUPED_KEY]))
+    const groups = deriveGroups(sessions, [workspace('first', ['owned'])], noArchive, view([UNGROUPED_KEY]))
    expect(groups.map(group => group.key)).toEqual(['first', UNGROUPED_KEY])
    expect(groups[1]!.sessions.map(session => session.id)).toEqual([sid('loose')])
  })
@@ -52,7 +54,7 @@ describe('deriveGroups', () => {
      current: currentBlank.id,
    }
    const groups = deriveGroups(
-      sessions, [workspace('first', ['shown', 'current-blank', 'stale-blank'])], view(['first']),
+      sessions, [workspace('first', ['shown', 'current-blank', 'stale-blank'])], noArchive, view(['first']),
    )
    expect(groups[0]!.sessions.map(session => session.id)).toEqual([real.id, currentBlank.id])
    const blankNode = groups[0]!.sessions.find(session => session.id === currentBlank.id)!
@@ -63,7 +65,7 @@ describe('deriveGroups', () => {
    expect(groups[0]!.sessions.find(session => session.id === real.id)!.blank).toBe(false)
    expect(groups[0]!.sessionCount).toBe(2)
    // A non-current blank stray never surfaces an Ungrouped bucket either.
-    const strayGroups = deriveGroups(list({ ...summary('stray', 2), blank: true }), [workspace('first', [])], view())
+    const strayGroups = deriveGroups(list({ ...summary('stray', 2), blank: true }), [workspace('first', [])], noArchive, view())
    expect(strayGroups.map(group => group.key)).toEqual(['first'])
  })

@@ -80,6 +82,7 @@ describe('deriveGroups', () => {
    const groups = deriveGroups(
      list(parent, oldChild, newChild, tieB, tieA, self, orphan, cycleA, cycleB),
      [],
+      noArchive,
      { expandedProjects: [UNGROUPED_KEY] },
    )

@@ -90,7 +93,7 @@ describe('deriveGroups', () => {
    ])

    // Equal timestamps use ids as a deterministic tiebreak in either input order.
-    expect(deriveGroups(list(summary('tie-a', 1), summary('tie-b', 1)), [], view([UNGROUPED_KEY]))[0]!
+    expect(deriveGroups(list(summary('tie-a', 1), summary('tie-b', 1)), [], noArchive, view([UNGROUPED_KEY]))[0]!
      .sessions.map(node => node.id)).toEqual([sid('tie-a'), sid('tie-b')])
  })

@@ -100,17 +103,32 @@ describe('deriveGroups', () => {
      ids: [sid('present')],
      byId: { [sid('present')]: summary('present', 1) },
    }
-    const groups = deriveGroups(partial, [workspace('project', ['missing', 'present'])], view(['project']))
+    const groups = deriveGroups(partial, [workspace('project', ['missing', 'present'])], noArchive, view(['project']))
    expect(groups[0]!.sessions.map(node => node.id)).toEqual([sid('present')])
  })

+  it('hides archived sessions from workspace groups and Ungrouped', () => {
+    const kept = summary('kept', 1, '/projects/first')
+    const gone = summary('gone', 2, '/projects/first')
+    const looseGone = summary('loose-gone', 3, '/other')
+    const sessions = list(kept, gone, looseGone)
+    const groups = deriveGroups(
+      sessions, [workspace('first', ['kept', 'gone'])], archived('gone', 'loose-gone'), view(['first', UNGROUPED_KEY]),
+    )
+    // The archived member drops from its group AND the archived stray never
+    // surfaces an Ungrouped bucket; counts follow the visible rows.
+    expect(groups.map(group => group.key)).toEqual(['first'])
+    expect(groups[0]!.sessions.map(node => node.id)).toEqual([kept.id])
+    expect(groups[0]!.sessionCount).toBe(1)
+  })
+
  it('marks selected Workspace and Ungrouped sessions without relying on an Intent', () => {
    const owned = summary('owned', 1)
    const loose = summary('loose', 2)
    const ws = workspace('project', ['owned'])
-    const ownedGroups = deriveGroups({ ...list(owned, loose), current: owned.id }, [ws], view())
+    const ownedGroups = deriveGroups({ ...list(owned, loose), current: owned.id }, [ws], noArchive, view())
    expect(ownedGroups.find(group => group.key === 'project')!.containsCurrent).toBe(true)
-    const looseGroups = deriveGroups({ ...list(owned, loose), current: loose.id }, [ws], view())
+    const looseGroups = deriveGroups({ ...list(owned, loose), current: loose.id }, [ws], noArchive, view())
    expect(looseGroups.find(group => group.key === UNGROUPED_KEY)!.containsCurrent).toBe(true)
  })
 })
@@ -121,13 +139,13 @@ describe('deriveFlat', () => {
    const child = { ...summary('child', 30), parentId: parent.id }
    const tieB = summary('tie-b', 20)
    const tieA = summary('tie-a', 20)
-    const rows = deriveFlat(list(parent, child, tieB, tieA))
+    const rows = deriveFlat(list(parent, child, tieB, tieA), noArchive)
    expect(rows.map(row => row.id)).toEqual([sid('child'), sid('tie-a'), sid('tie-b'), sid('parent')])
  })

  it('tolerates ids whose summary has not landed yet', () => {
    const partial: SessionListState = { ...list(summary('present', 1)), ids: [sid('ghost'), sid('present')] }
-    expect(deriveFlat(partial).map(row => row.id)).toEqual([sid('present')])
+    expect(deriveFlat(partial, noArchive).map(row => row.id)).toEqual([sid('present')])
  })

  it('shows only the current blank session and excludes blanks from search', () => {
@@ -137,11 +155,35 @@ describe('deriveFlat', () => {
      ...list(summary('real', 1), currentBlank, staleBlank),
      current: currentBlank.id,
    }
-    const rows = deriveFlat(sessions)
+    const rows = deriveFlat(sessions, noArchive)
    expect(rows.map(row => row.id)).toEqual([currentBlank.id, sid('real')])
    expect(rows.map(row => row.title)).toEqual(['New Session', 'real'])
    expect(rows.map(row => row.blank)).toEqual([true, false])
  })
+
+  it('hides archived sessions in flat mode', () => {
+    const kept = summary('kept', 1)
+    const gone = summary('gone', 2)
+    expect(deriveFlat(list(kept, gone), archived('gone')).map(row => row.id)).toEqual([kept.id])
+  })
+})
+
+describe('deriveSearchResults archive filtering', () => {
+  it('archived sessions never match — not by title and not via a backend content hit', () => {
+    const hit = summary('hit', 2)
+    hit.displayTitle = 'Needle row'
+    const gone = summary('gone', 1)
+    gone.displayTitle = 'Needle archived'
+    const result = deriveSearchResults(
+      list(hit, gone),
+      [],
+      'needle',
+      archived('gone'),
+      { items: [{ sessionId: gone.id, snippet: 'needle body' }], hasMore: false },
+      10,
+    )
+    expect(result.items.map(item => item.id)).toEqual([hit.id])
+  })
 })

 describe('deriveSearchResults', () => {
@@ -160,6 +202,7 @@ describe('deriveSearchResults', () => {
        workspace('duplicate-owner', ['title-hit'], 'Ignored duplicate owner'),
      ],
      ' NEEDLE ',
+      noArchive,
      {
        items: [
          { sessionId: contentHit.id, snippet: 'body needle excerpt' },
@@ -212,6 +255,7 @@ describe('deriveSearchResults', () => {
      sessions,
      [workspace('first', ['opaque-current', 'new session stale'])],
      'new session',
+      noArchive,
      {
        items: [
          { sessionId: staleBlank.id, snippet: 'stale body' },
@@ -234,6 +278,7 @@ describe('deriveSearchResults', () => {
      list(...rows),
      [],
      'needle',
+      noArchive,
      { items: [], hasMore: false },
      3,
    )
@@ -244,12 +289,13 @@ describe('deriveSearchResults', () => {
      list(summary('body', 1)),
      [],
      'needle',
+      noArchive,
      { items: [{ sessionId: sid('body'), snippet: 'needle' }], hasMore: true },
      3,
    )
    expect(backendMore.items).toHaveLength(1)
    expect(backendMore.hasMore).toBe(true)
-    expect(deriveSearchResults(list(), [], '  ', { items: [], hasMore: true }, 3))
+    expect(deriveSearchResults(list(), [], '  ', noArchive, { items: [], hasMore: true }, 3))
      .toEqual({ items: [], hasMore: false })
  })
 })
--- a/packages/client/ui-workspace/tests/workspace-browser.spec.tsx
+++ b/packages/client/ui-workspace/tests/workspace-browser.spec.tsx
@@ -35,8 +35,8 @@ const workspace = (id: string, sessionIds: string[], title = id): WorkspaceView
  workspaceId: wid(id), path: `/projects/${id}`, title,
  sessionIds: sessionIds.map(sid), createdAt: '2026-01-01T00:00:00.000Z', updatedAt: '2026-01-01T00:00:00.000Z',
 })
-const workspaceState = (items: readonly WorkspaceView[]): WorkspaceListState => ({
-  items, state: 'idle', phase: 'ready', error: null, baselinesReady: true,
+const workspaceState = (items: readonly WorkspaceView[], archivedSessionIds: readonly SessionId[] = []): WorkspaceListState => ({
+  items, archivedSessionIds, state: 'idle', phase: 'ready', error: null, baselinesReady: true,
  recentWorkspaceId: items[0]?.workspaceId,
 })
 function hook<T>(snapshot: T) {
@@ -68,6 +68,7 @@ function mount(overrides: Partial<WorkspaceBrowserProps> = {}) {
    forkSession: vi.fn(),
    renameWorkspace: vi.fn(async () => {}),
    deleteWorkspace: vi.fn(async () => {}),
+    archiveSession: vi.fn(async () => {}),
    insertSessionBefore: vi.fn(async () => {}),
    createWorkspace: vi.fn(async () => workspace('created', [])),
    useDirectoryFlow: bindSnapshotSelector({ getSnapshot: () => true, subscribe: () => () => {} }),
@@ -135,6 +136,50 @@ describe('WorkspaceBrowser', () => {
    expect(screen.queryByText('alpha-s')).toBeNull()
  })

+  it('archives a session from the row menu and hides archived rows in both modes', async () => {
+    const archiveSession = vi.fn(async () => {})
+    const b = mount({
+      useSessions: hook(sessionState([summary('kept-s', 2), summary('gone-s', 1)])),
+      useWorkspaces: hook(workspaceState([workspace('alpha', ['kept-s', 'gone-s'])])),
+      archiveSession,
+    })
+    fireEvent.click(screen.getByText('alpha'))
+    fireEvent.click(screen.getByRole('button', { name: '会话“gone-s”的操作' }))
+    fireEvent.click(screen.getByRole('menuitem', { name: '归档会话' }))
+    expect(archiveSession).toHaveBeenCalledWith(sid('gone-s'))
+
+    // The archive-set echo hides the row in grouped mode (count included) and flat mode.
+    rerender(b, { useWorkspaces: hook(workspaceState([workspace('alpha', ['kept-s', 'gone-s'])], [sid('gone-s')])) })
+    expect(screen.queryByText('gone-s')).toBeNull()
+    expect(screen.getByText('1 个会话')).toBeTruthy()
+    fireEvent.click(screen.getByRole('button', { name: '分组方式' }))
+    fireEvent.click(screen.getByRole('menuitem', { name: '单列表' }))
+    expect(screen.getByText('kept-s')).toBeTruthy()
+    expect(screen.queryByText('gone-s')).toBeNull()
+  })
+
+  it('logs and keeps the tree when the archive call rejects', async () => {
+    const rejection = new Error('archive exploded')
+    const archiveSession = vi.fn(async () => { throw rejection })
+    const warn = vi.spyOn(console, 'warn').mockImplementation(() => {})
+    try {
+      mount({
+        useSessions: hook(sessionState([summary('alpha-s', 1)])),
+        useWorkspaces: hook(workspaceState([workspace('alpha', ['alpha-s'])])),
+        archiveSession,
+      })
+      fireEvent.click(screen.getByText('alpha'))
+      fireEvent.click(screen.getByRole('button', { name: '会话“alpha-s”的操作' }))
+      fireEvent.click(screen.getByRole('menuitem', { name: '归档会话' }))
+      await Promise.resolve()
+      await Promise.resolve()
+      expect(warn).toHaveBeenCalledWith('session archive rejected:', rejection)
+      expect(screen.getByText('alpha-s')).toBeTruthy()
+    } finally {
+      warn.mockRestore()
+    }
+  })
+
  it('renders a fork child as a top-level row without a session twist', () => {
    const parent = summary('parent-s', 2)
    const child = { ...summary('child-s', 1), parentId: parent.id }
--- a/packages/client/ui-workspace/tests/workspace-picker.spec.tsx
+++ b/packages/client/ui-workspace/tests/workspace-picker.spec.tsx
@@ -32,7 +32,7 @@ const sessions: SessionListState = {
  ids: [], byId: {}, current: undefined, phase: 'ready',
 }
 const workspaceState = (items: readonly WorkspaceView[]): WorkspaceListState => ({
-  items, state: 'idle', phase: 'ready', error: null, baselinesReady: true,
+  items, archivedSessionIds: [], state: 'idle', phase: 'ready', error: null, baselinesReady: true,
  recentWorkspaceId: items[0]?.workspaceId,
 })
 function anchor(): { current: HTMLElement } {