From b00cd0cd8cc75517262b3f1eba93ffd818f7b05c Mon Sep 17 00:00:00 2001
From: imccyu <276526105+imccyu@users.noreply.github.com>
Date: Fri, 31 Jul 2026 02:39:26 +0800
Subject: [PATCH 01/13] feat(workspace): add registry-global archivedSessionIds
 set

The workspace domain global singleton gains archivedSessionIds (schema
default [], version unchanged): a display-layer archive set layered over
workspace accounting. archiveSession() rides the registry operation
chain, validates the session against live/persisted headers, and is
idempotent; archived sessions keep their sessionIds slot so a future
unarchive restores position.
---
 packages/workspace/workspace/README.i18n.yaml |  4 +-
 packages/workspace/workspace/README.md        |  1 +
 packages/workspace/workspace/README.zh.md     |  1 +
 packages/workspace/workspace/src/index.ts     | 61 +++++++++++++-
 packages/workspace/workspace/src/spec.ts      |  9 +-
 .../workspace/tests/workspace.spec.ts         | 83 +++++++++++++++++--
 6 files changed, 145 insertions(+), 14 deletions(-)

diff --git a/packages/workspace/workspace/README.i18n.yaml b/packages/workspace/workspace/README.i18n.yaml
index a24e81d977..0805eb6ddc 100644
--- a/packages/workspace/workspace/README.i18n.yaml
+++ b/packages/workspace/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/workspace/workspace/README.md
-README.md: bee3e4fcb5dded273f30942ee2e42ee93b839e62
-README.zh.md: 9a052f796fb7cc8756999bdc9b2ce905805730ab
+README.md: 2d69074d42c28ba5e340cef19c8007bcba94e755
+README.zh.md: f95246a0c970aede1944868489d122d7f309d8e7
diff --git a/packages/workspace/workspace/README.md b/packages/workspace/workspace/README.md
index bee3e4fcb5..2d69074d42 100644
--- a/packages/workspace/workspace/README.md
+++ b/packages/workspace/workspace/README.md
@@ -13,6 +13,7 @@ The entity/storage rationale lives in the [domain Agent Note](../../../.agents/n
 - `ctx.workspace.delete(id)` — removes only the Workspace registration, its durable order entry, and its session account. Unknown ids return `false`; a removed record returns `true`. The directory, user files, live Sessions, and persisted session logs are never touched, so those Sessions become Ungrouped. A table-write failure restores the prior order and published entity.
 - `Workspace.attachSession(id)` — validates a live or persisted session header cwd against the workspace path and prepends a new id. Unknown sessions, absent/unresolvable/non-directory cwd values, and mismatches reject without writing. `detachSession` removes only the candidate index entry.
 - `ctx.workspace.touchSession(id)` — moves only that validated, accounted session to the front. Ungrouped or filtered sessions are no-ops, and workspace order never changes.
+- `ctx.workspace.archiveSession(id)` / `archivedSessionIds` — the registry-global archive set, layered over workspace accounting: an archived session disappears from grouping surfaces but keeps its session log and its `sessionIds` slot, so a future unarchive restores its position. Archiving accepts any live or persisted session (accounted or Ungrouped), resolves without writing for an already archived id, and rejects an unknown id. State written before the field existed parses with an empty set.
 - `Workspace.sessionIds` — synchronous id-plus-canonical-cwd membership projection in durable candidate order. Missing headers, invalid cwd values, and mismatches are filtered; the next workspace mutation prunes them. A medium indexing one session under two workspaces, claiming one path from two records, or diverging from durable workspace order rejects at startup.
 - `Workspace.status()` — uncached directory check, `'ok' | 'missing-dir'`; a missing directory never mutates the record.
 
diff --git a/packages/workspace/workspace/README.zh.md b/packages/workspace/workspace/README.zh.md
index 9a052f796f..f95246a0c9 100644
--- a/packages/workspace/workspace/README.zh.md
+++ b/packages/workspace/workspace/README.zh.md
@@ -13,6 +13,7 @@ DeepSeek Harness 的 Workspace 实体注册表（`ctx.workspace`）：通过领
 - `ctx.workspace.delete(id)`：只移除 Workspace 注册记录、对应的持久顺序条目及会话归属记录。未知 id 返回 `false`，成功移除记录则返回 `true`。目录、用户文件、活跃会话和持久化会话日志绝不受影响，因此相关会话会进入 Ungrouped。表写入失败时会恢复原顺序和此前发布的实体。
 - `Workspace.attachSession(id)`：对照 workspace 路径验证实时或已持久化的会话头 cwd，并将新 id 前置。未知会话、缺失／无法解析／非目录的 cwd 值和不匹配情况都会在不写入的前提下被拒绝。`detachSession` 只移除候选索引条目。
 - `ctx.workspace.touchSession(id)`：仅将已验证、已记账的会话移到最前。未分组或被过滤的会话不会触发任何操作，workspace 顺序绝不改变。
+- `ctx.workspace.archiveSession(id)`/`archivedSessionIds`：覆盖在 workspace 记账之上的注册表级全局归档集合：被归档的会话从各分组视图中消失，但其会话日志和 `sessionIds` 席位保持不变，未来取消归档时可恢复原位置。归档接受任何实时或已持久化的会话（无论已记账还是 Ungrouped），对已归档的 id 直接完成而不写入，并拒绝未知 id。在该字段出现之前写入的状态解析为一个空集合。
 - `Workspace.sessionIds`：按持久候选顺序提供同步 id 加规范 cwd 成员投影。缺失头部、无效 cwd 值和不匹配情况都被过滤；下一次 workspace 变更会剪除它们。如果同一存储介质将一个会话索引到两个 workspace 下、用两条记录声明同一路径，或偏离持久 workspace 顺序，启动会被拒绝。
 - `Workspace.status()`：未缓存的目录检查，返回 `'ok' | 'missing-dir'`；目录缺失绝不会改动记录。
 
diff --git a/packages/workspace/workspace/src/index.ts b/packages/workspace/workspace/src/index.ts
index 5172c63805..742c328e29 100644
--- a/packages/workspace/workspace/src/index.ts
+++ b/packages/workspace/workspace/src/index.ts
@@ -49,6 +49,18 @@ export class WorkspaceNameConflictError extends Error {
   }
 }
 
+/** An archiveSession request named a session neither live nor in session persistence. */
+export class WorkspaceUnknownSessionError extends Error {
+  /**
+   * @param sessionId - The unknown session id.
+   * @param options - Standard error options (the header-read failure as `cause`).
+   */
+  constructor(readonly sessionId: SessionId, options?: ErrorOptions) {
+    super(`cannot archive session '${sessionId}': live sessions and session persistence hold no such session`, options)
+    this.name = 'WorkspaceUnknownSessionError'
+  }
+}
+
 
 declare module 'cordis' {
   interface Context {
@@ -181,6 +193,38 @@ export class WorkspaceRegistry extends Service {
     return this.enqueueOperation(() => this.deleteKnown(id))
   }
 
+  /**
+   * The registry-global archive set: sessions hidden from every grouping
+   * surface. Archiving never touches workspace accounting — an archived
+   * session keeps its `sessionIds` slot so unarchiving restores its position.
+   * @returns the archived session ids in archive order.
+   */
+  get archivedSessionIds(): readonly SessionId[] {
+    return this.requireState().archivedSessionIds
+  }
+
+  /**
+   * Archive one session durably. The session must exist (live or in session
+   * persistence); its workspace accounting — or lack of one — is irrelevant.
+   * An already archived id resolves without writing.
+   * @param sessionId - The session to archive.
+   * @returns resolution after durability.
+   */
+  archiveSession(sessionId: SessionId): Promise<void> {
+    return this.enqueueOperation(async () => {
+      // The chain slot serializes against every other registry write, so this
+      // check-then-write pair cannot interleave with another archive.
+      if (this.requireState().archivedSessionIds.includes(sessionId)) return
+      try {
+        await this.readSessionHeader(sessionId)
+      } catch (error) {
+        throw new WorkspaceUnknownSessionError(sessionId, { cause: error })
+      }
+      const state = this.requireState()
+      await this.setState({ ...state, archivedSessionIds: [...state.archivedSessionIds, sessionId] })
+    })
+  }
+
   /**
    * Resolve by canonical directory path without creating or mutating a
    * workspace. A missing path rejects during `realpath`; an existing unowned
@@ -245,7 +289,11 @@ export class WorkspaceRegistry extends Service {
     }
 
     try {
-      await this.setState({ initialized: true, workspaceIds: [id, ...state.workspaceIds] })
+      await this.setState({
+        initialized: true,
+        workspaceIds: [id, ...state.workspaceIds],
+        archivedSessionIds: state.archivedSessionIds,
+      })
     } catch (error) {
       this.entities.delete(id)
       try {
@@ -276,6 +324,7 @@ export class WorkspaceRegistry extends Service {
     const nextState = {
       initialized: true,
       workspaceIds: state.workspaceIds.filter(workspaceId => workspaceId !== id),
+      archivedSessionIds: state.archivedSessionIds,
     }
     await this.setState({
       ...nextState,
@@ -329,7 +378,11 @@ export class WorkspaceRegistry extends Service {
       )
     }
     await this.requireTable().delete(pending.workspaceId)
-    await this.setState({ initialized: state.initialized, workspaceIds: state.workspaceIds })
+    await this.setState({
+      initialized: state.initialized,
+      workspaceIds: state.workspaceIds,
+      archivedSessionIds: state.archivedSessionIds,
+    })
   }
 
   private async bootstrap(headers: readonly SessionHeader[]): Promise<void> {
@@ -411,9 +464,9 @@ export class WorkspaceRegistry extends Service {
       .map(([id]) => id)
 
     if (!sameIds(state.workspaceIds, workspaceIds)) {
-      await this.setState({ initialized: false, workspaceIds })
+      await this.setState({ initialized: false, workspaceIds, archivedSessionIds: state.archivedSessionIds })
     }
-    await this.setState({ initialized: true, workspaceIds })
+    await this.setState({ initialized: true, workspaceIds, archivedSessionIds: state.archivedSessionIds })
   }
 
   private validateStoredState(state: WorkspaceDomainState): void {
diff --git a/packages/workspace/workspace/src/spec.ts b/packages/workspace/workspace/src/spec.ts
index 7b1a6a41d0..ba1b89e39d 100644
--- a/packages/workspace/workspace/src/spec.ts
+++ b/packages/workspace/workspace/src/spec.ts
@@ -42,11 +42,16 @@ const workspacePendingMutation = z.discriminatedUnion('operation', [
 /**
  * Durable registry state. `initialized` distinguishes a valid empty registry
  * from one that still needs the header-only history bootstrap;
- * `workspaceIds` is the authoritative display order.
+ * `workspaceIds` is the authoritative display order. `archivedSessionIds` is
+ * the registry-global archive set layered over workspace accounting: an
+ * archived session keeps its `sessionIds` slot (unarchiving must restore the
+ * position), so the set never participates in the one-owner accounting
+ * invariant. Defaulted so records written before the field parse unchanged.
  */
 export const workspaceDomainState = z.object({
   initialized: z.boolean(),
   workspaceIds: z.array(workspaceId),
+  archivedSessionIds: z.array(z.string().transform(SessionId)).default([]),
   pendingMutation: workspacePendingMutation.optional(),
 })
 
@@ -64,7 +69,7 @@ export const workspaceDomainSpec = defineDomain({
   version: 2,
   global: {
     schema: workspaceDomainState,
-    initial: { initialized: false, workspaceIds: [] },
+    initial: { initialized: false, workspaceIds: [], archivedSessionIds: [] },
   },
   tables: { workspaces: domainTable<WorkspaceId, WorkspaceRecord>(workspaceRecord) },
 })
diff --git a/packages/workspace/workspace/tests/workspace.spec.ts b/packages/workspace/workspace/tests/workspace.spec.ts
index 4576155f3b..56910f67c8 100644
--- a/packages/workspace/workspace/tests/workspace.spec.ts
+++ b/packages/workspace/workspace/tests/workspace.spec.ts
@@ -135,9 +135,16 @@ function record(path: string, sessionIds: string[], createdAt = '2026-07-24T00:0
   }
 }
 
+/**
+ * Media written before archivedSessionIds existed omit the field; keeping the
+ * fixtures in that shape continuously proves the schema default upgrades them.
+ */
+type StoredDomainState = Omit<WorkspaceDomainState, 'archivedSessionIds'>
+  & Partial<Pick<WorkspaceDomainState, 'archivedSessionIds'>>
+
 function storedPool(
   entries: Array<[string, WorkspaceRecord]>,
-  state: WorkspaceDomainState,
+  state: StoredDomainState,
 ): MemoryMediaPool {
   const pool = new MemoryMediaPool()
   pool.versions.set('workspace', DOMAIN_VERSION)
@@ -185,7 +192,7 @@ describe('WorkspaceRegistry lifecycle and bootstrap', () => {
     await fiber.await()
     expect(ctx.workspace.list()).toEqual([])
     expect(list).toHaveBeenCalledTimes(1)
-    expect(storedState(pool)).toEqual({ initialized: true, workspaceIds: [] })
+    expect(storedState(pool)).toEqual({ initialized: true, workspaceIds: [], archivedSessionIds: [] })
   })
 
   it('bootstraps once from list headers only, in workspace/session createdAt order', async () => {
@@ -218,6 +225,7 @@ describe('WorkspaceRegistry lifecycle and bootstrap', () => {
     expect(storedState(result.pool)).toEqual({
       initialized: true,
       workspaceIds: result.registry.list().map(workspace => workspace.id),
+      archivedSessionIds: [],
     })
   })
 
@@ -246,7 +254,7 @@ describe('WorkspaceRegistry lifecycle and bootstrap', () => {
     const second = await harness({ pool, sessions: [header('late', late, 100)] })
     expect(second.list).not.toHaveBeenCalled()
     expect(second.registry.list()).toEqual([])
-    expect(storedState(pool)).toEqual({ initialized: true, workspaceIds: [] })
+    expect(storedState(pool)).toEqual({ initialized: true, workspaceIds: [], archivedSessionIds: [] })
   })
 
   it('reuses partial records after a bootstrap record write fails', async () => {
@@ -476,7 +484,7 @@ describe('WorkspaceRegistry create and lookup', () => {
     await expect(result.registry.delete(workspace.id)).resolves.toBe(false)
     expect(result.registry.get(workspace.id)).toBeUndefined()
     expect(result.registry.list()).toEqual([])
-    expect(storedState(result.pool)).toEqual({ initialized: true, workspaceIds: [] })
+    expect(storedState(result.pool)).toEqual({ initialized: true, workspaceIds: [], archivedSessionIds: [] })
     expect(result.pool.media.get('workspace')!.tables.get('workspaces')!.has(workspace.id)).toBe(false)
     await expect(realpath(dir)).resolves.toBe(dir)
     expect(result.list).toHaveBeenCalledTimes(1)
@@ -519,6 +527,7 @@ describe('WorkspaceRegistry create and lookup', () => {
     expect(storedState(pool)).toEqual({
       initialized: true,
       workspaceIds: [],
+      archivedSessionIds: [],
       pendingMutation: { operation: 'delete', workspaceId: workspace.id },
     })
     const reregistered = await first.registry.create(dir)
@@ -526,6 +535,7 @@ describe('WorkspaceRegistry create and lookup', () => {
     expect(storedState(pool)).toEqual({
       initialized: true,
       workspaceIds: [reregistered.id],
+      archivedSessionIds: [],
     })
     await first.fiber.dispose()
 
@@ -762,7 +772,7 @@ describe('header-validated membership projection', () => {
     const createRecovery = await harness({ pool: interruptedCreate })
     expect(createRecovery.registry.list()).toEqual([])
     expect(interruptedCreate.media.get('workspace')!.tables.get('workspaces')!.has(createId)).toBe(false)
-    expect(storedState(interruptedCreate)).toEqual({ initialized: true, workspaceIds: [] })
+    expect(storedState(interruptedCreate)).toEqual({ initialized: true, workspaceIds: [], archivedSessionIds: [] })
 
     const interruptedDelete = storedPool(
       [[deleteId, record(deleteDir, [])]],
@@ -775,7 +785,7 @@ describe('header-validated membership projection', () => {
     const deleteRecovery = await harness({ pool: interruptedDelete })
     expect(deleteRecovery.registry.list()).toEqual([])
     expect(interruptedDelete.media.get('workspace')!.tables.get('workspaces')!.has(deleteId)).toBe(false)
-    expect(storedState(interruptedDelete)).toEqual({ initialized: true, workspaceIds: [] })
+    expect(storedState(interruptedDelete)).toEqual({ initialized: true, workspaceIds: [], archivedSessionIds: [] })
 
     const corruptPending = storedPool(
       [[deleteId, record(deleteDir, [])]],
@@ -816,3 +826,64 @@ describe('workspace mutation and status', () => {
     expect(registry.get(workspace.id)).toBe(workspace)
   })
 })
+
+describe('registry-global session archive', () => {
+  it('archives durably in order, idempotently skips repeats, and leaves accounting untouched', async () => {
+    const dir = await makeDir('archive-home')
+    const result = await harness({ sessions: [header('kept', dir, 100), header('gone', dir, 200)] })
+    const workspace = result.registry.list()[0]!
+    expect(result.registry.archivedSessionIds).toEqual([])
+
+    await result.registry.archiveSession(SessionId('gone'))
+    expect(result.registry.archivedSessionIds).toEqual(['gone'])
+    // Archiving is a display-set write: the workspace account keeps the id.
+    expect(workspace.sessionIds).toContain('gone')
+    expect(storedState(result.pool).archivedSessionIds).toEqual(['gone'])
+    const changesAfterFirst = result.changes.filter(change => change.table === '').length
+
+    await result.registry.archiveSession(SessionId('gone'))
+    expect(result.registry.archivedSessionIds).toEqual(['gone'])
+    // The idempotent repeat neither rewrites the medium nor emits a change.
+    expect(result.changes.filter(change => change.table === '').length).toBe(changesAfterFirst)
+
+    await result.registry.archiveSession(SessionId('kept'))
+    expect(result.registry.archivedSessionIds).toEqual(['gone', 'kept'])
+  })
+
+  it('accepts unaccounted and live sessions but rejects unknown ids without writing', async () => {
+    const dir = await makeDir('archive-strays')
+    const live = await makeDir('archive-live')
+    const result = await harness({
+      sessions: [header('stray', dir, 100)],
+      liveSessions: [header('live-only', live, 200)],
+    })
+    await result.registry.archiveSession(SessionId('stray'))
+    await result.registry.archiveSession(SessionId('live-only'))
+    expect(result.registry.archivedSessionIds).toEqual(['stray', 'live-only'])
+
+    await expect(result.registry.archiveSession(SessionId('ghost')))
+      .rejects.toThrow(/cannot archive session 'ghost'/)
+    expect(storedState(result.pool).archivedSessionIds).toEqual(['stray', 'live-only'])
+  })
+
+  it('restores the archive set across restarts and defaults it for pre-field media', async () => {
+    const dir = await makeDir('archive-restart')
+    const pool = new MemoryMediaPool()
+    const first = await harness({ pool, sessions: [header('s1', dir, 100)] })
+    await first.registry.archiveSession(SessionId('s1'))
+    await first.fiber.dispose()
+
+    const second = await harness({ pool, sessions: [header('s1', dir, 100)] })
+    expect(second.registry.archivedSessionIds).toEqual(['s1'])
+    await second.fiber.dispose()
+
+    // A medium written before the field existed parses through the schema default.
+    const legacyId = WorkspaceId('00000000-0000-4000-8000-00000000000a')
+    const legacy = storedPool(
+      [[legacyId, record(dir, [])]],
+      { initialized: true, workspaceIds: [legacyId] },
+    )
+    const upgraded = await harness({ pool: legacy })
+    expect(upgraded.registry.archivedSessionIds).toEqual([])
+  })
+})

From 53ceab53b82fac05251653d8bd6de2191c9c75c9 Mon Sep 17 00:00:00 2001
From: imccyu <276526105+imccyu@users.noreply.github.com>
Date: Fri, 31 Jul 2026 02:40:03 +0800
Subject: [PATCH 02/13] feat(apiproxy): workspace.archiveSession RPC and
 archived-sessions frame

workspace.archiveSession answers the full updated archive set;
workspace.list carries the set as the reconnect baseline; the host
stream pushes host/archived-sessions-changed full snapshots from the
domain/changed global-put branch (same posture as workspace-changed).
Unknown sessions map to the existing session-not-found code.
---
 packages/host/apiproxy/README.i18n.yaml       |  4 +-
 packages/host/apiproxy/README.md              |  2 +-
 packages/host/apiproxy/README.zh.md           |  2 +-
 packages/host/apiproxy/src/api-proxy.ts       | 36 ++++++++++++++++-
 .../host/apiproxy/src/api/events.schema.ts    |  1 +
 packages/host/apiproxy/src/api/events.ts      |  5 ++-
 packages/host/apiproxy/src/api/rpc-map.ts     |  1 +
 .../host/apiproxy/src/api/workspace.schema.ts | 11 +++++
 packages/host/apiproxy/src/api/workspace.ts   | 20 +++++++++-
 packages/host/apiproxy/src/fetch/client.ts    |  4 ++
 packages/host/apiproxy/src/fetch/handler.ts   |  2 +
 .../tests/api-proxy-workspace.spec.ts         | 40 +++++++++++++++++++
 .../apiproxy/tests/client-handler.spec.ts     |  7 +++-
 .../host/apiproxy/tests/fetch-carrier.spec.ts |  5 ++-
 .../host/apiproxy/tests/rpc-schemas.spec.ts   | 12 +++++-
 15 files changed, 139 insertions(+), 13 deletions(-)

diff --git a/packages/host/apiproxy/README.i18n.yaml b/packages/host/apiproxy/README.i18n.yaml
index 573790009f..1bd0f19d0b 100644
--- a/packages/host/apiproxy/README.i18n.yaml
+++ b/packages/host/apiproxy/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/host/apiproxy/README.md
-README.md: b12c1179a7b64b4b67efa01598e19bffc9f4198c
-README.zh.md: 740c01bf46a0df56470fd2b4655e3c21317199bb
+README.md: 8f08d90f8a91afc2ff022761d2d83de055df18a0
+README.zh.md: febeba0e601d75cbc69490d29135c206189efe29
diff --git a/packages/host/apiproxy/README.md b/packages/host/apiproxy/README.md
index b12c1179a7..8f08d90f8a 100644
--- a/packages/host/apiproxy/README.md
+++ b/packages/host/apiproxy/README.md
@@ -22,7 +22,7 @@ Session model routing is a session-domain contract. `session.models` returns the
 
 Pending queued input is a live control-plane contract, not session history. The gateway mirrors queued `InboxItem` occurrences from `agent/inbox/*` and broadcasts authoritative `session/queue` snapshots on every queued change and reconnect; pending steering stays outside this Web projection. `session.updateQueue` addresses one `InboxItemId`: edit replaces pending content and remove discards it. A driver claim wins races by retiring the address before admission; a later operation returns `queue-item-not-found`. The operation queries only an attached Agent and never resumes a cold session because process-local inbox identities do not survive restart or disposal. The client never infers retirement from turn or status events.
 
-Workspace and Session lists are separate reconnect baselines. `workspace.create` creates a unique name or adopts an existing directory, `workspace.delete` removes only the Workspace registration, `session.create` accepts an optional preallocated Session id, and `host/workspace-changed`, `host/workspace-removed`, plus `host/session-added` carry committed increments in either arrival order. Registration deletion preserves the directory and session logs; its Sessions remain in `session.list` and become Ungrouped. `SessionSummary.blank` and the `host/session-added` frame carry the derived zero-events bit: clients hide blank sessions and reuse them per workspace, flip blank on the first `host/session-status(running:true)`, and treat `session.list` as the reconnect authority; cold summaries are never blank because lazy persistence keeps never-appended sessions out of `list()`.
+Workspace and Session lists are separate reconnect baselines. `workspace.create` creates a unique name or adopts an existing directory, `workspace.delete` removes only the Workspace registration, `session.create` accepts an optional preallocated Session id, and `host/workspace-changed`, `host/workspace-removed`, plus `host/session-added` carry committed increments in either arrival order. `workspace.archiveSession` adds one session to the registry-global archive set and answers the full updated set; `workspace.list` carries that set as the reconnect baseline and `host/archived-sessions-changed` pushes the full snapshot after every durable change. Archiving hides the session from grouping surfaces without touching its log or its workspace account; a session neither live nor persisted fails with `session-not-found`. Registration deletion preserves the directory and session logs; its Sessions remain in `session.list` and become Ungrouped. `SessionSummary.blank` and the `host/session-added` frame carry the derived zero-events bit: clients hide blank sessions and reuse them per workspace, flip blank on the first `host/session-status(running:true)`, and treat `session.list` as the reconnect authority; cold summaries are never blank because lazy persistence keeps never-appended sessions out of `list()`.
 
 `session.search` is a bounded content-search projection over the sessions visible through `session.list`. The gateway asks the optional `ctx.sessionQuery` service for globally ranked current-surface user, assistant, and steering matches, consumes that stream until it has at most 20 visible session/snippet pairs plus one lookahead, and revalidates every hit against the list-derived authorization set before returning it. Provider pages start at 20 hits; when a first-page request rejects that limit, the gateway probes 10, 5, 2, then 1 and retains the learned size for continuation and stale-generation restarts. Returned snippets contain at most 240 Unicode code points, and the response schema independently enforces that bound at each client boundary. Keeping the authorization set in Host memory avoids SQLite's variable ceiling for large valid corpora without weakening visibility or ranking.
 
diff --git a/packages/host/apiproxy/README.zh.md b/packages/host/apiproxy/README.zh.md
index 740c01bf46..febeba0e60 100644
--- a/packages/host/apiproxy/README.zh.md
+++ b/packages/host/apiproxy/README.zh.md
@@ -22,7 +22,7 @@
 
 待处理的 queued 输入属于实时控制平面契约，而非会话历史。网关镜像来自 `agent/inbox/*` 的 queued `InboxItem` 入队项，并在每次 queued 变更和重连时广播权威的 `session/queue` 快照；待处理 steering（中途引导）不进入此 Web 投影。`session.updateQueue` 通过 `InboxItemId` 寻址单个项：编辑会替换待处理内容，移除会将其丢弃。驱动器在接纳前退役寻址标识，因此认领会赢得竞态；之后的操作返回 `queue-item-not-found`。该操作只查询当前已挂载的 Agent，绝不恢复冷会话，因为进程本地 inbox 标识无法在重启或资源释放后存活。客户端绝不根据轮次或状态事件推断项已退役。
 
-Workspace 列表与 Session 列表是相互独立的重连基线。`workspace.create` 会创建唯一名称或接纳现有目录，`workspace.delete` 只移除 Workspace 注册记录，`session.create` 接受可选的预分配 Session id，`host/workspace-changed`、`host/workspace-removed` 与 `host/session-added` 则以任意到达顺序携带已提交的增量。删除注册记录会保留目录和会话日志；相关 Session 仍留在 `session.list` 中，并进入 Ungrouped。`SessionSummary.blank` 与 `host/session-added` 帧携带派生的零事件位：客户端隐藏空白会话并按 workspace 复用它们，在首个 `host/session-status(running:true)` 时翻转 blank，并以 `session.list` 作为重连权威；冷会话摘要永远不是空白：惰性持久化让从未追加过事件的会话根本不出现在 `list()` 中。
+Workspace 列表与 Session 列表是相互独立的重连基线。`workspace.create` 会创建唯一名称或接纳现有目录，`workspace.delete` 只移除 Workspace 注册记录，`session.create` 接受可选的预分配 Session id，`host/workspace-changed`、`host/workspace-removed` 与 `host/session-added` 则以任意到达顺序携带已提交的增量。`workspace.archiveSession` 向注册表级全局归档集合添加一个会话，并应答完整的更新后集合；`workspace.list` 携带该集合作为重连基线，`host/archived-sessions-changed` 在每次持久变更后推送完整快照。归档只把会话从各分组视图中隐藏，不触碰其日志和 workspace 记账；既非实时也未持久化的会话以 `session-not-found` 失败。删除注册记录会保留目录和会话日志；相关 Session 仍留在 `session.list` 中，并进入 Ungrouped。`SessionSummary.blank` 与 `host/session-added` 帧携带派生的零事件位：客户端隐藏空白会话并按 workspace 复用它们，在首个 `host/session-status(running:true)` 时翻转 blank，并以 `session.list` 作为重连权威；冷会话摘要永远不是空白：惰性持久化让从未追加过事件的会话根本不出现在 `list()` 中。
 
 `session.search` 是以 `session.list` 所列会话为范围的有界内容搜索投影。网关向可选的 `ctx.sessionQuery` 服务请求全局排序后的当前 surface user、assistant 和 steering（中途引导）匹配项，并持续消费该结果流，直到获得至多 20 个可见会话／snippet 对及一个前瞻项；返回前仍会依据从列表推导的授权集合重新校验每个命中。提供方分页初始请求 20 个命中；如果第一页请求因这一上限被拒绝，网关会依次探测 10、5、2、1，并在续传和陈旧世代重启中沿用探测所得的页面大小。返回的 snippet 最多包含 240 个 Unicode 码点，响应 schema 则会在每个客户端边界独立强制执行该上限。将授权集合保留在宿主内存中，可在不削弱可见性或排序的前提下避开有效大型语料库的 SQLite 变量上限。
 
diff --git a/packages/host/apiproxy/src/api-proxy.ts b/packages/host/apiproxy/src/api-proxy.ts
index 205c9912f5..b6365a4a52 100644
--- a/packages/host/apiproxy/src/api-proxy.ts
+++ b/packages/host/apiproxy/src/api-proxy.ts
@@ -21,7 +21,7 @@ import { SessionQueryError, type SessionSearchCursor } from '@deepseek-ai/dsh-se
 import type { Workspace, WorkspaceRecord } from '@deepseek-ai/dsh-workspace'
 import {
   workspaceDomainState, workspaceRecord, WorkspaceId as brandWorkspaceId,
-  WorkspaceMoveInvalidError, WorkspaceNameConflictError,
+  WorkspaceMoveInvalidError, WorkspaceNameConflictError, WorkspaceUnknownSessionError,
 } from '@deepseek-ai/dsh-workspace'
 // Type-only: brings the `ctx.tools` Context merge into this program (viewFor reads presenters).
 import type {} from '@deepseek-ai/dsh-tools'
@@ -1582,7 +1582,10 @@ export function createApiProxy(ctx: Context, defaults: ApiProxyDefaults): ApiPro
 
     workspace: {
       list(request) {
-        return Promise.resolve(ok(request, { items: ctx.workspace.list().map(workspaceView) }))
+        return Promise.resolve(ok(request, {
+          items: ctx.workspace.list().map(workspaceView),
+          archivedSessionIds: [...ctx.workspace.archivedSessionIds],
+        }))
       },
 
       // Exactly one of path/name arrives (schema refine). Existing-folder
@@ -1698,6 +1701,23 @@ export function createApiProxy(ctx: Context, defaults: ApiProxyDefaults): ApiPro
         }
         return ok(request, { workspace: workspaceView(workspace) })
       },
+
+      async archiveSession(request) {
+        const { sessionId } = request.payload
+        try {
+          await ctx.workspace.archiveSession(sessionId)
+        } catch (error: unknown) {
+          // Only the registry's unknown-session rejection is the business
+          // code; storage/durability failures propagate as internal errors.
+          if (!(error instanceof WorkspaceUnknownSessionError)) throw error
+          return err(request, {
+            code: 'session-not-found',
+            message: error.message,
+            details: { sessionId },
+          })
+        }
+        return ok(request, { archivedSessionIds: [...ctx.workspace.archivedSessionIds] })
+      },
     },
 
     host: {
@@ -2109,6 +2129,10 @@ export function createApiProxy(ctx: Context, defaults: ApiProxyDefaults): ApiPro
         const committedWorkspaceIds = new Set(
           ctx.workspace.list().map(workspace => String(workspace.id)),
         )
+        // Frame-dedup baseline, same posture as committedWorkspaceIds: the
+        // stream opens against the current set; workspace.list re-baselines
+        // reconnecting clients, so only later changes need frames.
+        let archivedSessionIds = ctx.workspace.archivedSessionIds
         const disposers = [
           ctx.on('session/created', (session: Session) => {
             queue.push(frame({
@@ -2145,6 +2169,14 @@ export function createApiProxy(ctx: Context, defaults: ApiProxyDefaults): ApiPro
                 committedWorkspaceIds.add(workspaceId)
                 queue.push(frame({ type: 'host/workspace-changed', workspace: workspaceView(workspace) }))
               }
+              if (state.archivedSessionIds.length !== archivedSessionIds.length
+                || state.archivedSessionIds.some((id, index) => id !== archivedSessionIds[index])) {
+                archivedSessionIds = state.archivedSessionIds
+                queue.push(frame({
+                  type: 'host/archived-sessions-changed',
+                  archivedSessionIds: [...state.archivedSessionIds],
+                }))
+              }
               return
             }
             if (change.table !== 'workspaces') return
diff --git a/packages/host/apiproxy/src/api/events.schema.ts b/packages/host/apiproxy/src/api/events.schema.ts
index 186c189879..ea4b6c892f 100644
--- a/packages/host/apiproxy/src/api/events.schema.ts
+++ b/packages/host/apiproxy/src/api/events.schema.ts
@@ -71,6 +71,7 @@ export const hostFrameSchema = z.discriminatedUnion('type', [
   z.object({ type: z.literal('host/agent-error'), sessionId: sessionIdSchema, message: z.string() }),
   z.object({ type: z.literal('host/workspace-changed'), workspace: workspaceViewSchema }),
   z.object({ type: z.literal('host/workspace-removed'), workspaceId: workspaceIdSchema }),
+  z.object({ type: z.literal('host/archived-sessions-changed'), archivedSessionIds: z.array(sessionIdSchema) }),
   z.object({ type: z.literal('host/commands-changed') }),
   z.object({ type: z.literal('host/settings-changed'), ns: z.string() }),
   z.object({ type: z.literal('host/credentials-changed'), ref: z.string() }),
diff --git a/packages/host/apiproxy/src/api/events.ts b/packages/host/apiproxy/src/api/events.ts
index d678f2f911..d8ee3f6bff 100644
--- a/packages/host/apiproxy/src/api/events.ts
+++ b/packages/host/apiproxy/src/api/events.ts
@@ -101,7 +101,9 @@ export type MuxFrame =
  * workspace mutation (create/attach/order change — the client upserts, while
  * `workspace.list` provides the reconnect baseline); workspace-removed is the
  * committed registration-deletion increment and never implies directory or
- * session-log deletion.
+ * session-log deletion; archived-sessions-changed pushes the full registry
+ * archive set after every durable change (same full-snapshot posture as
+ * workspace-changed — `workspace.list` re-baselines it on reconnect).
  */
 export type HostFrame =
   | { type: 'host/session-added'; sessionId: SessionId; blank: boolean; parentSessionId?: SessionId; cwd?: string }
@@ -110,6 +112,7 @@ export type HostFrame =
   | { type: 'host/agent-error'; sessionId: SessionId; message: string }
   | { type: 'host/workspace-changed'; workspace: WorkspaceView }
   | { type: 'host/workspace-removed'; workspaceId: WorkspaceView['workspaceId'] }
+  | { type: 'host/archived-sessions-changed'; archivedSessionIds: SessionId[] }
   /**
    * The command registry changed (`commands/change` passthrough). Pure
    * invalidation signal, no payload: clients refetch `command.list` in the
diff --git a/packages/host/apiproxy/src/api/rpc-map.ts b/packages/host/apiproxy/src/api/rpc-map.ts
index f2f112f7cd..88e2c05575 100644
--- a/packages/host/apiproxy/src/api/rpc-map.ts
+++ b/packages/host/apiproxy/src/api/rpc-map.ts
@@ -42,6 +42,7 @@ export interface RpcMethodMap {
   'workspace.rename': WorkspaceApi['rename']
   'workspace.delete': WorkspaceApi['delete']
   'workspace.insertSessionBefore': WorkspaceApi['insertSessionBefore']
+  'workspace.archiveSession': WorkspaceApi['archiveSession']
   'command.list': CommandsApi['list']
   'command.execute': CommandsApi['execute']
   'skill.list': SkillsApi['list']
diff --git a/packages/host/apiproxy/src/api/workspace.schema.ts b/packages/host/apiproxy/src/api/workspace.schema.ts
index e16e5339da..20b3038301 100644
--- a/packages/host/apiproxy/src/api/workspace.schema.ts
+++ b/packages/host/apiproxy/src/api/workspace.schema.ts
@@ -28,6 +28,7 @@ export const workspaceListRequestSchema = z.object({}) satisfies z.ZodType<Wire<
 /** workspace.list response value. */
 export const workspaceListValueSchema = z.object({
   items: z.array(workspaceViewSchema),
+  archivedSessionIds: z.array(sessionIdSchema),
 }) satisfies z.ZodType<Wire<ResponseValue<'workspace.list'>>>
 
 /** workspace.create request payload: exactly one of path/name (the contract's create spellings). */
@@ -80,3 +81,13 @@ export const workspaceInsertSessionBeforeRequestSchema = z.object({
 export const workspaceInsertSessionBeforeValueSchema = z.object({
   workspace: workspaceViewSchema,
 }) satisfies z.ZodType<Wire<ResponseValue<'workspace.insertSessionBefore'>>>
+
+/** workspace.archiveSession request payload. */
+export const workspaceArchiveSessionRequestSchema = z.object({
+  sessionId: sessionIdSchema,
+}) satisfies z.ZodType<Wire<RequestPayload<'workspace.archiveSession'>>>
+
+/** workspace.archiveSession response value: the full updated archive set. */
+export const workspaceArchiveSessionValueSchema = z.object({
+  archivedSessionIds: z.array(sessionIdSchema),
+}) satisfies z.ZodType<Wire<ResponseValue<'workspace.archiveSession'>>>
diff --git a/packages/host/apiproxy/src/api/workspace.ts b/packages/host/apiproxy/src/api/workspace.ts
index ff22d845fb..957c566bbd 100644
--- a/packages/host/apiproxy/src/api/workspace.ts
+++ b/packages/host/apiproxy/src/api/workspace.ts
@@ -37,8 +37,13 @@ export interface WorkspaceView {
 
 /** Workspace-domain unary methods (the map keys workspace.* of RpcMethodMap). */
 export interface WorkspaceApi {
-  /** Lists all workspaces in the registry's durable display order. */
-  list(request: RpcRequest<{}>): Promise<RpcResponse<{ items: WorkspaceView[] }>>
+  /**
+   * Lists all workspaces in the registry's durable display order, plus the
+   * registry-global archive set (the reconnect baseline of
+   * `host/archived-sessions-changed`). Archived sessions stay in their
+   * workspace's `sessionIds` account; grouping surfaces hide them.
+   */
+  list(request: RpcRequest<{}>): Promise<RpcResponse<{ items: WorkspaceView[]; archivedSessionIds: SessionId[] }>>
 
   /**
    * Creates (or idempotently resolves) a workspace. Exactly one of `path` /
@@ -86,4 +91,15 @@ export interface WorkspaceApi {
     sessionId: SessionId
     beforeSessionId?: SessionId
   }>): Promise<RpcResponse<{ workspace: WorkspaceView }>>
+
+  /**
+   * Adds one session to the registry-global archive set: the session
+   * disappears from every grouping surface but keeps its session log and its
+   * workspace accounting slot (a future unarchive restores its position).
+   * Idempotent for an already archived id. A session neither live nor in
+   * session persistence fails with `session-not-found`. Returns the full
+   * updated set (same snapshot the changed frame carries).
+   */
+  archiveSession(request: RpcRequest<{ sessionId: SessionId }>):
+  Promise<RpcResponse<{ archivedSessionIds: SessionId[] }>>
 }
diff --git a/packages/host/apiproxy/src/fetch/client.ts b/packages/host/apiproxy/src/fetch/client.ts
index 5261658ee0..7b5c1545de 100644
--- a/packages/host/apiproxy/src/fetch/client.ts
+++ b/packages/host/apiproxy/src/fetch/client.ts
@@ -31,6 +31,7 @@ import {
   sessionUpdateQueueValueSchema,
 } from '../api/sessions.schema.ts'
 import {
+  workspaceArchiveSessionValueSchema,
   workspaceCreateValueSchema,
   workspaceDeleteValueSchema,
   workspaceInsertSessionBeforeValueSchema,
@@ -98,6 +99,7 @@ export interface IApiClient {
     rename(payload: RequestPayload<'workspace.rename'>, signal?: AbortSignal): Promise<RpcResponse<ResponseValue<'workspace.rename'>>>
     delete(payload: RequestPayload<'workspace.delete'>, signal?: AbortSignal): Promise<RpcResponse<ResponseValue<'workspace.delete'>>>
     insertSessionBefore(payload: RequestPayload<'workspace.insertSessionBefore'>, signal?: AbortSignal): Promise<RpcResponse<ResponseValue<'workspace.insertSessionBefore'>>>
+    archiveSession(payload: RequestPayload<'workspace.archiveSession'>, signal?: AbortSignal): Promise<RpcResponse<ResponseValue<'workspace.archiveSession'>>>
   }
   commands: {
     list(payload: RequestPayload<'command.list'>, signal?: AbortSignal): Promise<RpcResponse<ResponseValue<'command.list'>>>
@@ -163,6 +165,7 @@ const UNARY_VALUE_SCHEMAS: { [K in keyof RpcMethodMap]: z.ZodType<Wire<ResponseV
   'workspace.rename': workspaceRenameValueSchema,
   'workspace.delete': workspaceDeleteValueSchema,
   'workspace.insertSessionBefore': workspaceInsertSessionBeforeValueSchema,
+  'workspace.archiveSession': workspaceArchiveSessionValueSchema,
   'command.list': commandListValueSchema,
   'command.execute': commandExecuteValueSchema,
   'skill.list': skillListValueSchema,
@@ -400,6 +403,7 @@ export abstract class AbstractApiClient implements IApiClient {
     rename: (payload, signal) => this.callUnary('workspace.rename', payload, signal),
     delete: (payload, signal) => this.callUnary('workspace.delete', payload, signal),
     insertSessionBefore: (payload, signal) => this.callUnary('workspace.insertSessionBefore', payload, signal),
+    archiveSession: (payload, signal) => this.callUnary('workspace.archiveSession', payload, signal),
   }
 
   readonly commands: IApiClient['commands'] = {
diff --git a/packages/host/apiproxy/src/fetch/handler.ts b/packages/host/apiproxy/src/fetch/handler.ts
index 0cf7625a65..6bc060e969 100644
--- a/packages/host/apiproxy/src/fetch/handler.ts
+++ b/packages/host/apiproxy/src/fetch/handler.ts
@@ -33,6 +33,7 @@ import {
   hostPickDirectoryRequestSchema,
 } from '../api/host.schema.ts'
 import {
+  workspaceArchiveSessionRequestSchema,
   workspaceCreateRequestSchema,
   workspaceDeleteRequestSchema,
   workspaceInsertSessionBeforeRequestSchema,
@@ -96,6 +97,7 @@ const UNARY_ROUTES: UnaryRoutes = {
   'workspace.rename': { schema: workspaceRenameRequestSchema, invoke: (api, r) => api.workspace.rename(r) },
   'workspace.delete': { schema: workspaceDeleteRequestSchema, invoke: (api, r) => api.workspace.delete(r) },
   'workspace.insertSessionBefore': { schema: workspaceInsertSessionBeforeRequestSchema, invoke: (api, r) => api.workspace.insertSessionBefore(r) },
+  'workspace.archiveSession': { schema: workspaceArchiveSessionRequestSchema, invoke: (api, r) => api.workspace.archiveSession(r) },
   'command.list': { schema: commandListRequestSchema, invoke: (api, r) => api.commands.list(r) },
   'command.execute': { schema: commandExecuteRequestSchema, invoke: (api, r, signal) => api.commands.execute(r, signal) },
   'skill.list': { schema: skillListRequestSchema, invoke: (api, r) => api.skills.list(r) },
diff --git a/packages/host/apiproxy/tests/api-proxy-workspace.spec.ts b/packages/host/apiproxy/tests/api-proxy-workspace.spec.ts
index f520f8766a..d9211dde6c 100644
--- a/packages/host/apiproxy/tests/api-proxy-workspace.spec.ts
+++ b/packages/host/apiproxy/tests/api-proxy-workspace.spec.ts
@@ -441,4 +441,44 @@ describe('Host Workspace increments', () => {
     expect(expectOk(await api.sessions.list(request({}))).items.map(item => item.sessionId)).toContain(sessionId)
     abort.abort()
   })
+
+  it('archives a session into the global set, keeps its accounting, and streams the set once', async () => {
+    const { api } = await harness()
+    const workspace = expectOk(await api.workspace.create(request({ name: 'archive-home' }))).workspace
+    const sessionId = SessionId('session-to-archive')
+    expectOk(await api.sessions.create(request({ workspaceId: workspace.workspaceId, sessionId })))
+    expect(expectOk(await api.workspace.list(request({}))).archivedSessionIds).toEqual([])
+
+    const abort = new AbortController()
+    const stream: AsyncIterator<RpcRequest<HostFrame>> =
+      api.events.host(request({}), abort.signal)[Symbol.asyncIterator]()
+    const changed = nextHostFrame(stream)
+    expect(expectOk(await api.workspace.archiveSession(request({ sessionId }))).archivedSessionIds)
+      .toEqual([sessionId])
+    expect(await changed).toMatchObject({
+      payload: { type: 'host/archived-sessions-changed', archivedSessionIds: [sessionId] },
+    })
+
+    // Accounting and the session itself are untouched; list re-baselines the set.
+    const listed = expectOk(await api.workspace.list(request({})))
+    expect(listed.archivedSessionIds).toEqual([sessionId])
+    expect(listed.items[0]?.sessionIds).toEqual([sessionId])
+    expect(expectOk(await api.sessions.list(request({}))).items.map(item => item.sessionId)).toContain(sessionId)
+
+    // The idempotent repeat emits no second frame: the next observed frame is
+    // the workspace-changed of a later attach, not another archive snapshot.
+    const after = nextHostFrame(stream)
+    expect(expectOk(await api.workspace.archiveSession(request({ sessionId }))).archivedSessionIds)
+      .toEqual([sessionId])
+    const otherSession = SessionId('session-after-archive')
+    expectOk(await api.sessions.create(request({ workspaceId: workspace.workspaceId, sessionId: otherSession })))
+    expect((await after).payload.type).not.toBe('host/archived-sessions-changed')
+
+    const missing = await api.workspace.archiveSession(request({ sessionId: SessionId('session-ghost') }))
+    expect(missing.result).toMatchObject({
+      ok: false,
+      error: { code: 'session-not-found', details: { sessionId: 'session-ghost' } },
+    })
+    abort.abort()
+  })
 })
diff --git a/packages/host/apiproxy/tests/client-handler.spec.ts b/packages/host/apiproxy/tests/client-handler.spec.ts
index 1a667bf4a6..6307dfe8f9 100644
--- a/packages/host/apiproxy/tests/client-handler.spec.ts
+++ b/packages/host/apiproxy/tests/client-handler.spec.ts
@@ -66,11 +66,12 @@ function scriptedApi(overrides: {
       ...overrides.host,
     },
     workspace: {
-      list: r => ok(r, { items: [] }),
+      list: r => ok(r, { items: [], archivedSessionIds: [] }),
       create: r => ok(r, { workspace: { workspaceId: 'w1' as never, path: '/t', title: 't', sessionIds: [], createdAt: '0', updatedAt: '0' }, created: true }),
       rename: r => ok(r, { workspace: { workspaceId: 'w1' as never, path: '/t', title: 't', sessionIds: [], createdAt: '0', updatedAt: '0' } }),
       delete: r => ok(r, { deleted: true as const }),
       insertSessionBefore: r => ok(r, { workspace: { workspaceId: 'w1' as never, path: '/t', title: 't', sessionIds: [], createdAt: '0', updatedAt: '0' } }),
+      archiveSession: r => ok(r, { archivedSessionIds: [r.payload.sessionId] }),
     },
     commands: {
       list: r => ok(r, { commands: [] }),
@@ -360,10 +361,12 @@ describe('workspace domain round trip', () => {
   it('routes both workspace methods through their handler rows and value schemas', async () => {
     const c = client(scriptedApi())
     const list = await c.workspace.list({})
-    expect(list.result).toEqual({ ok: true, value: { items: [] } })
+    expect(list.result).toEqual({ ok: true, value: { items: [], archivedSessionIds: [] } })
     const created = await c.workspace.create({ path: '/t' })
     expect(created.result.ok).toBe(true)
     if (created.result.ok) expect(created.result.value.created).toBe(true)
+    const archivedResponse = await c.workspace.archiveSession({ sessionId: 's-arch' as never })
+    expect(archivedResponse.result).toEqual({ ok: true, value: { archivedSessionIds: ['s-arch'] } })
   })
 
   it('rejects a create payload violating the exactly-one refine at the handler', async () => {
diff --git a/packages/host/apiproxy/tests/fetch-carrier.spec.ts b/packages/host/apiproxy/tests/fetch-carrier.spec.ts
index 3a21d6d1ce..ef111afe12 100644
--- a/packages/host/apiproxy/tests/fetch-carrier.spec.ts
+++ b/packages/host/apiproxy/tests/fetch-carrier.spec.ts
@@ -122,7 +122,7 @@ function fakeApi(overrides: Partial<{ muxFrames: MuxFrame[]; hostFrames: HostFra
     },
     workspace: {
       async list(request) {
-        return { rpcId: request.rpcId, result: { ok: true, value: { items: [] } } }
+        return { rpcId: request.rpcId, result: { ok: true, value: { items: [], archivedSessionIds: [] } } }
       },
       async create(request) {
         return {
@@ -145,6 +145,9 @@ function fakeApi(overrides: Partial<{ muxFrames: MuxFrame[]; hostFrames: HostFra
           result: { ok: true, value: { workspace: { workspaceId: 'w1' as never, path: '/w', title: 'w', sessionIds: [], createdAt: 't', updatedAt: 't' } } },
         }
       },
+      async archiveSession(request) {
+        return { rpcId: request.rpcId, result: { ok: true, value: { archivedSessionIds: [request.payload.sessionId] } } }
+      },
     },
     commands: {
       async list(request) {
diff --git a/packages/host/apiproxy/tests/rpc-schemas.spec.ts b/packages/host/apiproxy/tests/rpc-schemas.spec.ts
index aa9c46d9ae..f6bd093178 100644
--- a/packages/host/apiproxy/tests/rpc-schemas.spec.ts
+++ b/packages/host/apiproxy/tests/rpc-schemas.spec.ts
@@ -20,6 +20,7 @@ import {
   hostListDirectoryRequestSchema, hostListDirectoryValueSchema,
 } from '../src/api/host.schema.ts'
 import {
+  workspaceArchiveSessionRequestSchema, workspaceArchiveSessionValueSchema,
   workspaceCreateRequestSchema, workspaceCreateValueSchema, workspaceIdSchema,
   workspaceDeleteRequestSchema, workspaceDeleteValueSchema,
   workspaceInsertSessionBeforeRequestSchema, workspaceInsertSessionBeforeValueSchema,
@@ -312,7 +313,16 @@ describe('workspace domain schemas', () => {
     expect(workspaceViewSchema.parse(view).sessionIds).toEqual(['s1'])
     expect(() => workspaceViewSchema.parse({ ...view, sessionIds: 's1' })).toThrow()
     expect(workspaceListRequestSchema.parse({})).toEqual({})
-    expect(workspaceListValueSchema.parse({ items: [view] }).items).toHaveLength(1)
+    expect(workspaceListValueSchema.parse({ items: [view], archivedSessionIds: ['s1'] }).items).toHaveLength(1)
+    expect(() => workspaceListValueSchema.parse({ items: [view] })).toThrow()
+  })
+
+  it('archiveSession request/value carry the id and the full updated set', () => {
+    expect(workspaceArchiveSessionRequestSchema.parse({ sessionId: 's1' }).sessionId).toBe('s1')
+    expect(() => workspaceArchiveSessionRequestSchema.parse({})).toThrow()
+    expect(workspaceArchiveSessionValueSchema.parse({ archivedSessionIds: ['s1', 's2'] }).archivedSessionIds)
+      .toEqual(['s1', 's2'])
+    expect(() => workspaceArchiveSessionValueSchema.parse({ archivedSessionIds: 's1' })).toThrow()
   })
 
   it('create requires exactly one of path/name (both refine arms)', () => {

From c764ed7e640a1c4efa67ba9063e37d12618c1603 Mon Sep 17 00:00:00 2001
From: imccyu <276526105+imccyu@users.noreply.github.com>
Date: Fri, 31 Jul 2026 02:40:14 +0800
Subject: [PATCH 03/13] feat(client-runtime): project the archive set and the
 archiveSession action

WorkspaceListState gains archivedSessionIds (ReadonlySet, replaced only
on membership change), installed as full snapshots from the list
baseline, the unary echo, and the changed frame. Archiving the current
session clears the selection into the New Session view state. Test
doubles (test-runtime, fake APIs, fixture client) follow the widened
IWorkspaces/IApiClient faces.
---
 .../client/connection/src/client/fixture.ts   | 19 +++++++-
 packages/client/connection/tests/fake-api.ts  |  5 +-
 .../client/locale/tests/language-row.spec.tsx |  2 +-
 packages/client/runtime/README.i18n.yaml      |  4 +-
 packages/client/runtime/README.md             |  2 +
 packages/client/runtime/README.zh.md          |  2 +
 .../runtime/src/client/contract/workspaces.ts |  7 +++
 .../runtime/src/client/workspaces/manager.ts  | 30 ++++++++++++
 .../runtime/src/client/workspaces/service.ts  | 21 ++++++++-
 packages/client/runtime/tests/fake-api.ts     | 16 ++++++-
 .../runtime/tests/workspaces-service.spec.ts  | 46 +++++++++++++++++++
 packages/client/test-runtime/src/fixtures.ts  |  1 +
 .../client/test-runtime/src/workspaces.ts     | 17 +++++++
 .../tests/chat-code-subcalls.spec.tsx         |  2 +-
 .../ui-conversation/tests/chat-view.spec.tsx  |  2 +-
 .../tests/gate-branch-tails.spec.tsx          |  4 +-
 .../ui-conversation/tests/input-bar.spec.tsx  |  2 +-
 .../tests/input-matrix.spec.tsx               |  2 +-
 .../tests/input-scenarios.spec.tsx            |  2 +-
 .../ui-conversation/tests/skeleton.spec.tsx   |  2 +-
 .../tests/terminal-card.spec.tsx              |  4 +-
 .../client/ui-layout/tests/app-frame.spec.tsx |  2 +-
 .../ui-theme/tests/appearance-row.spec.tsx    |  2 +-
 .../client/ui-trajectory/tests/views.spec.tsx |  2 +-
 24 files changed, 177 insertions(+), 21 deletions(-)

diff --git a/packages/client/connection/src/client/fixture.ts b/packages/client/connection/src/client/fixture.ts
index 45445cc9cf..49f0aaf9dc 100644
--- 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)
diff --git a/packages/client/connection/tests/fake-api.ts b/packages/client/connection/tests/fake-api.ts
index 0d58800279..d599de1be7 100644
--- 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
diff --git a/packages/client/locale/tests/language-row.spec.tsx b/packages/client/locale/tests/language-row.spec.tsx
index 2fdc5d5f45..223b9761b2 100644
--- 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: new Set(), state: 'idle', phase: 'ready', error: null,
     baselinesReady: true, recentWorkspaceId: undefined,
   })
   return bindSnapshotSelector(store)
diff --git a/packages/client/runtime/README.i18n.yaml b/packages/client/runtime/README.i18n.yaml
index f42e4f09d0..60fcf831b4 100644
--- 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: 4c9122d87bfb0ea2d66478de03c69975b0577ab7
+README.zh.md: 1ee4731964ea75de29da47137933852581fc45b3
diff --git a/packages/client/runtime/README.md b/packages/client/runtime/README.md
index 9f2b165f1a..4c9122d87b 100644
--- 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 `ReadonlySet` replaced only when membership changes). 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 and, when the archived session is the current selection, clears it into the New Session view state; 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.
diff --git a/packages/client/runtime/README.zh.md b/packages/client/runtime/README.zh.md
index 3ed047e65d..1ee4731964 100644
--- 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 `ReadonlySet`，仅在成员变化时才替换）。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；当被归档的会话正是当前 selection 时，将其清空为 New Session 视图状态。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。
diff --git a/packages/client/runtime/src/client/contract/workspaces.ts b/packages/client/runtime/src/client/contract/workspaces.ts
index 9238ea5fd0..3e64ef3717 100644
--- 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>
 }
diff --git a/packages/client/runtime/src/client/workspaces/manager.ts b/packages/client/runtime/src/client/workspaces/manager.ts
index ce4198cd01..0eddae8445 100644
--- a/packages/client/runtime/src/client/workspaces/manager.ts
+++ b/packages/client/runtime/src/client/workspaces/manager.ts
@@ -14,6 +14,8 @@ export type WorkspaceListPhase = 'pending' | 'ready'
 /** Immutable workspace-list snapshot. */
 export interface WorkspaceListSnapshot {
   items: readonly WorkspaceView[]
+  /** Registry-global archive set (hidden from grouping surfaces; accounting slots retained). */
+  archivedSessionIds: ReadonlySet<SessionId>
   state: 'idle' | 'loading' | 'error'
   phase: WorkspaceListPhase
   error: RpcError | null
@@ -28,6 +30,9 @@ 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: ReadonlySet<SessionId> = new Set()
   private state: WorkspaceListSnapshot['state'] = 'idle'
   private phase: WorkspaceListPhase = 'pending'
   private error: RpcError | null = null
@@ -77,6 +82,7 @@ export class WorkspaceManager {
           items = items.filter(workspace => !this.removedIds.has(workspace.workspaceId))
           for (const delta of frames) items = applyWorkspaceDelta(items, delta)
           this.installViews(items)
+          this.installArchived(result.value.archivedSessionIds)
           this.state = 'idle'
           this.phase = 'ready'
         } else {
@@ -158,6 +164,18 @@ 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 +184,9 @@ 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 +215,21 @@ 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 (set identity backs Object.is short-circuits). */
+  private installArchived(archivedSessionIds: readonly SessionId[]): void {
+    if (archivedSessionIds.length === this.archivedSessionIds.size
+      && archivedSessionIds.every(id => this.archivedSessionIds.has(id))) return
+    this.archivedSessionIds = new Set(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
diff --git a/packages/client/runtime/src/client/workspaces/service.ts b/packages/client/runtime/src/client/workspaces/service.ts
index 1dd3319e79..f3125e6494 100644
--- a/packages/client/runtime/src/client/workspaces/service.ts
+++ b/packages/client/runtime/src/client/workspaces/service.ts
@@ -14,6 +14,12 @@ 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: grouping surfaces hide these sessions
+   * everywhere (workspace groups and the ungrouped bucket) while their
+   * session logs and workspace accounting slots remain.
+   */
+  archivedSessionIds: ReadonlySet<SessionId>
   state: 'idle' | 'loading' | 'error'
   phase: WorkspaceListPhase
   error: RpcError | null
@@ -58,7 +64,7 @@ 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: new Set(), state: 'idle', phase: 'pending', error: null,
       baselinesReady: false, recentWorkspaceId: undefined,
     })
     this.manager.subscribe(() => { this.project() })
@@ -249,6 +255,18 @@ 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. When the archived
+   * session is the current one, the selection is cleared into the New
+   * Session view state — a hidden row must not stay open behind the list.
+   * @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}`)
+    if (this.sessions.list.getSnapshot().current === sessionId) this.sessions.clear()
+  }
+
   /**
    * Move a session within its Workspace's manual order (DOM-insertBefore-like).
    * @param workspaceId - owning workspace.
@@ -293,6 +311,7 @@ export class WorkspacesService implements IWorkspaces {
     const baselinesReady = workspace.phase === 'ready' && sessions.phase === 'ready'
     this.list.set({
       items: workspace.items,
+      archivedSessionIds: workspace.archivedSessionIds,
       state: workspace.state,
       phase: workspace.phase,
       error: workspace.error,
diff --git a/packages/client/runtime/tests/fake-api.ts b/packages/client/runtime/tests/fake-api.ts
index 06d948ae83..9cf7971049 100644
--- 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
diff --git a/packages/client/runtime/tests/workspaces-service.spec.ts b/packages/client/runtime/tests/workspaces-service.spec.ts
index 7fd6934827..2bd462e5ee 100644
--- a/packages/client/runtime/tests/workspaces-service.spec.ts
+++ b/packages/client/runtime/tests/workspaces-service.spec.ts
@@ -285,6 +285,52 @@ 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'])
+  })
 })
 
 describe('startInitialSelection', () => {
diff --git a/packages/client/test-runtime/src/fixtures.ts b/packages/client/test-runtime/src/fixtures.ts
index 4219d233e2..d81adf7698 100644
--- 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: new Set(),
     state: 'idle',
     phase: 'ready',
     error: null,
diff --git a/packages/client/test-runtime/src/workspaces.ts b/packages/client/test-runtime/src/workspaces.ts
index 6c1a9d0aad..fab209c96c 100644
--- 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 = new Set([...draft.archivedSessionIds, sessionId])
+    })
+  }
 }
diff --git a/packages/client/ui-conversation/tests/chat-code-subcalls.spec.tsx b/packages/client/ui-conversation/tests/chat-code-subcalls.spec.tsx
index 49eeec29fd..16d070b04d 100644
--- 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: new Set(), state: 'idle', phase: 'ready', error: null,
       baselinesReady: true, recentWorkspaceId: undefined,
     }),
     startSession: vi.fn(),
diff --git a/packages/client/ui-conversation/tests/chat-view.spec.tsx b/packages/client/ui-conversation/tests/chat-view.spec.tsx
index bfaab93375..b59335fa3a 100644
--- 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: new Set(), state: 'idle', phase: 'ready', error: null,
     baselinesReady: true, recentWorkspaceId: undefined,
   })
   return bindSnapshotSelector(store)
diff --git a/packages/client/ui-conversation/tests/gate-branch-tails.spec.tsx b/packages/client/ui-conversation/tests/gate-branch-tails.spec.tsx
index 354b94ecdd..192470abfc 100644
--- 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: new Set(), 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: new Set(), state: 'idle', phase: 'ready', error: null,
       baselinesReady: true, recentWorkspaceId: undefined,
     })
     const view = render(
diff --git a/packages/client/ui-conversation/tests/input-bar.spec.tsx b/packages/client/ui-conversation/tests/input-bar.spec.tsx
index 6831b1a5a0..1974881357 100644
--- 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: new Set(), state: 'idle', phase: 'ready', error: null,
       baselinesReady: true, recentWorkspaceId: undefined,
     })),
     useProjection: ((key: string, selector?: (v: unknown) => unknown) =>
diff --git a/packages/client/ui-conversation/tests/input-matrix.spec.tsx b/packages/client/ui-conversation/tests/input-matrix.spec.tsx
index f619d380a0..4901ec2f9f 100644
--- 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: new Set(), state: 'idle', phase: 'ready', error: null,
       baselinesReady: true, recentWorkspaceId: undefined,
     })),
     useProjection: (() => undefined),
diff --git a/packages/client/ui-conversation/tests/input-scenarios.spec.tsx b/packages/client/ui-conversation/tests/input-scenarios.spec.tsx
index 60b02795fe..167b9c96af 100644
--- 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: new Set(), state: 'idle', phase: 'ready', error: null,
       baselinesReady: true, recentWorkspaceId: undefined,
     })),
     useProjection: (() => undefined),
diff --git a/packages/client/ui-conversation/tests/skeleton.spec.tsx b/packages/client/ui-conversation/tests/skeleton.spec.tsx
index a37074bd07..2669cbb8ab 100644
--- 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: new Set(), state: 'idle', phase: 'ready', error: null,
   baselinesReady: true, recentWorkspaceId: undefined,
 })
 
diff --git a/packages/client/ui-conversation/tests/terminal-card.spec.tsx b/packages/client/ui-conversation/tests/terminal-card.spec.tsx
index 213897e0f5..29f246d603 100644
--- 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: new Set(), 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: new Set(), state: 'idle', phase: 'ready', error: null,
           baselinesReady: true, recentWorkspaceId: undefined,
         }))}
         useInput={(() => { throw new Error('unused') })}
diff --git a/packages/client/ui-layout/tests/app-frame.spec.tsx b/packages/client/ui-layout/tests/app-frame.spec.tsx
index ab8a11706d..d30cd17877 100644
--- 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: new Set(), state: 'idle', phase: 'ready', error: null,
     baselinesReady: baselinesReady.current, recentWorkspaceId: undefined,
   }
   const element = () => (
diff --git a/packages/client/ui-theme/tests/appearance-row.spec.tsx b/packages/client/ui-theme/tests/appearance-row.spec.tsx
index f21fb26bdd..00cc0e3052 100644
--- 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: new Set(), state: 'idle', phase: 'ready', error: null,
     baselinesReady: true, recentWorkspaceId: undefined,
   })
   return bindSnapshotSelector(store)
diff --git a/packages/client/ui-trajectory/tests/views.spec.tsx b/packages/client/ui-trajectory/tests/views.spec.tsx
index 5c1e6c691d..d31b43d3e6 100644
--- 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: new Set(), state: 'idle', phase: 'ready', error: null, baselinesReady: true,
     recentWorkspaceId: undefined,
   })
   return bindSnapshotSelector(store)

From e235be2bac56f290832e6a67d4b7c4c985a697ab Mon Sep 17 00:00:00 2001
From: imccyu <276526105+imccyu@users.noreply.github.com>
Date: Fri, 31 Jul 2026 02:40:39 +0800
Subject: [PATCH 04/13] feat(ui-workspace): archive session from the row menu

The visual-only Delete session placeholder becomes a wired Archive
session action: no confirmation dialog (non-destructive), failures stay
console diagnostics. tree.ts hides archived sessions in every
derivation (workspace groups, Ungrouped, search, flat list) through the
sessionVisible predicate. The workspace-management e2e pins the archive
round trip across reload.
---
 apps/web/tests/workspace-management.e2e.ts    | 52 ++++++++++++--
 packages/client/ui-workspace/README.i18n.yaml |  4 +-
 packages/client/ui-workspace/README.md        |  4 +-
 packages/client/ui-workspace/README.zh.md     |  4 +-
 .../src/client/WorkspaceBrowser.tsx           | 44 +++++++++---
 .../ui-workspace/src/client/contract/slots.ts |  6 ++
 .../client/ui-workspace/src/client/index.ts   |  1 +
 .../client/ui-workspace/src/client/locales.ts |  4 +-
 .../ui-workspace/src/client/rows/Rows.tsx     | 20 ++++--
 .../client/ui-workspace/src/client/tree.ts    | 41 +++++++----
 .../client/ui-workspace/tests/rows.spec.tsx   | 26 ++++---
 .../client/ui-workspace/tests/tree.spec.ts    | 70 +++++++++++++++----
 .../tests/workspace-browser.spec.tsx          | 49 ++++++++++++-
 .../tests/workspace-picker.spec.tsx           |  2 +-
 14 files changed, 261 insertions(+), 66 deletions(-)

diff --git a/apps/web/tests/workspace-management.e2e.ts b/apps/web/tests/workspace-management.e2e.ts
index e6a7f31f18..86c9056d66 100644
--- a/apps/web/tests/workspace-management.e2e.ts
+++ b/apps/web/tests/workspace-management.e2e.ts
@@ -1,10 +1,13 @@
 // Web e2e scenarios: workspace management — the create-by-name dialog, the
 // rename round trip over the real wire (workspace.rename RPC + durable
 // registry), duplicate-name pre-check, the flat "In one list" view with its
-// persisted group-by preference, and the session hover card. Zero model
-// calls: workspace.create/rename are host RPCs with no model involvement,
-// and the one session row the flat/hover scenarios need comes from a seeded
-// fixture (the seeded-history seed reused verbatim — no new recording).
+// persisted group-by preference, the session hover card, and the session
+// archive round trip (row menu → workspace.archiveSession RPC → durable
+// global set → row hidden across reload). Zero model calls:
+// workspace.create/rename/archiveSession are host RPCs with no model
+// involvement, and the one session row the flat/hover/archive scenarios need
+// comes from a seeded fixture (the seeded-history seed reused verbatim — no
+// new recording).
 import { mkdir, readFile, stat, writeFile } from 'node:fs/promises'
 import { fileURLToPath } from 'node:url'
 import { join } from 'node:path'
@@ -413,6 +416,47 @@ describe('web e2e: workspace management (create / rename / flat view / hover car
     expect(tripwire.pageErrors).toEqual([])
   }, 60_000)
 
+  it('archives the seeded session from its row menu, hiding it durably across reload', async () => {
+    onTestFailed(() => saveFailureShot(page, 'web-e2e-ws-archive'))
+    // The seeded session lives under Ungrouped (expanded by the hover-card
+    // test's gesture; converge again for order independence).
+    const ungroupedRow = page.getByText('Ungrouped', { exact: true }).locator('..').locator('..')
+    const ungroupedSection = ungroupedRow.locator('..')
+    await expect.poll(async () => {
+      if (await ungroupedRow.getAttribute('aria-expanded') !== 'true') {
+        await page.getByText('Ungrouped', { exact: true }).click()
+        await page.waitForTimeout(50)
+      }
+      return await ungroupedRow.getAttribute('aria-expanded')
+    }, { timeout: 5_000 }).toBe('true')
+    const sessionRow = ungroupedSection.locator('[role="treeitem"]').nth(1)
+    const rowTitle = await sessionRow.locator('[class*="title"]').innerText()
+    // Row menu: hover reveals the actions button; Archive session commits
+    // without a confirmation dialog (non-destructive: log + accounting stay).
+    await sessionRow.hover()
+    await sessionRow.getByRole('button', { name: `Session actions for ${rowTitle}` }).click()
+    await page.getByRole('menuitem', { name: 'Archive session' }).click()
+    // The row disappears on the archive-set echo; with no other visible
+    // stray, the whole Ungrouped bucket withdraws.
+    await expect.poll(() => page.getByText(rowTitle, { exact: true }).count(), { timeout: 10_000 }).toBe(0)
+    await expect.poll(() => page.getByText('Ungrouped', { exact: true }).count(), { timeout: 10_000 }).toBe(0)
+    // Durable on the host: the registry-global set carries the id while the
+    // session log itself stays in persistence untouched.
+    expect([...scaffold.ctx.workspace.archivedSessionIds]).toEqual([SessionId(SEED_ID)])
+    expect((await scaffold.ctx.sessionPersistence.list()).map(header => header.id)).toContain(SessionId(SEED_ID))
+    // Reload: the hidden state is rebuilt from the workspace.list baseline.
+    const warningStart = tripwire.warnings.length
+    await page.reload({ waitUntil: 'load' })
+    await page.waitForSelector('[class*="frame"]', { timeout: 30_000 })
+    acknowledgeReloadConnectionLoss(tripwire, warningStart)
+    await expect.poll(() => page.getByText('Workspaces', { exact: true }).count(), { timeout: 15_000 }).toBe(1)
+    // The archived row must not resurface (the Ungrouped bucket itself may
+    // reappear if selection restore lands on another stray — not this test's
+    // concern).
+    expect(await page.getByText(rowTitle, { exact: true }).count()).toBe(0)
+    expect(tripwire.pageErrors).toEqual([])
+  }, 90_000)
+
   it.skipIf(MODE === 'record')('issued zero model calls and stayed clean', async () => {
     expect(tripwire.warnings).toEqual([])
     // The directory-browser aria golden is this spec's one owned artifact;
diff --git a/packages/client/ui-workspace/README.i18n.yaml b/packages/client/ui-workspace/README.i18n.yaml
index 3c61535e06..a21fd21697 100644
--- 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
diff --git a/packages/client/ui-workspace/README.md b/packages/client/ui-workspace/README.md
index f71bfa09c7..cc73214a28 100644
--- 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.
diff --git a/packages/client/ui-workspace/README.zh.md b/packages/client/ui-workspace/README.zh.md
index 80b53d85eb..c0b6472c7d 100644
--- 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。
diff --git a/packages/client/ui-workspace/src/client/WorkspaceBrowser.tsx b/packages/client/ui-workspace/src/client/WorkspaceBrowser.tsx
index f5b636ab1b..97cc2116a4 100644
--- 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}
diff --git a/packages/client/ui-workspace/src/client/contract/slots.ts b/packages/client/ui-workspace/src/client/contract/slots.ts
index e3e0ba319a..9525bd193a 100644
--- 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
diff --git a/packages/client/ui-workspace/src/client/index.ts b/packages/client/ui-workspace/src/client/index.ts
index 7dd8db5419..59574beed3 100644
--- 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)
     },
diff --git a/packages/client/ui-workspace/src/client/locales.ts b/packages/client/ui-workspace/src/client/locales.ts
index 3d8a5d657f..1ecc244329 100644
--- 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}',
diff --git a/packages/client/ui-workspace/src/client/rows/Rows.tsx b/packages/client/ui-workspace/src/client/rows/Rows.tsx
index 03634dbe1a..a8b28f17e4 100644
--- 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'
@@ -243,7 +243,7 @@ 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 +252,8 @@ 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 +262,13 @@ 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 = (
@@ -310,7 +315,8 @@ export function SessionNodeItem({ node, currentId, now, onOpen, onRename, onFork
           onSelect={(id) => {
             setMenuOpen(false)
             if (id === 'rename') onRename(node.id, row.title)
-            if (id === 'fork') onFork(node.id) // delete stays visual-only.
+            if (id === 'fork') onFork(node.id)
+            if (id === 'archive') onArchive(node.id)
           }}
           portal
           closeOnPointerLeave
diff --git a/packages/client/ui-workspace/src/client/tree.ts b/packages/client/ui-workspace/src/client/tree.ts
index aed01c21cb..7ed7e684d1 100644
--- 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 {
diff --git a/packages/client/ui-workspace/tests/rows.spec.tsx b/packages/client/ui-workspace/tests/rows.spec.tsx
index 59fe95fe0c..ee45b8628d 100644
--- 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 +157,20 @@ 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('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 +179,12 @@ 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 +198,7 @@ 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 +224,7 @@ 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 +241,7 @@ 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 +259,7 @@ 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 +273,7 @@ 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/)
   })
diff --git a/packages/client/ui-workspace/tests/tree.spec.ts b/packages/client/ui-workspace/tests/tree.spec.ts
index 8fb750a4ad..7476de29f5 100644
--- 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 })
   })
 })
diff --git a/packages/client/ui-workspace/tests/workspace-browser.spec.tsx b/packages/client/ui-workspace/tests/workspace-browser.spec.tsx
index 7dc3f7239b..5b12646a27 100644
--- 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: ReadonlySet<SessionId> = new Set()): 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'])], new Set([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 }
diff --git a/packages/client/ui-workspace/tests/workspace-picker.spec.tsx b/packages/client/ui-workspace/tests/workspace-picker.spec.tsx
index 3a1bb8e2b2..334020b37f 100644
--- 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: new Set(), state: 'idle', phase: 'ready', error: null, baselinesReady: true,
   recentWorkspaceId: items[0]?.workspaceId,
 })
 function anchor(): { current: HTMLElement } {

From 3b86c288d62c3a307660035e756a8b6bde90c976 Mon Sep 17 00:00:00 2001
From: imccyu <276526105+imccyu@users.noreply.github.com>
Date: Fri, 31 Jul 2026 02:40:49 +0800
Subject: [PATCH 05/13] docs: catalogs and Agent Note for the session archive
 set

---
 ...07-31-session-archive-global-set.i18n.yaml |  6 ++++
 .../2026-07-31-session-archive-global-set.md  | 33 +++++++++++++++++++
 ...026-07-31-session-archive-global-set.zh.md | 33 +++++++++++++++++++
 docs/cordis-catalog/services.md               | 13 +++++++-
 .../cordis/tool-cordis/src/api-catalog.ts     |  4 +++
 5 files changed, 88 insertions(+), 1 deletion(-)
 create mode 100644 .agents/notes/implemented/feature/2026-07-31-session-archive-global-set.i18n.yaml
 create mode 100644 .agents/notes/implemented/feature/2026-07-31-session-archive-global-set.md
 create mode 100644 .agents/notes/implemented/feature/2026-07-31-session-archive-global-set.zh.md

diff --git a/.agents/notes/implemented/feature/2026-07-31-session-archive-global-set.i18n.yaml b/.agents/notes/implemented/feature/2026-07-31-session-archive-global-set.i18n.yaml
new file mode 100644
index 0000000000..6ed5f6ed3b
--- /dev/null
+++ b/.agents/notes/implemented/feature/2026-07-31-session-archive-global-set.i18n.yaml
@@ -0,0 +1,6 @@
+# Bilingual-pair consistency record (docs/i18n/README.md): the git blob hash of each
+# side as of the last confirmed-consistent state. Both languages carry equal authority;
+# after editing either side, bring the other along and re-record with:
+#   pnpm run verify-translation-pairing --write .agents/notes/implemented/feature/2026-07-31-session-archive-global-set.md
+2026-07-31-session-archive-global-set.md: 0fe354ef0ed50ee60a69b0633522323124c80da7
+2026-07-31-session-archive-global-set.zh.md: 2b13f0eddc9aa62600a95ac5f412c51f3a38af7b
diff --git a/.agents/notes/implemented/feature/2026-07-31-session-archive-global-set.md b/.agents/notes/implemented/feature/2026-07-31-session-archive-global-set.md
new file mode 100644
index 0000000000..0fe354ef0e
--- /dev/null
+++ b/.agents/notes/implemented/feature/2026-07-31-session-archive-global-set.md
@@ -0,0 +1,33 @@
+# Agent Note: Session archive (registry-global set)
+
+Status: implemented
+
+English | [中文](2026-07-31-session-archive-global-set.zh.md)
+
+## Problem
+
+The session row menu in the sidebar workspace browser carried a purely visual "Delete session" placeholder (no handler). The product decision is **archive**, not delete: the session log and its workspace accounting stay untouched; the session merely disappears from every grouping surface (workspace groups, Ungrouped, search, the flat list). The archive record needs a home: an Ungrouped session belongs to no workspace entity, so a per-workspace field cannot carry it.
+
+## Decision
+
+**The archive set is a new field on the workspace domain's global singleton (`workspaceDomainState.archivedSessionIds`), layered over workspace accounting; display filtering converges entirely in the client's `tree.ts` derivation layer; the wire surface uses the full-snapshot posture.**
+
+- Storage: `archivedSessionIds: z.array(sessionId).default([])`, domain version stays 2 — a purely additive field; pre-field media parse to an empty set through the schema default, no migration code. An archived session keeps its `sessionIds` slot (a future unarchive restores its position), so the set never touches the one-owner accounting invariant.
+- Registry: `ctx.workspace.archiveSession(id)` rides `enqueueOperation`, serialized with create/delete; a session neither live nor persisted throws `WorkspaceUnknownSessionError`; an already archived id neither writes nor emits. The `archivedSessionIds` getter exposes the read-only set.
+- RPC: `workspace.archiveSession({sessionId}) → {archivedSessionIds}` (answers the full updated set); the `workspace.list` response carries the set as the reconnect baseline; a new host frame `host/archived-sessions-changed` pushes the full snapshot after every durable change (same posture as `host/workspace-changed`, emitted from the `domain/changed` global-put branch by set comparison). Unknown sessions reuse the `session-not-found` error code.
+- Client runtime: `WorkspaceListState.archivedSessionIds` (a `ReadonlySet`, reference replaced only on membership change); the list baseline, the unary echo, and the changed frame each install the complete set. `WorkspacesService.archiveSession` calls `sessions.clear()` when the archived session is the current selection, returning to the New Session view (user decision: archiving the open session sends the main view back to the hero).
+- UI: the `delete` menu row (visual-only) becomes `archive` (label "Archive session", non-danger styling, no confirmation dialog — a non-destructive action whose worst misfire is list hiding); filtering is one extra arm in `tree.ts`'s `sessionVisible` predicate, with `deriveGroups`/`deriveFlat` taking an `archived` set parameter so all four surfaces (group loop, stray bucket, search, flat) share one source.
+
+## Alternatives considered
+
+**Per-workspace archivedSessionIds (the original phrasing).** Rejected: Ungrouped sessions have no home; the user switched to global.
+
+**An archived flag on SessionSummary (session.list layer).** Rejected: it joins a workspace-domain fact into the sessions-domain projection, summaries have no incremental frame so a separate notification would still be needed — cross-domain coupling outweighs the saving.
+
+**Host-side filtering in `workspaceView`/the `sessionIds` getter.** Rejected: archiving ≠ changing accounting, and filtering the projection muddles the two concepts; a future restore surface also needs the client to see full accounting.
+
+**Incremental frames (single archived/removed rows).** Rejected: the set is tiny and changes rarely; full snapshots spare the client merge logic and dedup state and match the existing workspace-changed posture.
+
+## Consequences
+
+Archived sessions have no viewing or unarchive surface yet (this iteration's scope; recorded as a README Known Limitation); data and accounting slots stay intact, so a future restore is one UI surface plus one inverse RPC. The `workspace.list` response shape change is a pre-release direct edit (no compatibility layer). The workspace-management e2e pins the full chain (archive → row disappears → still hidden after reload, log still present); domain tests pin idempotence, unknown-id rejection, restart recovery, and the pre-field media default upgrade.
diff --git a/.agents/notes/implemented/feature/2026-07-31-session-archive-global-set.zh.md b/.agents/notes/implemented/feature/2026-07-31-session-archive-global-set.zh.md
new file mode 100644
index 0000000000..2b13f0eddc
--- /dev/null
+++ b/.agents/notes/implemented/feature/2026-07-31-session-archive-global-set.zh.md
@@ -0,0 +1,33 @@
+# Agent Note: Session 归档（注册表级全局集合）
+
+状态：implemented
+
+[English](2026-07-31-session-archive-global-set.md) | 中文
+
+## 问题
+
+Sidebar workspace 浏览区的 session 行菜单里，「Delete session」一直是纯视觉占位（无 handler）。产品口径定为**归档**而非删除：session 日志与 workspace 记账都不动，只把该 session 从所有分组视图（workspace 分组、Ungrouped、搜索、平铺列表）里隐藏。归档记录需要一个落点：Ungrouped 的 session 不属于任何 workspace 实体，per-workspace 字段放不下它。
+
+## 决策
+
+**归档集合是 workspace domain 全局单例（`workspaceDomainState.archivedSessionIds`）上的一个新字段，覆盖在 workspace 记账之上；显示过滤全部收敛在 client 的 `tree.ts` 派生层；wire 面走全快照姿态。**
+
+- 存储：`archivedSessionIds: z.array(sessionId).default([])`，domain version 保持 2——纯增量字段，旧介质经 schema default 解析为空集合，无迁移代码。被归档的 session 保留其 `sessionIds` 席位（未来取消归档恢复原位置），因此与「一个 session 只被一个 workspace 记账」不变式零纠缠。
+- Registry：`ctx.workspace.archiveSession(id)` 走 `enqueueOperation` 与 create/delete 串行；未知 session（实时与持久化都查不到）抛 `WorkspaceUnknownSessionError`；已归档 id 不写盘不发事件。`archivedSessionIds` getter 暴露只读集合。
+- RPC：`workspace.archiveSession({sessionId}) → {archivedSessionIds}`（应答完整更新后集合）；`workspace.list` 响应携带集合作为重连基线；新 host 帧 `host/archived-sessions-changed` 在每次持久变更后推完整快照（与 `host/workspace-changed` 同姿态，从 `domain/changed` 的 global put 分支比对推帧）。未知 session 复用错误码 `session-not-found`。
+- client runtime：`WorkspaceListState.archivedSessionIds`（`ReadonlySet`，成员不变不换引用）；list 基线、unary 回声、changed 帧三路都整体替换安装。`WorkspacesService.archiveSession` 在归档对象恰为当前 selection 时调 `sessions.clear()` 回 New Session 视图（用户拍板：归档当前打开的 session 主视图回 hero）。
+- UI：菜单项 `delete`（visual-only）改为 `archive`（label「Archive session」，非 danger 样式，无确认对话框——非破坏性操作，误触后果只是列表隐藏）；过滤实现为 `tree.ts` 的 `sessionVisible` 判据加一档，`deriveGroups`/`deriveFlat` 增加 `archived` 集合入参，四个视图（分组循环、stray 兜底、搜索、平铺）同源生效。
+
+## 已考虑的替代方案
+
+**per-workspace archivedSessionIds（最初表述）。** 否决：Ungrouped session 无落点；用户改口全局。
+
+**SessionSummary 打 archived 标（session.list 层）。** 否决：要把 workspace domain 事实 join 进 sessions domain 投影，summary 无增量帧还得另发通知，跨域耦合大于收益。
+
+**host 侧在 `workspaceView`/`sessionIds` getter 过滤。** 否决：归档 ≠ 改记账，投影过滤会把两个概念搅浑；未来恢复入口也需要 client 拿到全量记账。
+
+**增量帧（archived/removed 单条）。** 否决：集合极小、变更频率低，全快照免去 client 侧合并逻辑与去重状态，与 workspace-changed 现有姿态一致。
+
+## 后果
+
+归档后 UI 无查看/取消归档入口（本期口径，README Known Limitation 记账）；数据与席位完好，后续加恢复面只是 UI + 一个逆向 RPC。`workspace.list` 响应形状变化是 pre-release 直改（无兼容层）。e2e（workspace-management）钉住了「归档→行消失→reload 后仍隐藏、日志仍在」的全链路；domain 层测试钉住幂等、未知 id 拒绝、跨重启恢复与旧介质默认升级。
diff --git a/docs/cordis-catalog/services.md b/docs/cordis-catalog/services.md
index 0adc848ea5..958dcc10cd 100644
--- a/docs/cordis-catalog/services.md
+++ b/docs/cordis-catalog/services.md
@@ -2544,6 +2544,15 @@ list(): Workspace[]
  */
 delete(id: WorkspaceId): Promise<boolean>
 
+/**
+ * Archive one session durably. The session must exist (live or in session
+ * persistence); its workspace accounting — or lack of one — is irrelevant.
+ * An already archived id resolves without writing.
+ * @param sessionId - The session to archive.
+ * @returns resolution after durability.
+ */
+archiveSession(sessionId: SessionId): Promise<void>
+
 /**
  * Resolve by canonical directory path without creating or mutating a
  * workspace. A missing path rejects during `realpath`; an existing unowned
@@ -2554,7 +2563,9 @@ delete(id: WorkspaceId): Promise<boolean>
 async resolveByPath(path: string): Promise<Workspace | undefined>
 ```
 
-Source: [`packages/workspace/workspace/src/index.ts:78`](../../packages/workspace/workspace/src/index.ts)
+Types: [SessionId](../core-data-structures/core.md)
+
+Source: [`packages/workspace/workspace/src/index.ts:90`](../../packages/workspace/workspace/src/index.ts)
 
 ## Inherited `ctx` members (cordis core + loader/hmr/timer)
 
diff --git a/packages/cordis/tool-cordis/src/api-catalog.ts b/packages/cordis/tool-cordis/src/api-catalog.ts
index 4d986582d4..66ac086b49 100644
--- a/packages/cordis/tool-cordis/src/api-catalog.ts
+++ b/packages/cordis/tool-cordis/src/api-catalog.ts
@@ -1162,6 +1162,10 @@ export const SERVICE_API: readonly ServiceApiEntry[] = [
         signature: 'delete(id: WorkspaceId): Promise<boolean>',
         jsDoc: '/**\n * Delete one workspace registration while retaining its directory and every\n * session log. The durable order is updated before the table deletion; a\n * failed table write restores the prior order and keeps the entity\n * published. Unknown ids are an idempotent no-op for domain callers.\n * @param id - Workspace registration to remove.\n * @returns `true` when a record was deleted, `false` when it was unknown.\n */',
       },
+      {
+        signature: 'archiveSession(sessionId: SessionId): Promise<void>',
+        jsDoc: '/**\n * Archive one session durably. The session must exist (live or in session\n * persistence); its workspace accounting — or lack of one — is irrelevant.\n * An already archived id resolves without writing.\n * @param sessionId - The session to archive.\n * @returns resolution after durability.\n */',
+      },
       {
         signature: 'async resolveByPath(path: string): Promise<Workspace | undefined>',
         jsDoc: '/**\n * Resolve by canonical directory path without creating or mutating a\n * workspace. A missing path rejects during `realpath`; an existing unowned\n * directory returns `undefined`.\n * @param path - Existing directory path in any spelling.\n * @returns the workspace owning the canonical path, when one exists.\n */',

From fc0042e47e3bdc7375ac9d1b5356ef5ed7bab554 Mon Sep 17 00:00:00 2001
From: imccyu <276526105+imccyu@users.noreply.github.com>
Date: Fri, 31 Jul 2026 03:07:53 +0800
Subject: [PATCH 06/13] fix(client-runtime): never reuse an archived blank
 session in connectWorkspace

Reusing one would open a session no grouping surface can show; the New
Session flow mints a fresh blank instead.
---
 packages/client/runtime/src/client/workspaces/service.ts | 6 +++++-
 packages/client/runtime/tests/workspaces-service.spec.ts | 6 ++++++
 2 files changed, 11 insertions(+), 1 deletion(-)

diff --git a/packages/client/runtime/src/client/workspaces/service.ts b/packages/client/runtime/src/client/workspaces/service.ts
index f3125e6494..3204407e20 100644
--- a/packages/client/runtime/src/client/workspaces/service.ts
+++ b/packages/client/runtime/src/client/workspaces/service.ts
@@ -94,10 +94,14 @@ 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.has(summary.id)) return summary.id
     }
     const attempt = this.sessions.create({ workspaceId })
       .finally(() => { this.connecting.delete(workspaceId) })
diff --git a/packages/client/runtime/tests/workspaces-service.spec.ts b/packages/client/runtime/tests/workspaces-service.spec.ts
index 2bd462e5ee..e280f843d1 100644
--- 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 () => {

From c00f0dccda7f26372ed65f0651eac30a22d63c61 Mon Sep 17 00:00:00 2001
From: imccyu <276526105+imccyu@users.noreply.github.com>
Date: Fri, 31 Jul 2026 03:23:26 +0800
Subject: [PATCH 07/13] test(test-runtime): cover the archiveSession double's
 default and stub arms

The default arm builds the next Set outside the immer draft: reading a
Set through a draft requires the MapSet plugin, assigning a fresh Set
does not.
---
 packages/client/test-runtime/src/workspaces.ts      |  5 ++++-
 packages/client/test-runtime/tests/runtime.spec.tsx | 10 +++++++++-
 2 files changed, 13 insertions(+), 2 deletions(-)

diff --git a/packages/client/test-runtime/src/workspaces.ts b/packages/client/test-runtime/src/workspaces.ts
index fab209c96c..d27139cd48 100644
--- a/packages/client/test-runtime/src/workspaces.ts
+++ b/packages/client/test-runtime/src/workspaces.ts
@@ -199,8 +199,11 @@ export class TestWorkspaces implements IWorkspaces {
       await (stub(sessionId) as Promise<void>)
       return
     }
+    // Built outside the draft: reading a Set through an immer draft needs
+    // the MapSet plugin, while assigning a fresh Set does not.
+    const next = new Set([...this.list.getSnapshot().archivedSessionIds, sessionId])
     await this.update((draft) => {
-      draft.archivedSessionIds = new Set([...draft.archivedSessionIds, sessionId])
+      draft.archivedSessionIds = next
     })
   }
 }
diff --git a/packages/client/test-runtime/tests/runtime.spec.tsx b/packages/client/test-runtime/tests/runtime.spec.tsx
index 8909f88162..f48e96b832 100644
--- 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()
   })
 })

From d3e8f17a54e93c0d090537ae0afc0f8c936e5bed Mon Sep 17 00:00:00 2001
From: imccyu <276526105+imccyu@users.noreply.github.com>
Date: Fri, 31 Jul 2026 03:44:35 +0800
Subject: [PATCH 08/13] fix: review follow-ups for the session archive set

- WorkspaceRegistry.archiveSession no longer wraps persistence-listing
  failures as WorkspaceUnknownSessionError: only a definite miss (live
  lookup, header index, then a fresh list) maps to session-not-found;
  storage faults propagate as internal errors, with a negative test.
- The archived-current sweep moves from the unary path into the
  projection: any install path (local echo, another tab's frame, a
  reconnect baseline) clears a selection that landed in the archive set.
- An archive set installed while workspace.list is in flight supersedes
  the stale baseline's set instead of being rolled back by it.
- The workspace-management e2e anchors the archived row by its session
  actions button and asserts the single-stray fixture assumption loudly.
- Drop the stale touchSession rows from the workspace READMEs (the
  method was removed with its Agent Note).
---
 ...07-31-session-archive-global-set.i18n.yaml |  4 +--
 .../2026-07-31-session-archive-global-set.md  |  2 +-
 ...026-07-31-session-archive-global-set.zh.md |  2 +-
 apps/web/tests/workspace-management.e2e.ts    | 10 +++++-
 packages/client/runtime/README.i18n.yaml      |  4 +--
 packages/client/runtime/README.md             |  2 +-
 packages/client/runtime/README.zh.md          |  2 +-
 .../runtime/src/client/workspaces/manager.ts  | 11 ++++++-
 .../runtime/src/client/workspaces/service.ts  | 15 ++++++---
 .../runtime/tests/workspaces-service.spec.ts  | 32 +++++++++++++++++++
 packages/workspace/workspace/README.i18n.yaml |  4 +--
 packages/workspace/workspace/README.md        |  1 -
 packages/workspace/workspace/README.zh.md     |  1 -
 packages/workspace/workspace/src/index.ts     | 29 ++++++++++++-----
 .../workspace/tests/workspace.spec.ts         | 10 ++++++
 15 files changed, 103 insertions(+), 26 deletions(-)

diff --git a/.agents/notes/implemented/feature/2026-07-31-session-archive-global-set.i18n.yaml b/.agents/notes/implemented/feature/2026-07-31-session-archive-global-set.i18n.yaml
index 6ed5f6ed3b..ace89283b1 100644
--- a/.agents/notes/implemented/feature/2026-07-31-session-archive-global-set.i18n.yaml
+++ b/.agents/notes/implemented/feature/2026-07-31-session-archive-global-set.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 .agents/notes/implemented/feature/2026-07-31-session-archive-global-set.md
-2026-07-31-session-archive-global-set.md: 0fe354ef0ed50ee60a69b0633522323124c80da7
-2026-07-31-session-archive-global-set.zh.md: 2b13f0eddc9aa62600a95ac5f412c51f3a38af7b
+2026-07-31-session-archive-global-set.md: b318be9985b197171a046a5abeab3c93b879c710
+2026-07-31-session-archive-global-set.zh.md: 8e3157f4c55c54c3fdd3132034b28567b9b25013
diff --git a/.agents/notes/implemented/feature/2026-07-31-session-archive-global-set.md b/.agents/notes/implemented/feature/2026-07-31-session-archive-global-set.md
index 0fe354ef0e..b318be9985 100644
--- a/.agents/notes/implemented/feature/2026-07-31-session-archive-global-set.md
+++ b/.agents/notes/implemented/feature/2026-07-31-session-archive-global-set.md
@@ -15,7 +15,7 @@ The session row menu in the sidebar workspace browser carried a purely visual "D
 - Storage: `archivedSessionIds: z.array(sessionId).default([])`, domain version stays 2 — a purely additive field; pre-field media parse to an empty set through the schema default, no migration code. An archived session keeps its `sessionIds` slot (a future unarchive restores its position), so the set never touches the one-owner accounting invariant.
 - Registry: `ctx.workspace.archiveSession(id)` rides `enqueueOperation`, serialized with create/delete; a session neither live nor persisted throws `WorkspaceUnknownSessionError`; an already archived id neither writes nor emits. The `archivedSessionIds` getter exposes the read-only set.
 - RPC: `workspace.archiveSession({sessionId}) → {archivedSessionIds}` (answers the full updated set); the `workspace.list` response carries the set as the reconnect baseline; a new host frame `host/archived-sessions-changed` pushes the full snapshot after every durable change (same posture as `host/workspace-changed`, emitted from the `domain/changed` global-put branch by set comparison). Unknown sessions reuse the `session-not-found` error code.
-- Client runtime: `WorkspaceListState.archivedSessionIds` (a `ReadonlySet`, reference replaced only on membership change); the list baseline, the unary echo, and the changed frame each install the complete set. `WorkspacesService.archiveSession` calls `sessions.clear()` when the archived session is the current selection, returning to the New Session view (user decision: archiving the open session sends the main view back to the hero).
+- Client runtime: `WorkspaceListState.archivedSessionIds` (a `ReadonlySet`, reference replaced only on membership change); the list baseline, the unary echo, and the changed frame each install the complete set. the projection sweep clears the current selection whenever it lands in the archive set, returning to the New Session view (user decision: archiving the open session sends the main view back to the hero) — one rule covering the local unary echo, another tab's changed frame, and a reconnect baseline restoring a selection archived while this client was away; a frame or echo landing during an in-flight `workspace.list` also shields the newer set from the stale baseline.
 - UI: the `delete` menu row (visual-only) becomes `archive` (label "Archive session", non-danger styling, no confirmation dialog — a non-destructive action whose worst misfire is list hiding); filtering is one extra arm in `tree.ts`'s `sessionVisible` predicate, with `deriveGroups`/`deriveFlat` taking an `archived` set parameter so all four surfaces (group loop, stray bucket, search, flat) share one source.
 
 ## Alternatives considered
diff --git a/.agents/notes/implemented/feature/2026-07-31-session-archive-global-set.zh.md b/.agents/notes/implemented/feature/2026-07-31-session-archive-global-set.zh.md
index 2b13f0eddc..8e3157f4c5 100644
--- a/.agents/notes/implemented/feature/2026-07-31-session-archive-global-set.zh.md
+++ b/.agents/notes/implemented/feature/2026-07-31-session-archive-global-set.zh.md
@@ -15,7 +15,7 @@ Sidebar workspace 浏览区的 session 行菜单里，「Delete session」一直
 - 存储：`archivedSessionIds: z.array(sessionId).default([])`，domain version 保持 2——纯增量字段，旧介质经 schema default 解析为空集合，无迁移代码。被归档的 session 保留其 `sessionIds` 席位（未来取消归档恢复原位置），因此与「一个 session 只被一个 workspace 记账」不变式零纠缠。
 - Registry：`ctx.workspace.archiveSession(id)` 走 `enqueueOperation` 与 create/delete 串行；未知 session（实时与持久化都查不到）抛 `WorkspaceUnknownSessionError`；已归档 id 不写盘不发事件。`archivedSessionIds` getter 暴露只读集合。
 - RPC：`workspace.archiveSession({sessionId}) → {archivedSessionIds}`（应答完整更新后集合）；`workspace.list` 响应携带集合作为重连基线；新 host 帧 `host/archived-sessions-changed` 在每次持久变更后推完整快照（与 `host/workspace-changed` 同姿态，从 `domain/changed` 的 global put 分支比对推帧）。未知 session 复用错误码 `session-not-found`。
-- client runtime：`WorkspaceListState.archivedSessionIds`（`ReadonlySet`，成员不变不换引用）；list 基线、unary 回声、changed 帧三路都整体替换安装。`WorkspacesService.archiveSession` 在归档对象恰为当前 selection 时调 `sessions.clear()` 回 New Session 视图（用户拍板：归档当前打开的 session 主视图回 hero）。
+- client runtime：`WorkspaceListState.archivedSessionIds`（`ReadonlySet`，成员不变不换引用）；list 基线、unary 回声、changed 帧三路都整体替换安装。投影层在当前 selection 落入归档集合时统一清空回 New Session 视图（用户拍板：归档当前打开的 session 主视图回 hero）——一条规则同时覆盖本地 unary 回声、其他标签页的 changed 帧、以及重连基线恢复出一个离线期间被归档的 selection；帧/回声落在 in-flight `workspace.list` 期间时还会屏蔽旧基线对新集合的回滚。
 - UI：菜单项 `delete`（visual-only）改为 `archive`（label「Archive session」，非 danger 样式，无确认对话框——非破坏性操作，误触后果只是列表隐藏）；过滤实现为 `tree.ts` 的 `sessionVisible` 判据加一档，`deriveGroups`/`deriveFlat` 增加 `archived` 集合入参，四个视图（分组循环、stray 兜底、搜索、平铺）同源生效。
 
 ## 已考虑的替代方案
diff --git a/apps/web/tests/workspace-management.e2e.ts b/apps/web/tests/workspace-management.e2e.ts
index 86c9056d66..48483e512d 100644
--- a/apps/web/tests/workspace-management.e2e.ts
+++ b/apps/web/tests/workspace-management.e2e.ts
@@ -429,7 +429,15 @@ describe('web e2e: workspace management (create / rename / flat view / hover car
       }
       return await ungroupedRow.getAttribute('aria-expanded')
     }, { timeout: 5_000 }).toBe('true')
-    const sessionRow = ungroupedSection.locator('[role="treeitem"]').nth(1)
+    // Anchor on session rows (the rows carrying a session actions button),
+    // not a positional index, and assert the single-stray assumption loudly
+    // so a fixture gaining a second stray fails here instead of archiving
+    // the wrong row. CSS attribute match, not getByRole: the button is
+    // display:none until its row hovers, and role queries skip hidden nodes.
+    const sessionRows = ungroupedSection.locator('[role="treeitem"]')
+      .filter({ has: page.locator('button[aria-label^="Session actions for "]') })
+    await expect.poll(() => sessionRows.count(), { timeout: 10_000 }).toBe(1)
+    const sessionRow = sessionRows.first()
     const rowTitle = await sessionRow.locator('[class*="title"]').innerText()
     // Row menu: hover reveals the actions button; Archive session commits
     // without a confirmation dialog (non-destructive: log + accounting stay).
diff --git a/packages/client/runtime/README.i18n.yaml b/packages/client/runtime/README.i18n.yaml
index 60fcf831b4..34f1a33cc5 100644
--- 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: 4c9122d87bfb0ea2d66478de03c69975b0577ab7
-README.zh.md: 1ee4731964ea75de29da47137933852581fc45b3
+README.md: 52d2caf51d2fdaf48a06e6d56292fe087568eba5
+README.zh.md: d7e807cd7dffdd81a106488884031fccbb8a6d65
diff --git a/packages/client/runtime/README.md b/packages/client/runtime/README.md
index 4c9122d87b..52d2caf51d 100644
--- a/packages/client/runtime/README.md
+++ b/packages/client/runtime/README.md
@@ -10,7 +10,7 @@ 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 `ReadonlySet` replaced only when membership changes). 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 and, when the archived session is the current selection, clears it into the New Session view state; grouping surfaces hide members everywhere while the session rows stay in the list store.
+`WorkspaceListState.archivedSessionIds` mirrors the Host's registry-global archive set (a `ReadonlySet` replaced only when membership changes). 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.
 
diff --git a/packages/client/runtime/README.zh.md b/packages/client/runtime/README.zh.md
index 1ee4731964..d7e807cd7d 100644
--- a/packages/client/runtime/README.zh.md
+++ b/packages/client/runtime/README.zh.md
@@ -10,7 +10,7 @@ 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 `ReadonlySet`，仅在成员变化时才替换）。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；当被归档的会话正是当前 selection 时，将其清空为 New Session 视图状态。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。
+`WorkspaceListState.archivedSessionIds` 镜像 Host 的注册表级全局归档集合（一个 `ReadonlySet`，仅在成员变化时才替换）。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。
 
diff --git a/packages/client/runtime/src/client/workspaces/manager.ts b/packages/client/runtime/src/client/workspaces/manager.ts
index 0eddae8445..ba8344533a 100644
--- a/packages/client/runtime/src/client/workspaces/manager.ts
+++ b/packages/client/runtime/src/client/workspaces/manager.ts
@@ -38,6 +38,13 @@ export class WorkspaceManager {
   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
@@ -82,7 +89,7 @@ export class WorkspaceManager {
           items = items.filter(workspace => !this.removedIds.has(workspace.workspaceId))
           for (const delta of frames) items = applyWorkspaceDelta(items, delta)
           this.installViews(items)
-          this.installArchived(result.value.archivedSessionIds)
+          if (!this.archivedSupersedesRefresh) this.installArchived(result.value.archivedSessionIds)
           this.state = 'idle'
           this.phase = 'ready'
         } else {
@@ -96,6 +103,7 @@ export class WorkspaceManager {
         this.error = folded.ok ? null : folded.error
       } finally {
         this.refreshFrames = null
+        this.archivedSupersedesRefresh = false
         this.inflight = null
         this.notifier.markDirty()
       }
@@ -224,6 +232,7 @@ export class WorkspaceManager {
 
   /** Replace the archive set when membership actually changed (set identity backs Object.is short-circuits). */
   private installArchived(archivedSessionIds: readonly SessionId[]): void {
+    if (this.refreshFrames !== null) this.archivedSupersedesRefresh = true
     if (archivedSessionIds.length === this.archivedSessionIds.size
       && archivedSessionIds.every(id => this.archivedSessionIds.has(id))) return
     this.archivedSessionIds = new Set(archivedSessionIds)
diff --git a/packages/client/runtime/src/client/workspaces/service.ts b/packages/client/runtime/src/client/workspaces/service.ts
index 3204407e20..2ef6f77867 100644
--- a/packages/client/runtime/src/client/workspaces/service.ts
+++ b/packages/client/runtime/src/client/workspaces/service.ts
@@ -260,15 +260,14 @@ export class WorkspacesService implements IWorkspaces {
   }
 
   /**
-   * Archive a session into the registry-global set. When the archived
-   * session is the current one, the selection is cleared into the New
-   * Session view state — a hidden row must not stay open behind the list.
+   * 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}`)
-    if (this.sessions.list.getSnapshot().current === sessionId) this.sessions.clear()
   }
 
   /**
@@ -313,6 +312,14 @@ 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.has(sessions.current)) {
+      this.sessions.clear()
+    }
     this.list.set({
       items: workspace.items,
       archivedSessionIds: workspace.archivedSessionIds,
diff --git a/packages/client/runtime/tests/workspaces-service.spec.ts b/packages/client/runtime/tests/workspaces-service.spec.ts
index e280f843d1..71769a8e79 100644
--- a/packages/client/runtime/tests/workspaces-service.spec.ts
+++ b/packages/client/runtime/tests/workspaces-service.spec.ts
@@ -337,6 +337,38 @@ describe('WorkspacesService', () => {
     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', () => {
diff --git a/packages/workspace/workspace/README.i18n.yaml b/packages/workspace/workspace/README.i18n.yaml
index 0805eb6ddc..33f0029093 100644
--- a/packages/workspace/workspace/README.i18n.yaml
+++ b/packages/workspace/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/workspace/workspace/README.md
-README.md: 2d69074d42c28ba5e340cef19c8007bcba94e755
-README.zh.md: f95246a0c970aede1944868489d122d7f309d8e7
+README.md: 11dc8172392e530ab4ea16f1b60473e5befb8089
+README.zh.md: 5c6e3cefe31759df27b8008861505527648ce3c4
diff --git a/packages/workspace/workspace/README.md b/packages/workspace/workspace/README.md
index 2d69074d42..11dc817239 100644
--- a/packages/workspace/workspace/README.md
+++ b/packages/workspace/workspace/README.md
@@ -12,7 +12,6 @@ The entity/storage rationale lives in the [domain Agent Note](../../../.agents/n
 - `ctx.workspace.get(id)` / `list()` / `resolveByPath(path)` — cache-served lookups. `list()` is synchronous and follows durable registry order; `resolveByPath` is async because it applies the same `realpath` canon and rejects a missing path rather than creating it.
 - `ctx.workspace.delete(id)` — removes only the Workspace registration, its durable order entry, and its session account. Unknown ids return `false`; a removed record returns `true`. The directory, user files, live Sessions, and persisted session logs are never touched, so those Sessions become Ungrouped. A table-write failure restores the prior order and published entity.
 - `Workspace.attachSession(id)` — validates a live or persisted session header cwd against the workspace path and prepends a new id. Unknown sessions, absent/unresolvable/non-directory cwd values, and mismatches reject without writing. `detachSession` removes only the candidate index entry.
-- `ctx.workspace.touchSession(id)` — moves only that validated, accounted session to the front. Ungrouped or filtered sessions are no-ops, and workspace order never changes.
 - `ctx.workspace.archiveSession(id)` / `archivedSessionIds` — the registry-global archive set, layered over workspace accounting: an archived session disappears from grouping surfaces but keeps its session log and its `sessionIds` slot, so a future unarchive restores its position. Archiving accepts any live or persisted session (accounted or Ungrouped), resolves without writing for an already archived id, and rejects an unknown id. State written before the field existed parses with an empty set.
 - `Workspace.sessionIds` — synchronous id-plus-canonical-cwd membership projection in durable candidate order. Missing headers, invalid cwd values, and mismatches are filtered; the next workspace mutation prunes them. A medium indexing one session under two workspaces, claiming one path from two records, or diverging from durable workspace order rejects at startup.
 - `Workspace.status()` — uncached directory check, `'ok' | 'missing-dir'`; a missing directory never mutates the record.
diff --git a/packages/workspace/workspace/README.zh.md b/packages/workspace/workspace/README.zh.md
index f95246a0c9..5c6e3cefe3 100644
--- a/packages/workspace/workspace/README.zh.md
+++ b/packages/workspace/workspace/README.zh.md
@@ -12,7 +12,6 @@ DeepSeek Harness 的 Workspace 实体注册表（`ctx.workspace`）：通过领
 - `ctx.workspace.get(id)`/`list()`/`resolveByPath(path)`：由缓存提供的查找。`list()` 为同步操作，并遵循持久注册表顺序；`resolveByPath` 为异步操作，因为它采用相同的 `realpath` 规范化方式，并会拒绝缺失路径，而不是创建路径。
 - `ctx.workspace.delete(id)`：只移除 Workspace 注册记录、对应的持久顺序条目及会话归属记录。未知 id 返回 `false`，成功移除记录则返回 `true`。目录、用户文件、活跃会话和持久化会话日志绝不受影响，因此相关会话会进入 Ungrouped。表写入失败时会恢复原顺序和此前发布的实体。
 - `Workspace.attachSession(id)`：对照 workspace 路径验证实时或已持久化的会话头 cwd，并将新 id 前置。未知会话、缺失／无法解析／非目录的 cwd 值和不匹配情况都会在不写入的前提下被拒绝。`detachSession` 只移除候选索引条目。
-- `ctx.workspace.touchSession(id)`：仅将已验证、已记账的会话移到最前。未分组或被过滤的会话不会触发任何操作，workspace 顺序绝不改变。
 - `ctx.workspace.archiveSession(id)`/`archivedSessionIds`：覆盖在 workspace 记账之上的注册表级全局归档集合：被归档的会话从各分组视图中消失，但其会话日志和 `sessionIds` 席位保持不变，未来取消归档时可恢复原位置。归档接受任何实时或已持久化的会话（无论已记账还是 Ungrouped），对已归档的 id 直接完成而不写入，并拒绝未知 id。在该字段出现之前写入的状态解析为一个空集合。
 - `Workspace.sessionIds`：按持久候选顺序提供同步 id 加规范 cwd 成员投影。缺失头部、无效 cwd 值和不匹配情况都被过滤；下一次 workspace 变更会剪除它们。如果同一存储介质将一个会话索引到两个 workspace 下、用两条记录声明同一路径，或偏离持久 workspace 顺序，启动会被拒绝。
 - `Workspace.status()`：未缓存的目录检查，返回 `'ok' | 'missing-dir'`；目录缺失绝不会改动记录。
diff --git a/packages/workspace/workspace/src/index.ts b/packages/workspace/workspace/src/index.ts
index 742c328e29..5262043b03 100644
--- a/packages/workspace/workspace/src/index.ts
+++ b/packages/workspace/workspace/src/index.ts
@@ -49,14 +49,16 @@ export class WorkspaceNameConflictError extends Error {
   }
 }
 
-/** An archiveSession request named a session neither live nor in session persistence. */
+/**
+ * An archiveSession request named a session neither live nor in session
+ * persistence — a definite miss only; storage faults propagate as themselves.
+ */
 export class WorkspaceUnknownSessionError extends Error {
   /**
    * @param sessionId - The unknown session id.
-   * @param options - Standard error options (the header-read failure as `cause`).
    */
-  constructor(readonly sessionId: SessionId, options?: ErrorOptions) {
-    super(`cannot archive session '${sessionId}': live sessions and session persistence hold no such session`, options)
+  constructor(readonly sessionId: SessionId) {
+    super(`cannot archive session '${sessionId}': live sessions and session persistence hold no such session`)
     this.name = 'WorkspaceUnknownSessionError'
   }
 }
@@ -215,16 +217,27 @@ export class WorkspaceRegistry extends Service {
       // The chain slot serializes against every other registry write, so this
       // check-then-write pair cannot interleave with another archive.
       if (this.requireState().archivedSessionIds.includes(sessionId)) return
-      try {
-        await this.readSessionHeader(sessionId)
-      } catch (error) {
-        throw new WorkspaceUnknownSessionError(sessionId, { cause: error })
+      if (!(await this.sessionKnown(sessionId))) {
+        throw new WorkspaceUnknownSessionError(sessionId)
       }
       const state = this.requireState()
       await this.setState({ ...state, archivedSessionIds: [...state.archivedSessionIds, sessionId] })
     })
   }
 
+  /**
+   * Whether a session is live, header-indexed, or present in a fresh
+   * persistence listing. Only a definite miss returns false — a failing
+   * `sessionPersistence.list()` propagates so storage faults never
+   * masquerade as an unknown session.
+   */
+  private async sessionKnown(id: SessionId): Promise<boolean> {
+    if (this.ctx.get('sessions')?.get(id) !== undefined) return true
+    if (this.headers.has(id)) return true
+    await this.indexHeaders(await this.ctx.sessionPersistence.list())
+    return this.headers.has(id)
+  }
+
   /**
    * Resolve by canonical directory path without creating or mutating a
    * workspace. A missing path rejects during `realpath`; an existing unowned
diff --git a/packages/workspace/workspace/tests/workspace.spec.ts b/packages/workspace/workspace/tests/workspace.spec.ts
index 56910f67c8..ae4567b27e 100644
--- a/packages/workspace/workspace/tests/workspace.spec.ts
+++ b/packages/workspace/workspace/tests/workspace.spec.ts
@@ -866,6 +866,16 @@ describe('registry-global session archive', () => {
     expect(storedState(result.pool).archivedSessionIds).toEqual(['stray', 'live-only'])
   })
 
+  it('propagates a persistence-listing failure instead of reporting an unknown session', async () => {
+    const result = await harness({ sessions: [] })
+    result.list.mockRejectedValueOnce(new Error('persistence backend down'))
+    // The storage fault is the error — never WorkspaceUnknownSessionError,
+    // which the API layer would misreport as session-not-found.
+    await expect(result.registry.archiveSession(SessionId('unlisted')))
+      .rejects.toThrow(/persistence backend down/)
+    expect(storedState(result.pool).archivedSessionIds).toEqual([])
+  })
+
   it('restores the archive set across restarts and defaults it for pre-field media', async () => {
     const dir = await makeDir('archive-restart')
     const pool = new MemoryMediaPool()

From 5fc2645afc706f67283ac68d031ec4588f2fd490 Mon Sep 17 00:00:00 2001
From: imccyu <276526105+imccyu@users.noreply.github.com>
Date: Fri, 31 Jul 2026 03:45:51 +0800
Subject: [PATCH 09/13] docs: regenerate the cordis catalog for the
 archiveSession contract change

---
 docs/cordis-catalog/services.md | 2 +-
 1 file changed, 1 insertion(+), 1 deletion(-)

diff --git a/docs/cordis-catalog/services.md b/docs/cordis-catalog/services.md
index 958dcc10cd..fdd1712705 100644
--- a/docs/cordis-catalog/services.md
+++ b/docs/cordis-catalog/services.md
@@ -2565,7 +2565,7 @@ async resolveByPath(path: string): Promise<Workspace | undefined>
 
 Types: [SessionId](../core-data-structures/core.md)
 
-Source: [`packages/workspace/workspace/src/index.ts:90`](../../packages/workspace/workspace/src/index.ts)
+Source: [`packages/workspace/workspace/src/index.ts:92`](../../packages/workspace/workspace/src/index.ts)
 
 ## Inherited `ctx` members (cordis core + loader/hmr/timer)
 

From 9ed87a6dbaf6e8ecf3e04c987b921d7dd5f202b2 Mon Sep 17 00:00:00 2001
From: imccyu <276526105+imccyu@users.noreply.github.com>
Date: Fri, 31 Jul 2026 10:40:09 +0800
Subject: [PATCH 10/13] refactor(client): archivedSessionIds public face
 becomes a plain array
MIME-Version: 1.0
Content-Type: text/plain; charset=UTF-8
Content-Transfer-Encoding: 8bit

Public snapshot state stays in the store engine's plain-data vocabulary
(immer drafts reject Sets without the MapSet plugin, which stays off):
manager/service/contract carry readonly SessionId[] in Host order, and
the tree derivations build their own transient Set — the
expandedProjects pattern. Membership-unchanged installs still keep the
array reference for Object.is short-circuits.
---
 ...07-31-session-archive-global-set.i18n.yaml |  4 ++--
 .../2026-07-31-session-archive-global-set.md  |  2 +-
 ...026-07-31-session-archive-global-set.zh.md |  2 +-
 .../client/locale/tests/language-row.spec.tsx |  2 +-
 packages/client/runtime/README.i18n.yaml      |  4 ++--
 packages/client/runtime/README.md             |  2 +-
 packages/client/runtime/README.zh.md          |  2 +-
 .../runtime/src/client/workspaces/manager.ts  | 24 +++++++++++++------
 .../runtime/src/client/workspaces/service.ts  | 16 +++++++------
 .../runtime/tests/workspaces-service.spec.ts  | 14 +++++------
 packages/client/test-runtime/src/fixtures.ts  |  2 +-
 .../client/test-runtime/src/workspaces.ts     |  5 +---
 .../test-runtime/tests/runtime.spec.tsx       |  4 ++--
 .../tests/chat-code-subcalls.spec.tsx         |  2 +-
 .../ui-conversation/tests/chat-view.spec.tsx  |  2 +-
 .../tests/gate-branch-tails.spec.tsx          |  4 ++--
 .../ui-conversation/tests/input-bar.spec.tsx  |  2 +-
 .../tests/input-matrix.spec.tsx               |  2 +-
 .../tests/input-scenarios.spec.tsx            |  2 +-
 .../ui-conversation/tests/skeleton.spec.tsx   |  2 +-
 .../tests/terminal-card.spec.tsx              |  4 ++--
 .../client/ui-layout/tests/app-frame.spec.tsx |  2 +-
 .../ui-theme/tests/appearance-row.spec.tsx    |  2 +-
 .../client/ui-trajectory/tests/views.spec.tsx |  2 +-
 .../tests/workspace-browser.spec.tsx          |  4 ++--
 .../tests/workspace-picker.spec.tsx           |  2 +-
 26 files changed, 62 insertions(+), 53 deletions(-)

diff --git a/.agents/notes/implemented/feature/2026-07-31-session-archive-global-set.i18n.yaml b/.agents/notes/implemented/feature/2026-07-31-session-archive-global-set.i18n.yaml
index ace89283b1..cca8f8a597 100644
--- a/.agents/notes/implemented/feature/2026-07-31-session-archive-global-set.i18n.yaml
+++ b/.agents/notes/implemented/feature/2026-07-31-session-archive-global-set.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 .agents/notes/implemented/feature/2026-07-31-session-archive-global-set.md
-2026-07-31-session-archive-global-set.md: b318be9985b197171a046a5abeab3c93b879c710
-2026-07-31-session-archive-global-set.zh.md: 8e3157f4c55c54c3fdd3132034b28567b9b25013
+2026-07-31-session-archive-global-set.md: fab99a405a6f8264c36453473327e32905bac9c8
+2026-07-31-session-archive-global-set.zh.md: e33f3b5272a6d8fc90cfad247ba21d4d10afb045
diff --git a/.agents/notes/implemented/feature/2026-07-31-session-archive-global-set.md b/.agents/notes/implemented/feature/2026-07-31-session-archive-global-set.md
index b318be9985..fab99a405a 100644
--- a/.agents/notes/implemented/feature/2026-07-31-session-archive-global-set.md
+++ b/.agents/notes/implemented/feature/2026-07-31-session-archive-global-set.md
@@ -15,7 +15,7 @@ The session row menu in the sidebar workspace browser carried a purely visual "D
 - Storage: `archivedSessionIds: z.array(sessionId).default([])`, domain version stays 2 — a purely additive field; pre-field media parse to an empty set through the schema default, no migration code. An archived session keeps its `sessionIds` slot (a future unarchive restores its position), so the set never touches the one-owner accounting invariant.
 - Registry: `ctx.workspace.archiveSession(id)` rides `enqueueOperation`, serialized with create/delete; a session neither live nor persisted throws `WorkspaceUnknownSessionError`; an already archived id neither writes nor emits. The `archivedSessionIds` getter exposes the read-only set.
 - RPC: `workspace.archiveSession({sessionId}) → {archivedSessionIds}` (answers the full updated set); the `workspace.list` response carries the set as the reconnect baseline; a new host frame `host/archived-sessions-changed` pushes the full snapshot after every durable change (same posture as `host/workspace-changed`, emitted from the `domain/changed` global-put branch by set comparison). Unknown sessions reuse the `session-not-found` error code.
-- Client runtime: `WorkspaceListState.archivedSessionIds` (a `ReadonlySet`, reference replaced only on membership change); the list baseline, the unary echo, and the changed frame each install the complete set. the projection sweep clears the current selection whenever it lands in the archive set, returning to the New Session view (user decision: archiving the open session sends the main view back to the hero) — one rule covering the local unary echo, another tab's changed frame, and a reconnect baseline restoring a selection archived while this client was away; a frame or echo landing during an in-flight `workspace.list` also shields the newer set from the stale baseline.
+- Client runtime: `WorkspaceListState.archivedSessionIds` (a `readonly SessionId[]` in Host order, reference replaced only on membership change — public snapshot state stays in the store engine's plain-data vocabulary since immer drafts reject Sets without the MapSet plugin; membership lookups build a transient Set in the derivation, the expandedProjects pattern); the list baseline, the unary echo, and the changed frame each install the complete set. the projection sweep clears the current selection whenever it lands in the archive set, returning to the New Session view (user decision: archiving the open session sends the main view back to the hero) — one rule covering the local unary echo, another tab's changed frame, and a reconnect baseline restoring a selection archived while this client was away; a frame or echo landing during an in-flight `workspace.list` also shields the newer set from the stale baseline.
 - UI: the `delete` menu row (visual-only) becomes `archive` (label "Archive session", non-danger styling, no confirmation dialog — a non-destructive action whose worst misfire is list hiding); filtering is one extra arm in `tree.ts`'s `sessionVisible` predicate, with `deriveGroups`/`deriveFlat` taking an `archived` set parameter so all four surfaces (group loop, stray bucket, search, flat) share one source.
 
 ## Alternatives considered
diff --git a/.agents/notes/implemented/feature/2026-07-31-session-archive-global-set.zh.md b/.agents/notes/implemented/feature/2026-07-31-session-archive-global-set.zh.md
index 8e3157f4c5..e33f3b5272 100644
--- a/.agents/notes/implemented/feature/2026-07-31-session-archive-global-set.zh.md
+++ b/.agents/notes/implemented/feature/2026-07-31-session-archive-global-set.zh.md
@@ -15,7 +15,7 @@ Sidebar workspace 浏览区的 session 行菜单里，「Delete session」一直
 - 存储：`archivedSessionIds: z.array(sessionId).default([])`，domain version 保持 2——纯增量字段，旧介质经 schema default 解析为空集合，无迁移代码。被归档的 session 保留其 `sessionIds` 席位（未来取消归档恢复原位置），因此与「一个 session 只被一个 workspace 记账」不变式零纠缠。
 - Registry：`ctx.workspace.archiveSession(id)` 走 `enqueueOperation` 与 create/delete 串行；未知 session（实时与持久化都查不到）抛 `WorkspaceUnknownSessionError`；已归档 id 不写盘不发事件。`archivedSessionIds` getter 暴露只读集合。
 - RPC：`workspace.archiveSession({sessionId}) → {archivedSessionIds}`（应答完整更新后集合）；`workspace.list` 响应携带集合作为重连基线；新 host 帧 `host/archived-sessions-changed` 在每次持久变更后推完整快照（与 `host/workspace-changed` 同姿态，从 `domain/changed` 的 global put 分支比对推帧）。未知 session 复用错误码 `session-not-found`。
-- client runtime：`WorkspaceListState.archivedSessionIds`（`ReadonlySet`，成员不变不换引用）；list 基线、unary 回声、changed 帧三路都整体替换安装。投影层在当前 selection 落入归档集合时统一清空回 New Session 视图（用户拍板：归档当前打开的 session 主视图回 hero）——一条规则同时覆盖本地 unary 回声、其他标签页的 changed 帧、以及重连基线恢复出一个离线期间被归档的 selection；帧/回声落在 in-flight `workspace.list` 期间时还会屏蔽旧基线对新集合的回滚。
+- client runtime：`WorkspaceListState.archivedSessionIds`（按 Host 顺序的 `readonly SessionId[]`，成员不变不换引用——公有快照状态保持 store 引擎的纯数据词汇：immer draft 不开 MapSet 插件就不接受 Set；membership 查询在派生函数内自建临时 Set，与 expandedProjects 同款）；list 基线、unary 回声、changed 帧三路都整体替换安装。投影层在当前 selection 落入归档集合时统一清空回 New Session 视图（用户拍板：归档当前打开的 session 主视图回 hero）——一条规则同时覆盖本地 unary 回声、其他标签页的 changed 帧、以及重连基线恢复出一个离线期间被归档的 selection；帧/回声落在 in-flight `workspace.list` 期间时还会屏蔽旧基线对新集合的回滚。
 - UI：菜单项 `delete`（visual-only）改为 `archive`（label「Archive session」，非 danger 样式，无确认对话框——非破坏性操作，误触后果只是列表隐藏）；过滤实现为 `tree.ts` 的 `sessionVisible` 判据加一档，`deriveGroups`/`deriveFlat` 增加 `archived` 集合入参，四个视图（分组循环、stray 兜底、搜索、平铺）同源生效。
 
 ## 已考虑的替代方案
diff --git a/packages/client/locale/tests/language-row.spec.tsx b/packages/client/locale/tests/language-row.spec.tsx
index 223b9761b2..2908583191 100644
--- 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: [], archivedSessionIds: new Set(), state: 'idle', phase: 'ready', error: null,
+    items: [], archivedSessionIds: [], state: 'idle', phase: 'ready', error: null,
     baselinesReady: true, recentWorkspaceId: undefined,
   })
   return bindSnapshotSelector(store)
diff --git a/packages/client/runtime/README.i18n.yaml b/packages/client/runtime/README.i18n.yaml
index 34f1a33cc5..60d011aeb1 100644
--- 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: 52d2caf51d2fdaf48a06e6d56292fe087568eba5
-README.zh.md: d7e807cd7dffdd81a106488884031fccbb8a6d65
+README.md: 022dc6f82ea7aa1490144449ea61a84a512906a2
+README.zh.md: 4d0f74f573a5e03b05755cfcfea930e69ef386e2
diff --git a/packages/client/runtime/README.md b/packages/client/runtime/README.md
index 52d2caf51d..022dc6f82e 100644
--- a/packages/client/runtime/README.md
+++ b/packages/client/runtime/README.md
@@ -10,7 +10,7 @@ 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 `ReadonlySet` replaced only when membership changes). 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.
+`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.
 
diff --git a/packages/client/runtime/README.zh.md b/packages/client/runtime/README.zh.md
index d7e807cd7d..4d0f74f573 100644
--- a/packages/client/runtime/README.zh.md
+++ b/packages/client/runtime/README.zh.md
@@ -10,7 +10,7 @@ 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 `ReadonlySet`，仅在成员变化时才替换）。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。
+`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。
 
diff --git a/packages/client/runtime/src/client/workspaces/manager.ts b/packages/client/runtime/src/client/workspaces/manager.ts
index ba8344533a..ccf0c46fe1 100644
--- a/packages/client/runtime/src/client/workspaces/manager.ts
+++ b/packages/client/runtime/src/client/workspaces/manager.ts
@@ -14,8 +14,14 @@ export type WorkspaceListPhase = 'pending' | 'ready'
 /** Immutable workspace-list snapshot. */
 export interface WorkspaceListSnapshot {
   items: readonly WorkspaceView[]
-  /** Registry-global archive set (hidden from grouping surfaces; accounting slots retained). */
-  archivedSessionIds: ReadonlySet<SessionId>
+  /**
+   * 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
@@ -32,7 +38,7 @@ export class WorkspaceManager {
   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: ReadonlySet<SessionId> = new Set()
+  private archivedSessionIds: readonly SessionId[] = []
   private state: WorkspaceListSnapshot['state'] = 'idle'
   private phase: WorkspaceListPhase = 'pending'
   private error: RpcError | null = null
@@ -230,12 +236,16 @@ export class WorkspaceManager {
     }
   }
 
-  /** Replace the archive set when membership actually changed (set identity backs Object.is short-circuits). */
+  /**
+   * 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.size
-      && archivedSessionIds.every(id => this.archivedSessionIds.has(id))) return
-    this.archivedSessionIds = new Set(archivedSessionIds)
+    if (archivedSessionIds.length === this.archivedSessionIds.length
+      && archivedSessionIds.every((id, index) => id === this.archivedSessionIds[index])) return
+    this.archivedSessionIds = [...archivedSessionIds]
     this.notifier.markDirty()
   }
 
diff --git a/packages/client/runtime/src/client/workspaces/service.ts b/packages/client/runtime/src/client/workspaces/service.ts
index 2ef6f77867..a0a76670f2 100644
--- a/packages/client/runtime/src/client/workspaces/service.ts
+++ b/packages/client/runtime/src/client/workspaces/service.ts
@@ -15,11 +15,13 @@ import { WorkspaceManager, type WorkspaceListPhase } from './manager.ts'
 export interface WorkspaceListState {
   items: readonly WorkspaceView[]
   /**
-   * Registry-global archive set: grouping surfaces hide these sessions
-   * everywhere (workspace groups and the ungrouped bucket) while their
-   * session logs and workspace accounting slots remain.
+   * 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: ReadonlySet<SessionId>
+  archivedSessionIds: readonly SessionId[]
   state: 'idle' | 'loading' | 'error'
   phase: WorkspaceListPhase
   error: RpcError | null
@@ -64,7 +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: [], archivedSessionIds: new Set(), state: 'idle', phase: 'pending', error: null,
+      items: [], archivedSessionIds: [], state: 'idle', phase: 'pending', error: null,
       baselinesReady: false, recentWorkspaceId: undefined,
     })
     this.manager.subscribe(() => { this.project() })
@@ -101,7 +103,7 @@ export class WorkspacesService implements IWorkspaces {
     for (const id of sessions.ids) {
       const summary = sessions.byId[id]
       if (summary !== undefined && summary.blank && summary.cwd === workspace.path
-        && !archived.has(summary.id)) return summary.id
+        && !archived.includes(summary.id)) return summary.id
     }
     const attempt = this.sessions.create({ workspaceId })
       .finally(() => { this.connecting.delete(workspaceId) })
@@ -317,7 +319,7 @@ export class WorkspacesService implements IWorkspaces {
     // 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.has(sessions.current)) {
+    if (sessions.current !== undefined && workspace.archivedSessionIds.includes(sessions.current)) {
       this.sessions.clear()
     }
     this.list.set({
diff --git a/packages/client/runtime/tests/workspaces-service.spec.ts b/packages/client/runtime/tests/workspaces-service.spec.ts
index 71769a8e79..4323d7ffce 100644
--- a/packages/client/runtime/tests/workspaces-service.spec.ts
+++ b/packages/client/runtime/tests/workspaces-service.spec.ts
@@ -309,13 +309,13 @@ describe('WorkspacesService', () => {
     // 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(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(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.
@@ -323,7 +323,7 @@ describe('WorkspacesService', () => {
       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'])
+    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({
@@ -332,10 +332,10 @@ describe('WorkspacesService', () => {
     } 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'])
+    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'])
+    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 () => {
@@ -363,11 +363,11 @@ describe('WorkspacesService', () => {
     expect(sessions.list.getSnapshot().current).toBeUndefined()
     gate.resolve(ok({ items: [], archivedSessionIds: [] }))
     await hydration
-    expect([...workspaces.list.getSnapshot().archivedSessionIds]).toEqual(['s-open'])
+    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([])
+    expect(workspaces.list.getSnapshot().archivedSessionIds).toEqual([])
   })
 })
 
diff --git a/packages/client/test-runtime/src/fixtures.ts b/packages/client/test-runtime/src/fixtures.ts
index d81adf7698..e4c9ef946d 100644
--- a/packages/client/test-runtime/src/fixtures.ts
+++ b/packages/client/test-runtime/src/fixtures.ts
@@ -73,7 +73,7 @@ export function conversationSnapshot(sessionId: SessionId): ConversationSnapshot
 export function workspaceListState(): WorkspaceListState {
   return {
     items: [],
-    archivedSessionIds: new Set(),
+    archivedSessionIds: [],
     state: 'idle',
     phase: 'ready',
     error: null,
diff --git a/packages/client/test-runtime/src/workspaces.ts b/packages/client/test-runtime/src/workspaces.ts
index d27139cd48..7e626a3660 100644
--- a/packages/client/test-runtime/src/workspaces.ts
+++ b/packages/client/test-runtime/src/workspaces.ts
@@ -199,11 +199,8 @@ export class TestWorkspaces implements IWorkspaces {
       await (stub(sessionId) as Promise<void>)
       return
     }
-    // Built outside the draft: reading a Set through an immer draft needs
-    // the MapSet plugin, while assigning a fresh Set does not.
-    const next = new Set([...this.list.getSnapshot().archivedSessionIds, sessionId])
     await this.update((draft) => {
-      draft.archivedSessionIds = next
+      draft.archivedSessionIds = [...draft.archivedSessionIds, sessionId]
     })
   }
 }
diff --git a/packages/client/test-runtime/tests/runtime.spec.tsx b/packages/client/test-runtime/tests/runtime.spec.tsx
index f48e96b832..3675671f26 100644
--- a/packages/client/test-runtime/tests/runtime.spec.tsx
+++ b/packages/client/test-runtime/tests/runtime.spec.tsx
@@ -554,7 +554,7 @@ describe('workspaces action face', () => {
     // 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.list.getSnapshot().archivedSessionIds).toEqual(['s1'])
     expect(ws.calls.map(c => c.method)).toEqual(
       ['create', 'create', 'pickDirectory', 'rename', 'delete', 'openPath', 'insertSessionBefore', 'archiveSession'])
 
@@ -573,7 +573,7 @@ describe('workspaces action face', () => {
     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'])
+    expect(ws.list.getSnapshot().archivedSessionIds).toEqual(['s1'])
     await runtime.dispose()
   })
 })
diff --git a/packages/client/ui-conversation/tests/chat-code-subcalls.spec.tsx b/packages/client/ui-conversation/tests/chat-code-subcalls.spec.tsx
index 16d070b04d..1f9b8b7356 100644
--- 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: [], archivedSessionIds: new Set(), state: 'idle', phase: 'ready', error: null,
+      items: [], archivedSessionIds: [], state: 'idle', phase: 'ready', error: null,
       baselinesReady: true, recentWorkspaceId: undefined,
     }),
     startSession: vi.fn(),
diff --git a/packages/client/ui-conversation/tests/chat-view.spec.tsx b/packages/client/ui-conversation/tests/chat-view.spec.tsx
index b59335fa3a..ca81d225a9 100644
--- 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: [], archivedSessionIds: new Set(), state: 'idle', phase: 'ready', error: null,
+    items: [], archivedSessionIds: [], state: 'idle', phase: 'ready', error: null,
     baselinesReady: true, recentWorkspaceId: undefined,
   })
   return bindSnapshotSelector(store)
diff --git a/packages/client/ui-conversation/tests/gate-branch-tails.spec.tsx b/packages/client/ui-conversation/tests/gate-branch-tails.spec.tsx
index 192470abfc..4de44d367c 100644
--- 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: [], archivedSessionIds: new Set(), 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: [], archivedSessionIds: new Set(), state: 'idle', phase: 'ready', error: null,
+      items: [], archivedSessionIds: [], state: 'idle', phase: 'ready', error: null,
       baselinesReady: true, recentWorkspaceId: undefined,
     })
     const view = render(
diff --git a/packages/client/ui-conversation/tests/input-bar.spec.tsx b/packages/client/ui-conversation/tests/input-bar.spec.tsx
index 1974881357..e8154ca957 100644
--- 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: [], archivedSessionIds: new Set(), 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) =>
diff --git a/packages/client/ui-conversation/tests/input-matrix.spec.tsx b/packages/client/ui-conversation/tests/input-matrix.spec.tsx
index 4901ec2f9f..04f20d56c6 100644
--- 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: [], archivedSessionIds: new Set(), state: 'idle', phase: 'ready', error: null,
+      items: [], archivedSessionIds: [], state: 'idle', phase: 'ready', error: null,
       baselinesReady: true, recentWorkspaceId: undefined,
     })),
     useProjection: (() => undefined),
diff --git a/packages/client/ui-conversation/tests/input-scenarios.spec.tsx b/packages/client/ui-conversation/tests/input-scenarios.spec.tsx
index 167b9c96af..11ee8fa4e4 100644
--- 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: [], archivedSessionIds: new Set(), state: 'idle', phase: 'ready', error: null,
+      items: [], archivedSessionIds: [], state: 'idle', phase: 'ready', error: null,
       baselinesReady: true, recentWorkspaceId: undefined,
     })),
     useProjection: (() => undefined),
diff --git a/packages/client/ui-conversation/tests/skeleton.spec.tsx b/packages/client/ui-conversation/tests/skeleton.spec.tsx
index 2669cbb8ab..3841930d2c 100644
--- 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, archivedSessionIds: new Set(), state: 'idle', phase: 'ready', error: null,
+  items, archivedSessionIds: [], state: 'idle', phase: 'ready', error: null,
   baselinesReady: true, recentWorkspaceId: undefined,
 })
 
diff --git a/packages/client/ui-conversation/tests/terminal-card.spec.tsx b/packages/client/ui-conversation/tests/terminal-card.spec.tsx
index 29f246d603..71de19b152 100644
--- 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: [], archivedSessionIds: new Set(), 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: [], archivedSessionIds: new Set(), state: 'idle', phase: 'ready', error: null,
+          items: [], archivedSessionIds: [], state: 'idle', phase: 'ready', error: null,
           baselinesReady: true, recentWorkspaceId: undefined,
         }))}
         useInput={(() => { throw new Error('unused') })}
diff --git a/packages/client/ui-layout/tests/app-frame.spec.tsx b/packages/client/ui-layout/tests/app-frame.spec.tsx
index d30cd17877..11b5e48e0a 100644
--- 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: [], archivedSessionIds: new Set(), state: 'idle', phase: 'ready', error: null,
+    items: [], archivedSessionIds: [], state: 'idle', phase: 'ready', error: null,
     baselinesReady: baselinesReady.current, recentWorkspaceId: undefined,
   }
   const element = () => (
diff --git a/packages/client/ui-theme/tests/appearance-row.spec.tsx b/packages/client/ui-theme/tests/appearance-row.spec.tsx
index 00cc0e3052..d028affd69 100644
--- 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: [], archivedSessionIds: new Set(), state: 'idle', phase: 'ready', error: null,
+    items: [], archivedSessionIds: [], state: 'idle', phase: 'ready', error: null,
     baselinesReady: true, recentWorkspaceId: undefined,
   })
   return bindSnapshotSelector(store)
diff --git a/packages/client/ui-trajectory/tests/views.spec.tsx b/packages/client/ui-trajectory/tests/views.spec.tsx
index d31b43d3e6..1ebe8d2f61 100644
--- 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: [], archivedSessionIds: new Set(), state: 'idle', phase: 'ready', error: null, baselinesReady: true,
+    items: [], archivedSessionIds: [], state: 'idle', phase: 'ready', error: null, baselinesReady: true,
     recentWorkspaceId: undefined,
   })
   return bindSnapshotSelector(store)
diff --git a/packages/client/ui-workspace/tests/workspace-browser.spec.tsx b/packages/client/ui-workspace/tests/workspace-browser.spec.tsx
index 5b12646a27..e5c89ce0de 100644
--- a/packages/client/ui-workspace/tests/workspace-browser.spec.tsx
+++ b/packages/client/ui-workspace/tests/workspace-browser.spec.tsx
@@ -35,7 +35,7 @@ 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[], archivedSessionIds: ReadonlySet<SessionId> = new Set()): WorkspaceListState => ({
+const workspaceState = (items: readonly WorkspaceView[], archivedSessionIds: readonly SessionId[] = []): WorkspaceListState => ({
   items, archivedSessionIds, state: 'idle', phase: 'ready', error: null, baselinesReady: true,
   recentWorkspaceId: items[0]?.workspaceId,
 })
@@ -149,7 +149,7 @@ describe('WorkspaceBrowser', () => {
     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'])], new Set([sid('gone-s')]))) })
+    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' }))
diff --git a/packages/client/ui-workspace/tests/workspace-picker.spec.tsx b/packages/client/ui-workspace/tests/workspace-picker.spec.tsx
index 334020b37f..b2d1479d17 100644
--- 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, archivedSessionIds: new Set(), 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 } {

From d2dff405606704a9f8a6ed268b71aa15f90a661c Mon Sep 17 00:00:00 2001
From: imccyu <276526105+imccyu@users.noreply.github.com>
Date: Fri, 31 Jul 2026 10:48:39 +0800
Subject: [PATCH 11/13] feat(ui-workspace): blank New Session rows render no
 menu and no time

A blank row is a provisional placeholder: nothing has happened in it,
so the row verbs (rename/fork/archive) and a 'now' stamp would act on
content that does not exist. The trailing cells and the hover card's
time line stay off until the first prompt lands.
---
 .../ui-workspace/src/client/rows/Rows.tsx     | 62 +++++++++++--------
 .../client/ui-workspace/tests/rows.spec.tsx   | 23 +++++++
 2 files changed, 58 insertions(+), 27 deletions(-)

diff --git a/packages/client/ui-workspace/src/client/rows/Rows.tsx b/packages/client/ui-workspace/src/client/rows/Rows.tsx
index a8b28f17e4..77583140c1 100644
--- a/packages/client/ui-workspace/src/client/rows/Rows.tsx
+++ b/packages/client/ui-workspace/src/client/rows/Rows.tsx
@@ -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>
@@ -306,32 +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)
-            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>
+      {/* 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 (
diff --git a/packages/client/ui-workspace/tests/rows.spec.tsx b/packages/client/ui-workspace/tests/rows.spec.tsx
index ee45b8628d..c0b4959b17 100644
--- a/packages/client/ui-workspace/tests/rows.spec.tsx
+++ b/packages/client/ui-workspace/tests/rows.spec.tsx
@@ -157,6 +157,29 @@ describe('workspace browser rows', () => {
     expect(screen.queryByRole('button', { name: /工作区/ })).toBeNull()
   })
 
+  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()

From b8b5403f0abaed29cad110eaa288c22c39232666 Mon Sep 17 00:00:00 2001
From: imccyu <276526105+imccyu@users.noreply.github.com>
Date: Fri, 31 Jul 2026 11:59:10 +0800
Subject: [PATCH 12/13] fix: ci

---
 apps/web/tests/snapshots/lifecycle-chrome/hero.expected.md      | 2 +-
 .../tests/snapshots/lifecycle-chrome/plan-active.expected.md    | 2 +-
 package.json                                                    | 1 +
 packages/client/ui-conversation/tests/web-card.spec.tsx         | 2 +-
 4 files changed, 4 insertions(+), 3 deletions(-)

diff --git a/apps/web/tests/snapshots/lifecycle-chrome/hero.expected.md b/apps/web/tests/snapshots/lifecycle-chrome/hero.expected.md
index 7024719a3a..dc4cbca241 100644
--- a/apps/web/tests/snapshots/lifecycle-chrome/hero.expected.md
+++ b/apps/web/tests/snapshots/lifecycle-chrome/hero.expected.md
@@ -16,7 +16,7 @@
   - treeitem "workspace 1 session" [expanded]:
     - img
     - text: workspace 1 session
-  - treeitem "New Session now" [selected]
+  - treeitem "New Session" [selected]
 - button "Settings":
   - img
   - text: Settings
diff --git a/apps/web/tests/snapshots/lifecycle-chrome/plan-active.expected.md b/apps/web/tests/snapshots/lifecycle-chrome/plan-active.expected.md
index 15bee7afe4..7f62e80503 100644
--- a/apps/web/tests/snapshots/lifecycle-chrome/plan-active.expected.md
+++ b/apps/web/tests/snapshots/lifecycle-chrome/plan-active.expected.md
@@ -16,7 +16,7 @@
   - treeitem "workspace 1 session" [expanded]:
     - img
     - text: workspace 1 session
-  - treeitem "New Session now" [selected]
+  - treeitem "New Session" [selected]
 - button "Settings":
   - img
   - text: Settings
diff --git a/package.json b/package.json
index fc315cb146..96f72d1c1c 100644
--- a/package.json
+++ b/package.json
@@ -31,6 +31,7 @@
     "test:snapshot:refresh": "DSH_SNAPSHOT=refresh vitest run --config vitest.snapshot.config.ts",
     "migrate:packed-session-fixtures": "tsx scripts/migrate-packed-session-fixtures.ts",
     "test:web": "npm run build && npm run test:web:built",
+    "test:web:refresh": "npm run build && DSH_SNAPSHOT=refresh vitest run --config vitest.web.config.ts",
     "test:web:built": "vitest run --config vitest.web.config.ts",
     "test:gui": "vitest run packages/client packages/host",
     "check:all": "tsx scripts/run-gates.ts check-all",
diff --git a/packages/client/ui-conversation/tests/web-card.spec.tsx b/packages/client/ui-conversation/tests/web-card.spec.tsx
index cea95e61f6..fc4a27c78b 100644
--- 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(

From f5680ffabec9b461deb5e4b66bff14a55a2bc7af Mon Sep 17 00:00:00 2001
From: imccyu <276526105+imccyu@users.noreply.github.com>
Date: Fri, 31 Jul 2026 14:02:34 +0800
Subject: [PATCH 13/13] fix: ci

---
 packages/client/ui-conversation/tests/diff-card.spec.tsx | 2 +-
 1 file changed, 1 insertion(+), 1 deletion(-)

diff --git a/packages/client/ui-conversation/tests/diff-card.spec.tsx b/packages/client/ui-conversation/tests/diff-card.spec.tsx
index 10af914bed..e25045c9f0 100644
--- 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(