feat: revert crumbs navigation for subagents

apps/web/tests/snapshots/code-mode-round/ui.expected.md

@@ -1,5 +1,6 @@
 - banner:
-  - 'heading "Using ONE run_code program: run" [level=1]'
+  - navigation "Session hierarchy":
+    - 'button "Using ONE run_code program: run" [disabled]'
   - tablist:
     - tab "Chat" [selected]
     - tab "Trajectory"

apps/web/tests/snapshots/cordis-tool-round/ui.expected.md

@@ -1,5 +1,6 @@
 - banner:
-  - heading "Use only Cordis tools. First" [level=1]
+  - navigation "Session hierarchy":
+    - button "Use only Cordis tools. First" [disabled]
   - tablist:
     - tab "Chat" [selected]
     - tab "Trajectory"

apps/web/tests/snapshots/fresh-round-trip/ui.expected.md

@@ -1,5 +1,6 @@
 - banner:
-  - heading "Use the bash tool to" [level=1]
+  - navigation "Session hierarchy":
+    - button "Use the bash tool to" [disabled]
   - tablist:
     - tab "Chat" [selected]
     - tab "Trajectory"

apps/web/tests/snapshots/lifecycle-chrome/reloaded.expected.md

@@ -1,5 +1,6 @@
 - banner:
-  - heading "Reply with the single word" [level=1]
+  - navigation "Session hierarchy":
+    - button "Reply with the single word" [disabled]
   - tablist:
     - tab "Chat" [selected]
     - tab "Trajectory"

apps/web/tests/snapshots/live-interactions/cancel.expected.md

@@ -1,5 +1,6 @@
 - banner:
-  - heading "Reply with a one-sentence description" [level=1]
+  - navigation "Session hierarchy":
+    - button "Reply with a one-sentence description" [disabled]
   - tablist:
     - tab "Chat" [selected]
     - tab "Trajectory"

apps/web/tests/snapshots/live-interactions/error-auth.expected.md

@@ -1,5 +1,6 @@
 - banner:
-  - heading "Reply with a one-sentence description" [level=1]
+  - navigation "Session hierarchy":
+    - button "Reply with a one-sentence description" [disabled]
   - tablist:
     - tab "Chat" [selected]
     - tab "Trajectory"

apps/web/tests/snapshots/live-interactions/loading.expected.md

@@ -1,5 +1,6 @@
 - banner:
-  - heading "Reply with a one-sentence description" [level=1]
+  - navigation "Session hierarchy":
+    - button "Reply with a one-sentence description" [disabled]
   - tablist:
     - tab "Chat" [selected]
     - tab "Trajectory"

apps/web/tests/snapshots/live-interactions/retry.expected.md

@@ -1,5 +1,6 @@
 - banner:
-  - heading "Reply with a one-sentence description" [level=1]
+  - navigation "Session hierarchy":
+    - button "Reply with a one-sentence description" [disabled]
   - tablist:
     - tab "Chat" [selected]
     - tab "Trajectory"

apps/web/tests/snapshots/message-actions/ui.expected.md

@@ -1,5 +1,6 @@
 - banner:
-  - heading "Use the read tool twice" [level=1]
+  - navigation "Session hierarchy":
+    - button "Use the read tool twice" [disabled]
   - tablist:
     - tab "Chat" [selected]
     - tab "Trajectory"

apps/web/tests/snapshots/plan-review/approved.expected.md

@@ -1,5 +1,6 @@
 - banner:
-  - 'heading "Plan a small change: add" [level=1]'
+  - navigation "Session hierarchy":
+    - 'button "Plan a small change: add" [disabled]'
   - tablist:
     - tab "Chat" [selected]
     - tab "Trajectory"

apps/web/tests/snapshots/question-composer/answered.expected.md

@@ -1,5 +1,6 @@
 - banner:
-  - heading "Use the ask_user_question tool to" [level=1]
+  - navigation "Session hierarchy":
+    - button "Use the ask_user_question tool to" [disabled]
   - tablist:
     - tab "Chat" [selected]
     - tab "Trajectory"

apps/web/tests/snapshots/queue-actions/collapsed.expected.md

@@ -1,5 +1,6 @@
 - banner:
-  - heading "Reply with a one-sentence description" [level=1]
+  - navigation "Session hierarchy":
+    - button "Reply with a one-sentence description" [disabled]
   - tablist:
     - tab "Chat" [selected]
     - tab "Trajectory"

apps/web/tests/snapshots/queue-actions/editing.expected.md

@@ -1,5 +1,6 @@
 - banner:
-  - heading "Reply with a one-sentence description" [level=1]
+  - navigation "Session hierarchy":
+    - button "Reply with a one-sentence description" [disabled]
   - tablist:
     - tab "Chat" [selected]
     - tab "Trajectory"

apps/web/tests/snapshots/queue-actions/preserved.expected.md

@@ -1,5 +1,6 @@
 - banner:
-  - heading "Reply with a one-sentence description" [level=1]
+  - navigation "Session hierarchy":
+    - button "Reply with a one-sentence description" [disabled]
   - tablist:
     - tab "Chat" [selected]
     - tab "Trajectory"

apps/web/tests/snapshots/queue-actions/ui.expected.md

@@ -1,5 +1,6 @@
 - banner:
-  - heading "Reply with a one-sentence description" [level=1]
+  - navigation "Session hierarchy":
+    - button "Reply with a one-sentence description" [disabled]
   - tablist:
     - tab "Chat" [selected]
     - tab "Trajectory"

apps/web/tests/snapshots/seeded-history/command-row.expected.md

@@ -1,5 +1,6 @@
 - banner:
-  - heading "Use the read tool twice" [level=1]
+  - navigation "Session hierarchy":
+    - button "Use the read tool twice" [disabled]
   - tablist:
     - tab "Chat" [selected]
     - tab "Trajectory"

apps/web/tests/snapshots/seeded-history/ui.expected.md

@@ -1,5 +1,6 @@
 - banner:
-  - heading "Use the read tool twice" [level=1]
+  - navigation "Session hierarchy":
+    - button "Use the read tool twice" [disabled]
   - tablist:
     - tab "Chat" [selected]
     - tab "Trajectory"

apps/web/tests/snapshots/steering/mid-steer.expected.md

@@ -1,5 +1,6 @@
 - banner:
-  - heading "Use the ask_user_question tool to" [level=1]
+  - navigation "Session hierarchy":
+    - button "Use the ask_user_question tool to" [disabled]
   - tablist:
     - tab "Chat" [selected]
     - tab "Trajectory"

apps/web/tests/snapshots/steering/settled.expected.md

@@ -1,5 +1,6 @@
 - banner:
-  - heading "Use the ask_user_question tool to" [level=1]
+  - navigation "Session hierarchy":
+    - button "Use the ask_user_question tool to" [disabled]
   - tablist:
     - tab "Chat" [selected]
     - tab "Trajectory"

apps/web/tests/snapshots/subagent-conversation/ui.expected.md

@@ -1,5 +1,8 @@
 - banner:
-  - heading "event-sourcing researcher" [level=1]
+  - navigation "Session hierarchy":
+    - button "Ask a research subagent to"
+    - text: /
+    - button "event-sourcing researcher" [disabled]
   - button "1 个子代理":
     - text: 1 个子代理
     - img

apps/web/tests/snapshots/web-search-round/ui.expected.md

@@ -1,5 +1,6 @@
 - banner:
-  - heading "Use web_search to search exactly" [level=1]
+  - navigation "Session hierarchy":
+    - button "Use web_search to search exactly" [disabled]
   - tablist:
     - tab "Chat" [selected]
     - tab "Trajectory"

packages/client/ui-conversation/src/client/apply.ts

@@ -165,6 +165,7 @@ export function apply(ctx: Context): void {
   // the resident parent keeps Hero and composer layout identity stable.
   slots.register({
     name: 'conversation.session',
+    locale: NS,
     children: {
       'conversation.view': { kind: 'list', scope: 'session' },
       'conversation.session.header.actions': { kind: 'list', scope: 'session' },
@@ -177,6 +178,7 @@ export function apply(ctx: Context): void {
         version: () => slots.getVersion('conversation.view'),
       },
       bindDraftMirror: write => inputHub.shell(sessionId).bindMirror(write),
+      open: (id) => { sessions.open(id) },
     }),
   }, ConversationSession)
 

packages/client/ui-conversation/src/client/contract/slots.ts

@@ -3,7 +3,7 @@ import type { ReactNode, RefObject } from 'react'
 import type {
   InjectFace, MaybeSnapshotSelectorHook, PropsLocale, PropsRenderSlots, PropsRuntime, PropsStore, SnapshotSelectorHook,
 } from '@deepseek-ai/dsh-client-ui-slots'
-import type { CommandNode, ConversationSnapshot, ObservableSnapshot, PendingInteraction, PendingWait, ToolCallBlock, WorkspaceId } from '@deepseek-ai/dsh-client-runtime/client'
+import type { CommandNode, ConversationSnapshot, ObservableSnapshot, PendingInteraction, PendingWait, SessionId, ToolCallBlock, WorkspaceId } from '@deepseek-ai/dsh-client-runtime/client'
 import type {} from '@deepseek-ai/dsh-client-ui-layout/client'
 import type { ComposerKeyboard, EditSelection, InputActions, InputNotice, InputState } from '../input/contract.ts'
 import type { createChatStore } from '../stores.ts'
@@ -249,6 +249,8 @@ export interface ConversationSessionInjected {
   }
   /** Bind the input machine's draft persistence mirror to the session store. */
   bindDraftMirror: (write: (text: string) => void) => () => void
+  /** Select a real Session through the runtime navigation owner. */
+  open: (sessionId: SessionId) => void
 }
 
 /**
@@ -360,6 +362,7 @@ export type ConversationSessionSlotProps =
   & PropsRenderSlots<'conversation.view' | 'conversation.session.header.actions'>
   & PropsStore<ChatStore>
   & ConversationSessionInjected
+  & PropsLocale<'conversation'>
 
 /** The pending approval carrier the owner dispatches into the composer chain. */
 export type ApprovalWait = PendingWait<'approval'>

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

@@ -30,6 +30,7 @@ export const zh = {
   'access.confirm.enable': '启用 Full access',
   'hero.headline': '开始构建吧',
   'hero.chooseWorkspace': '选择工作区',
+  'session.hierarchy': '会话层级',
   'details.title': '详情',
   'details.close': '关闭详情',
   'details.empty': '点击消息流中的工具行查看详情',
@@ -129,6 +130,7 @@ export const en = {
   'access.confirm.enable': 'Enable Full access',
   'hero.headline': 'Let\'s start building',
   'hero.chooseWorkspace': 'Choose workspace',
+  'session.hierarchy': 'Session hierarchy',
   'details.title': 'Details',
   'details.close': 'Close details',
   'details.empty': 'Click a tool row in the message flow to view its details',

packages/client/ui-conversation/src/client/skeleton/ConversationRoot.module.css

@@ -1,4 +1,4 @@
-/* Conversation column skeleton: header (session title + tabs) over the view
+/* Conversation column skeleton: header (breadcrumb row only for subagents not fork + tabs) over the view
    area, composer InputBar at the bottom. Column width/squeeze is layout's;
    this fills its cell. Figma: Header 39:27730 (83px two-row), tabs 13px with
    a 3px active bar. */
@@ -26,23 +26,55 @@
 .titleRow {
   display: flex;
   align-items: center;
-  justify-content: space-between;
   gap: 10px;
   min-height: 32px;
 }
-
+.crumbs {
-.sessionTitle {
+  display: flex;
+  align-items: center;
+  gap: 4px;
   min-width: 0;
-  max-width: 100%;
   overflow: hidden;
-  margin: 0;
+  white-space: nowrap;
-  padding: 4px 8px;
+}
+
+.crumbSeg {
+  display: inline-flex;
+  align-items: center;
+  gap: 4px;
+  min-width: 0;
+}
+
+.crumbSep {
+  /* figma: "/" separators are 14px caption gray (75:7903), one tint lighter than crumb text. */
+  color: var(--dsw-alias-label-caption);
   font-size: 14px;
   line-height: 20px;
-  font-weight: 500;
+}
-  color: var(--dsw-alias-label-primary);
+
+.crumb {
+  max-width: 220px;
+  overflow: hidden;
+  padding: 4px 8px;
+  border: none;
+  border-radius: 12px;
+  background: transparent;
+  font-size: 14px;
+  line-height: 20px;
+  color: var(--dsw-alias-label-tertiary);
   text-overflow: ellipsis;
   white-space: nowrap;
+  cursor: pointer;
+}
+
+.crumb:hover:not(:disabled) {
+  background: var(--dsw-alias-interactive-bg-hover);
+}
+
+.crumbCurrent {
+  font-weight: 500;
+  color: var(--dsw-alias-label-primary);
+  cursor: default;
 }
 
 .headerActions {

packages/client/ui-conversation/src/client/skeleton/ConversationSession.tsx

@@ -2,21 +2,35 @@
 
 import { useEffect, useSyncExternalStore, type ReactNode } from 'react'
 import clsx from 'clsx'
+import { shallowEqual } from '@deepseek-ai/dsh-client-runtime/client'
+import type { SessionId, SessionListState, SessionSummary } from '@deepseek-ai/dsh-client-runtime/client'
 import type { ConversationSessionSlotProps } from '../contract/slots.ts'
 import css from './ConversationRoot.module.css'
 
 /** Full props composed from the strict session slot contract. */
 export type ConversationSessionProps = ConversationSessionSlotProps
 
+function deriveAncestry(list: SessionListState, id: SessionId): readonly SessionSummary[] {
+  const chain: SessionSummary[] = []
+  let cursor: SessionId | undefined = id
+  while (cursor !== undefined) {
+    const summary: SessionSummary | undefined = list.byId[cursor]
+    if (summary === undefined || chain.includes(summary)) break
+    chain.unshift(summary)
+    cursor = summary.parentId
+  }
+  return chain
+}
+
 export function ConversationSession({
   sessionId, useSession, useSessions, useInput, inputActions, useStore, actions,
-  renderSlot, views, bindDraftMirror, wrapActiveBody,
+  renderSlot, views, bindDraftMirror, open, wrapActiveBody, t
 }: ConversationSessionProps) {
   useSyncExternalStore(views.subscribe, views.version)
   const tabs = views.list()
   const activeId = useStore(s => s.view) ?? 'chat'
   const active = tabs.find(view => view.id === activeId) ?? tabs[0]
-  const title = useSessions(s => s.byId[sessionId]?.displayTitle ?? sessionId)
+  const ancestry = useSessions(s => deriveAncestry(s, sessionId), shallowEqual)
   const composerPhase = useSession(s => s.composerPhase)
   const blank = useSession(s => s.blank)
   const inputState = useInput(s => s)
@@ -56,7 +70,25 @@ export function ConversationSession({
         {!hideChrome && (
           <>
             <div className={css.titleRow}>
-              <h1 className={css.sessionTitle}>{title}</h1>
+              <nav className={css.crumbs} aria-label={t('session.hierarchy')}>
+                {ancestry.map((summary, index) => {
+                  const last = index === ancestry.length - 1
+                  return (
+                    <span key={summary.id} className={css.crumbSeg}>
+                      {index > 0 && <span className={css.crumbSep}>/</span>}
+                      <button
+                        type="button"
+                        className={clsx(css.crumb, last && css.crumbCurrent)}
+                        disabled={last}
+                        onClick={() => { open(summary.id) }}
+                      >
+                        {summary.displayTitle}
+                      </button>
+                    </span>
+                  )
+                })}
+                {ancestry.length === 0 && <span className={css.crumbCurrent}>{sessionId}</span>}
+              </nav>
               <div className={css.headerActions}>
                 {renderSlot('conversation.session.header.actions', {})}
               </div>

packages/client/ui-conversation/tests/skeleton.spec.tsx

@@ -111,6 +111,7 @@ function mount(
   const useInput = bindSnapshotSelector(wiring.state)
   const inputActions = wiring.actions
   const stop = vi.fn()
+  const open = vi.fn()
   const slotCalls: string[] = []
   let pickerOwner: unknown
   const renderSlot = ((key: string, owner: object, opts?: { only?: string }) => {
@@ -139,6 +140,8 @@ function mount(
             version: () => 1,
           }}
           bindDraftMirror={write => wiring.bindMirror(write)}
+          open={open}
+          t={t}
           {...owner}
         />
       )

packages/client/ui-trajectory/tests/views.spec.tsx

@@ -23,6 +23,7 @@ import type {
 import type { ConvViewProps, ViewTab } from '@deepseek-ai/dsh-client-ui-conversation/client'
 import { ConversationSession, type ConversationSessionProps } from '@deepseek-ai/dsh-client-ui-conversation/src/client/skeleton/ConversationSession.tsx'
 import { createChatStore } from '@deepseek-ai/dsh-client-ui-conversation/src/client/stores.ts'
+import { zh as conversationZh } from '@deepseek-ai/dsh-client-ui-conversation/src/client/locales.ts'
 import { apply, inject } from '@deepseek-ai/dsh-client-ui-trajectory/client'
 import { apply as nodeApply } from '@deepseek-ai/dsh-client-ui-trajectory'
 import type { TrajectoryTurnModel } from '../src/client/layout.ts'
@@ -35,6 +36,11 @@ import { deriveTrajectoryTimeline } from '../src/client/timeline.ts'
 
 const SID = 's1' as SessionId
 
+// Stub of the conversation package's standard locale seat (this spec mounts
+// its ConversationSession chrome); answers from the zh dictionary and falls
+// back to the key like the real chain.
+const tConversation: ConversationSessionProps['t'] =
+  key => (conversationZh as Record<string, string>)[key] ?? key
 afterEach(cleanup)
 // The chat store persists under its declared key; clear so one case's active
 // view cannot rehydrate into the next.
@@ -213,6 +219,7 @@ function mount(slots: SlotsService, nodes: ConversationSnapshot['nodes'] = NODES
   return render(
     <ConversationSession
       sessionId={SID}
+      t={tConversation}
       SessionProvider={({ children }) => children(SID)}
       useSession={useSession}
       useSessions={emptySessions()}
@@ -229,6 +236,7 @@ function mount(slots: SlotsService, nodes: ConversationSnapshot['nodes'] = NODES
       useInput={bindSnapshotSelector(createSnapshotStore({ draft: '', draftRev: 0, phase: 'plain', queue: [] })) as never}
       inputActions={{ setDraft: vi.fn(), submit: vi.fn() }}
       bindDraftMirror={() => () => {}}
+      open={vi.fn()}
     />,
   )
 }