Merge remote-tracking branch 'origin/master' into xtr/react-loop-simplification

# Conflicts: # .agents/notes/implemented/architecture/2026-07-12-agent-scope-runtime-design.i18n.yaml # .agents/notes/implemented/architecture/2026-07-31-goal-owned-durable-events.i18n.yaml # .agents/notes/implemented/feature/2026-07-19-model-facing-goal-tools.i18n.yaml # .agents/notes/implemented/feature/2026-07-22-docked-web-goal-bar.i18n.yaml # docs/architecture.i18n.yaml # docs/architecture.md # docs/architecture.zh.md # docs/config-catalog.md # docs/cordis-catalog/events.md # docs/cordis-catalog/services.md # docs/core-data-structures/core.i18n.yaml # docs/core-data-structures/core.md # docs/core-data-structures/core.zh.md # docs/event-producer-consumer.md # docs/module-graph.md # docs/persistence-catalog.md # examples/acp-agent/tests/snapshots/advanced-toolchain/session.1.jsonl # examples/acp-agent/tests/snapshots/advanced-toolchain/session.2.jsonl # examples/acp-agent/tests/snapshots/code-mode-workspace-context/session.jsonl # examples/acp-agent/tests/snapshots/cordis-inspect-jsdoc/session.jsonl # examples/acp-agent/tests/snapshots/skill-load/session.jsonl # examples/acp-agent/tests/snapshots/subagent-depth-two-rejection/session.1.jsonl # examples/acp-agent/tests/snapshots/subagent-depth-two-rejection/session.2.jsonl # examples/acp-agent/tests/snapshots/subagent-fork/session.1.jsonl # examples/acp-agent/tests/snapshots/subagent-mixed/session.1.jsonl # examples/acp-agent/tests/snapshots/subagent-mixed/session.2.jsonl # examples/acp-agent/tests/snapshots/subagent-multi/session.1.jsonl # examples/acp-agent/tests/snapshots/subagent-multi/session.2.jsonl # examples/acp-agent/tests/snapshots/subagent-spawn/session.1.jsonl # examples/acp-agent/tests/snapshots/workflow-run/session.1.jsonl # examples/acp-agent/tests/snapshots/workspace-context/session.jsonl # examples/headless-agent/tests/snapshots/advanced-toolchain/session.1.jsonl # examples/headless-agent/tests/snapshots/advanced-toolchain/session.2.jsonl # examples/headless-agent/tests/snapshots/advanced-toolchain/session.jsonl # examples/headless-agent/tests/snapshots/pty-tools/session.jsonl # examples/headless-agent/tests/subagent-inheritance-snapshots/parent-override/child.expected.jsonl # examples/jsonrpc-agent/tests/snapshots/subagent-spawn/notifications.expected.jsonl # examples/jsonrpc-agent/tests/snapshots/subagent-spawn/session.1.jsonl # packages/acp/acp/README.i18n.yaml # packages/acp/acp/src/index.ts # packages/client/connection/src/client/index.ts # packages/client/runtime/README.i18n.yaml # packages/client/runtime/README.md # packages/client/runtime/README.zh.md # packages/client/runtime/src/client/sessions/conversation.ts # packages/client/runtime/src/client/sessions/session.ts # packages/client/runtime/tests/queue-store.spec.ts # packages/client/ui-conversation/src/client/input/contract.ts # packages/client/ui-goal/README.i18n.yaml # packages/compact/compact-basic/src/index.ts # packages/context/time-context/tests/time-context.spec.ts # packages/context/tmux-context/tests/tmux-context.spec.ts # packages/context/workspace-context/tests/workspace-context.spec.ts # packages/cordis/tool-cordis/src/api-catalog.ts # packages/core/agent-loop/README.i18n.yaml # packages/core/agent-loop/README.md # packages/core/agent-loop/README.zh.md # packages/core/agent-loop/src/agent.ts # packages/core/agent-loop/tests/agent.spec.ts # packages/core/agent-loop/tests/loop.spec.ts # packages/core/agent/README.i18n.yaml # packages/core/agent/README.md # packages/core/agent/README.zh.md # packages/core/agent/src/types.ts # packages/core/session/README.i18n.yaml # packages/core/session/README.md # packages/core/session/README.zh.md # packages/goal/command-goal/tests/command-goal.spec.ts # packages/goal/goal/tests/goal.spec.ts # packages/goal/tool-goal/README.i18n.yaml # packages/goal/tool-goal/README.md # packages/goal/tool-goal/README.zh.md # packages/host/apiproxy/README.i18n.yaml # packages/host/apiproxy/README.md # packages/host/apiproxy/README.zh.md # packages/host/apiproxy/src/api-proxy.ts # packages/host/apiproxy/src/api/events.schema.ts # packages/host/apiproxy/src/api/events.ts # packages/host/apiproxy/src/api/rpc.ts # packages/host/apiproxy/tests/api-proxy-commands.spec.ts # packages/host/apiproxy/tests/api-proxy-projections.spec.ts # packages/host/apiproxy/tests/rpc-schemas.spec.ts # packages/pty/pty-local/tests/index.spec.ts # packages/pty/pty-local/tests/local.spec.ts # packages/pty/tool-pty/tests/loader-composition.spec.ts # packages/pty/tool-pty/tests/tools.spec.ts # packages/session-persistence/session-checkpoint-policy/src/index.ts # packages/session-persistence/session-persistence/tests/coordinator-contract.ts # packages/skill/tool-skill/tests/tool-skill.spec.ts # packages/subagent/subagent-inprocess/README.i18n.yaml # packages/subagent/subagent-inprocess/README.md # packages/subagent/subagent-inprocess/README.zh.md # packages/subagent/subagent-inprocess/src/index.ts # packages/subagent/subagent-inprocess/tests/subagent-inprocess.spec.ts # packages/support/acp-snapshot/src/harness.ts # packages/ui/tui/tests/tui.spec.ts
2026-08-03 10:56:09 +08:00
parent b4258a2c4a 8bf606ba80
commit dc1d542092
605 changed files with 25740 additions and 2265 deletions
--- a/packages/client/ui-conversation/src/client/apply.ts
+++ b/packages/client/ui-conversation/src/client/apply.ts
@@ -1,6 +1,6 @@
 /** Registers the conversation components, shared store, and service callbacks. */
 import type { Context } from 'cordis'
-import { resolveSlotLabel, type BoundActions } from '@deepseek-ai/dsh-client-ui-slots'
+import { deferRegistration, resolveSlotLabel, type BoundActions } from '@deepseek-ai/dsh-client-ui-slots'
 import type { ISessions, SessionId } from '@deepseek-ai/dsh-client-runtime/client'
 import type {} from '@deepseek-ai/dsh-client-ui-layout/client'
 // Type-only: pulls the locale plugin's Context merge (ctx.locale).
@@ -16,7 +16,10 @@ import { createChatStore } from './stores.ts'
 import { ConversationService } from './service.ts'
 import type { IConversation } from './service.ts'
 import { InputHub } from './input/hub.ts'
+import { ComposerSubmissionPolicy } from './input/submission-policy.ts'
 import { InputBar } from './skeleton/InputBar.tsx'
+import { EnterBehaviorRow } from './settings/EnterBehaviorRow.tsx'
+import type { EnterBehaviorRowInjected } from './settings/EnterBehaviorRow.tsx'
 import { ChatView } from './chat/ChatView.tsx'
 import { StatsLine } from './chat/StatsLine.tsx'
 import { bashToolviewSample } from './toolviews/bash-sample.tsx'
@@ -93,6 +96,22 @@ export function apply(ctx: Context): void {

  // Apply-time construction keeps store identity bound to this fiber.
  const chatStore = createChatStore()
+  const submissionPolicy = new ComposerSubmissionPolicy()
+
+  ctx.effect(() => {
+    const row = deferRegistration(ctx.slots, 'settings.general.item', EnterBehaviorRow, () =>
+      ctx.slots.register({
+        name: 'settings.general.item',
+        id: 'composer-enter',
+        order: 20,
+        locale: NS,
+        inject: (): EnterBehaviorRowInjected => ({
+          hooks: { busyEnter: submissionPolicy.busyEnter },
+          setBusyEnter: (behavior) => { submissionPolicy.setBusyEnter(behavior) },
+        }),
+      }, EnterBehaviorRow))
+    return () => { row.dispose() }
+  }, 'ui-conversation: Enter behavior settings row')

  // Chat scroll offsets by session, surviving view switches (the chat view
  // unmounts under the tab ring). Deliberately not persisted: a fresh page
@@ -165,7 +184,11 @@ export function apply(ctx: Context): void {
  // the resident parent keeps Hero and composer layout identity stable.
  slots.register({
    name: 'conversation.session',
-    children: { 'conversation.view': { kind: 'list', scope: 'session' } },
+    locale: NS,
+    children: {
+      'conversation.view': { kind: 'list', scope: 'session' },
+      'conversation.session.header.actions': { kind: 'list', scope: 'session' },
+    },
    store: chatStore,
    inject: (sessionId: SessionId, _actions: BoundActions<typeof chatStore>): ConversationSessionInjected => ({
      views: {
@@ -174,6 +197,7 @@ export function apply(ctx: Context): void {
        version: () => slots.getVersion('conversation.view'),
      },
      bindDraftMirror: write => inputHub.shell(sessionId).bindMirror(write),
+      open: (id) => { sessions.open(id) },
    }),
  }, ConversationSession)

@@ -198,6 +222,8 @@ export function apply(ctx: Context): void {
      if (sessionId === undefined) {
        return {
          keyboard: undefined,
+          resolveSubmitMode: (running, gesture, steeringAvailable) =>
+            submissionPolicy.resolve(running, gesture, steeringAvailable),
          toggleCommandMenu: undefined,
          stop: undefined,
          command: undefined,
@@ -208,6 +234,8 @@ export function apply(ctx: Context): void {
      const slash = inputHub.slash(sessionId)
      return {
        keyboard: shell,
+        resolveSubmitMode: (running, gesture, steeringAvailable) =>
+          submissionPolicy.resolve(running, gesture, steeringAvailable),
        toggleCommandMenu: slash === undefined
          ? undefined
          : (selection) => {
--- a/packages/client/ui-conversation/src/client/chat/AssistantMarkdown.tsx
+++ b/packages/client/ui-conversation/src/client/chat/AssistantMarkdown.tsx
@@ -39,6 +39,13 @@ function firstLine(text: string): string {
  return nl === -1 ? text : text.slice(0, nl)
 }

+/** Latest non-blank reasoning line while the block is still streaming. */
+function latestLine(text: string): string {
+  const visible = text.trimEnd()
+  const nl = visible.lastIndexOf('\n')
+  return nl === -1 ? visible : visible.slice(nl + 1)
+}
+
 /** Joined text blocks for the copy action (reasoning / tool heads stay out). */
 function copyText(blocks: readonly AssistantBlock[]): string {
  const parts: string[] = []
@@ -61,7 +68,7 @@ function ThinkRow({ text, running, t }: { text: string; running: boolean; t: Ass
      variant="think"
      icon={<IconThinkOutline14 size={14} />}
      title="Think"
-      summary={firstLine(text)}
+      summary={running ? latestLine(text) : firstLine(text)}
      body={text}
      state={running ? 'running' : 'ok'}
    />
--- a/packages/client/ui-conversation/src/client/chat/ChatView.tsx
+++ b/packages/client/ui-conversation/src/client/chat/ChatView.tsx
@@ -34,7 +34,7 @@ import { assistantActionsSeqs, deriveChatFlow, type ChatFlowItem } from './chat-
 import { AssistantMarkdown } from './AssistantMarkdown.tsx'
 import { GenericCommandCard } from './GenericCommandCard.tsx'
 import { GenericToolCard } from './GenericToolCard.tsx'
-import { MessageItem } from './MessageItem.tsx'
+import { MessageItem, PendingSteeringBubble } from './MessageItem.tsx'
 import css from './ChatView.module.css'

 const FOLLOW_THRESHOLD = 24
@@ -236,6 +236,7 @@ export function ChatView({
  useSession, useSessions, useStore, renderSlot, sessionId, openFile, loadOlder, inspectCall, chatScroll, forkAt, t,
 }: ChatViewSlotProps) {
  const nodes = useSession(s => s.nodes)
+  const inbox = useSession(s => s.queue)
  // Workspace root off the session list row: path summaries display relative to it.
  const cwd = useSessions(s => s.byId[sessionId]?.cwd)
  const running = useSession(s => s.running)
@@ -248,6 +249,10 @@ export function ChatView({
  const selectedCallId = useStore(s => s.selection?.callId)

  const items = useMemo(() => deriveChatFlow(nodes), [nodes])
+  const pendingSteering = useMemo(
+    () => inbox.filter(item => item.placement === 'steering'),
+    [inbox],
+  )
  const activeRetry = useMemo(() => activeRetrySeq(nodes, running), [nodes, running])
  // Only the last content assistant of each turn owns IconActions; mid-turn
  // text (before tools) omits `time` so AssistantMarkdown stays chrome-free.
@@ -261,6 +266,7 @@ export function ChatView({
  const firstSeqRef = useRef<number | null>(null)
  const openedRef = useRef(false)
  const lastKeyRef = useRef<string | null>(null)
+  const lastSteeringIdRef = useRef<string | null>(null)
  /** Flow tip signature — follow-scroll only when this moves, never on a
   *  scroll-driven at-bottom chrome re-render (that was snapping inertial
   *  scrolls the rest of the way to the floor). */
@@ -269,7 +275,8 @@ export function ChatView({
  const firstSeq = nodes[0]?.seq ?? null
  const lastItem = items[items.length - 1]
  const lastKey = lastItem?.key ?? null
-  const followSig = `${openState}:${firstSeq}:${lastKey}:${nodes.length}:${running ? 1 : 0}:${runningCalls.length}`
+  const lastSteeringId = pendingSteering[pendingSteering.length - 1]?.id ?? null
+  const followSig = `${openState}:${firstSeq}:${lastKey}:${nodes.length}:${running ? 1 : 0}:${runningCalls.length}:${lastSteeringId ?? ''}`

  const toBottom = (el: HTMLElement): void => {
    el.scrollTop = el.scrollHeight
@@ -298,6 +305,7 @@ export function ChatView({
      }
      firstSeqRef.current = firstSeq
      lastKeyRef.current = lastKey
+      lastSteeringIdRef.current = lastSteeringId
      followSigRef.current = followSig
      return
    }
@@ -308,6 +316,7 @@ export function ChatView({
      firstSeqRef.current = firstSeq
      /* v8 ignore next -- ?? arm: a prepend adds nodes, so the flow list here is never empty. */
      lastKeyRef.current = lastKey
+      lastSteeringIdRef.current = lastSteeringId
      followSigRef.current = followSig
      return
    }
@@ -316,12 +325,14 @@ export function ChatView({
    // (send lives in the composer, so arrival is detected here, not armed there).
    const appendedUser = lastKey !== lastKeyRef.current
      && lastItem !== undefined && lastItem.kind === 'node' && lastItem.node.kind === 'user'
+    const appendedSteering = lastSteeringId !== null && lastSteeringId !== lastSteeringIdRef.current
    const tipMoved = followSigRef.current !== followSig
    lastKeyRef.current = lastKey
+    lastSteeringIdRef.current = lastSteeringId
    followSigRef.current = followSig
    // Follow new flow content while pinned; do NOT re-pin on every render
    // merely because atBottomRef is true (scroll threshold → setState → snap).
-    if (appendedUser || (tipMoved && atBottomRef.current)) toBottom(el)
+    if (appendedUser || appendedSteering || (tipMoved && atBottomRef.current)) toBottom(el)
  })

  const onScrollRef = useRef(() => {})
@@ -467,6 +478,9 @@ export function ChatView({
          {/* Turn-level loading signal: rides the whole running turn (first-token
              wait, tool execution, streaming) so it never flickers per step. */}
          {running && <TurnStatus />}
+          {pendingSteering.map(item => (
+            <PendingSteeringBubble key={item.id} content={item.content} t={t} />
+          ))}
        </div>
        {!atBottom && (
          <div className={css.toBottomSlot}>
--- a/packages/client/ui-conversation/src/client/chat/MessageIconActions.tsx
+++ b/packages/client/ui-conversation/src/client/chat/MessageIconActions.tsx
@@ -1,5 +1,5 @@
-// Shared IconActions chrome for user and assistant messages: copy live,
-// branch wired through onBranch, date-aware clock.
+// Shared IconActions chrome for user, steering, and assistant messages: copy
+// live, optional branch wiring, and an optional date-aware clock.

 import { useCallback } from 'react'
 import {
@@ -13,12 +13,14 @@ import css from './MessageIconActions.module.css'
 export interface MessageIconActionsProps {
  /** Plain text the copy action writes. */
  text: string
-  /** Unix epoch ms for the clock label. */
-  time: number
+  /** Unix epoch ms for the clock label; omitted for transient messages. */
+  time?: number | undefined
  /** Clock before icons (user) or after (assistant). */
  clock: 'start' | 'end'
  /** Fork the session at this message. */
  onBranch?: (() => void) | undefined
+  /** Whether to render the branch action; defaults to true. */
+  showBranch?: boolean | undefined
  /** Parent layout class composed onto the actions row. */
  className?: string | undefined
  /** The owning view's locale seat, passed down as a plain prop. */
@@ -31,13 +33,13 @@ export interface MessageIconActionsProps {
 * @returns The actions row element.
 */
 export function MessageIconActions({
-  text, time, clock, onBranch, className, t,
+  text, time, clock, onBranch, showBranch = true, className, t,
 }: MessageIconActionsProps) {
  const day = useCalendarDay()
  const onCopy = useCallback(() => {
    void writeClipboard(text)
  }, [text])
-  const clockEl = (
+  const clockEl = time === undefined ? null : (
    <span className={clock === 'start' ? css.timeStart : css.timeEnd}>
      {formatMessageClock(time, t, day)}
    </span>
@@ -50,11 +52,13 @@ export function MessageIconActions({
          <IconCopyOutline16 />
        </button>
      </Tooltip>
-      <Tooltip label={t('message.branch')} side="bottom">
-        <button type="button" className={css.action} aria-label={t('message.branch')} onClick={onBranch}>
-          <IconBranchOutline16 />
-        </button>
-      </Tooltip>
+      {showBranch && (
+        <Tooltip label={t('message.branch')} side="bottom">
+          <button type="button" className={css.action} aria-label={t('message.branch')} onClick={onBranch}>
+            <IconBranchOutline16 />
+          </button>
+        </Tooltip>
+      )}
      {clock === 'end' ? clockEl : null}
    </div>
  )
--- a/packages/client/ui-conversation/src/client/chat/MessageItem.tsx
+++ b/packages/client/ui-conversation/src/client/chat/MessageItem.tsx
@@ -1,6 +1,6 @@
-// MessageItem: simple chat nodes — user bubble (right-aligned, with
-// clock + copy / branch IconActions), steering (same bubble, no actions),
-// context injection, compaction marker, retry disclosure, and
+// MessageItem: simple chat nodes — user and consumed-steering bubbles
+// (right-aligned, with clock + copy / branch IconActions), pending steering
+// (copy only), context injection, compaction marker, retry disclosure, and
 // unknown-surface JSON rows.

 import { memo, useEffect, useMemo, useState } from 'react'
@@ -167,19 +167,21 @@ function projectUserText(text: string): ReactNode {
  return <>{parts}</>
 }

-/** Right-aligned bubble shared by user and steering rows (steering has no actions). */
+/** Right-aligned bubble shared by user and steering rows. */
 function UserStyleBubble({
-  content, actions, t,
+  content, actions, pending = false, t,
 }: {
  content: readonly unknown[]
  /** Optional IconActions (or similar) below the bubble; receives the joined text. */
  actions?: (text: string) => ReactNode
+  /** Whether this is the Host-authoritative pre-admission steering projection. */
+  pending?: boolean
  t: ChatViewSlotProps['t']
 }): ReactNode {
  const { text, rest } = contentText(content)
  const truncated = (total: number): string => t('json.truncated', { total })
  return (
-    <div className={css.userRow}>
+    <div className={css.userRow} data-pending-steering={pending || undefined}>
      <div className={css.bubble}>
        {projectUserText(text)}
        {rest.map((block, i) => <JsonBlock key={i} label={t('message.extraBlock')} payload={block} truncatedLabel={truncated} />)}
@@ -189,12 +191,41 @@ function UserStyleBubble({
  )
 }

+/**
+ * Render one Host-authoritative pending steering item with the same visual
+ * language as its eventual durable transcript node.
+ * @param props - Pending message content and conversation translator.
+ * @returns the pending steering bubble.
+ */
+export function PendingSteeringBubble({ content, t }: {
+  content: readonly unknown[]
+  t: ChatViewSlotProps['t']
+}): ReactNode {
+  return (
+    <UserStyleBubble
+      content={content}
+      pending
+      t={t}
+      actions={text => (
+        <MessageIconActions
+          text={text}
+          clock="start"
+          showBranch={false}
+          className={css.actions}
+          t={t}
+        />
+      )}
+    />
+  )
+}
+
 export const MessageItem = memo(function MessageItem({
  node, retryActive = false, onFork, t,
 }: MessageItemProps) {
  const truncated = (total: number): string => t('json.truncated', { total })
  switch (node.kind) {
    case 'user':
+    case 'steering':
      return (
        <UserStyleBubble
          content={node.content}
@@ -211,8 +242,6 @@ export const MessageItem = memo(function MessageItem({
          )}
        />
      )
-    case 'steering':
-      return <UserStyleBubble content={node.content} t={t} />
    case 'context':
      return (
        <ContextInjectionRow content={node.content} source={node.source} t={t} />
--- a/packages/client/ui-conversation/src/client/chat/ToolRow.module.css
+++ b/packages/client/ui-conversation/src/client/chat/ToolRow.module.css
@@ -84,6 +84,11 @@
  color: var(--dsw-alias-label-tertiary);
 }

+/* Live reasoning follows its one-line summary to the inline end. */
+.summary[data-follow-end] {
+  text-overflow: clip;
+}
+
 /* File-tool path: same geometry as .summary; hover underline + pointer. */
 .fileLink {
  flex: 1 1 auto;
--- a/packages/client/ui-conversation/src/client/chat/ToolRow.tsx
+++ b/packages/client/ui-conversation/src/client/chat/ToolRow.tsx
@@ -5,7 +5,8 @@
 // Enter / Space, icon→chevron hover preview). The collapsed row is always
 // one line; every row with body, output, or a card material (terminal, diff,
 // read, search, web) is expandable; the summary stays inline while open,
-// except Think, whose body opens with the same first line and would repeat it.
+// except Think, where the running collapsed row follows the latest line at its
+// scroll end and the summary yields while open to avoid repeating the body.
 // The expanded body — an IN/OUT gutter-labeled card (figma 1249:35657) for
 // text input/output, the run_code program through CodeBlock, or a card
 // primitive (TerminalBlock, DiffBlock, ReadBlock, SearchBlock, WebBlock) for a
@@ -19,7 +20,7 @@
 // independent); an error row's collapsed summary is the failure's first line in
 // the error color.

-import { useState, type KeyboardEvent, type MouseEvent, type ReactNode } from 'react'
+import { useLayoutEffect, useRef, useState, type KeyboardEvent, type MouseEvent, type ReactNode } from 'react'
 import clsx from 'clsx'
 import {
  CodeBlock, DiffBlock, ReadBlock, SearchBlock, StateDot, TerminalBlock, WebBlock,
@@ -152,6 +153,7 @@ export function ToolRow({
  inspect,
 }: ToolRowProps) {
  const [expanded, setExpanded] = useState(false)
+  const summaryRef = useRef<HTMLSpanElement>(null)
  const terminalBody = terminal ?? null
  const diffBody = diff ?? null
  const readBody = read ?? null
@@ -173,6 +175,15 @@ export function ToolRow({
  const summaryText = failureLine ?? summary
  // The failure line is error prose, not the path: no open-file affordance.
  const fileLink = filePath !== undefined && onOpenFile !== undefined && failureLine === null
+  const isThink = variant === 'think'
+  const followSummaryEnd = isThink && state === 'running' && !open
+  useLayoutEffect(() => {
+    const summaryElement = summaryRef.current
+    if (summaryElement === null) return
+    summaryElement.scrollLeft = followSummaryEnd
+      ? summaryElement.scrollWidth - summaryElement.clientWidth
+      : 0
+  }, [followSummaryEnd, summaryText])
  const toggleExpand = () => {
    setExpanded(v => !v)
  }
@@ -188,9 +199,8 @@ export function ToolRow({
    if (event.key === 'Enter' || event.key === ' ') event.stopPropagation()
  }
  // Think reasoning is prose, not an input payload: expanded, it renders as
-  // plain indented text (no IN/OUT card) and the inline summary — the body's
-  // own first line — yields to avoid repeating itself.
-  const isThink = variant === 'think'
+  // plain indented text (no IN/OUT card) and the inline summary yields to avoid
+  // repeating the body.
  // The code variant's program renders through CodeBlock (shiki), so only its
  // output joins the IN/OUT card; every other variant's input does too.
  const cardBody = variant === 'code' ? null : body
@@ -227,7 +237,11 @@ export function ToolRow({
                {summaryText}
              </button>
            ) : (
-              <span className={clsx(css.summary, failureLine !== null && css.errorSummary)}>
+              <span
+                ref={isThink ? summaryRef : undefined}
+                className={clsx(css.summary, failureLine !== null && css.errorSummary)}
+                data-follow-end={followSummaryEnd || undefined}
+              >
                {summaryText}
              </span>
            )}
--- a/packages/client/ui-conversation/src/client/contract/composer-submission.ts
+++ b/packages/client/ui-conversation/src/client/contract/composer-submission.ts
@@ -0,0 +1,10 @@
+/** Composer submission vocabulary shared by the input and settings domains. */
+
+/** Delivery mode requested for one ordinary composer message. */
+export type InputSubmitMode = 'queue' | 'steer'
+
+/** Configurable meaning of plain Enter while the addressed agent is busy. */
+export type BusyEnterBehavior = InputSubmitMode
+
+/** Keyboard gesture whose delivery mode the submission policy resolves. */
+export type ComposerSubmitGesture = 'enter' | 'accelerated'
--- a/packages/client/ui-conversation/src/client/contract/slots.ts
+++ b/packages/client/ui-conversation/src/client/contract/slots.ts
@@ -3,10 +3,11 @@ 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'
+import type { ComposerSubmitGesture, InputSubmitMode } from './composer-submission.ts'
 import type { CallId, SelectionTarget, ViewTab } from './views.ts'

 declare module '@deepseek-ai/dsh-client-ui-slots' {
@@ -17,6 +18,8 @@ declare module '@deepseek-ai/dsh-client-ui-slots' {
     * remounted when the current session id changes.
     */
    'conversation.session': { kind: 'single'; scope: 'session'; owner: ConversationSessionOwnerProps }
+    /** Session-header actions contributed by feature plugins. */
+    'conversation.session.header.actions': { kind: 'list'; scope: 'session'; owner: ConversationHeaderActionOwnerProps }
    /**
     * The conversation view ring: one list entry per view tab (chat here;
     * trajectory/waterfall from ui-trajectory), rendered one-at-a-time by
@@ -135,6 +138,9 @@ export interface ConversationSessionOwnerProps {
  wrapActiveBody?: (view: ReactNode) => ReactNode
 }

+/** Header actions derive their state from the standard session/global kit. */
+export interface ConversationHeaderActionOwnerProps {}
+
 /**
 * The input-region slot currency (plan §1.4): dock/left/right entries read
 * the conversation snapshot and the live input state as owner props (both
@@ -244,6 +250,8 @@ 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
 }

 /**
@@ -278,6 +286,12 @@ export interface ComposerBarOwnerProps {
 export interface ComposerBarInjected {
  /** The InputBar-exclusive keyboard/DOM command face (decision 20 private plane); absent with the session. */
  keyboard: ComposerKeyboard | undefined
+  /** Resolve one keyboard submission gesture against the current running state and persisted preference. */
+  resolveSubmitMode: (
+    running: boolean,
+    gesture: ComposerSubmitGesture,
+    steeringAvailable: boolean,
+  ) => InputSubmitMode
  /** Toggle the shared slash menu with only its command source; absent without ui-slash or a session. */
  toggleCommandMenu: ((selection: EditSelection) => void) | undefined
  /** Cancel the in-flight turn; absent with the session. */
@@ -329,6 +343,8 @@ export type ComposerBarProps =
 */
 export interface ComposerChainProps {
  interactions: readonly PendingInteraction[]
+  /** Current conversation facts for feature-owned takeover selectors. */
+  session: ConversationSnapshot | undefined
 }

 /**
@@ -350,9 +366,10 @@ export type ConversationSlotProps =
 /** Full strict-session content props: per-session store, view ring, callbacks, and the locale seat. */
 export type ConversationSessionSlotProps =
  PropsRuntime<'conversation.session'>
-  & PropsRenderSlots<'conversation.view'>
+  & 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'>
--- a/packages/client/ui-conversation/src/client/input/facade.ts
+++ b/packages/client/ui-conversation/src/client/input/facade.ts
@@ -16,6 +16,7 @@ import type {
  EditRange, EditSelection, InputActions, InputEffect, InputNotice, InputState,
  PasteComponent, QueuedMessage, SessionInput, SubmitAttempt,
 } from './contract.ts'
+import type { InputSubmitMode } from '../contract/composer-submission.ts'
 import { InputMachine } from './machine.ts'

 /** Popup face the shell needs (dismissal only; typed structurally to avoid a value import). */
@@ -39,7 +40,7 @@ export interface SessionInputDeps {
  /** Queue read face; overlaid onto InputState.queue (absent = empty). */
  queue?: ObservableSnapshot<readonly QueuedMessage[]> | undefined
  /** The plain-message sink (send choreography / materialize fork — the hub owns it). */
-  defaultSink(text: string): void
+  defaultSink(text: string, mode: InputSubmitMode): void
 }

 /** Guard tier from the machine phase. */
@@ -68,7 +69,7 @@ export class SessionInputShell implements SessionInput {
  /** The public provide-channel action face (one stable identity per session — decision 20). */
  readonly actions: InputActions = {
    setDraft: (text) => { this.setDraft(text) },
-    submit: () => { this.submit() },
+    submit: () => { this.submit('queue') },
  }

  // Real wall clock: the typing-run merge window must actually expire in
@@ -106,15 +107,6 @@ export class SessionInputShell implements SessionInput {
    this.run(this.core.dispatch({ type: 'send-committed' }))
  }

-  /**
-   * Insert a newline at the selection as one machine transaction (the
-   * execCommand path is gone — a second undo history would fork).
-   * @param selection - current DOM selection in draft coordinates.
-   */
-  newline(selection: EditSelection): void {
-    this.run(this.core.dispatch({ type: 'newline', selection }))
-  }
-
  /** Undo the latest transaction (InputBar intercepts the platform chord). */
  undo(): void {
    this.run(this.core.dispatch({ type: 'undo' }))
@@ -152,8 +144,8 @@ export class SessionInputShell implements SessionInput {
   * (adjudicating/submitting) force-closes the transient layers: the popup
   * dismisses and the menu tracks frozen.
   */
-  submit(): void {
-    this.run(this.core.dispatch({ type: 'enter' }))
+  submit(mode: InputSubmitMode = 'queue'): void {
+    this.run(this.core.dispatch({ type: 'enter', mode }))
    const phase = this.snapshot.phase
    if (phase === 'adjudicating' || phase === 'submitting') {
      this.deps.popup?.()?.dismiss()
@@ -338,7 +330,7 @@ export class SessionInputShell implements SessionInput {
        return
      }
      case 'default-sink': {
-        this.sinkSerialized(fx.draft)
+        this.sinkSerialized(fx.draft, fx.mode)
        return
      }
      default:
@@ -353,10 +345,10 @@ export class SessionInputShell implements SessionInput {
   * send — notice + draft and chips retained, never a silent downgrade to
   * the clipboard text. Chip-free drafts skip the async detour.
   */
-  private sinkSerialized(draft: string): void {
+  private sinkSerialized(draft: string, mode: InputSubmitMode): void {
    const occurrences = this.core.state.occurrences
    if (occurrences.length === 0) {
-      this.deps.defaultSink(draft.trim())
+      this.deps.defaultSink(draft.trim(), mode)
      return
    }
    const slash = this.deps.slash?.()
@@ -376,7 +368,7 @@ export class SessionInputShell implements SessionInput {
          cursor = part.offset + 1
        }
        out += draft.slice(cursor)
-        this.deps.defaultSink(out.trim())
+        this.deps.defaultSink(out.trim(), mode)
      },
      (error: unknown) => {
        controller.abort()
--- a/packages/client/ui-conversation/src/client/input/hub.ts
+++ b/packages/client/ui-conversation/src/client/input/hub.ts
@@ -12,6 +12,7 @@ import type { ClientContext, ISessions, SessionBinding, SessionFace, SessionId }
 import type { SlashController } from '@deepseek-ai/dsh-client-ui-slash/client'
 import { queueReadFaceOf } from '../queue/store.ts'
 import type { ComposerKeyboard, InputService, SessionInput } from './contract.ts'
+import type { InputSubmitMode } from '../contract/composer-submission.ts'
 import type { PopupDismissFace } from './facade.ts'
 import { SessionInputShell } from './facade.ts'

@@ -56,7 +57,7 @@ export class InputHub implements InputService {
      slash: () => this.controller(actx),
      popup: () => this.popup(actx),
      queue: queueReadFaceOf(session),
-      defaultSink: (text) => { this.sink(session, text) },
+      defaultSink: (text, mode) => { this.sink(session, text, mode) },
    })
    this.shells.set(id, shell)
    // The one teardown axis: listeners, shell, and map entries all ride the
@@ -123,12 +124,12 @@ export class InputHub implements InputService {
   * exactly one path; a failed first prompt is an ordinary prompt failure
   * (error strip via promptError, draft restored only while untouched).
   */
-  private sink(session: SessionFace, text: string): void {
+  private sink(session: SessionFace, text: string, mode: InputSubmitMode): void {
    if (text === '') return
    const shell = this.shells.get(session.sessionId)
    // Commit, not an editable clear: undo must not resurrect sent content.
    shell?.commitSend()
-    void session.prompt([{ type: 'text', text }], 'queue').then(
+    void session.prompt([{ type: 'text', text }], mode).then(
      (result) => {
        if (!result.ok && shell?.snapshot.draft === '') shell.setDraft(text)
      },
--- a/packages/client/ui-conversation/src/client/input/machine.ts
+++ b/packages/client/ui-conversation/src/client/input/machine.ts
@@ -14,6 +14,7 @@
 * paste-upgrade all answer their bail events this way).
 */
 import type { CommandClaim, ReferenceInsert, TokenSpan } from '@deepseek-ai/dsh-client-ui-slash/client'
+import type { InputSubmitMode } from '../contract/composer-submission.ts'
 import type {
  ConsumeTokenGuard, EditRange, EditSelection, InputEffect, InputEvent, InputMachineOptions,
  InputState, Occurrence, PasteAttemptState, PasteComponent, SubmitAttempt,
@@ -149,7 +150,6 @@ export class InputMachine {
  dispatch(ev: InputEvent): readonly InputEffect[] {
    switch (ev.type) {
      case 'draft-changed': return this.onDraftChanged(ev.draft, ev.editRange)
-      case 'newline': return this.onNewline(ev.selection)
      case 'begin-command': return this.onBeginCommand(ev.claim, ev.span)
      case 'insert-ref': return this.onInsertRef(ev.reference, ev.span)
      case 'consume-token': return this.onConsumeToken(ev.guard)
@@ -162,7 +162,7 @@ export class InputMachine {
        this.paste = undefined
        return []
      }
-      case 'enter': return this.onEnter()
+      case 'enter': return this.onEnter(ev.mode)
      case 'adjudicated': return this.onAdjudicated(ev.attempt, ev.outcome)
      case 'adjudication-failed': return this.onAdjudicationFailed(ev.attempt, ev.message)
      case 'submit-settled': return this.onSubmitSettled(ev)
@@ -254,19 +254,6 @@ export class InputMachine {
    return []
  }

-  /** F1: caret newline as an ordinary machine transaction (execCommand path removed). */
-  private onNewline(selection: EditSelection): InputEffect[] {
-    const { start, end } = selection
-    if (start < 0 || start > end || end > this.draft.length) return []
-    this.pushTxn(selection)
-    this.typingRun = undefined
-    this.reconcile({ start, end, insertedLength: 1 })
-    this.adopt(this.draft.slice(0, start) + '\n' + this.draft.slice(end))
-    this.watchClaim()
-    this.paste = undefined
-    return []
-  }
-
  /** Span CAS: revision equality (content identity follows) plus bounds sanity. */
  private casOk(span: TokenSpan): boolean {
    return span.draftRev === this.draftRev
@@ -461,18 +448,18 @@ export class InputMachine {
  // ---- submit plane ----

  /** Mint the next SubmitAttempt and take the in-flight slot. */
-  private beginAttempt(): SubmitAttempt {
+  private beginAttempt(mode: InputSubmitMode): SubmitAttempt {
    const controller = new AbortController()
    this.seq += 1
-    const attempt: SubmitAttempt = { seq: this.seq, signal: controller.signal, draftSnapshot: this.draft }
+    const attempt: SubmitAttempt = { seq: this.seq, signal: controller.signal, draftSnapshot: this.draft, mode }
    this.inflight = { attempt, controller }
    return attempt
  }

-  private onEnter(): InputEffect[] {
+  private onEnter(mode: InputSubmitMode): InputEffect[] {
    if (this.phase === 'adjudicating' || this.phase === 'submitting') return []
    if (this.phase === 'claimed' && this.claim !== undefined) {
-      const attempt = this.beginAttempt()
+      const attempt = this.beginAttempt(mode)
      this.phase = 'submitting'
      this.paste = undefined
      return [{ type: 'begin-submit', attempt, claim: this.claim, args: argsAfter(this.draft, this.claim.token) }]
@@ -481,11 +468,11 @@ export class InputMachine {
    if (trimmed === '') return []
    this.paste = undefined
    if (trimmed.startsWith('/')) {
-      const attempt = this.beginAttempt()
+      const attempt = this.beginAttempt(mode)
      this.phase = 'adjudicating'
      return [{ type: 'adjudicate', attempt, draft: this.draft }]
    }
-    return [{ type: 'default-sink', draft: this.draft }]
+    return [{ type: 'default-sink', draft: this.draft, mode }]
  }

  private onAdjudicated(attempt: SubmitAttempt, outcome: Extract<InputEvent, { type: 'adjudicated' }>['outcome']): InputEffect[] {
@@ -506,7 +493,7 @@ export class InputMachine {
    this.inflight = undefined
    this.phase = 'plain'
    return outcome === undefined
-      ? [{ type: 'default-sink', draft: attempt.draftSnapshot }]
+      ? [{ type: 'default-sink', draft: attempt.draftSnapshot, mode: attempt.mode }]
      : []
  }

--- a/packages/client/ui-conversation/src/client/input/submission-policy.ts
+++ b/packages/client/ui-conversation/src/client/input/submission-policy.ts
@@ -0,0 +1,77 @@
+/**
+ * Browser-local Composer submission policy. It owns the persisted busy-Enter
+ * preference and resolves keyboard gestures into queue/steer delivery modes;
+ * Host and Agent keep the actual delivery-window authority.
+ */
+import { createSnapshotStore, type SnapshotStore } from '@deepseek-ai/dsh-client-runtime/client'
+import type {
+  BusyEnterBehavior, ComposerSubmitGesture, InputSubmitMode,
+} from '../contract/composer-submission.ts'
+
+/** localStorage key holding the busy-Enter preference. */
+export const BUSY_ENTER_STORAGE_KEY = 'dsh.conversation.busyEnter'
+
+/** Default preserves Enter-as-Queue for running conversations. */
+export const DEFAULT_BUSY_ENTER_BEHAVIOR: BusyEnterBehavior = 'queue'
+
+/**
+ * Persisted policy used by both the composer inject face and its Settings row.
+ * Direct `steer` is intentionally best-effort: AgentLoop turns a closed-window
+ * submission into the next waking Queue item.
+ */
+export class ComposerSubmissionPolicy {
+  /** Reactive preference source for the Settings row. */
+  readonly busyEnter: SnapshotStore<BusyEnterBehavior> = createSnapshotStore(restoreBusyEnter())
+
+  /**
+   * Resolve one keyboard gesture without changing state.
+   * @param running - whether the addressed agent currently reports busy.
+   * @param gesture - plain Enter or the Cmd/Ctrl-accelerated chord.
+   * @param steeringAvailable - whether this session transport supports steering.
+   * @returns Queue outside steer-capable busy state; otherwise the preferred mode or its opposite.
+   */
+  resolve(
+    running: boolean,
+    gesture: ComposerSubmitGesture,
+    steeringAvailable: boolean,
+  ): InputSubmitMode {
+    if (!running || !steeringAvailable) return 'queue'
+    const preferred = this.busyEnter.getSnapshot()
+    if (gesture === 'enter') return preferred
+    return preferred === 'queue' ? 'steer' : 'queue'
+  }
+
+  /**
+   * Change and persist the plain-Enter behavior used during busy state.
+   * @param behavior - Queue or Steer.
+   */
+  setBusyEnter(behavior: BusyEnterBehavior): void {
+    if (this.busyEnter.getSnapshot() === behavior) return
+    this.busyEnter.set(behavior)
+    persistBusyEnter(behavior)
+  }
+}
+
+/** Restore a valid preference; unavailable or corrupt storage uses Queue. */
+function restoreBusyEnter(): BusyEnterBehavior {
+  if (typeof localStorage === 'undefined') return DEFAULT_BUSY_ENTER_BEHAVIOR
+  let stored: string | null
+  try {
+    stored = localStorage.getItem(BUSY_ENTER_STORAGE_KEY)
+  } catch {
+    // Storage access can fail in privacy modes; the default remains usable.
+    return DEFAULT_BUSY_ENTER_BEHAVIOR
+  }
+  if (stored === 'queue' || stored === 'steer') return stored
+  return DEFAULT_BUSY_ENTER_BEHAVIOR
+}
+
+/** Persist a preference when browser storage is available. */
+function persistBusyEnter(behavior: BusyEnterBehavior): void {
+  if (typeof localStorage === 'undefined') return
+  try {
+    localStorage.setItem(BUSY_ENTER_STORAGE_KEY, behavior)
+  } catch {
+    // A storage failure makes the preference session-only; input stays usable.
+  }
+}
--- a/packages/client/ui-conversation/src/client/locales.ts
+++ b/packages/client/ui-conversation/src/client/locales.ts
@@ -23,6 +23,10 @@ export const zh = {
  'input.stop': '停止生成',
  'input.send': '发送消息',
  'input.accessMode': '访问模式，当前：{name}',
+  'settings.enter.title': '繁忙时 Enter 键行为',
+  'settings.enter.description': '仅在智能体运行时生效；Cmd/Ctrl+Enter 使用另一行为',
+  'settings.enter.queue': '排队发送',
+  'settings.enter.steer': '插话发送',
  'access.confirm.title': '确认启用 Full access？',
  'access.confirm.description': '启用 Full access 后，agent 将减少确认步骤，并且可以直接执行更多操作，包括敏感操作、文件修改或外部命令。仅建议在你信任当前任务时使用。',
  'access.confirm.acknowledge': '我已了解风险，并愿意继续',
@@ -30,6 +34,7 @@ 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',
@@ -88,8 +93,11 @@ export const zh = {
  'queue.save': '保存排队消息',
  'queue.cancelEdit': '取消编辑',
  'queue.remove': '删除排队消息',
+  'queue.steer': '插话发送',
+  'queue.steer.unavailable': '仅运行中可插话发送',
  'queue.editFailed': '编辑失败：这条消息可能已经开始发送。',
  'queue.removeFailed': '删除失败：这条消息可能已经开始发送。',
+  'queue.steerFailed': '插话发送失败，请重试。',
  'terminal.signal': '信号 {signal}',
  'terminal.exitCode': '退出码 {code}',
  'terminal.running': '运行中',
@@ -122,6 +130,10 @@ export const en = {
  'input.stop': 'Stop generating',
  'input.send': 'Send message',
  'input.accessMode': 'Access mode, current: {name}',
+  'settings.enter.title': 'Enter behavior while busy',
+  'settings.enter.description': 'Busy only; Cmd/Ctrl+Enter uses the other behavior',
+  'settings.enter.queue': 'Queue',
+  'settings.enter.steer': 'Steer',
  'access.confirm.title': 'Enable Full access?',
  'access.confirm.description': 'Full access reduces confirmation steps and lets the agent perform more actions directly, including sensitive operations, file changes, or external commands. Only use it when you trust the current task.',
  'access.confirm.acknowledge': 'I understand the risks and want to continue',
@@ -129,6 +141,7 @@ 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',
@@ -187,8 +200,11 @@ export const en = {
  'queue.save': 'Save queued message',
  'queue.cancelEdit': 'Cancel editing',
  'queue.remove': 'Remove queued message',
+  'queue.steer': 'Steer queued message',
+  'queue.steer.unavailable': 'Steering is available only while the agent is running',
  'queue.editFailed': 'Edit failed: this message may have already started sending.',
  'queue.removeFailed': 'Removal failed: this message may have already started sending.',
+  'queue.steerFailed': 'Steering failed. Try again.',
  'terminal.signal': 'signal {signal}',
  'terminal.exitCode': 'exit code {code}',
  'terminal.running': 'Running',
--- a/packages/client/ui-conversation/src/client/queue/QueueDock.tsx
+++ b/packages/client/ui-conversation/src/client/queue/QueueDock.tsx
@@ -4,12 +4,12 @@
 // The 'conversation.input.dock' SlotMap declaration lives in
 // ../contract/slots.ts beside the other input-region slots.
 import type { Context } from 'cordis'
-import { useEffect, useId, useState } from 'react'
+import { useEffect, useId, useMemo, useState } from 'react'
 import type { PropsLocale, PropsRuntime } from '@deepseek-ai/dsh-client-ui-slots'
 import type { SessionId } from '@deepseek-ai/dsh-client-runtime/client'
 import {
  IconCheckOutline16, IconChevronDownOutline14, IconChevronUpOutline14,
-  IconCloseOutline16, IconEditOutline16, IconTrashOutline16,
+  IconCloseOutline16, IconEditOutline16, IconSendOutline16, IconTrashOutline16,
 } from '@deepseek-ai/dsh-client-ui-primitives'
 import type { QueueAction, QueueItemId } from '../contract/queue.ts'
 import { NS } from '../locales.ts'
@@ -29,7 +29,10 @@ export type QueueDockProps = PropsRuntime<'conversation.input.dock'> & QueueDock
 * collapsible count header; an empty queue renders nothing.
 */
 export function QueueDock({ useSession, updateQueue, notify, t }: QueueDockProps) {
-  const queue = useSession(s => s.queue)
+  const inbox = useSession(s => s.queue)
+  const queue = useMemo(() => inbox.filter(row => row.placement === 'queued'), [inbox])
+  const running = useSession(s => s.running)
+  const queueMutable = useSession(s => s.subagent === null)
  const [editing, setEditing] = useState<{ id: QueueItemId; text: string } | null>(null)
  const [busy, setBusy] = useState<QueueItemId | null>(null)
  const [collapsed, setCollapsed] = useState(true)
@@ -37,12 +40,12 @@ export function QueueDock({ useSession, updateQueue, notify, t }: QueueDockProps

  useEffect(() => {
    if (queue.length === 0 && !collapsed) setCollapsed(true)
-    if (editing !== null && !queue.some(row => row.id === editing.id)) setEditing(null)
-  }, [collapsed, editing, queue])
+    if (editing !== null && (!queueMutable || !queue.some(row => row.id === editing.id))) setEditing(null)
+  }, [collapsed, editing, queue, queueMutable])

  if (queue.length === 0) return null

-  const interactionActive = editing !== null || busy !== null
+  const interactionActive = queueMutable && (editing !== null || busy !== null)
  const expanded = !collapsed || interactionActive
  const listVisible = queue.length === 1 || expanded

@@ -114,7 +117,7 @@ export function QueueDock({ useSession, updateQueue, notify, t }: QueueDockProps
                  />
                )
                : <span className={css.preview}>{row.preview}</span>}
-              <div className={css.actions}>
+              {queueMutable && <div className={css.actions}>
                {editing?.id === row.id
                  ? (
                    <>
@@ -170,9 +173,25 @@ export function QueueDock({ useSession, updateQueue, notify, t }: QueueDockProps
                      >
                        <IconTrashOutline16 size={14} />
                      </button>
+                      <button
+                        type="button"
+                        className={css.action}
+                        aria-label={t('queue.steer')}
+                        title={running ? t('queue.steer') : t('queue.steer.unavailable')}
+                        disabled={busy !== null || !running}
+                        onClick={() => {
+                          void applyAction(
+                            row.id,
+                            { kind: 'steer' },
+                            t('queue.steerFailed'),
+                          )
+                        }}
+                      >
+                        <IconSendOutline16 size={14} />
+                      </button>
                    </>
                  )}
-              </div>
+              </div>}
            </li>
          ))}
        </ul>
--- a/packages/client/ui-conversation/src/client/queue/store.ts
+++ b/packages/client/ui-conversation/src/client/queue/store.ts
@@ -1,7 +1,7 @@
 /**
 * Queue read face for the InputState.queue projection (frozen contract in
 * ../input/contract.ts): a uSES-compatible observable over one session's
- * queue rows. The Session snapshot already keeps the queue array
+ * transient inbox rows. The Session snapshot already keeps the queue array
 * reference-stable across unrelated snapshot swaps, so this is a pure
 * projection — no second store, no copy.
 */
@@ -9,7 +9,7 @@ import type { ObservableSnapshot, SessionFace } from '@deepseek-ai/dsh-client-ru
 import type { QueuedMessage } from '../input/contract.ts'

 /**
- * Project a session's queue rows as a bare observable (subscribe/getSnapshot).
+ * Project a session's transient inbox rows as a bare observable (subscribe/getSnapshot).
 * The wiring layer (T5) overlays this onto InputState.queue; the runtime
 * QueuedMessage and the input-contract QueuedMessage are structurally
 * identical.
--- a/packages/client/ui-conversation/src/client/service.ts
+++ b/packages/client/ui-conversation/src/client/service.ts
@@ -31,10 +31,10 @@ export interface IConversation {
   */
  send(text: string): Promise<void>
  /**
-   * Apply one operation to a pending queue occurrence.
+   * Apply one edit, remove, or strict steer operation to a pending queue occurrence.
   * @param itemId - agent-owned inbox occurrence identity.
-   * @param action - edit or remove operation.
-   * @returns completion; business failures reject.
+   * @param action - requested queue operation.
+   * @returns completion; converged strict-steer races resolve, while other failures reject.
   */
  updateQueue(itemId: QueueItemId, action: QueueAction): Promise<void>
  /**
@@ -82,6 +82,10 @@ export class ConversationService extends Service implements IConversation {
    const session = this.scopedSession('updateQueue')
    const result = await session.updateQueue(itemId, action)
    if (!result.ok) {
+      if (
+        action.kind === 'steer'
+        && (result.error.code === 'steer-unavailable' || result.error.code === 'queue-item-not-found')
+      ) return
      throw new Error(`conversation.updateQueue failed: ${result.error.code}: ${result.error.message}`)
    }
  }
--- a/packages/client/ui-conversation/src/client/settings/EnterBehaviorRow.module.css
+++ b/packages/client/ui-conversation/src/client/settings/EnterBehaviorRow.module.css
@@ -0,0 +1,56 @@
+/* Composer Enter preference row: title/description plus selector pill. */
+
+.row {
+  display: flex;
+  align-items: center;
+  gap: 8px;
+  padding: 16px 0;
+  border-bottom: 1px solid var(--dsw-alias-border-l2);
+}
+
+.rowText {
+  flex: 1;
+  min-width: 0;
+  display: flex;
+  flex-direction: column;
+  gap: 4px;
+  padding-right: 48px;
+}
+
+.title {
+  font-size: 14px;
+  font-weight: 400;
+  line-height: 22px;
+  color: var(--dsw-alias-label-primary);
+}
+
+.desc {
+  font-size: 12px;
+  font-weight: 400;
+  line-height: 18px;
+  color: var(--dsw-alias-label-tertiary);
+}
+
+.selector {
+  display: inline-flex;
+  align-items: center;
+  gap: 12px;
+  height: 36px;
+  padding: 0 14px;
+  border: none;
+  border-radius: 18px;
+  background: var(--dsw-alias-bg-module-platform);
+  font: inherit;
+  font-size: 14px;
+  line-height: 22px;
+  color: var(--dsw-alias-label-primary);
+  cursor: pointer;
+}
+
+.selector:hover {
+  background: var(--dsw-alias-interactive-bg-hover);
+}
+
+.chevron {
+  flex: none;
+}
--- a/packages/client/ui-conversation/src/client/settings/EnterBehaviorRow.tsx
+++ b/packages/client/ui-conversation/src/client/settings/EnterBehaviorRow.tsx
@@ -0,0 +1,76 @@
+/** General Settings row for the Composer's busy-state Enter preference. */
+import { useState } from 'react'
+import type { SnapshotStore } from '@deepseek-ai/dsh-client-runtime/client'
+import type { InjectFace, PropsLocale, PropsRuntime } from '@deepseek-ai/dsh-client-ui-slots'
+import { IconChevronDownOutline14, Menu } from '@deepseek-ai/dsh-client-ui-primitives'
+import type { BusyEnterBehavior } from '../contract/composer-submission.ts'
+import type { ConversationKey } from '../locales.ts'
+import css from './EnterBehaviorRow.module.css'
+
+/** Registration-side preference face. */
+export interface EnterBehaviorRowInjected {
+  hooks: {
+    /** Persisted busy-state preference bound as useBusyEnter. */
+    busyEnter: SnapshotStore<BusyEnterBehavior>
+  }
+  /** Change the busy-state plain-Enter behavior. */
+  setBusyEnter: (behavior: BusyEnterBehavior) => void
+}
+
+/** Full Settings-row props. */
+export type EnterBehaviorRowProps =
+  PropsRuntime<'settings.general.item'>
+  & PropsLocale<'conversation'>
+  & InjectFace<EnterBehaviorRowInjected>
+
+const OPTIONS: readonly {
+  id: BusyEnterBehavior
+  label: ConversationKey
+}[] = [
+  { id: 'queue', label: 'settings.enter.queue' },
+  { id: 'steer', label: 'settings.enter.steer' },
+]
+
+/**
+ * Render the busy-state Enter behavior selector.
+ * @param props - composed Settings slot props.
+ * @returns the preference row.
+ */
+export function EnterBehaviorRow({ useBusyEnter, setBusyEnter, t }: EnterBehaviorRowProps) {
+  const behavior = useBusyEnter(value => value)
+  const [open, setOpen] = useState(false)
+  const selectedLabel = behavior === 'queue' ? 'settings.enter.queue' : 'settings.enter.steer'
+
+  return (
+    <div className={css.row}>
+      <div className={css.rowText}>
+        <div className={css.title}>{t('settings.enter.title')}</div>
+        <div className={css.desc}>{t('settings.enter.description')}</div>
+      </div>
+      <Menu
+        open={open}
+        onClose={() => { setOpen(false) }}
+        items={OPTIONS.map(option => ({ id: option.id, label: t(option.label) }))}
+        selectedId={behavior}
+        onSelect={(id) => {
+          setOpen(false)
+          setBusyEnter(id as BusyEnterBehavior)
+        }}
+        align="end"
+        portal
+        anchor={(
+          <button
+            type="button"
+            className={css.selector}
+            aria-haspopup="menu"
+            aria-expanded={open}
+            onClick={() => { setOpen(value => !value) }}
+          >
+            {t(selectedLabel)}
+            <IconChevronDownOutline14 className={css.chevron} />
+          </button>
+        )}
+      />
+    </div>
+  )
+}
--- a/packages/client/ui-conversation/src/client/skeleton/ConversationRoot.module.css
+++ b/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. */
@@ -26,21 +26,62 @@
 .titleRow {
  display: flex;
  align-items: center;
+  gap: 10px;
  min-height: 32px;
 }
-
-.sessionTitle {
+.crumbs {
+  display: flex;
+  align-items: center;
+  gap: 4px;
  min-width: 0;
-  max-width: 100%;
  overflow: hidden;
-  margin: 0;
-  padding: 4px 8px;
+  white-space: nowrap;
+}
+
+.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 {
+  display: flex;
+  flex: none;
+  align-items: center;
+  gap: 8px;
 }

 /* figma Tab_Group 34:11441: 35px strip, gap 36, pad-left 8, tabs bottom-aligned. */
--- a/packages/client/ui-conversation/src/client/skeleton/ConversationRoot.tsx
+++ b/packages/client/ui-conversation/src/client/skeleton/ConversationRoot.tsx
@@ -153,7 +153,7 @@ export function ConversationRoot({
  const phase = settling ? 'settling' : hero ? 'hero' : 'active'
  const composer = renderSlotChain(
    'conversation.composer',
-    { interactions: pending },
+    { interactions: pending, session },
    { fallback: composerBar, overlay: true },
  )

--- a/packages/client/ui-conversation/src/client/skeleton/ConversationSession.tsx
+++ b/packages/client/ui-conversation/src/client/skeleton/ConversationSession.tsx
@@ -2,21 +2,51 @@

 import { useEffect, useSyncExternalStore, type ReactNode } from 'react'
 import clsx from 'clsx'
+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

+interface Breadcrumb {
+  readonly id: SessionId
+  readonly displayTitle: string
+}
+
+function deriveAncestry(list: SessionListState, id: SessionId): readonly Breadcrumb[] {
+  const chain: Breadcrumb[] = []
+  const seen = new Set<SessionId>()
+  let cursor: SessionId | undefined = id
+  while (cursor !== undefined) {
+    if (seen.has(cursor)) break
+    seen.add(cursor)
+    const summary: SessionSummary | undefined = list.byId[cursor]
+    if (summary === undefined) break
+    chain.unshift({ id: summary.id, displayTitle: summary.displayTitle })
+    if (summary.origin !== 'subagent') break
+    cursor = summary.parentId
+  }
+  return chain
+}
+
+function equalBreadcrumbs(left: readonly Breadcrumb[], right: readonly Breadcrumb[]): boolean {
+  return left.length === right.length
+    && left.every((item, index) => {
+      const other = right.at(index)
+      return other !== undefined && item.id === other.id && item.displayTitle === other.displayTitle
+    })
+}
+
 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), equalBreadcrumbs)
  const composerPhase = useSession(s => s.composerPhase)
  const blank = useSession(s => s.blank)
  const inputState = useInput(s => s)
@@ -56,7 +86,28 @@ 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>
            </div>
            {tabs.length > 1 && (
              <div className={css.tabs} role="tablist">
--- a/packages/client/ui-conversation/src/client/skeleton/InputBar.tsx
+++ b/packages/client/ui-conversation/src/client/skeleton/InputBar.tsx
@@ -34,7 +34,7 @@ export interface InputBarError {
 export type InputBarProps = ComposerBarProps

 export function InputBar({
-  useSession, useInput, inputActions, keyboard, toggleCommandMenu, stop, command, t,
+  useSession, useInput, inputActions, keyboard, resolveSubmitMode, toggleCommandMenu, stop, command, t,
  renderSlot, useNotices, useLexicon, useMenuLauncher,
  useProjection, sessionId, variant, disabled: inert = false, placeholder, accessory, overlay, leftItems, rightItems, footer,
 }: InputBarProps) {
@@ -44,6 +44,7 @@ export function InputBar({
  const commandMenuOpen = useMenuLauncher(source => source === 'command')
  const promptError = useSession(s => s.promptError) ?? null
  const running = useSession(s => s.running) ?? false
+  const subagent = useSession(s => s.subagent) ?? null
  const removed = useSession(s => s.removed) ?? false
  // Plan mode swaps the textarea placeholder (the projection is the folded
  // host value; owner-prop placeholders — hero, session-unavailable — win).
@@ -177,23 +178,14 @@ export function InputBar({
      e.preventDefault()
      return
    }
-    if (e.ctrlKey || e.metaKey) {
-      // Newline as a machine transaction (the machine owns undo history; an
-      // execCommand write would fork a second, browser-owned history).
-      e.preventDefault()
-      if (!machineBusy && !locked) {
-        const el = e.currentTarget
-        const sel = selectionOf(el)
-        keyboard.newline(sel)
-        const caret = sel.start + 1
-        requestAnimationFrame(() => { el.setSelectionRange(caret, caret) })
-      }
-      return
-    }
    e.preventDefault()
    if (e.repeat) return // held-down Enter must not machine-gun sends
    if (locked || machineBusy) return
-    inputActions.submit()
+    keyboard.submit(resolveSubmitMode(
+      running,
+      e.ctrlKey || e.metaKey ? 'accelerated' : 'enter',
+      subagent === null,
+    ))
  }

  const onChange = (e: ChangeEvent<HTMLTextAreaElement>): void => {
@@ -283,13 +275,15 @@ export function InputBar({
    if (el !== null) toggleCommandMenu?.(selectionOf(el))
  }

-  const primaryLabel = running ? t('input.stop') : t('input.send')
+  const ordinary = subagent === null
+  const stopping = running && ordinary
+  const primaryLabel = stopping ? t('input.stop') : t('input.send')
  const onPrimary = (): void => {
-    if (inputActions === undefined || stop === undefined) return // absent machine: the button is disabled
-    if (running) {
-      stop()
+    if (stopping) {
+      stop?.()
      return
    }
+    if (inputActions === undefined) return // absent machine: the button is disabled
    /* v8 ignore next -- defensive: the primary button is disabled while empty||disabled, so a click cannot reach the false arm. */
    if (!empty && !disabled && !machineBusy) inputActions.submit()
  }
@@ -465,11 +459,11 @@ export function InputBar({
              className={css.primary}
              aria-label={primaryLabel}
              title={primaryLabel}
-              disabled={!running && (empty || disabled || machineBusy)}
+              disabled={stopping ? stop === undefined : empty || disabled || machineBusy}
              onMouseDown={keepFocus}
              onClick={onPrimary}
            >
-              {running ? (
+              {stopping ? (
                <svg viewBox="0 0 16 16" width="16" height="16" aria-hidden>
                  <rect x="3" y="3" width="10" height="10" rx="3" fill="currentColor" />
                </svg>
--- a/packages/client/ui-conversation/src/client/skeleton/TodoPanel.module.css
+++ b/packages/client/ui-conversation/src/client/skeleton/TodoPanel.module.css
@@ -1,6 +1,6 @@
-/* Todo strip in the composer context stack (Figma 9:959): tip surface,
-   14px radius, status icons + secondary item labels. It shares the composer
-   card geometry and adds the dock inset on both sides. */
+/* Todo strip in the composer context stack (Figma 1236:32276): tip surface,
+   14px radius, status icons + secondary item labels. Its visible card aligns
+   with the GoalBar and the Queue panel inside their shared dock column. */

 .root {
  box-sizing: border-box;
@@ -12,11 +12,15 @@
    var(--dsh-composer-side-clearance) -
    var(--dsh-composer-side-clearance) -
    var(--dsh-composer-dock-inset) -
+    var(--dsh-composer-dock-inset) -
+    var(--dsh-composer-dock-inset) -
    var(--dsh-composer-dock-inset)
  );
  max-width: calc(
    var(--dsh-composer-card-max-width) -
    var(--dsh-composer-dock-inset) -
+    var(--dsh-composer-dock-inset) -
+    var(--dsh-composer-dock-inset) -
    var(--dsh-composer-dock-inset)
  );
  border: 1px solid var(--dsw-alias-border-l1);
--- a/packages/client/ui-conversation/src/client/skeleton/TodoPanel.tsx
+++ b/packages/client/ui-conversation/src/client/skeleton/TodoPanel.tsx
@@ -138,10 +138,10 @@ export const todoDockEntry = {
  name: 'conversation-todo-dock',
  inject: ['slots', 'conversation'],
  /**
-   * Register the plan strip between the goal and queue entries (order 10).
+   * Register the plan strip before the goal and queue entries (order 0).
   * @param ctx - registrant context (disposal rides ctx.effect inside slots.register).
   */
  apply(ctx: Context): void {
-    ctx.slots.register({ name: 'conversation.input.dock', id: 'todo', order: 10, locale: NS }, TodoDock)
+    ctx.slots.register({ name: 'conversation.input.dock', id: 'todo', order: 0, locale: NS }, TodoDock)
  },
 }