Merge pull request #933 from deepseek-harness/codex/web-steer-support

feat(web): steer queued messages into active turns

.agents/notes/implemented/feature/2026-07-29-addressable-queue-operations.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/2026-07-29-addressable-queue-operations.md
-2026-07-29-addressable-queue-operations.md: 02519f8fe8be60823ac773ac4cceecb9f12f88b2
-2026-07-29-addressable-queue-operations.zh.md: 998fc49ae7289b07c97312d4814d85b5cc84387b
+2026-07-29-addressable-queue-operations.md: 04bcaa26be2f4f70c4003f6cc2fce4798499d205
+2026-07-29-addressable-queue-operations.zh.md: a16bf8667294de8d08da54ddb0d317bf9938e4eb

.agents/notes/implemented/feature/2026-07-29-addressable-queue-operations.md

@@ -12,13 +12,13 @@ The Web queue rendered pending messages but could not edit or delete one row. `M
 
 **Each accepted FIFO occurrence has its own identity.** AgentLoop mints an opaque `InboxItemId` and publishes an `InboxItem` containing that id, the identified `UserMessage`, and its acceptance-time `queued | steering` placement. Reusing one `MessageId` creates distinct inbox identities. Injection bypasses the FIFOs and receives no inbox identity.
 
-**Mutation ends at driver claim.** `Agent.updateInbox(id, action)` synchronously searches the pending queued FIFO. Edit replaces frozen content while preserving `InboxItemId`, `MessageId`, source, wake policy, and position. Remove emits the occurrence’s terminal discard. Steering and driver-claimed occurrences return `not-found`, so queue operations never rewrite active-turn input or durable history.
+**Mutation ends at driver claim.** `Agent.updateInbox(id, action)` synchronously searches the pending queued FIFO. Edit replaces frozen content while preserving `InboxItemId`, `MessageId`, source, wake policy, and position. Remove emits the occurrence’s terminal discard. Strict steer transfers the message into an open next-step window as a new steering occurrence; a closed window returns `steer-unavailable` without changing the queued item. Pending steering and driver-claimed occurrences return `not-found`, so later mutations never rewrite active-turn input or durable history.
 
 **The live ledger is authoritative.** `agent/inbox/enqueue`, `update`, `dequeue`, and `discard` maintain a Host mirror of queued occurrences. A synchronously re-entrant update or terminal event may reach the mirror before its outer enqueue listener; the mirror retains that unseen outcome for the current dispatch and folds it into the enqueue, so listener registration order cannot publish stale content or a ghost row. The wire sends complete `session/queue` snapshots rather than incremental guesses. Reconnect sends the current baseline, and every queued mutation or terminal event replaces it. The client applies no optimistic edit and never retires a row from durable turn events or status changes.
 
 **Queue addresses require a live ordinary-session Agent.** `session.updateQueue` queries only the mounted Agent registry and never resumes a cold session: an `InboxItemId` is process-local and cannot name work after restart or disposal. A session-backed subagent returns `agent-busy` before inbox access and retains its continuation owner; for ordinary sessions, a missing Agent and a driver-claimed occurrence both return `queue-item-not-found`.
 
-**Web actions address Queue only.** The Host excludes pending steering from `session/queue`; steering retains its existing durable transcript path after consumption. QueueDock hides while empty, renders one pending occurrence directly, and defaults two or more occurrences to a collapsed `"<n> 条排队消息"` header that expands or collapses the complete list. The header exposes `aria-expanded` and `aria-controls`; the expanded list scrolls within a 180px height bound. An active edit or mutation keeps its rows visible, and emptying the queue restores the collapsed default for the next queue. Visible rows expose edit and delete, but no send-now control. The UI derives queue row and mutation types from the runtime `SessionFace` contract rather than importing the connection plugin, so plugin cooperation continues through services and snapshots. Edit is available only when all content blocks are text; the editor cannot silently drop non-text blocks. An editing row exposes only save and cancel, with Enter and Escape as their keyboard equivalents. Delete removes the exact occurrence. The Web stop action preserves pending Queue work; AgentLoop claims the next waking occurrence only after the interrupted turn reaches quiescence, and its dequeue event retires that row without a browser resend.
+**Web actions address Queue only.** The placement-aware `session/queue` snapshot carries both queued and pending-steering occurrences; QueueDock selects only queued items, while ChatView projects steering and retains the existing durable transcript path after consumption. QueueDock hides while empty, renders one pending occurrence directly, and defaults two or more occurrences to a collapsed `"<n> 条排队消息"` header that expands or collapses the complete list. The header exposes `aria-expanded` and `aria-controls`; the expanded list scrolls within a 180px height bound. An active edit or mutation keeps its rows visible, and emptying the queue restores the collapsed default for the next queue. Visible rows expose edit, delete, and a running-only strict-steer action. The UI derives queue row and mutation types from the runtime `SessionFace` contract rather than importing the connection plugin, so plugin cooperation continues through services and snapshots. Edit is available only when all content blocks are text; the editor cannot silently drop non-text blocks. An editing row exposes only save and cancel, with Enter and Escape as their keyboard equivalents. Delete removes the exact occurrence, while strict steer preserves every content block and retires the row only through the authoritative snapshot. The Web stop action preserves pending Queue work; AgentLoop claims the next waking occurrence only after the interrupted turn reaches quiescence, and its dequeue event retires that row without a browser resend. The [Web Queue steer action](2026-07-30-web-queue-steer-action.md) owns the strict transfer and pending-projection contract.
 
 ## Alternatives considered
 
@@ -26,7 +26,7 @@ The Web queue rendered pending messages but could not edit or delete one row. `M
 
 **Apply optimistic browser mutations.** Rejected because driver claim and another client can win before the Host action. Waiting for the authoritative snapshot makes the ownership boundary visible and lets `queue-item-not-found` report a real race.
 
-**Include pending steering in the queue mutation protocol.** Rejected because QueueDock has no steering interaction, and editing or deleting active-turn input would widen this feature beyond its current consumer. A dedicated steering interaction owns that delivery contract.
+**Allow editing or removal of pending steering.** Rejected because QueueDock only addresses independent queued turns. Once strict steer succeeds, the new steering occurrence belongs to the active turn and remains outside this mutation surface.
 
 **Expose a protocol-only promotion operation.** Rejected because no product interaction reorders Queue. A public operation without a current consumer would add ordering semantics and tests for speculative use.
 
@@ -34,10 +34,10 @@ The Web queue rendered pending messages but could not edit or delete one row. `M
 
 ## Verification
 
-AgentLoop contract tests hold prompt admission while editing and removing exact queued occurrences, reject mutations of steering occurrences, and verify the resulting independent turn and terminal lifecycle events. Host schema and proxy tests cover queued-only authoritative snapshots, synchronous re-entrant mutation order, reconnect, cold-Agent rejection, typed not-found errors, and the RPC transport. Client runtime and QueueDock tests cover non-optimistic projection, single-row presentation, default multi-row collapse, interaction-forced visibility, reset after emptying, expansion, text-only editing, save and cancel affordances, removal, retirement races, and disabled mixed-content editing. A keyless browser scenario captures the default collapsed header, drives edit and delete through the built Web composition and real HTTP/SSE wire, then stops consecutive active turns to prove the preserved FIFO advances without clearing its tail.
+AgentLoop contract tests hold prompt admission while editing, removing, and strictly steering exact queued occurrences; they reject mutations of steering occurrences and verify the resulting independent turn and terminal lifecycle events. Host schema and proxy tests cover queued-only authoritative snapshots, synchronous re-entrant mutation order, reconnect, cold-Agent rejection, typed race errors, and the RPC transport. Client runtime and QueueDock tests cover non-optimistic projection, single-row presentation, default multi-row collapse, interaction-forced visibility, reset after emptying, expansion, text-only editing, save and cancel affordances, removal, strict steer, retirement races, and disabled mixed-content editing. Keyless browser scenarios drive all three exposed actions through the built Web composition and real HTTP/SSE wire, then stop consecutive active turns to prove the preserved FIFO advances without clearing its tail.
 
 ## Consequences
 
-Queued work gains precise row operations without becoming durable session history. Occurrence identity is a live process-local capability and disappears at claim, broad cancellation, disposal, or restart; the Web stop action preserves it until a later claim, while reconnect recovers only queued items still held by the live Agent. Editing excludes mixed content until an editor can preserve every block, while pending steering remains outside this operation surface.
+Queued work gains precise row operations without becoming durable session history. Occurrence identity is a live process-local capability and disappears at claim, strict transfer, broad cancellation, disposal, or restart; the Web stop action preserves queued occurrences until a later claim, while reconnect recovers only queued items still held by the live Agent. Editing excludes mixed content until an editor can preserve every block, while pending steering remains outside the projection and operation surface.
 
 The protocol now carries full queue snapshots on each change. Queues are expected to remain short, so deterministic recovery and multi-client convergence are preferred over an incremental mutation protocol.

.agents/notes/implemented/feature/2026-07-29-addressable-queue-operations.zh.md

@@ -12,13 +12,13 @@ Web 队列能够渲染待处理消息，但无法编辑或删除其中某一行
 
 **每次获准进入 FIFO 的项都有独立标识。** AgentLoop 会铸造不透明的 `InboxItemId`，并发布一个 `InboxItem`，其中包含该 id、已有标识的 `UserMessage`，以及接受时确定的 `queued | steering` 放置方式。复用同一个 `MessageId` 会创建不同的 inbox 标识。注入绕过 FIFO，因此不会获得 inbox 标识。
 
-**变更边界止于驱动器认领。** `Agent.updateInbox(id, action)` 会同步搜索待处理的 queued FIFO。编辑会替换已冻结的内容，同时保留 `InboxItemId`、`MessageId`、来源、唤醒策略和位置。移除会发出该次入队项的终态 discard。steering（中途引导）项和已被驱动器认领的项会返回 `not-found`，因此队列操作绝不会改写活动轮次输入或持久历史。
+**变更边界止于驱动器认领。** `Agent.updateInbox(id, action)` 会同步搜索待处理的 queued FIFO。编辑会替换已冻结的内容，同时保留 `InboxItemId`、`MessageId`、来源、唤醒策略和位置。移除会发出该次入队项的终态 discard。严格 steering（中途引导）会把消息作为新的 steering 单次入队项转移到开放的 next-step 窗口；窗口关闭时返回 `steer-unavailable`，且不改变 queued 项。待处理 steering 和已被驱动器认领的项会返回 `not-found`，因此后续变更绝不会改写活动轮次输入或持久历史。
 
 **实时账本是权威状态。** `agent/inbox/enqueue`、`update`、`dequeue` 和 `discard` 共同维护 queued 入队项的 Host 镜像。同步可重入的 update 或终态事件可能先于外层 enqueue 监听器到达镜像；镜像会在当前分发期间保留这一尚不可见的结果，并在处理 enqueue 时把它合并进去，因此监听器注册顺序不会导致系统发布陈旧内容或不存在的行。协议发送完整的 `session/queue` 快照，而非增量猜测。重连会发送当前基线，每次 queued 变更或终态事件都会整体替换它。客户端不会进行乐观编辑，也绝不根据持久轮次事件或状态变化退役队列行。
 
 **Queue 寻址要求普通会话的 Agent 存活。** `session.updateQueue` 只查询已挂载的 Agent 注册表，绝不恢复冷会话：`InboxItemId` 属于进程本地标识，无法在重启或资源释放后继续指向工作。由会话支撑的 subagent 会在访问 inbox 前返回 `agent-busy`，并保留其继续执行 owner；对于普通会话，Agent 缺失和单次入队项已被驱动器认领这两种情况都返回 `queue-item-not-found`。
 
-**Web 操作只面向 Queue。** Host 从 `session/queue` 中排除待处理 steering；steering 消费后仍沿用既有的持久 transcript（文本记录）路径。QueueDock 在队列为空时隐藏，只有一个待处理项时直接渲染该行，存在两个或更多待处理项时则默认收起为可展开或收起完整列表的 `"<n> 条排队消息"` 表头。表头暴露 `aria-expanded` 和 `aria-controls`；展开后的列表以 180px 为高度上限，并可滚动。存在进行中的编辑或变更时，列表行会保持可见；队列清空后，下一次出现队列时会恢复默认收起状态。可见行暴露编辑和删除操作，不提供立即发送控件。UI 从运行时 `SessionFace` 契约派生队列行与变更类型，而不是导入连接插件，因此插件仍通过服务和快照协作。仅当所有内容块都是文本时才提供编辑功能；编辑器不能静默丢弃非文本块。编辑中的行只展示保存和取消操作，对应的键盘操作分别是 Enter 和 Escape。删除会移除对应的精确入队项。Web 停止操作会保留待处理 Queue 工作；只有在被中断轮次达到完全停稳后，AgentLoop 才认领下一个可唤醒入队项，其出队事件会退役该行，无需浏览器重发。
+**Web 操作只面向 Queue。** 带 placement 的 `session/queue` 会同时携带 queued 和待处理 steering；QueueDock 只选择 queued 项，ChatView 则投影 steering，并在消费后沿用既有的持久 transcript（文本记录）路径。QueueDock 在队列为空时隐藏，只有一个待处理项时直接渲染该行，存在两个或更多待处理项时则默认收起为可展开或收起完整列表的 `"<n> 条排队消息"` 表头。表头暴露 `aria-expanded` 和 `aria-controls`；展开后的列表以 180px 为高度上限，并可滚动。存在进行中的编辑或变更时，列表行会保持可见；队列清空后，下一次出现队列时会恢复默认收起状态。可见行暴露编辑、删除以及仅在运行期间可用的严格 steering 操作。UI 从运行时 `SessionFace` 契约派生队列行与变更类型，而不是导入连接插件，因此插件仍通过服务和快照协作。仅当所有内容块都是文本时才提供编辑功能；编辑器不能静默丢弃非文本块。编辑中的行只展示保存和取消操作，对应的键盘操作分别是 Enter 和 Escape。删除会移除对应的精确入队项；严格 steering 会保留每个内容块，并且只通过权威快照退役该行。Web 停止操作会保留待处理 Queue 工作；只有在被中断轮次达到完全停稳后，AgentLoop 才认领下一个可唤醒入队项，其出队事件会退役该行，无需浏览器重发。[Web Queue steering 操作](2026-07-30-web-queue-steer-action.md)负责定义严格转移与待处理投影契约。
 
 ## 考虑过的替代方案
 
@@ -26,7 +26,7 @@ Web 队列能够渲染待处理消息，但无法编辑或删除其中某一行
 
 **在浏览器中进行乐观变更。** 不予采纳，因为驱动器认领或另一个客户端可能先于 Host 操作完成。等待权威快照可以显式呈现所有权边界，并让 `queue-item-not-found` 报告真实竞态。
 
-**将待处理 steering 纳入队列变更协议。** 不予采纳，因为 QueueDock 没有 steering 交互，而编辑或删除活动轮次输入会把此功能扩展到当前消费方之外。应由专用 steering 交互负责该投递契约。
+**允许编辑或移除待处理 steering。** 不予采纳，因为 QueueDock 只寻址独立的 queued 轮次。严格 steering 一旦成功，新的 steering 单次入队项就属于活动轮次，并且不再位于此变更接口内。
 
 **暴露仅协议层的前移操作。** 不予采纳，因为当前没有产品交互会重新排序 Queue。公开一个没有当前消费方的操作，会为了推测性用途引入排序语义和测试。
 
@@ -34,10 +34,10 @@ Web 队列能够渲染待处理消息，但无法编辑或删除其中某一行
 
 ## 验证
 
-AgentLoop 契约测试会在编辑和移除精确 queued 入队项时阻塞提示词接纳，拒绝对 steering 入队项的变更，并验证所得独立轮次及终态生命周期事件。Host schema 与代理测试覆盖仅含 queued 项的权威快照、同步可重入变更顺序、重连、拒绝冷 Agent、类型化 not-found 错误和 RPC 传输。客户端运行时和 QueueDock 测试覆盖非乐观投影、单行呈现、多行默认收起、交互期间强制保持可见、清空后重置、展开、仅文本编辑、保存与取消入口、移除、退役竞态，以及禁用混合内容编辑。一个无密钥浏览器场景会捕获默认收起的表头，通过构建后的 Web 组合和真实 HTTP／SSE 协议执行编辑和删除，随后连续停止活动轮次，证明保留的 FIFO 会继续推进且不清空队尾。
+AgentLoop 契约测试会在编辑、移除和严格 steering 精确 queued 入队项时保持提示词接纳窗口打开，拒绝对 steering 入队项的变更，并验证所得独立轮次及终态生命周期事件。Host schema 与代理测试覆盖仅含 queued 项的权威快照、同步可重入变更顺序、重连、拒绝冷 Agent、类型化竞态错误和 RPC 传输。客户端运行时和 QueueDock 测试覆盖非乐观投影、单行呈现、多行默认收起、交互期间强制保持可见、清空后重置、展开、仅文本编辑、保存与取消入口、移除、严格 steering、退役竞态，以及禁用混合内容编辑。无密钥浏览器场景会通过构建后的 Web 组合和真实 HTTP／SSE 协议执行公开的全部三项操作，随后连续停止活动轮次，证明保留的 FIFO 会继续推进且不清空队尾。
 
 ## 后果
 
-queued 工作获得精确的行操作，但不会因此成为持久会话历史。单次入队标识是进程本地的实时寻址凭据，会在认领、广义取消、dispose 或重启时消失；Web 停止操作会将其保留到后续认领，而重连只能恢复仍由活跃 Agent 持有的 queued 项。编辑会排除混合内容，直至编辑器能够保留每个块；待处理 steering 则不属于此操作接口。
+queued 工作获得精确的行操作，但不会因此成为持久会话历史。单次入队标识是进程本地的实时寻址凭据，会在认领、严格转移、广义取消、dispose 或重启时消失；Web 停止操作会将 queued 入队项保留到后续认领，而重连只能恢复仍由活跃 Agent 持有的 queued 项。编辑会排除混合内容，直至编辑器能够保留每个块；待处理 steering 则不属于此投影和操作接口。
 
 现在，协议会在每次变更时携带完整队列快照。队列预期保持较短，因此系统优先选择确定性恢复和多客户端收敛，而非增量变更协议。

.agents/notes/implemented/feature/2026-07-30-web-queue-steer-action.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/2026-07-30-web-queue-steer-action.md
+2026-07-30-web-queue-steer-action.md: b5bc3547e0f72ba8211f4338fb4c1f5223a3d0cc
+2026-07-30-web-queue-steer-action.zh.md: 6edde8e2cc2bee0a52a0b05df8f62f77b3d9ccfa

.agents/notes/implemented/feature/2026-07-30-web-queue-steer-action.md

@@ -0,0 +1,71 @@
+# Agent Note: Steer a queued Web message into the active turn
+
+Status: implemented
+
+English | [中文](2026-07-30-web-queue-steer-action.zh.md)
+
+## Problem
+
+The Web composer originally queued every Enter submission while an agent ran. QueueDock already gives each pending message an addressable row, and the durable transcript already renders consumed `steering/message` events as user-style bubbles, but Web had neither an action connecting those two surfaces nor a direct composer gesture for choosing current-turn steering.
+
+Implementing the row action as a client-side delete followed by `session.prompt(mode: 'steer')` would split one user intent across two RPCs. Driver claim could win between them, the steer could fail after deletion, or the existing best-effort `agent.steer()` fallback could silently append a new Queue item after the original occurrence was removed. A send-now action must therefore distinguish current-turn steering from Queue promotion and preserve the original row when steering is no longer possible.
+
+## Decision
+
+### Product contract
+
+Each non-editing ordinary-session QueueDock row exposes the upward-arrow action as “插话发送”. The action is enabled only while the session reports a running agent; mixed-content messages remain eligible because steering forwards the complete immutable `UserMessage` rather than the row's text projection. An addressed subagent keeps its Queue projection read-only because its continuation transport does not expose queue mutation.
+
+Activating the action requests strict current-turn steering for that exact `InboxItemId`. Success removes the Queue row through the authoritative Host snapshot and immediately projects the same pending steering after the `Deep diving...` running-status row; that bubble offers Copy but no Fork because the message has no durable event sequence yet. Once AgentLoop drains it, the existing durable `steering/message` event takes over the same user-style bubble and restores its clock, Copy, and Fork without a separate durable presentation path.
+
+The running bit is only an interaction hint. AgentLoop's `acceptsNextStep` value is authoritative at the synchronous mutation boundary. If that window has closed, the operation leaves the Queue occurrence unchanged and returns a typed `steer-unavailable` error, after which the original waking occurrence proceeds through Queue. If the driver already claimed the occurrence, it returns the existing `queue-item-not-found` error and independent-turn delivery is already underway. The UI treats both races as converged Queue delivery without a failure notice; transport and unknown errors still surface.
+
+The composer uses a separate best-effort contract for newly typed input. While the addressed session is idle, Enter and Cmd/Ctrl+Enter both perform an ordinary Queue send. While a primary session is running, a General Settings preference assigns plain Enter to Queue (the default) or Steer, and Cmd/Ctrl+Enter performs the other behavior; Shift+Enter inserts a newline. An addressed subagent keeps both gestures on its Queue-only continuation transport. The browser persists the preference, and it affects only the steer-capable busy-state gesture pair. If a direct composer Steer misses the current next-step window, AgentLoop automatically admits it as the next waking Queue turn and the Web does not report a failure.
+
+### Agent and lifecycle boundary
+
+`InboxAction` gains a consumer-backed `{ kind: 'steer' }` operation alongside edit and remove. `Agent.updateInbox()` handles it only after locating the queued occurrence and proving `acceptsNextStep`; it never delegates to the best-effort `agent.steer()` alias.
+
+An applied action ends the queued occurrence and accepts the same immutable `UserMessage` as a new steering occurrence. The steering occurrence receives a new `InboxItemId` and truthful `placement: 'steering'`, while the message retains its `MessageId`, content, source, and any pending `SteeringReceipt` delivery controller. AgentLoop installs the new outbox entry before publishing lifecycle events, then emits its enqueue before the old occurrence's discard so re-entrant cancellation cannot observe or retire an unannounced item. The existing inbox conservation invariant therefore continues to require one enqueue and one terminal dequeue or discard for each occurrence.
+
+The action does not run `agent/prompt-submit`: choosing steering intentionally changes delivery from an independently admitted turn to current-turn next-step input. It neither cancels current work nor reorders the remaining Queue.
+
+### Host and client boundary
+
+`session.updateQueue` carries the `steer` action and maps the two negative outcomes to typed RPC errors. The conversion is one synchronous Agent operation; the Host never reconstructs it by combining remove and prompt calls.
+
+The Host's existing `queuedMirror` remains the sole transient inbox authority. Its `session/queue` snapshot carries every live occurrence with `placement: 'queued' | 'steering'`: QueueDock renders only queued rows, while ChatView renders pending steering at the conversation tail after the `Deep diving...` running-status row, with Copy but without Fork, edit, or delete actions. Reconnect replays the same snapshot, so this visibility does not require client optimism or a second registry.
+
+When AgentLoop claims pending steering, it emits `agent/inbox/dequeue` immediately before synchronously appending `steering/message`. The Host retires that steering row on the following microtask, allowing the durable session event to enter the linear mux stream first. On the accepted live event, the client Session retires the first matching current steering occurrence before publishing its snapshot; history replay does not consume a later occurrence that reused the same `MessageId`. ChatView therefore renders one authority at a time without scanning durable history, and the durable projection restores the clock, Copy, and Fork against its logged event time and sequence. An append failure still retires the claimed row.
+
+The existing `session.prompt(mode: 'steer')` contract remains best-effort for new primary-session input: outside the next-step window it becomes a waking follow-up. The composer carries an explicit `queue | steer` mode through slash adjudication and reference serialization before calling that contract. A browser-local submission policy owns the persisted busy-Enter preference and resolves plain versus accelerated Enter as complementary gestures only for steer-capable sessions; the Settings row and InputBar share that policy without duplicating storage or delivery-window authority. Only the Queue row action is strict, because either negative result converges through the original Queue occurrence.
+
+### Verification
+
+AgentLoop contract coverage holds prompt admission open, converts one exact queued occurrence, and proves the replacement steering occurrence keeps the message value and delivery receipt, drains as `steering/message`, and never starts its former independent turn. It also pins unavailable-window retention, claimed-address rejection, and re-entrant cancellation lifecycle conservation.
+
+Host schema and proxy tests cover the new action, both typed errors, placement-aware snapshots and reconnect replay, plus durable-before-retirement ordering. Client tests cover silent convergence of both semantic races, genuine error reporting, read-only subagent rows and Queue-only subagent gestures. Runtime and ChatView tests cover occurrence-aware pending-to-durable handoff, including repeated `MessageId` values, while Web ARIA snapshots cover pending steering after the running-status row with Copy alone and the durable node with clock, Copy, and Fork.
+
+The keyless Web steering scenario queues a message through the real composer while the first response streams, activates the row arrow, then uses `ask_user_question` as a stable pending-steering barrier. It proves the Host-backed pending bubble appears before admission, hands off to one durable interjection after the answer, and affects the next model request. Assembled composer scenarios prove default-mode Cmd+Enter reaches the same pending and durable path without creating a Queue row, while Steer-mode Cmd+Enter creates a Queue row instead. Settings and submission-policy coverage pin the default, persistence, busy-only scope, and complementary gesture mapping; Queue edit/delete scenarios continue to prove those actions are unchanged.
+
+## Alternatives considered
+
+**Delete the row, then call `session.prompt(mode: 'steer')` from Web.** Rejected because two RPCs cannot make deletion and steering atomic; failure and driver-claim races can lose or duplicate the user's message.
+
+**Restore Queue promotion under the upward arrow.** Rejected because moving an item to the front still creates an independent admitted turn. The control promises current-turn steering, not priority within Queue.
+
+**Use the existing best-effort `agent.steer()` behavior for the Queue row.** Rejected for that action because a closed next-step window would create a new queued occurrence, possibly at a different position and identity. Strict refusal preserves the original occurrence so the UI can treat it as the same accepted Queue delivery. Newly typed composer input has no existing Queue occurrence to preserve, so it intentionally uses the best-effort behavior.
+
+**Change `agent.steer()` to be strict for every caller.** Rejected because TUI and plugin callers use its safe follow-up fallback for newly submitted input. A queued row has recoverable state that those callers do not.
+
+**Preserve the same `InboxItemId` while changing placement.** Rejected because `InboxItemId` identifies one FIFO acceptance and `placement` records that acceptance's resolved delivery. Ending one queued occurrence and accepting one steering occurrence keeps lifecycle facts truthful and leaves the conservation invariant unchanged.
+
+**Add a dedicated pending-steering projection and client store.** Rejected because queued and steering occurrences already share one Agent inbox lifecycle and one Host mirror. A second projection would duplicate reconnect state and ordering authority; a placement tag lets each client surface select its rows without widening Queue mutation semantics.
+
+**Cancel the active turn and run the selected Queue item.** Rejected because it destroys unrelated in-flight work and starts a new turn rather than steering the current one.
+
+## Consequences
+
+`session/queue` describes a placement-aware transient inbox snapshot rather than a Queue-only list, so every consumer must filter by placement. Pending steering survives reconnect and appears immediately, but remains non-durable until `steering/message` commits. The running bit can also remain true briefly after the strict next-step window closes, so an enabled action may internally return `steer-unavailable` while the product continues through Queue without reporting failure.
+
+The explicit action changes delivery from an independently admitted turn to current-turn steering, so prompt-admission plugins do not process the converted message. Enqueue-before-discard lifecycle publication remains required for re-entrant cancellation safety; focused regression coverage protects that ordering.

.agents/notes/implemented/feature/2026-07-30-web-queue-steer-action.zh.md

@@ -0,0 +1,71 @@
+# Agent Note（agent 决策记录）：将 Web 已排队消息转为活动轮次的 steering（中途引导）
+
+Status: implemented
+
+[English](2026-07-30-web-queue-steer-action.md) | 中文
+
+## 问题
+
+Web composer 原本会在 agent 运行期间把所有 Enter 提交作为 Queue 入队。QueueDock 已经为每条待处理消息提供可寻址的行，持久 transcript（文本记录）也已能把消费后的 `steering/message` 事件渲染为用户样式气泡，但 Web 既没有连接这两个界面的操作，也没有让用户从 composer 直接选择当前轮次 steering 的手势。
+
+如果 Web 先在客户端删除该行，再调用 `session.prompt(mode: 'steer')`，就会把用户的一次意图拆分到两个 RPC 中。驱动器可能在两次调用之间先认领该项，steering 投递也可能在删除后失败；现有尽力而为的 `agent.steer()` 回退还可能在原单次入队项被移除后，静默追加一个新的 Queue 项。因此，立即发送操作必须区分当前轮次 steering 与 Queue 前移，并在 steering 已不可用时保留原行。
+
+## 决策
+
+### 产品契约
+
+普通会话中每个非编辑态的 QueueDock 行都会提供名为“插话发送”的向上箭头操作。仅当会话报告 agent 正在运行时，该操作才会启用；包含混合内容的消息仍可使用，因为 steering 会转发完整且不可变的 `UserMessage`，而非该行的文本投影。已寻址 subagent 的 Queue 投影保持只读，因为其继续执行传输不提供 Queue 变更。
+
+触发该操作会针对对应的 `InboxItemId` 请求严格的当前轮次 steering。操作成功后，权威 Host 快照会移除 Queue 行，并在 `Deep diving...` 运行状态行之后立即投影同一条待处理 steering；该气泡提供复制，但消息尚无持久事件序号，因此不提供 fork。AgentLoop 排空该项后，现有持久 `steering/message` 事件会接管同一个用户样式气泡，并恢复时钟、复制和 fork，无需另建持久展示路径。
+
+running 标志位只用于提示交互状态。在同步变更边界上，AgentLoop 的 `acceptsNextStep` 值才是权威依据。如果该窗口已经关闭，操作会保持 Queue 单次入队项不变并返回类型化的 `steer-unavailable` 错误，随后原唤醒单次入队项会经 Queue 继续执行。如果驱动器已经认领该项，则返回现有的 `queue-item-not-found` 错误，且独立轮次投递已经开始。UI 会把两种竞态都视为已收敛的 Queue 投递，不显示失败通知；传输和未知错误仍会显示。
+
+Composer 对新输入采用另一套尽力而为契约。所寻址会话空闲时，Enter 和 Cmd/Ctrl+Enter 都执行普通 Queue 发送。主会话运行期间，General Settings 偏好会把普通 Enter 分配为 Queue（默认值）或 Steer，Cmd/Ctrl+Enter 则执行另一种行为；Shift+Enter 用于换行。已寻址 subagent 会让这两个手势都使用其仅支持 Queue 的继续执行传输。浏览器会持久化该偏好，并且它只影响支持 steering 的繁忙态手势对。如果 composer 直接发出的 Steer 错过当前 next-step 窗口，AgentLoop 会自动将其接纳为下一条唤醒 Queue 轮次，Web 不显示失败。
+
+### Agent 与生命周期边界
+
+`InboxAction` 会在编辑和移除之外，新增由实际消费方支撑的 `{ kind: 'steer' }` 操作。`Agent.updateInbox()` 只有在找到 queued 单次入队项并确认 `acceptsNextStep` 后才会处理该操作，绝不会委托给尽力而为的 `agent.steer()` 别名。
+
+操作成功应用后，系统会结束 queued 单次入队项，并把同一个不可变 `UserMessage` 接受为新的 steering 单次入队项。steering 单次入队项会获得新的 `InboxItemId` 和如实反映投递方式的 `placement: 'steering'`，消息则保留其 `MessageId`、内容、来源和任何待处理 `SteeringReceipt` 投递控制器。AgentLoop 会先安装新的 outbox 项，再发布生命周期事件；随后先发出新单次入队项的 enqueue，再发出旧单次入队项的 discard，确保可重入取消无法观察或退役一个尚未公布的项。因此，现有 inbox 守恒不变量仍然要求每个单次入队项恰好对应一个 enqueue，以及一个终态 dequeue 或 discard。
+
+该操作不会运行 `agent/prompt-submit`：选择 steering 会有意把投递方式从经独立接纳的轮次改为当前轮次的 next-step 输入。它既不会取消当前工作，也不会重新排序 Queue 中的剩余项。
+
+### Host 与客户端边界
+
+`session.updateQueue` 会携带 `steer` 操作，并把两种负面结果映射为类型化 RPC 错误。这项转换是一次同步 Agent 操作；Host 绝不会通过组合移除和提示词调用来重建它。
+
+Host 仍以现有 `queuedMirror` 作为唯一的瞬态 inbox 权威。`session/queue` 快照会携带所有存活单次入队项及其 `placement: 'queued' | 'steering'`：QueueDock 只渲染 queued 行，ChatView 则在会话流末尾、`Deep diving...` 运行状态行之后渲染待处理 steering，提供复制操作，但不提供 fork、编辑或删除操作。重连会重放同一份快照，因此这项可见性既不依赖客户端乐观展示，也不需要第二个 registry。
+
+AgentLoop 认领待处理 steering 时，会在同步追加 `steering/message` 之前立即发出 `agent/inbox/dequeue`。Host 会等到下一个微任务才退役该 steering 行，让持久 session 事件先进入线性 mux 流。客户端 Session 接纳该实时事件时，会在发布快照前退役第一个匹配的当前 steering 单次入队项；历史回放不会消费后来复用同一 `MessageId` 的单次入队项。因此，ChatView 无需扫描持久历史就能每次只渲染一份权威，持久投影则会根据已记录的事件时间与序号恢复时钟、复制与 fork 操作。追加失败时，已认领行仍会退役。
+
+现有 `session.prompt(mode: 'steer')` 对主会话新输入仍采用尽力而为的契约：在 next-step 窗口之外，它会变为唤醒 agent 的后续轮次。Composer 会让显式 `queue | steer` 模式经过 slash 裁决与引用序列化，再调用该契约。浏览器本地的提交策略拥有持久化的繁忙态 Enter 偏好，并且只为支持 steering 的会话把普通 Enter 与加速 Enter 解析为互补手势；Settings 行和 InputBar 共享该策略，不重复实现存储或投递窗口权威。只有 Queue 行操作采用严格语义，因为任一种负面结果都会经原 Queue 单次入队项收敛。
+
+### 验证
+
+AgentLoop 契约覆盖保持提示词接纳窗口打开，转换一个精确的 queued 单次入队项，并证明替代它的 steering 单次入队项保留消息值和投递回执、以 `steering/message` 的形式排空，且绝不启动原本的独立轮次。该覆盖还钉住窗口不可用时保留原项、拒绝已被认领的地址，以及可重入取消下的生命周期守恒。
+
+Host schema 和代理测试覆盖新操作、两种类型化错误、带 placement 的快照与重连重放，以及先持久化再退役的顺序。客户端测试覆盖两种语义竞态的静默收敛、真实错误报告、只读 subagent 行和仅支持 Queue 的 subagent 手势。运行时与 ChatView 测试覆盖按单次入队项完成的待处理到持久交接，包括重复的 `MessageId` 值；Web ARIA 快照则覆盖位于运行状态行之后且仅有复制的待处理 steering，以及带时钟、复制和 fork 的持久节点。
+
+无密钥 Web steering 场景在第一次响应流式输出期间，通过真实 composer 排队一条消息并触发行上的箭头，再用 `ask_user_question` 作为稳定的待处理 steering 屏障。该场景证明 Host 支撑的待处理气泡会在准入前出现，在回答后交接为唯一一条持久插话，并影响下一次模型请求。组装后的 composer 场景证明默认模式下的 Cmd+Enter 无需创建 Queue 行，也会进入同一条待处理与持久路径；Steer 模式下的 Cmd+Enter 则会创建 Queue 行。Settings 与提交策略覆盖会固定默认值、持久化、仅限繁忙态的作用域和互补手势映射；Queue 编辑／删除场景继续证明这些操作没有变化。
+
+## 考虑过的替代方案
+
+**在 Web 中删除该行，再调用 `session.prompt(mode: 'steer')`。** 不予采纳，因为两个 RPC 无法让删除和 steering 成为原子操作；失败和驱动器认领竞态可能丢失或重复用户消息。
+
+**恢复向上箭头对应的 Queue 前移操作。** 不予采纳，因为把某个项移到队首仍然会创建一个独立接纳的轮次。该控件承诺的是当前轮次 steering，而不是 Queue 内的优先级。
+
+**为 Queue 行使用现有尽力而为的 `agent.steer()` 行为。** 不予采纳，因为关闭的 next-step 窗口会创建新的 queued 单次入队项，而且位置和标识可能不同。严格拒绝会保留原单次入队项，让 UI 能将其视为同一次已接纳的 Queue 投递。新输入的 composer 消息没有需要保留的现有 Queue 单次入队项，因此有意采用尽力而为行为。
+
+**让每个调用方使用的 `agent.steer()` 都采用严格语义。** 不予采纳，因为 TUI 和插件调用方会针对新提交的输入使用其安全的后续轮次回退。queued 行具有这些调用方不具备的可恢复状态。
+
+**改变投递方式时保留同一个 `InboxItemId`。** 不予采纳，因为 `InboxItemId` 标识一次 FIFO 接受，而 `placement` 记录该次接受解析出的投递方式。结束一个 queued 单次入队项并接受一个 steering 单次入队项，能够使生命周期事实保持如实，并让守恒不变量保持不变。
+
+**增加专用的待处理 steering 投影和客户端 store。** 不予采纳，因为 queued 与 steering 单次入队项已经共享同一套 Agent inbox 生命周期和 Host mirror。第二份投影会重复保存重连状态与顺序权威；placement 标签能让各客户端界面选取自己的行，而不扩大 Queue 变更语义。
+
+**取消活动轮次并运行选中的 Queue 项。** 不予采纳，因为这会破坏无关的进行中工作，并且会启动新轮次，而不是 steering 当前轮次。
+
+## 后果
+
+`session/queue` 表示带 placement 的瞬态 inbox 快照，而不只是 Queue 列表，因此每个消费方都必须按 placement 过滤。待处理 steering 会在界面中立即出现并能在重连后恢复，但在 `steering/message` 提交前仍不持久。严格 next-step 窗口关闭后，running 标志位仍可能短暂保持为 true，因此已启用的操作可能会在内部返回 `steer-unavailable`，而产品仍经 Queue 继续执行且不显示失败。
+
+这项显式操作会把投递方式从经独立接纳的轮次改为当前轮次 steering，因此提示词接纳插件不会处理转换后的消息。为保证可重入取消安全，生命周期事件仍必须先发布 enqueue 再发布 discard；有针对性的回归覆盖会保护这一顺序。

apps/web/tests/settings-chrome.e2e.ts

@@ -2,8 +2,9 @@
 // section switching, both close paths), the Appearance preference row (the
 // real theme gesture — click 深色 and the whole cascade runs: ThemeService preference -> localStorage dsh.theme
 // -> theme/change -> ui-layout's presenter -> body attribute -> alias token)
-// and the Language row (settings-scoped localization + persisted dsh.locale),
-// plus Permission as the persisted default for subsequently created sessions.
+// the Language row (settings-scoped localization + persisted dsh.locale),
+// the busy-state Enter preference, plus Permission as the persisted default
+// for subsequently created sessions.
 // Zero model calls: everything is pure client + persistence state on a blank
 // frame, so there is no fixture and a stray stream would fail loud on the
 // open llm seam.
@@ -182,6 +183,32 @@ describe('web e2e: settings modal and General preferences', () => {
     expect(tripwire.pageErrors).toEqual([])
   }, 90_000)
 
+  it('persists the busy-state Enter behavior across reload and restores Queue', async () => {
+    onTestFailed(() => saveFailureShot(page, 'web-e2e-settings-enter-behavior'))
+    await page.getByRole('button', { name: '设置', exact: true }).click()
+    const dialog = page.getByRole('dialog', { name: '设置' })
+    await dialog.waitFor({ timeout: 10_000 })
+    await dialog.getByRole('button', { name: '排队发送' }).click()
+    await page.getByRole('menuitem', { name: '插话发送' }).click()
+    await dialog.getByRole('button', { name: '插话发送' }).waitFor({ timeout: 10_000 })
+    expect(await page.evaluate(() => localStorage.getItem('dsh.conversation.busyEnter'))).toBe('steer')
+    await page.keyboard.press('Escape')
+
+    const warningStart = tripwire.warnings.length
+    await page.reload({ waitUntil: 'load' })
+    await page.waitForSelector('[class*="frame"]', { timeout: 30_000 })
+    acknowledgeReloadConnectionLoss(tripwire, warningStart)
+    await page.getByRole('button', { name: '设置', exact: true }).click()
+    const reloaded = page.getByRole('dialog', { name: '设置' })
+    await reloaded.getByRole('button', { name: '插话发送' }).waitFor({ timeout: 10_000 })
+    await reloaded.getByRole('button', { name: '插话发送' }).click()
+    await page.getByRole('menuitem', { name: '排队发送' }).click()
+    await reloaded.getByRole('button', { name: '排队发送' }).waitFor({ timeout: 10_000 })
+    expect(await page.evaluate(() => localStorage.getItem('dsh.conversation.busyEnter'))).toBe('queue')
+    await page.keyboard.press('Escape')
+    expect(tripwire.pageErrors).toEqual([])
+  }, 90_000)
+
   it('switches the settings surface language and persists dsh.locale', async () => {
     onTestFailed(() => saveFailureShot(page, 'web-e2e-settings-language'))
     await page.getByRole('button', { name: '设置', exact: true }).click()

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

@@ -23,6 +23,8 @@
       - img
     - button "Remove queued message":
       - img
+    - button "Steer queued message":
+      - img
   - listitem:
     - textbox "Edit queued message": Edited queue item
     - button "Save queued message":

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

@@ -33,6 +33,8 @@
       - img
     - button "Remove queued message":
       - img
+    - button "Steer queued message":
+      - img
 - textbox "Message the agent"
 - button "Commands":
   - img

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

@@ -22,6 +22,8 @@
       - img
     - button "Remove queued message":
       - img
+    - button "Steer queued message":
+      - img
 - textbox "Message the agent"
 - button "Commands":
   - img

apps/web/tests/snapshots/settings-chrome/dialog.expected.md

@@ -28,3 +28,7 @@
   - button "跟随系统" [pressed]:
     - img
     - text: 跟随系统
+  - text: 繁忙时 Enter 键行为 仅在智能体运行时生效；Cmd/Ctrl+Enter 使用另一行为
+  - button "排队发送":
+    - text: 排队发送
+    - img

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

@@ -23,6 +23,9 @@
   - img
   - text: Ask question waiting
 - status: Deep diving...
+- text: "Interjection: include the word BANANA in your final reply."
+- button "Copy":
+  - img
 - region "Ready to continue?":
   - text: Checkpoint
   - heading "Ready to continue?" [level=2]

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

@@ -21,7 +21,11 @@
   - img
   - img
   - text: Ask question 1/1 answered
-- text: "Interjection: include the word BANANA in your final reply."
+- text: "Interjection: include the word BANANA in your final reply. {{clock}}"
+- button "Copy":
+  - img
+- button "Branch into a new conversation":
+  - img
 - button "Think The user selected \"Yes\" and wants me to include the word \"BANANA\" in my final reply. Let me acknowledge their answer.":
   - img
   - img

apps/web/tests/steering.e2e.ts

@@ -1,15 +1,7 @@
-// Web e2e scenario: mid-turn steering over the host wire. The Web UI has no
-// steer entry, so the steer is POSTed from the page over the same
-// same-origin /api transport the client uses. Everything downstream is
-// product: the gateway routes mode:'steer' to Agent.steer, the loop drains
-// it at the step boundary into a durable steering/message event, the SSE mux
-// pushes it, and the transcript shows the text as a plain bubble (no
-// interjection chrome). The question composer supplies the deterministic
-// mid-turn window: while ask_user_question blocks, the turn is provably
-// running, so record and replay perform the identical steer-then-answer
-// sequence with zero timing dependence — and the recorded final reply proves
-// the steer reached the MODEL (it obeys an instruction that only the
-// steering message carries).
+// Web e2e scenarios for both steering entry points: QueueDock strictly
+// transfers one queued occurrence, while the complementary composer gestures
+// choose Queue or Steer. The question tool supplies a deterministic pending-
+// steering snapshot before the step can drain.
 import { readFile } from 'node:fs/promises'
 import { fileURLToPath } from 'node:url'
 import { join } from 'node:path'
@@ -26,16 +18,18 @@ import { connectFreshWorkspace, newEnglishPage, saveFailureShot } from './suppor
 
 const SNAPSHOT_DIR = fileURLToPath(new URL('./snapshots/steering', import.meta.url))
 const FIXTURE = join(SNAPSHOT_DIR, 'session.jsonl')
-// Two goldens for the two distinct states this interaction produces: the
-// mid-turn moment (steer ACCEPTED but deliberately invisible — the loop
-// drains steering at the step boundary, so no steering text exists while
-// the question still blocks the step) and the settled transcript (plain
-// bubble in place, final reply obeying it). The pair pins the timing
-// semantics visually: if the client ever starts rendering pending steers
-// eagerly, the mid-steer golden flips first.
+// Two goldens pin the transient Host projection and its durable handoff: the
+// mid-turn state renders accepted steering from session/queue while the
+// question blocks admission, then the settled state renders the same message
+// from steering/message beside the reply that obeys it.
 const MID_EXPECTED = join(SNAPSHOT_DIR, 'mid-steer.expected.md')
 const SETTLED_EXPECTED = join(SNAPSHOT_DIR, 'settled.expected.md')
 const MODE = webSnapshotMode()
+// The question composer replaces the textarea, so fill → Queue row → Steer
+// must finish inside the first replay chunk window. At 15 ms that window is
+// shorter than Playwright's round trips; 100 ms supplies test-only headroom,
+// while larger values lengthen all three replay scenarios linearly.
+const REPLAY_PACE_MS = 100
 
 const PROMPT = 'Use the ask_user_question tool to ask me exactly one question with id "checkpoint", question "Ready to continue?", header "Checkpoint", and options labeled "Yes" and "No". After I answer, reply with one short sentence acknowledging my answer and stop.'
 const STEER = 'Interjection: include the word BANANA in your final reply.'
@@ -56,15 +50,13 @@ describe('web e2e: mid-turn steering lands durably and visibly', () => {
   let browser: Browser
   let page: Page
   let tripwire: ReturnType<typeof watchConsole>
-  let liveSessionId: string | undefined
   const sessionEvents: SessionEvent[] = []
 
   beforeAll(async () => {
-    scaffold = await launchWebScaffold(MODE === 'record' ? {} : { replayFixture: FIXTURE, paceMs: 15 })
-    scaffold.ctx.on('session/event', (session, event) => {
-      liveSessionId ??= session.id
-      sessionEvents.push(event)
-    })
+    scaffold = await launchWebScaffold(MODE === 'record'
+      ? {}
+      : { replayFixture: FIXTURE, paceMs: REPLAY_PACE_MS })
+    scaffold.ctx.on('session/event', (_session, event) => { sessionEvents.push(event) })
     browser = await chromium.launch()
     page = await newEnglishPage(browser)
     tripwire = watchConsole(page)
@@ -79,7 +71,7 @@ describe('web e2e: mid-turn steering lands durably and visibly', () => {
     await scaffold?.close()
   })
 
-  it('steers during the blocked step; the message is logged, rendered, and obeyed', async () => {
+  it('strictly steers one queued row; the interjection is logged, rendered, and obeyed', async () => {
     onTestFailed(() => saveFailureShot(page, 'web-e2e-steering'))
     if (MODE !== 'record') {
       // The steer must NOT be a user/message — it lands as steering/message.
@@ -91,36 +83,29 @@ describe('web e2e: mid-turn steering lands durably and visibly', () => {
     await input.fill(PROMPT)
     await input.press('Enter')
 
-    // The blocked composer is the mid-turn barrier: its presence proves the
-    // ask_user_question step is executing, i.e. the turn is running NOW.
+    // Enter remains the Queue gesture. The row action then atomically moves
+    // this exact occurrence into the current turn's steering outbox.
+    await input.fill(STEER)
+    await input.press('Enter')
+    const queued = page.getByText(STEER, { exact: true })
+    await queued.waitFor({ timeout: 10_000 })
+    const queuedRow = page.getByRole('listitem').filter({ hasText: STEER })
+    const steerButton = queuedRow.getByRole('button', { name: 'Steer queued message' })
+    await expect.poll(() => steerButton.isEnabled(), { timeout: 10_000 }).toBe(true)
+    await steerButton.click({ timeout: 10_000 })
+    const pendingSteering = page.locator('[data-pending-steering]').filter({ hasText: STEER })
+    // A timeout while the Queue row remains means strict steer lost to a
+    // closing window (`steer-unavailable`); inspect replay pacing first.
+    await pendingSteering.waitFor({ timeout: 10_000 })
+
+    // The blocked composer keeps steering pending long enough to observe the
+    // Host-authoritative mirror before the loop admits it durably.
     const composer = page.locator('[data-question-key]')
     await composer.waitFor({ timeout: MODE === 'record' ? 120_000 : 30_000 })
 
-    // Steer through the real wire from the page (same envelope + endpoint the
-    // web client's session.prompt uses). accepted:true is the transport proof.
-    expect(liveSessionId).toBeDefined()
-    const reply = await page.evaluate(async ({ sessionId, text }) => {
-      const response = await fetch('/api/session.prompt', {
-        method: 'POST',
-        headers: { 'content-type': 'application/json' },
-        body: JSON.stringify({
-          type: 'client-request',
-          rpcId: crypto.randomUUID(),
-          method: 'session.prompt',
-          payload: { sessionId, mode: 'steer', content: [{ type: 'text', text }] },
-        }),
-      })
-      return await response.json() as { result?: { ok?: boolean } }
-    }, { sessionId: liveSessionId!, text: STEER })
-    expect(reply.result?.ok).toBe(true)
-
     if (MODE !== 'record') {
-      // Mid-turn golden: the ACCEPTED steer is durable in the inbox but the
-      // loop drains steering only at the step boundary, so no steering/message
-      // exists yet and no steer text renders — the composer still blocks,
-      // alone. The DOM is stable here (no further SSE frames can arrive until
-      // the question is answered), making this state capturable.
-      expect(await page.getByText(STEER, { exact: true }).count()).toBe(0)
+      expect(await page.getByText(STEER, { exact: true }).count()).toBe(1)
+      expect(await pendingSteering.count()).toBe(1)
       expect(await page.getByRole('button', { name: 'Edit queued message' }).count()).toBe(0)
       const snapshot = await captureStableAria(page, '[class*="centerCol"]', scaffold.workspaceCwd)
       await compareOrRefreshGolden(MID_EXPECTED, snapshot, MODE)
@@ -156,6 +141,7 @@ describe('web e2e: mid-turn steering lands durably and visibly', () => {
     // Visible: the plain steering bubble plus the reply that obeys it
     // (steer text + final reply each contain the marker word).
     await expect.poll(() => page.getByText(STEER, { exact: true }).count(), { timeout: 15_000 }).toBe(1)
+    expect(await pendingSteering.count()).toBe(0)
     await expect.poll(() => page.getByText('BANANA', { exact: false }).count(), { timeout: 10_000 }).toBeGreaterThanOrEqual(2)
     expect(await page.locator('[data-question-key]').count()).toBe(0)
     // Settled golden: steer text between the question round trip and the
@@ -170,3 +156,120 @@ describe('web e2e: mid-turn steering lands durably and visibly', () => {
     await assertFixtureInventory(SNAPSHOT_DIR, ['session.jsonl', 'mid-steer.expected.md', 'settled.expected.md'])
   })
 })
+
+describe('web e2e: composer shortcut steers directly', () => {
+  let scaffold: WebScaffold
+  let browser: Browser
+  let page: Page
+  let tripwire: ReturnType<typeof watchConsole>
+  const sessionEvents: SessionEvent[] = []
+
+  beforeAll(async () => {
+    scaffold = await launchWebScaffold({ replayFixture: FIXTURE, paceMs: REPLAY_PACE_MS })
+    scaffold.ctx.on('session/event', (_session, event) => { sessionEvents.push(event) })
+    browser = await chromium.launch()
+    page = await newEnglishPage(browser)
+    tripwire = watchConsole(page)
+    await page.goto(scaffold.baseUrl, { waitUntil: 'load' })
+    await page.waitForSelector('[class*="frame"]', { timeout: 30_000 })
+    await connectFreshWorkspace(page, scaffold.workspaceCwd)
+  }, 120_000)
+
+  afterAll(async () => {
+    await browser?.close()
+    await scaffold?.close()
+  })
+
+  it.skipIf(MODE === 'record')('uses Cmd+Enter without creating a Queue row', async () => {
+    onTestFailed(() => saveFailureShot(page, 'web-e2e-composer-steering'))
+    expect(fixtureUserPrompts(await readFile(FIXTURE, 'utf8'))).toEqual([PROMPT])
+    const input = page.locator('textarea').first()
+    await input.waitFor({ timeout: 10_000 })
+    const settled = scaffold.whenTurnSettled(30_000)
+    await input.fill(PROMPT)
+    await input.press('Enter')
+    await page.getByRole('button', { name: 'Stop generating' }).waitFor({ timeout: 10_000 })
+
+    await input.fill(STEER)
+    await input.press('Meta+Enter')
+    await expect.poll(() => input.inputValue(), { timeout: 5_000 }).toBe('')
+    expect(await page.locator('[data-queue-dock]').count()).toBe(0)
+
+    const composer = page.locator('[data-question-key]')
+    await composer.waitFor({ timeout: 30_000 })
+    const pendingSteering = page.locator('[data-pending-steering]').filter({ hasText: STEER })
+    await pendingSteering.waitFor({ timeout: 10_000 })
+    await composer.getByRole('radio', { name: 'Yes' }).click()
+    await composer.getByRole('radio', { name: 'Yes' }).press('Enter')
+    await settled
+
+    const steerEvents = sessionEvents.filter(event => event.type === 'steering/message')
+    expect(steerEvents).toHaveLength(1)
+    expect((steerEvents[0] as SessionEvent & { data: { turn: number } }).data.turn).toBe(1)
+    await expect.poll(() => page.getByText(STEER, { exact: true }).count(), { timeout: 15_000 }).toBe(1)
+    expect(await pendingSteering.count()).toBe(0)
+    await expect.poll(() => page.getByText('BANANA', { exact: false }).count(), { timeout: 10_000 })
+      .toBeGreaterThanOrEqual(2)
+    expect(tripwire.pageErrors).toEqual([])
+    expect(tripwire.warnings).toEqual([])
+  }, 90_000)
+})
+
+describe('web e2e: composer shortcut follows the swapped busy behavior', () => {
+  let scaffold: WebScaffold
+  let browser: Browser
+  let page: Page
+  let tripwire: ReturnType<typeof watchConsole>
+  const sessionEvents: SessionEvent[] = []
+
+  beforeAll(async () => {
+    scaffold = await launchWebScaffold({ replayFixture: FIXTURE, paceMs: REPLAY_PACE_MS })
+    scaffold.ctx.on('session/event', (_session, event) => { sessionEvents.push(event) })
+    browser = await chromium.launch()
+    page = await newEnglishPage(browser)
+    tripwire = watchConsole(page)
+    await page.goto(scaffold.baseUrl, { waitUntil: 'load' })
+    await page.waitForSelector('[class*="frame"]', { timeout: 30_000 })
+    await connectFreshWorkspace(page, scaffold.workspaceCwd)
+  }, 120_000)
+
+  afterAll(async () => {
+    await browser?.close()
+    await scaffold?.close()
+  })
+
+  it.skipIf(MODE === 'record')('queues Cmd+Enter when plain Enter is configured to Steer', async () => {
+    onTestFailed(() => saveFailureShot(page, 'web-e2e-composer-swapped-shortcut'))
+    await page.getByRole('button', { name: 'Settings', exact: true }).click()
+    const dialog = page.getByRole('dialog', { name: 'Settings' })
+    await dialog.getByRole('button', { name: 'Queue' }).click()
+    await page.getByRole('menuitem', { name: 'Steer' }).click()
+    await dialog.getByRole('button', { name: 'Steer' }).waitFor({ timeout: 10_000 })
+    await page.keyboard.press('Escape')
+
+    const input = page.locator('textarea').first()
+    const settled = scaffold.whenTurnSettled(30_000)
+    await input.fill(PROMPT)
+    await input.press('Enter')
+    await page.getByRole('button', { name: 'Stop generating' }).waitFor({ timeout: 10_000 })
+
+    const queuedText = 'Queued by the complementary Cmd+Enter shortcut.'
+    await input.fill(queuedText)
+    await input.press('Meta+Enter')
+    const queuedRow = page.locator('[data-queue-dock]').getByRole('listitem').filter({ hasText: queuedText })
+    await queuedRow.getByText(queuedText, { exact: true }).waitFor({ timeout: 10_000 })
+    expect(await page.locator('[data-pending-steering]').filter({ hasText: queuedText }).count()).toBe(0)
+    expect(sessionEvents.filter(event => event.type === 'steering/message')).toHaveLength(0)
+
+    // Remove the asserted Queue row, then finish the recorded question turn
+    // so replay teardown still proves that every fixture call was consumed.
+    await queuedRow.getByRole('button', { name: 'Remove queued message' }).click()
+    const composer = page.locator('[data-question-key]')
+    await composer.waitFor({ timeout: 30_000 })
+    await composer.getByRole('radio', { name: 'Yes' }).click()
+    await composer.getByRole('radio', { name: 'Yes' }).press('Enter')
+    await settled
+    expect(tripwire.pageErrors).toEqual([])
+    expect(tripwire.warnings).toEqual([])
+  }, 90_000)
+})

docs/architecture.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 docs/architecture.md
-architecture.md: 6aa942ba2702d8d30ae94d9968f07abb5e1fe88d
-architecture.zh.md: c8aaa68527f34f4879f882a08260a4e0bd4f4c5f
+architecture.md: 4bb0cb1f29bb48adf89c97af7c85c90219d0558a
+architecture.zh.md: 4c6ff721d894aaee4cc14ff321967580997aba56

docs/architecture.md

@@ -123,6 +123,8 @@ Each step assembles ordered stable system sections, cache-safe dynamic contexts,
 
 Admission-time and active-turn `inject()` stage for the next step; tool-time injection and post-tool `additionalContexts` settle after results. Steering shares the outbox but remains provisional until a request admits it. `steer()` returns a message-owned receipt: after `agent/step` and asynchronous prompt assembly succeed, the loop commits the stable batch, snapshots request history, opens `step/start`, then resolves its receipts as admitted with the turn and step; later arrivals wait. A turn-concluding tool result, broad cancellation, disposal, or a claimed idle-steering turn that never opens a step rejects affected receipts, while `cancel(..., { keepInbox: true })` and non-terminal routing preserve pending delivery. Idle `inject()` appends immediately without changing turn numbers; persistence drains eagerly.
 
+Before driver claim, `updateInbox()` may edit or remove a queued occurrence, or strictly transfer its immutable message into an open next-step window. That transfer ends the queued occurrence and accepts a new steering occurrence; a closed window leaves Queue unchanged. Direct `steer()` remains best-effort for newly submitted input and falls back to a waking follow-up outside the window ([decision](../.agents/notes/implemented/feature/2026-07-30-web-queue-steer-action.md)).
+
 Pruning precedes summaries; overflow retries require durable progress. `agent/request-error` may authorize one retry turn between failed-step and turn close; cancellation wins. Adapter-owned `retryPolicy` makes normal mode bounded; always mode delegates specialized recovery before retrying until success or cancellation ([compaction](../.agents/notes/implemented/architecture/2026-07-10-after-call-compaction-pressure-and-overflow-recovery.md), [retry foundation](../.agents/notes/implemented/architecture/2026-06-21-bounded-llm-request-recovery.md), [provider policy](../.agents/notes/implemented/feature/2026-07-24-provider-retry-policies.md)).
 
 ### Failure Boundaries

docs/architecture.zh.md

@@ -123,6 +123,8 @@ idle inject:
 
 接纳期间和活跃轮次内的 `inject()` 会为下一步骤暂存；工具执行期间的注入和工具执行后的 `additionalContexts` 会在结果记录完毕后落定。steering 与其共用 outbox，但在请求接纳前始终处于待准入状态。`steer()` 会返回归属于该消息的回执：`agent/step` 和异步提示词组装成功后，循环提交稳定批次、捕获请求历史并开启 `step/start`，再将其回执解析为已准入并附带轮次与步骤；后续消息继续等待。结束轮次的工具结果、广义取消、dispose（资源释放），以及已领取 idle-steering 消息却从未开启步骤的轮次，都会拒绝受影响的回执；`cancel(..., { keepInbox: true })` 和非终止型路由则保留待处理投递。空闲状态下的 `inject()` 会立即追加，且不改变轮次编号；持久化层会尽快排空。
 
+驱动器认领之前，`updateInbox()` 可以编辑或移除 queued 单次入队项，也可以严格地把其不可变消息转移到开放的 next-step 窗口。该转移会结束 queued 单次入队项，并接受一个新的 steering 单次入队项；窗口关闭时 Queue 保持不变。直接调用 `steer()` 时，对新提交的输入仍采用尽力而为的语义，并在窗口之外回退为会唤醒 agent 的后续轮次（[决策](../.agents/notes/implemented/feature/2026-07-30-web-queue-steer-action.md)）。
+
 裁剪先于摘要；溢出重试必须取得持久进展。`agent/request-error` 可以在失败步骤与轮次关闭之间授权一个重试轮次；取消优先。适配器拥有的 `retryPolicy` 使 normal mode 保持有界；always mode 先委托专门恢复，再持续重试直至成功或取消（[压缩](../.agents/notes/implemented/architecture/2026-07-10-after-call-compaction-pressure-and-overflow-recovery.md)、[重试基础](../.agents/notes/implemented/architecture/2026-06-21-bounded-llm-request-recovery.md)、[提供方策略](../.agents/notes/implemented/feature/2026-07-24-provider-retry-policies.md)）。
 
 ### 失败边界

docs/cordis-catalog/events.md

@@ -32,7 +32,7 @@ Effective broad cancellation was requested, before queued/outbox work is cleared
 
 Types: [Agent](../core-data-structures/core.md) · [AgentCancelCause](../core-data-structures/core.md) · [Scoped](../core-data-structures/scope.md)
 
-Source: [`packages/core/agent/src/types.ts:349`](../../packages/core/agent/src/types.ts)
+Source: [`packages/core/agent/src/types.ts:353`](../../packages/core/agent/src/types.ts)
 
 ### `agent/created` — emit
 
@@ -54,7 +54,7 @@ A fully configured agent and live session were published. Setup is composition-o
 
 Types: [Agent](../core-data-structures/core.md) · [Scoped](../core-data-structures/scope.md)
 
-Source: [`packages/core/agent/src/types.ts:280`](../../packages/core/agent/src/types.ts)
+Source: [`packages/core/agent/src/types.ts:284`](../../packages/core/agent/src/types.ts)
 
 ### `agent/disposed` — emit
 
@@ -74,7 +74,7 @@ An agent left the registry; AgentLoop emits this after driver quiescence and sco
 
 Types: [Agent](../core-data-structures/core.md) · [Scoped](../core-data-structures/scope.md)
 
-Source: [`packages/core/agent/src/types.ts:289`](../../packages/core/agent/src/types.ts)
+Source: [`packages/core/agent/src/types.ts:293`](../../packages/core/agent/src/types.ts)
 
 ### `agent/error` — emit
 
@@ -96,7 +96,7 @@ A step or turn errored. The machine reports a failure here (plus the logger) eve
 
 Types: [Agent](../core-data-structures/core.md) · [Scoped](../core-data-structures/scope.md)
 
-Source: [`packages/core/agent/src/types.ts:463`](../../packages/core/agent/src/types.ts)
+Source: [`packages/core/agent/src/types.ts:467`](../../packages/core/agent/src/types.ts)
 
 ### `agent/inbox/dequeue` — emit
 
@@ -117,7 +117,7 @@ The driver claimed one item out of the inbox: a queued item at a turn boundary,
 
 Types: [Agent](../core-data-structures/core.md) · [InboxItem](../core-data-structures/core.md) · [Scoped](../core-data-structures/scope.md)
 
-Source: [`packages/core/agent/src/types.ts:327`](../../packages/core/agent/src/types.ts)
+Source: [`packages/core/agent/src/types.ts:331`](../../packages/core/agent/src/types.ts)
 
 ### `agent/inbox/discard` — emit
 
@@ -140,7 +140,7 @@ Pending inbox items were dropped without delivering them, so every enqueue occur
 
 Types: [Agent](../core-data-structures/core.md) · [InboxItem](../core-data-structures/core.md) · [Scoped](../core-data-structures/scope.md)
 
-Source: [`packages/core/agent/src/types.ts:339`](../../packages/core/agent/src/types.ts)
+Source: [`packages/core/agent/src/types.ts:343`](../../packages/core/agent/src/types.ts)
 
 ### `agent/inbox/enqueue` — emit
 
@@ -161,7 +161,7 @@ An item entered the queued or steering inbox. `placement` is the acceptance-time
 
 Types: [Agent](../core-data-structures/core.md) · [InboxItem](../core-data-structures/core.md) · [Scoped](../core-data-structures/scope.md)
 
-Source: [`packages/core/agent/src/types.ts:308`](../../packages/core/agent/src/types.ts)
+Source: [`packages/core/agent/src/types.ts:312`](../../packages/core/agent/src/types.ts)
 
 ### `agent/inbox/update` — emit
 
@@ -181,7 +181,7 @@ A still-pending queued item changed content. The item id, placement, and positio
 
 Types: [Agent](../core-data-structures/core.md) · [InboxItem](../core-data-structures/core.md) · [Scoped](../core-data-structures/scope.md)
 
-Source: [`packages/core/agent/src/types.ts:317`](../../packages/core/agent/src/types.ts)
+Source: [`packages/core/agent/src/types.ts:321`](../../packages/core/agent/src/types.ts)
 
 ### `agent/prompt-submit` — waterfall
 
@@ -204,7 +204,7 @@ Allow, rewrite, or block one claimed prompt before it becomes a user message or
 
 Types: [Agent](../core-data-structures/core.md) · [PromptDecision](../core-data-structures/core.md) · [Scoped](../core-data-structures/scope.md) · [UserMessage](../core-data-structures/session.md)
 
-Source: [`packages/core/agent/src/types.ts:376`](../../packages/core/agent/src/types.ts)
+Source: [`packages/core/agent/src/types.ts:380`](../../packages/core/agent/src/types.ts)
 
 ### `agent/request` — waterfall
 
@@ -228,7 +228,7 @@ Replace the frozen call configuration. `await next()` yields the config the mach
 
 Types: [Agent](../core-data-structures/core.md) · [LlmCallConfig](../core-data-structures/core.md) · [Scoped](../core-data-structures/scope.md)
 
-Source: [`packages/core/agent/src/types.ts:402`](../../packages/core/agent/src/types.ts)
+Source: [`packages/core/agent/src/types.ts:406`](../../packages/core/agent/src/types.ts)
 
 ### `agent/request-error` — waterfall
 
@@ -258,7 +258,7 @@ Handle a model-request failure after its failed step has closed but before the f
 
 Types: [Agent](../core-data-structures/core.md) · [LlmFailure](../core-data-structures/llm-streaming.md) · [RequestError](../core-data-structures/core.md) · [RequestErrorAction](../core-data-structures/core.md) · [ResolvedRetryPolicy](../core-data-structures/llm-streaming.md) · [Scoped](../core-data-structures/scope.md)
 
-Source: [`packages/core/agent/src/types.ts:421`](../../packages/core/agent/src/types.ts)
+Source: [`packages/core/agent/src/types.ts:425`](../../packages/core/agent/src/types.ts)
 
 ### `agent/session-start` — emit
 
@@ -280,7 +280,7 @@ The session lifecycle began, once before the first turn. Use `agent.inject()` to
 
 Types: [Agent](../core-data-structures/core.md) · [Scoped](../core-data-structures/scope.md) · [SessionStartSource](../core-data-structures/core.md)
 
-Source: [`packages/core/agent/src/types.ts:362`](../../packages/core/agent/src/types.ts)
+Source: [`packages/core/agent/src/types.ts:366`](../../packages/core/agent/src/types.ts)
 
 ### `agent/settled` — emit
 
@@ -305,7 +305,7 @@ One drain chain reached its terminal turn: that turn's `turn/end` is already com
 
 Types: [Agent](../core-data-structures/core.md) · [Scoped](../core-data-structures/scope.md) · [SettleReason](../core-data-structures/core.md)
 
-Source: [`packages/core/agent/src/types.ts:450`](../../packages/core/agent/src/types.ts)
+Source: [`packages/core/agent/src/types.ts:454`](../../packages/core/agent/src/types.ts)
 
 ### `agent/status` — emit
 
@@ -325,7 +325,7 @@ Agent status changed (`idle` ⇄ `running`). `send()` does not enter `running` s
 
 Types: [Agent](../core-data-structures/core.md) · [AgentStatus](../core-data-structures/core.md) · [Scoped](../core-data-structures/scope.md)
 
-Source: [`packages/core/agent/src/types.ts:298`](../../packages/core/agent/src/types.ts)
+Source: [`packages/core/agent/src/types.ts:302`](../../packages/core/agent/src/types.ts)
 
 ### `agent/step` — serial
 
@@ -349,7 +349,7 @@ Awaited serial checkpoint before EVERY request of a turn is built (the first as
 
 Types: [Agent](../core-data-structures/core.md) · [Scoped](../core-data-structures/scope.md)
 
-Source: [`packages/core/agent/src/types.ts:389`](../../packages/core/agent/src/types.ts)
+Source: [`packages/core/agent/src/types.ts:393`](../../packages/core/agent/src/types.ts)
 
 ### `agent/turn-stopping` — serial
 
@@ -375,7 +375,7 @@ The turn is about to close: the model owes no response (no live tool calls, no f
 
 Types: [Agent](../core-data-structures/core.md) · [Scoped](../core-data-structures/scope.md)
 
-Source: [`packages/core/agent/src/types.ts:436`](../../packages/core/agent/src/types.ts)
+Source: [`packages/core/agent/src/types.ts:440`](../../packages/core/agent/src/types.ts)
 
 ## `agent-loop/*`
 

docs/core-data-structures/core.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 docs/core-data-structures/core.md
-core.md: 795256a2b30e44771baf8bcb7c1d541134692a02
-core.zh.md: 5cebff049aae53df9f0494da1fadc8dfa5d9ad09
+core.md: 1b5704384157688b45ae0900bf2d9924426bbd6b
+core.zh.md: 05802039920163ac8185703ab483c5603087ed96

docs/core-data-structures/core.md

@@ -516,11 +516,12 @@ interface InboxItem {
 type InboxAction =
   | { readonly kind: 'edit'; readonly content: ContentBlock[] }
   | { readonly kind: 'remove' }
+  | { readonly kind: 'steer' }
 ```
 
 ```ts type-equiv
 /** Result of applying an inbox action at the synchronous ownership boundary. */
-type InboxActionResult = 'applied' | 'not-found'
+type InboxActionResult = 'applied' | 'not-found' | 'steer-unavailable'
 ```
 
 ```ts type-equiv
@@ -546,7 +547,7 @@ interface SendOptions {
 }
 ```
 
-The fixed-preset aliases own `target` and `wakeup`; their already identified `UserMessage` carries role, content, and provenance. Its `MessageId` remains stable when an edit replaces the message content, while the enclosing `InboxItemId` identifies one accepted occurrence across `agent/inbox/enqueue`, `agent/inbox/update`, and its terminal dequeue or discard. Injection bypasses the FIFOs and never appears on those events.
+The fixed-preset aliases own `target` and `wakeup`; their already identified `UserMessage` carries role, content, and provenance. Its `MessageId` remains stable when an edit replaces content or strict steer transfers the immutable message. The original queued occurrence ends and strict steer accepts a new steering occurrence with a distinct `InboxItemId`. Injection bypasses the FIFOs and never appears on inbox lifecycle events.
 
 ```ts type-equiv
 /** Options for {@link Agent.cancel}. */
@@ -633,10 +634,13 @@ interface Agent {
   /**
    * Mutate one still-pending queued occurrence synchronously. Editing preserves
    * the message identity and queue position; removal publishes its terminal
-   * discard. Steering occurrences and driver-claimed items return `not-found`.
+   * discard. Steer strictly transfers the message into the current next-step
+   * window, or returns `steer-unavailable` without changing the queued
+   * occurrence. Steering occurrences and driver-claimed items return
+   * `not-found`.
    * @param id - independently addressable queued occurrence.
-   * @param action - edit or remove operation.
-   * @returns whether the pending occurrence was found and updated.
+   * @param action - edit, remove, or strict steer operation.
+   * @returns the applied outcome or the reason no mutation occurred.
    */
   updateInbox(id: InboxItemId, action: InboxAction): InboxActionResult
 

docs/core-data-structures/core.zh.md

@@ -524,11 +524,12 @@ interface InboxItem {
 type InboxAction =
   | { readonly kind: 'edit'; readonly content: ContentBlock[] }
   | { readonly kind: 'remove' }
+  | { readonly kind: 'steer' }
 ```
 
 ```ts type-equiv
 /** Result of applying an inbox action at the synchronous ownership boundary. */
-type InboxActionResult = 'applied' | 'not-found'
+type InboxActionResult = 'applied' | 'not-found' | 'steer-unavailable'
 ```
 
 ```ts type-equiv
@@ -554,7 +555,7 @@ interface SendOptions {
 }
 ```
 
-固定预设的别名方法自带 `target` 与 `wakeup`；其已有标识的 `UserMessage` 会携带角色、内容与 provenance。编辑替换消息内容时，其 `MessageId` 保持稳定；外层 `InboxItemId` 则在 `agent/inbox/enqueue`、`agent/inbox/update` 及终态 dequeue 或 discard 之间标识同一次入队。注入绕过两个 FIFO，从不出现在这些事件中。
+固定预设的别名方法自带 `target` 与 `wakeup`；其已有标识的 `UserMessage` 会携带角色、内容与 provenance。编辑替换内容或严格 steering（中途引导）转移不可变消息时，其 `MessageId` 都保持稳定。原 queued 单次入队项会结束，严格 steering 则接受一个具有不同 `InboxItemId` 的新 steering 单次入队项。注入绕过两个 FIFO，从不出现在 inbox 生命周期事件中。
 
 ```ts type-equiv
 /** Options for {@link Agent.cancel}. */
@@ -641,10 +642,13 @@ interface Agent {
   /**
    * Mutate one still-pending queued occurrence synchronously. Editing preserves
    * the message identity and queue position; removal publishes its terminal
-   * discard. Steering occurrences and driver-claimed items return `not-found`.
+   * discard. Steer strictly transfers the message into the current next-step
+   * window, or returns `steer-unavailable` without changing the queued
+   * occurrence. Steering occurrences and driver-claimed items return
+   * `not-found`.
    * @param id - independently addressable queued occurrence.
-   * @param action - edit or remove operation.
-   * @returns whether the pending occurrence was found and updated.
+   * @param action - edit, remove, or strict steer operation.
+   * @returns the applied outcome or the reason no mutation occurred.
    */
   updateInbox(id: InboxItemId, action: InboxAction): InboxActionResult
 

docs/event-producer-consumer.md

@@ -8,22 +8,22 @@ This matrix shows which packages dispatch each harness-owned event and which pac
 | Event | Mode | Declared in | Dispatchers | Listeners |
 | --- | --- | --- | --- | --- |
 | `agent-loop/config-start-failed` | `emit` | [`packages/core/agent-loop/src/index.ts:157`](../packages/core/agent-loop/src/index.ts) | [`agent-loop`](../packages/core/agent-loop) (`events.dispatch`) | [`tui`](../packages/ui/tui) |
-| `agent/cancel-requested` | `emit` | [`packages/core/agent/src/types.ts:349`](../packages/core/agent/src/types.ts) | [`agent-loop`](../packages/core/agent-loop) (`emitAgentEvent`) | [`goal-session`](../packages/goal/goal-session) |
-| `agent/created` | `emit` | [`packages/core/agent/src/types.ts:280`](../packages/core/agent/src/types.ts) | [`agent`](../packages/core/agent) (`events.dispatch`) | [`goal-session`](../packages/goal/goal-session), [`tui`](../packages/ui/tui) |
-| `agent/disposed` | `emit` | [`packages/core/agent/src/types.ts:289`](../packages/core/agent/src/types.ts) | [`agent`](../packages/core/agent) (`events.dispatch`) | [`agent-loop`](../packages/core/agent-loop), [`goal-session`](../packages/goal/goal-session), [`subagent`](../packages/subagent/subagent), [`tui`](../packages/ui/tui) |
-| `agent/error` | `emit` | [`packages/core/agent/src/types.ts:463`](../packages/core/agent/src/types.ts) | [`agent-loop`](../packages/core/agent-loop) (`emitAgentEvent`) | `apiproxy`, [`goal-session`](../packages/goal/goal-session), [`session-telemetry`](../packages/telemetry/session-telemetry), [`tui`](../packages/ui/tui) |
-| `agent/inbox/dequeue` | `emit` | [`packages/core/agent/src/types.ts:327`](../packages/core/agent/src/types.ts) | [`agent-loop`](../packages/core/agent-loop) (`emitAgentEvent`) | [`agent`](../packages/core/agent), `apiproxy`, [`subagent`](../packages/subagent/subagent), [`tui`](../packages/ui/tui) |
-| `agent/inbox/discard` | `emit` | [`packages/core/agent/src/types.ts:339`](../packages/core/agent/src/types.ts) | [`agent-loop`](../packages/core/agent-loop) (`emitAgentEvent`) | [`agent`](../packages/core/agent), `apiproxy`, [`subagent`](../packages/subagent/subagent), [`tui`](../packages/ui/tui) |
-| `agent/inbox/enqueue` | `emit` | [`packages/core/agent/src/types.ts:308`](../packages/core/agent/src/types.ts) | [`agent-loop`](../packages/core/agent-loop) (`emitAgentEvent`) | [`agent`](../packages/core/agent), `apiproxy`, [`goal-session`](../packages/goal/goal-session) |
-| `agent/inbox/update` | `emit` | [`packages/core/agent/src/types.ts:317`](../packages/core/agent/src/types.ts) | [`agent-loop`](../packages/core/agent-loop) (`emitAgentEvent`) | `apiproxy` |
-| `agent/prompt-submit` | `waterfall` | [`packages/core/agent/src/types.ts:376`](../packages/core/agent/src/types.ts) | [`agent-loop`](../packages/core/agent-loop) (`waterfall`) | [`goal-session`](../packages/goal/goal-session), [`hooks-claude`](../packages/hooks/hooks-claude), [`hooks-codex`](../packages/hooks/hooks-codex), [`repeat-tool-guard`](../packages/guard/repeat-tool-guard), [`tui`](../packages/ui/tui) |
-| `agent/request` | `waterfall` | [`packages/core/agent/src/types.ts:402`](../packages/core/agent/src/types.ts) | [`agent-loop`](../packages/core/agent-loop) (`waterfall`) | [`agent`](../packages/core/agent) |
-| `agent/request-error` | `waterfall` | [`packages/core/agent/src/types.ts:421`](../packages/core/agent/src/types.ts) | [`agent-loop`](../packages/core/agent-loop) (`waterfall`) | [`compact-basic`](../packages/compact/compact-basic), [`llm-retry`](../packages/llm/llm-retry) |
-| `agent/session-start` | `emit` | [`packages/core/agent/src/types.ts:362`](../packages/core/agent/src/types.ts) | [`agent-loop`](../packages/core/agent-loop) (`emitAgentEvent`) | [`goal`](../packages/goal/goal), [`goal-session`](../packages/goal/goal-session), [`hooks-claude`](../packages/hooks/hooks-claude), [`hooks-codex`](../packages/hooks/hooks-codex), [`workspace-context`](../packages/context/workspace-context) |
-| `agent/settled` | `emit` | [`packages/core/agent/src/types.ts:450`](../packages/core/agent/src/types.ts) | [`agent-loop`](../packages/core/agent-loop) (`emitAgentEvent`) | [`compact-basic`](../packages/compact/compact-basic) |
-| `agent/status` | `emit` | [`packages/core/agent/src/types.ts:298`](../packages/core/agent/src/types.ts) | [`agent-loop`](../packages/core/agent-loop) (`emitAgentEvent`) | [`agent`](../packages/core/agent), `apiproxy`, [`goal-session`](../packages/goal/goal-session), [`tui`](../packages/ui/tui) |
-| `agent/step` | `serial` | [`packages/core/agent/src/types.ts:389`](../packages/core/agent/src/types.ts) | [`agent-loop`](../packages/core/agent-loop) (`serial`) | [`compact-basic`](../packages/compact/compact-basic), [`plan-mode`](../packages/plan/plan-mode), [`session-checkpoint-policy`](../packages/session-persistence/session-checkpoint-policy), [`subagent-inprocess`](../packages/subagent/subagent-inprocess), [`time-context`](../packages/context/time-context), [`tmux-context`](../packages/context/tmux-context), [`tool-skill`](../packages/skill/tool-skill), [`workspace-context`](../packages/context/workspace-context) |
-| `agent/turn-stopping` | `serial` | [`packages/core/agent/src/types.ts:436`](../packages/core/agent/src/types.ts) | [`agent-loop`](../packages/core/agent-loop) (`serial`) | [`hooks-claude`](../packages/hooks/hooks-claude), [`hooks-codex`](../packages/hooks/hooks-codex) |
+| `agent/cancel-requested` | `emit` | [`packages/core/agent/src/types.ts:353`](../packages/core/agent/src/types.ts) | [`agent-loop`](../packages/core/agent-loop) (`emitAgentEvent`) | [`goal-session`](../packages/goal/goal-session) |
+| `agent/created` | `emit` | [`packages/core/agent/src/types.ts:284`](../packages/core/agent/src/types.ts) | [`agent`](../packages/core/agent) (`events.dispatch`) | [`goal-session`](../packages/goal/goal-session), [`tui`](../packages/ui/tui) |
+| `agent/disposed` | `emit` | [`packages/core/agent/src/types.ts:293`](../packages/core/agent/src/types.ts) | [`agent`](../packages/core/agent) (`events.dispatch`) | [`agent-loop`](../packages/core/agent-loop), [`goal-session`](../packages/goal/goal-session), [`subagent`](../packages/subagent/subagent), [`tui`](../packages/ui/tui) |
+| `agent/error` | `emit` | [`packages/core/agent/src/types.ts:467`](../packages/core/agent/src/types.ts) | [`agent-loop`](../packages/core/agent-loop) (`emitAgentEvent`) | `apiproxy`, [`goal-session`](../packages/goal/goal-session), [`session-telemetry`](../packages/telemetry/session-telemetry), [`tui`](../packages/ui/tui) |
+| `agent/inbox/dequeue` | `emit` | [`packages/core/agent/src/types.ts:331`](../packages/core/agent/src/types.ts) | [`agent-loop`](../packages/core/agent-loop) (`emitAgentEvent`) | [`agent`](../packages/core/agent), `apiproxy`, [`subagent`](../packages/subagent/subagent), [`tui`](../packages/ui/tui) |
+| `agent/inbox/discard` | `emit` | [`packages/core/agent/src/types.ts:343`](../packages/core/agent/src/types.ts) | [`agent-loop`](../packages/core/agent-loop) (`emitAgentEvent`) | [`agent`](../packages/core/agent), `apiproxy`, [`subagent`](../packages/subagent/subagent), [`tui`](../packages/ui/tui) |
+| `agent/inbox/enqueue` | `emit` | [`packages/core/agent/src/types.ts:312`](../packages/core/agent/src/types.ts) | [`agent-loop`](../packages/core/agent-loop) (`emitAgentEvent`) | [`agent`](../packages/core/agent), `apiproxy`, [`goal-session`](../packages/goal/goal-session) |
+| `agent/inbox/update` | `emit` | [`packages/core/agent/src/types.ts:321`](../packages/core/agent/src/types.ts) | [`agent-loop`](../packages/core/agent-loop) (`emitAgentEvent`) | `apiproxy` |
+| `agent/prompt-submit` | `waterfall` | [`packages/core/agent/src/types.ts:380`](../packages/core/agent/src/types.ts) | [`agent-loop`](../packages/core/agent-loop) (`waterfall`) | [`goal-session`](../packages/goal/goal-session), [`hooks-claude`](../packages/hooks/hooks-claude), [`hooks-codex`](../packages/hooks/hooks-codex), [`repeat-tool-guard`](../packages/guard/repeat-tool-guard), [`tui`](../packages/ui/tui) |
+| `agent/request` | `waterfall` | [`packages/core/agent/src/types.ts:406`](../packages/core/agent/src/types.ts) | [`agent-loop`](../packages/core/agent-loop) (`waterfall`) | [`agent`](../packages/core/agent) |
+| `agent/request-error` | `waterfall` | [`packages/core/agent/src/types.ts:425`](../packages/core/agent/src/types.ts) | [`agent-loop`](../packages/core/agent-loop) (`waterfall`) | [`compact-basic`](../packages/compact/compact-basic), [`llm-retry`](../packages/llm/llm-retry) |
+| `agent/session-start` | `emit` | [`packages/core/agent/src/types.ts:366`](../packages/core/agent/src/types.ts) | [`agent-loop`](../packages/core/agent-loop) (`emitAgentEvent`) | [`goal`](../packages/goal/goal), [`goal-session`](../packages/goal/goal-session), [`hooks-claude`](../packages/hooks/hooks-claude), [`hooks-codex`](../packages/hooks/hooks-codex), [`workspace-context`](../packages/context/workspace-context) |
+| `agent/settled` | `emit` | [`packages/core/agent/src/types.ts:454`](../packages/core/agent/src/types.ts) | [`agent-loop`](../packages/core/agent-loop) (`emitAgentEvent`) | [`compact-basic`](../packages/compact/compact-basic) |
+| `agent/status` | `emit` | [`packages/core/agent/src/types.ts:302`](../packages/core/agent/src/types.ts) | [`agent-loop`](../packages/core/agent-loop) (`emitAgentEvent`) | [`agent`](../packages/core/agent), `apiproxy`, [`goal-session`](../packages/goal/goal-session), [`tui`](../packages/ui/tui) |
+| `agent/step` | `serial` | [`packages/core/agent/src/types.ts:393`](../packages/core/agent/src/types.ts) | [`agent-loop`](../packages/core/agent-loop) (`serial`) | [`compact-basic`](../packages/compact/compact-basic), [`plan-mode`](../packages/plan/plan-mode), [`session-checkpoint-policy`](../packages/session-persistence/session-checkpoint-policy), [`subagent-inprocess`](../packages/subagent/subagent-inprocess), [`time-context`](../packages/context/time-context), [`tmux-context`](../packages/context/tmux-context), [`tool-skill`](../packages/skill/tool-skill), [`workspace-context`](../packages/context/workspace-context) |
+| `agent/turn-stopping` | `serial` | [`packages/core/agent/src/types.ts:440`](../packages/core/agent/src/types.ts) | [`agent-loop`](../packages/core/agent-loop) (`serial`) | [`hooks-claude`](../packages/hooks/hooks-claude), [`hooks-codex`](../packages/hooks/hooks-codex) |
 | `approval/request` | `waterfall` | [`packages/ui/user-approval/src/index.ts:30`](../packages/ui/user-approval/src/index.ts) | [`user-approval`](../packages/ui/user-approval) (`waterfall`) | [`acp`](../packages/acp/acp), `apiproxy` |
 | `commands/change` | `emit` | [`packages/ui/commands/src/index.ts:154`](../packages/ui/commands/src/index.ts) | [`commands`](../packages/ui/commands) (`events.dispatch`) | `apiproxy`, [`tui`](../packages/ui/tui) |
 | `credentials/updated` | `emit` | [`packages/credentials/credentials/src/index.ts:67`](../packages/credentials/credentials/src/index.ts) | [`credentials`](../packages/credentials/credentials) (`events.dispatch`) | `apiproxy`, [`credentials`](../packages/credentials/credentials) |

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: f956be22384a42e9ed30e8aa5f25fe8173cc9f9c
-README.zh.md: 49449c51d89d957b5bd39798c9167607f72a5c3a
+README.md: eca7db1f9b2d5c7e28fa86a363ca4408703b99df
+README.zh.md: 6a2e8c6085d06a9f04c1270e5976452b995a7e77

packages/client/runtime/README.md

@@ -22,7 +22,7 @@ SlotsService gives the renderer separate bare observables for `useSessions` and
 
 ## Pending queue projection
 
-`ConversationSnapshot.queue` is the Host's authoritative transient Queue snapshot; pending steering stays outside this projection. Each row carries its `InboxItemId`, complete editable text when every content block is text, and a flattened preview. `session/queue` replaces the whole projection; reconnect buffering retains only the latest snapshot, and neither durable turn events nor running-status changes guess that an item was claimed. `Session.updateQueue()` sends edit/remove operations without optimistic mutation, so the next Host snapshot is the sole visible commit and a claim race can surface `queue-item-not-found`.
+`ConversationSnapshot.queue` is the Host's authoritative transient inbox snapshot and carries both queued and pending-steering occurrences with their resolved placement. Each row carries its `InboxItemId`, stable `MessageId`, complete editable text when every content block is text, and a flattened preview. `session/queue` replaces the whole projection, while an accepted live `steering/message` event retires only the first matching current steering occurrence so the durable node can take over before the following Host snapshot; history replay never consumes a later occurrence that reused the same `MessageId`. Reconnect buffering retains only the latest snapshot, and neither ordinary durable turn events nor running-status changes guess that an item was claimed. `Session.updateQueue()` sends edit, remove, and strict-steer operations without optimistic mutation; claim and closed-window races surface `queue-item-not-found` and `steer-unavailable`.
 
 ## The human transcript
 

packages/client/runtime/README.zh.md

@@ -22,7 +22,7 @@ SlotsService 分别为 renderer 提供 `useSessions` 与 `useWorkspaces` 的裸
 
 ## 待处理队列投影
 
-`ConversationSnapshot.queue` 是 Host 提供的权威瞬态 Queue 快照；待处理 steering（中途引导）不进入此投影。每行都携带其 `InboxItemId`、所有内容块均为文本时的完整可编辑文本，以及扁平化预览。`session/queue` 会整体替换该投影；重连缓冲只保留最新快照，持久轮次事件和 running 状态变化都不会猜测某个项已被认领。`Session.updateQueue()` 发送编辑／移除操作，不进行乐观更新，因此下一份 Host 快照是唯一可见的提交结果，认领竞态则会返回 `queue-item-not-found`。
+`ConversationSnapshot.queue` 是 Host 提供的权威瞬态 inbox 快照，携带 queued 与待处理 steering（中途引导）单次入队项及其已解析 placement。每行都携带其 `InboxItemId`、稳定的 `MessageId`、所有内容块均为文本时的完整可编辑文本，以及扁平化预览。`session/queue` 会整体替换该投影；已接纳的实时 `steering/message` 事件则只退役第一个匹配的当前 steering 单次入队项，让持久节点能在下一份 Host 快照之前接管，而历史回放绝不会消费后来复用同一 `MessageId` 的单次入队项。重连缓冲只保留最新快照，普通持久轮次事件和 running 状态变化都不会猜测某个项已被认领。`Session.updateQueue()` 发送编辑、移除和严格 steering 操作，不进行乐观更新；认领与窗口关闭竞态分别会返回 `queue-item-not-found` 和 `steer-unavailable`。
 
 ## 面向人的 transcript（文本记录）
 

packages/client/runtime/src/client/contract/session.ts

@@ -39,9 +39,9 @@ export interface ISession {
    */
   prompt(content: ContentBlock[], mode: 'queue' | 'steer'): Promise<RpcResult<{ accepted: true }>>
   /**
-   * Apply one mutation to a still-pending queue occurrence.
+   * Apply one edit, remove, or strict steer action to a still-pending queue occurrence.
    * @param itemId - agent-owned inbox occurrence identity.
-   * @param action - edit or remove operation.
+   * @param action - requested queue operation.
    * @returns acceptance, or a business/transport error.
    */
   updateQueue(itemId: InboxItemId, action: QueueAction): Promise<RpcResult<{ accepted: true }>>

packages/client/runtime/src/client/session-history/history-fold.ts

@@ -146,7 +146,8 @@ function materializeNode(
       }
     case 'steering/message':
       return {
-        kind: 'steering', seq: event.seq, time: event.time, turn: event.data.turn,
+        kind: 'steering', messageId: event.data.message.id,
+        seq: event.seq, time: event.time, turn: event.data.turn,
         content: event.data.message.content, source: event.data.message.source,
       }
     case 'tool/result': {

packages/client/runtime/src/client/sessions/conversation.ts

@@ -4,6 +4,7 @@
 // string here (narrow to real brands when convenient).
 
 import type { CommandId } from '@deepseek-ai/dsh-commands/brand'
+import type { MessageId } from '@deepseek-ai/dsh-llm/brand'
 import type { ContentBlock } from '@deepseek-ai/dsh-llm/types'
 import type { LlmRetryEventData } from '@deepseek-ai/dsh-llm-retry/types'
 import type { TodoItem } from '@deepseek-ai/dsh-session/types'
@@ -104,6 +105,8 @@ export interface AssistantMessageNode {
 /** A steering message injected mid-turn. */
 export interface SteeringMessageNode {
   kind: 'steering'
+  /** Stable identity shared with its pre-admission inbox occurrence. */
+  messageId: MessageId
   seq: number
   /** Unix epoch ms from the source session event. */
   time: number
@@ -271,9 +274,15 @@ export interface RunningToolCall {
 }
 
 
-/** One independently addressable row from the transient queue snapshot. */
+/** One transient inbox occurrence from the authoritative `session/queue` snapshot. */
 export interface QueuedMessage {
   readonly id: InboxItemId
+  /** Stable message identity used for transient-to-durable steering handoff. */
+  readonly messageId: MessageId
+  /** Agent-resolved placement; only queued rows accept queue mutations. */
+  readonly placement: 'queued' | 'steering'
+  /** Complete content used to render pending steering before it becomes durable. */
+  readonly content: readonly ContentBlock[]
   readonly preview: string
   /** Complete editable text; null when the message contains non-text blocks. */
   readonly text: string | null
@@ -332,7 +341,7 @@ export interface ConversationSnapshot {
    */
   codeDispatches: ReadonlyMap<string, readonly CodeSubCall[]>
   pending: readonly PendingInteraction[]
-  /** Authoritative transient inbox snapshot, replaced after every host-side change. */
+  /** Authoritative transient inbox snapshot, including queued and steering placements. */
   queue: readonly QueuedMessage[]
   running: boolean
   /**

packages/client/runtime/src/client/sessions/session.ts

@@ -446,6 +446,9 @@ export class Session implements SessionFace {
       case 'session/queue': {
         this.queued = frame.items.map(item => ({
           id: item.id,
+          messageId: item.message.id,
+          placement: item.placement,
+          content: item.message.content,
           preview: queuePreviewOf(item.message.content),
           text: queueTextOf(item.message.content),
         }))
@@ -647,9 +650,20 @@ export class Session implements SessionFace {
     this.events.push(event)
     this.views.push(view)
     this.transcript.append(event, view)
+    this.handoffPendingSteering(event)
     this.applyEventSideEffects(event, view)
   }
 
+  /** Retire the first matching live steering occurrence when its durable event takes over. */
+  private handoffPendingSteering(event: SessionEvent): void {
+    if (event.type !== 'steering/message') return
+    const index = this.queued.findIndex(item =>
+      item.placement === 'steering' && item.messageId === event.data.message.id)
+    if (index === -1) return
+    this.queued = this.queued.filter((_item, candidate) => candidate !== index)
+    this.queueRev++
+  }
+
   /** Land a live session/event (open/repair in flight -> buffer; overlapping seq -> drop;
    *  a seq gap -> buffer + tail-page repull instead of appending a hole (audit S3: a gap is an
    *  expected reconnect-window artifact, repaired by refetch). The window stays one contiguous

packages/client/runtime/src/client/sessions/transcript-adapter.ts

@@ -74,7 +74,8 @@ function materializeNode(
       }
     case 'steering/message':
       return {
-        kind: 'steering', seq: event.seq, time: event.time, turn: event.data.turn,
+        kind: 'steering', messageId: event.data.message.id,
+        seq: event.seq, time: event.time, turn: event.data.turn,
         content: event.data.message.content, source: event.data.message.source,
       }
     case 'tool/result': {

packages/client/runtime/tests/queue-store.spec.ts

@@ -5,7 +5,8 @@
  */
 import { describe, expect, it } from 'vitest'
 import { createUserMessage } from '@deepseek-ai/dsh-llm'
-import type { ContentBlock } from '@deepseek-ai/dsh-llm/types'
+import type { ContentBlock, UserMessage } from '@deepseek-ai/dsh-llm/types'
+import type { SessionEvent } from '@deepseek-ai/dsh-session/types'
 import type {
   InboxItemId, MuxFrame, RpcId, SessionId,
 } from '@deepseek-ai/dsh-client-connection/client'
@@ -22,6 +23,8 @@ interface QueueFixture {
   id: string
   body: string
   content?: ContentBlock[]
+  placement?: 'queued' | 'steering'
+  message?: UserMessage
 }
 
 /** Build one authoritative queue snapshot. */
@@ -31,7 +34,8 @@ function queueFrame(items: QueueFixture[]): MuxFrame {
     sessionId: SID,
     items: items.map(item => ({
       id: iid(item.id),
-      message: createUserMessage({
+      placement: item.placement ?? 'queued',
+      message: item.message ?? createUserMessage({
         content: item.content ?? text(item.body),
         source: { kind: 'user', rpcId: rid(`rpc-${item.id}`) } as never,
       }),
@@ -49,8 +53,14 @@ describe('queue snapshot intake', () => {
     session.handleMuxEnvelope(rid('env-1'), queueFrame([
       { id: 'q-1', body: '第一条  排队\n消息' },
     ]))
-    expect(session.getSnapshot().queue).toEqual([
-      { id: 'q-1', preview: '第一条 排队 消息', text: '第一条  排队\n消息' },
+    const queue = session.getSnapshot().queue
+    expect(typeof queue[0]?.messageId).toBe('string')
+    expect(queue).toMatchObject([
+      {
+        id: 'q-1', placement: 'queued',
+        content: [{ type: 'text', text: '第一条  排队\n消息' }],
+        preview: '第一条 排队 消息', text: '第一条  排队\n消息',
+      },
     ])
   })
 
@@ -61,8 +71,14 @@ describe('queue snapshot intake', () => {
       body: '',
       content: [{ type: 'text', text: 'hi' }, { type: 'image', data: 'x' } as never],
     }]))
-    expect(session.getSnapshot().queue).toEqual([
-      { id: 'q-image', preview: 'hi [image]', text: null },
+    const queue = session.getSnapshot().queue
+    expect(typeof queue[0]?.messageId).toBe('string')
+    expect(queue).toMatchObject([
+      {
+        id: 'q-image', placement: 'queued',
+        content: [{ type: 'text', text: 'hi' }, { type: 'image', data: 'x' }],
+        preview: 'hi [image]', text: null,
+      },
     ])
   })
 
@@ -85,8 +101,14 @@ describe('queue snapshot intake', () => {
     session.handleMuxEnvelope(rid('env-5'), queueFrame([
       { id: 'q-2', body: 'two edited' },
     ]))
-    expect(session.getSnapshot().queue).toEqual([
-      { id: 'q-2', preview: 'two edited', text: 'two edited' },
+    const queue = session.getSnapshot().queue
+    expect(typeof queue[0]?.messageId).toBe('string')
+    expect(queue).toMatchObject([
+      {
+        id: 'q-2', placement: 'queued',
+        content: [{ type: 'text', text: 'two edited' }],
+        preview: 'two edited', text: 'two edited',
+      },
     ])
     session.handleMuxEnvelope(rid('env-6'), queueFrame([]))
     expect(session.getSnapshot().queue).toEqual([])
@@ -99,6 +121,55 @@ describe('queue snapshot intake', () => {
     session.handleAgentError('unrelated')
     expect(session.getSnapshot().queue).toBe(before)
   })
+
+  it('retains steering placement and complete content in the same authoritative snapshot', () => {
+    const session = makeSession()
+    session.handleMuxEnvelope(rid('env-steering'), queueFrame([
+      { id: 'q-next', body: 'later' },
+      { id: 's-now', body: 'interrupt now', placement: 'steering' },
+    ]))
+
+    expect(session.getSnapshot().queue.map(item => ({
+      id: item.id, placement: item.placement, content: item.content,
+    }))).toEqual([
+      { id: 'q-next', placement: 'queued', content: text('later') },
+      { id: 's-now', placement: 'steering', content: text('interrupt now') },
+    ])
+  })
+
+  it('hands off exactly one current occurrence when live steering becomes durable', async () => {
+    const session = makeSession()
+    await session.open()
+    const message = createUserMessage({
+      content: text('same message'),
+      source: { kind: 'user' },
+    })
+    session.handleMuxEnvelope(rid('env-same-id'), queueFrame([
+      { id: 's-first', body: '', placement: 'steering', message },
+      { id: 's-second', body: '', placement: 'steering', message },
+    ]))
+    const durable = {
+      seq: 0,
+      time: 1_700_000_000_000,
+      type: 'steering/message',
+      surfaceOp: 'append',
+      data: { turn: 1, message },
+    } as SessionEvent
+
+    session.handleMuxEnvelope(rid('env-durable'), {
+      type: 'session/event', sessionId: SID, event: durable,
+    })
+    expect(session.getSnapshot().queue.map(item => item.id)).toEqual(['s-second'])
+    expect(session.getSnapshot().nodes.filter(node => node.kind === 'steering')).toHaveLength(1)
+
+    session.handleMuxEnvelope(rid('env-reused-id'), queueFrame([
+      { id: 's-later', body: '', placement: 'steering', message },
+    ]))
+    session.handleMuxEnvelope(rid('env-replayed-durable'), {
+      type: 'session/event', sessionId: SID, event: durable,
+    })
+    expect(session.getSnapshot().queue.map(item => item.id)).toEqual(['s-later'])
+  })
 })
 
 describe('queue operation transport', () => {
@@ -110,11 +181,20 @@ describe('queue operation transport', () => {
 
     await expect(session.updateQueue(iid('q-op'), { kind: 'edit', content: text('next') }))
       .resolves.toEqual({ ok: true, value: { accepted: true } })
-    expect(api.callsOf('session.updateQueue')).toEqual([{
-      sessionId: SID,
-      itemId: 'q-op',
-      action: { kind: 'edit', content: text('next') },
-    }])
+    await expect(session.updateQueue(iid('q-op'), { kind: 'steer' }))
+      .resolves.toEqual({ ok: true, value: { accepted: true } })
+    expect(api.callsOf('session.updateQueue')).toEqual([
+      {
+        sessionId: SID,
+        itemId: 'q-op',
+        action: { kind: 'edit', content: text('next') },
+      },
+      {
+        sessionId: SID,
+        itemId: 'q-op',
+        action: { kind: 'steer' },
+      },
+    ])
     expect(session.getSnapshot().queue).toBe(before)
   })
 })

packages/client/ui-conversation/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-conversation/README.md
-README.md: d92202e6dc2b1003db0cdf97910746a0de133357
-README.zh.md: a75ee75a5fb2b3d8e5278283b6b6da15bf9c02cd
+README.md: ea48725b02ad0c440984af4aadfec17d0e63791d
+README.zh.md: 654901caca68762e313dda456c1e0df23faf734a

packages/client/ui-conversation/README.md

@@ -34,7 +34,11 @@ Tool rows are slots too — the standalone tool ring (`ToolViewRegistry`/`ctx.to
 
 The todo surfaces are two registrations over that shape, both plain registrant plugins with `inject: ['slots', 'conversation']`. `TodoRow` takes the `'conversation.chat.toolview'` key `todo_write` and summarizes what the call attempted (`<done>/<total> 已完成 · <active item>` parsed from its args, falling back to the generic summary on malformed or wrongly-shaped model JSON, and keeping the generic dot for non-ok execution states so a cancelled call never reads as a completed update). `TodoDock` takes the `'conversation.input.dock'` list slot at `order: 0` — before Goal and Queue — and is the plan strip: it reads the host-computed `todos` projection via `useProjection` (standing plan: latest `todo/write` with no later `turn/start`) and renders `TodoPanel`, which takes the plain list, hides itself while the list is empty, and starts collapsed as a header of title plus `"<done>/<total> tasks · <n> in progress"` (status glyphs are the figma check / progress / dashed-pending set). The dock adapter owns the selection so the panel stays a pure function of its props; the standing list lives here rather than in the row so the row stays one line. Anything the input-zone composer chain hides (a `conversation.composer` takeover such as ui-question's) hides the whole dock, this strip included.
 
-`QueueDock` is the terminal input-dock entry at `order: 20`. It hides while empty, renders one pending row directly, and defaults two or more rows to a collapsed `"<n> 条排队消息"` header whose button expands or collapses the complete list. The header exposes `aria-expanded` and `aria-controls`; the expanded list scrolls within a 180px height bound. An active edit or mutation keeps its rows visible, and emptying the queue restores the collapsed default for the next queue. Each visible row remains a single-line preview with its exact-occurrence edit and delete actions.
+`QueueDock` is the terminal input-dock entry at `order: 20`. It hides while empty, renders one pending row directly, and defaults two or more rows to a collapsed `"<n> 条排队消息"` header whose button expands or collapses the complete list. The header exposes `aria-expanded` and `aria-controls`; the expanded list scrolls within a 180px height bound. An active edit or mutation keeps its rows visible, and emptying the queue restores the collapsed default for the next queue. Each visible ordinary-session row remains a single-line preview with its exact-occurrence edit, delete, and strict-steer actions; addressed subagents retain the rows as a read-only projection because their continuation transport does not expose queue mutation. If strict steer loses to a closed window, the original occurrence remains queued for normal delivery; if the driver already claimed it, normal delivery is already underway. Neither converged race displays a failure, while transport and unknown failures do.
+
+The Host's placement-aware `session/queue` snapshot also carries pending steering. QueueDock filters it out, while ChatView projects it as a user-style bubble with Copy at the conversation tail; Fork stays absent because the message has not entered a durable turn. The Host delays steering retirement until the durable `steering/message` has entered the mux stream. On that accepted live event, the client runtime retires the first matching current steering occurrence before publishing the snapshot; historical events cannot hide later occurrences that reuse the same `MessageId`. The bubble therefore hands off without a gap or duplicate, restores Copy and Fork from the durable node, and survives reconnect from the same authority.
+
+Keyboard message submission resolves delivery from the addressed session's running state and steering capability. While idle, Enter and Cmd/Ctrl+Enter both perform an ordinary Queue send. While a primary session is running, the browser-persisted General Settings preference assigns plain Enter to `Queue` (the default) or `Steer`, and Cmd/Ctrl+Enter performs the other behavior; Shift+Enter remains a newline. Addressed subagents keep both gestures on their Queue-only continuation transport even while running. The preference affects only the steer-capable busy-state gesture pair, and the send button and non-keyboard submit actions remain Queue. Composer Steer uses the existing best-effort `session.prompt(mode: 'steer')` contract: if the current next-step window closes before acceptance, AgentLoop admits the message as the next waking Queue turn without surfacing a failure or losing the draft transaction.
 
 Per-session UI state for selection and the active view lives in the declared chat store (`stores.ts` `createChatStore`); the InputHub owns the composer state machine and mirrors its draft into that store for persistence. Apply passes one store handle to the strict session subtree, chat view, and details registrations, so each session shares one instance and the framework owns its lifecycle. Components are pure: the framework standard kit supplies `useSession`/`sessionId`, global `useSessions`/`useWorkspaces`, and the input machine's `useInput`/`inputActions`; store faces and inject factories supply the remaining state and callbacks.
 
@@ -62,5 +66,5 @@ None; this package neither assembles nor sends a provider request.
 - **The sparkle icon for the others tool row is a hand-drawn approximation** — the design glyph's vector geometry is not exportable locally; promotion into ui-primitives waits on an exact export.
 - **The approval panel's "Always allow this type" is deferred** — durable grants need a grant-storage design; only allow-once/reject answer today.
 - **TodoPanel truncates long item text to one ellipsized line** — the figma strip has no wrap or expand affordance; full text is not readable inline.
-- **Queue edit is text-only** — rows containing non-text blocks still show a flattened preview, but their edit control is disabled because the inline editor cannot preserve those blocks. A text row's edit mode replaces delete with save and cancel; Enter saves and Escape cancels. QueueDock exposes no send-now control.
-- **Web exposes pending Queue only** — the composer and `conversation.send` never submit `mode:'steer'`. The Host omits pending steering from the Queue snapshot. A consumed `steering/message` still folds into the durable transcript as a plain bubble (no interjection chrome) so external/host steering remains truthful on replay.
+- **Queue edit is text-only** — rows containing non-text blocks still show a flattened preview, but their edit control is disabled because the inline editor cannot preserve those blocks. A text row's edit mode replaces delete and strict steer with save and cancel; Enter saves and Escape cancels.
+- **Queue strict steer preserves complete messages** — while the Agent is running, the steer action atomically transfers the addressed Queue occurrence into the current next-step window. Mixed-content rows remain eligible because the action forwards the immutable message instead of the text projection. The placement-aware Host snapshot renders pending steering at the conversation tail until the consumed `steering/message` folds into the durable transcript, so immediate display, reconnect, and replay share one linear authority.

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

@@ -34,7 +34,11 @@
 
 todo 两个面就是在该形状上的两个注册项，都是普通注册方插件，`inject: ['slots', 'conversation']`。`TodoRow` 占用 `'conversation.chat.toolview'` 的 `todo_write` key，摘要该次调用「试图写入」的内容（从其 args 解析出 `<已完成>/<总数> 已完成 · <进行中条目>`；模型 JSON 残缺或形状不对时回落到通用摘要；非 ok 执行状态保留通用状态点，使被取消的调用绝不读成一次已完成的更新）。`TodoDock` 以 `order: 0` 占用 `'conversation.input.dock'` 列表 slot（位于 Goal 与 Queue 之前），是计划条：它经 `useProjection` 读取 host 计算的 `todos` 投影（站立计划：其后没有更晚 `turn/start` 的最近一次 `todo/write`）并渲染 `TodoPanel`，后者接收纯列表，在列表为空时自我隐藏；列表非空时面板初始折叠，表头显示标题加 `"<已完成>/<总数> tasks · <n> in progress"`（状态图标为 figma 的勾选／进行中／虚线未开始一组）。选取由 dock 适配器负责，因此面板保持为其 props 的纯函数；站立列表放在此处而非行内，行才能保持单行。输入区 composer 链隐藏的一切（例如 ui-question 对 `conversation.composer` 的接管）也会隐藏整个 dock，包括这条计划条。
 
-`QueueDock` 是 `order: 20` 的末端 input-dock 条目。队列为空时隐藏；只有一个待处理项时直接渲染该行；存在两个或更多待处理项时，默认收起为 `"<n> 条排队消息"` 表头，其按钮可展开或收起完整列表。表头暴露 `aria-expanded` 和 `aria-controls`；展开后的列表以 180px 为高度上限，并可滚动。存在进行中的编辑或变更时，列表行会保持可见；队列清空后，下一次出现队列时会恢复默认收起状态。每条可见行仍是单行预览，并提供针对精确单次入队项的编辑和删除操作。
+`QueueDock` 是 `order: 20` 的末端 input-dock 条目。队列为空时隐藏；只有一个待处理项时直接渲染该行；存在两个或更多待处理项时，默认收起为 `"<n> 条排队消息"` 表头，其按钮可展开或收起完整列表。表头暴露 `aria-expanded` 和 `aria-controls`；展开后的列表以 180px 为高度上限，并可滚动。存在进行中的编辑或变更时，列表行会保持可见；队列清空后，下一次出现队列时会恢复默认收起状态。普通会话中的每条可见行仍是单行预览，并提供针对精确单次入队项的编辑、删除和严格 steering（中途引导）操作；已寻址 subagent 则保留只读行，因为其继续执行传输不提供 Queue 变更。如果严格 steering 输给已关闭的窗口，原单次入队项会留在 Queue 中正常投递；如果驱动器已经认领该项，正常投递就已开始。这两种已收敛的竞态都不显示失败，传输和未知错误仍会显示。
+
+Host 带 placement 的 `session/queue` 快照也会携带待处理 steering。QueueDock 会将其过滤掉，ChatView 则把它投影为会话流末尾带复制操作的用户样式气泡；消息尚未进入持久轮次，因此不显示 fork。Host 会等持久 `steering/message` 进入 mux 流之后再退役 steering。客户端运行时接纳该实时事件时，会在发布快照前退役第一个匹配的当前 steering 单次入队项；历史事件无法隐藏后来复用同一 `MessageId` 的单次入队项。气泡交接时因而不会产生空档或重复，会从持久节点恢复复制与 fork 操作，并能在重连后从同一权威恢复。
+
+键盘消息提交会根据所寻址会话的运行状态和 steering 能力解析投递方式。空闲时，Enter 和 Cmd/Ctrl+Enter 都执行普通 Queue 发送。主会话运行期间，浏览器持久化的 General Settings 偏好会把普通 Enter 分配为 `Queue`（默认值）或 `Steer`，Cmd/Ctrl+Enter 则执行另一种行为；Shift+Enter 仍然换行。已寻址 subagent 即使正在运行，也会让这两个手势都使用其仅支持 Queue 的继续执行传输。该偏好只影响支持 steering 的繁忙态手势对，发送按钮与非键盘提交操作仍使用 Queue。Composer Steer 复用现有尽力而为的 `session.prompt(mode: 'steer')` 契约：如果当前 next-step 窗口在接纳前关闭，AgentLoop 会把消息接纳为下一条唤醒 Queue 轮次，不显示失败，也不会丢失草稿事务。
 
 逐 Session UI 状态中的选择与活跃视图位于已声明的聊天 store（`stores.ts` `createChatStore`）中；InputHub 拥有输入区状态机，并将草稿镜像到该 store 以便持久化。apply 将同一个 store handle 传给严格限定于会话的子树、聊天视图和详情注册，因此每个会话内共享一个实例，框架拥有其生命周期。组件保持纯粹：框架标准工具包提供 `useSession`／`sessionId`、全局 `useSessions`／`useWorkspaces`，以及输入状态机的 `useInput`／`inputActions`；store 表层与 inject factory 提供其余状态和回调。
 
@@ -62,5 +66,5 @@ todo 两个面就是在该形状上的两个注册项，都是普通注册方插
 - **others 工具行的闪光图标是手绘近似版本**：无法在本地导出设计字形的矢量几何；等到存在精确导出后再将其提升到 ui-primitives。
 - **审批面板的「始终允许此类」暂缓**：持久授权需要授权存储设计；今天只能回答允许一次／拒绝。
 - **TodoPanel 将过长条目截成单行省略号**：figma 条没有换行或展开入口，完整文本无法在行内读完。
-- **Queue 编辑仅支持文本**：包含非文本块的行仍显示扁平化预览，但由于内联编辑器无法保留这些块，其编辑控件会被禁用。文本行进入编辑模式后，删除会替换为保存和取消；Enter 保存，Escape 取消。QueueDock 不提供立即发送控件。
-- **Web 仅暴露待处理 Queue**：composer 与 `conversation.send` 从不提交 `mode:'steer'`。Host 不会把待处理 steering（中途引导）纳入 Queue 快照。已消费的 `steering/message` 仍会折叠进持久 transcript（文本记录），并以无「插话」徽章的普通气泡呈现，因此从外部／Host 提交的 steering 在回放时仍能如实呈现。
+- **Queue 编辑仅支持文本**：包含非文本块的行仍显示扁平化预览，但由于内联编辑器无法保留这些块，其编辑控件会被禁用。文本行进入编辑模式后，删除和严格 steering（中途引导）操作会被保存和取消取代；Enter 保存，Escape 取消。
+- **Queue 严格 steering 会保留完整消息**：Agent 运行期间，steering 操作会以原子方式把所寻址的 Queue 单次入队项转移到当前 next-step 窗口。包含混合内容的行仍可使用此操作，因为它会转发不可变消息，而非文本投影。带 placement 的 Host 快照会在会话流末尾渲染待处理 steering，直到已消费的 `steering/message` 折叠进持久 transcript（文本记录），因此立即展示、重连和回放共享同一个线性权威。

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
@@ -203,6 +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,
@@ -213,6 +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) => {

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}>

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>
   )

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} />

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'

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

@@ -7,6 +7,7 @@ import type { CommandNode, ConversationSnapshot, ObservableSnapshot, PendingInte
 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' {
@@ -285,6 +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. */

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

@@ -11,6 +11,7 @@ import type {
   ReferenceInsert, SubmitOutcome, TokenSpan,
 } from '@deepseek-ai/dsh-client-ui-slash/client'
 import type { QueueRow } from '../contract/queue.ts'
+import type { InputSubmitMode } from '../contract/composer-submission.ts'
 
 /**
  * The scoped-event application verbs: the hub's bail listeners call these,
@@ -28,8 +29,11 @@ export interface InputTarget {
 export interface SessionInput extends InputTarget {
   /** Single write path for draft text (all mutation rides machine events). */
   setDraft(text: string): void
-  /** THE complexity sink: enter adjudication, submit transaction, and the default sink live inside. */
-  submit(): void
+  /**
+   * THE complexity sink: enter adjudication, submit transaction, and the default sink live inside.
+   * @param mode - delivery intent retained through asynchronous adjudication and serialization.
+   */
+  submit(mode?: InputSubmitMode): void
   /**
    * Surface a notice outside the machine's own effect stream: detached
    * command results and business notifications render through here.
@@ -82,8 +86,8 @@ export interface ComposerKeyboard {
   readonly snapshot: InputState
   /** Draft write with the DOM-observed edit shape (narrows occurrence math). */
   setDraft(text: string, editRange?: EditRange): void
-  /** Newline at the selection as a machine transaction (Ctrl+Enter path). */
-  newline(selection: EditSelection): void
+  /** Submit with an explicit delivery mode resolved by the keyboard policy. */
+  submit(mode: InputSubmitMode): void
   undo(): void
   redo(): void
   /** Paste over the selection (sync components ride the same transaction). */
@@ -191,7 +195,7 @@ export interface InputState {
   readonly occurrences: readonly Occurrence[]
   /** Live paste-match attempt (absent when no paste is matchable). */
   readonly paste?: PasteAttemptState
-  /** Read-only queue projection (session/queued frames + connect snapshot). */
+  /** Read-only transient inbox projection (`session/queue`, including pending steering). */
   readonly queue: readonly QueuedMessage[]
 }
 
@@ -206,6 +210,8 @@ export interface SubmitAttempt {
   readonly signal: AbortSignal
   /** Draft at enter time; rollback restores it only while the live draft still equals it. */
   readonly draftSnapshot: string
+  /** Default-message delivery intent retained while slash adjudication is pending. */
+  readonly mode: InputSubmitMode
 }
 
 /**
@@ -217,8 +223,6 @@ export interface SubmitAttempt {
 export type InputEvent =
   /** Full next draft from the textarea; editRange narrows the occurrence math (absent → diff scan). */
   | { readonly type: 'draft-changed'; readonly draft: string; readonly editRange?: EditRange }
-  /** Insert '\n' replacing the selection (F1: the execCommand newline path moved into the machine). */
-  | { readonly type: 'newline'; readonly selection: EditSelection }
   | { readonly type: 'begin-command'; readonly claim: CommandClaim; readonly span: TokenSpan }
   /** Place one U+FFFC at the span and mint the occurrence (scoped insert-reference event payload). */
   | { readonly type: 'insert-ref'; readonly reference: ReferenceInsert; readonly span: TokenSpan }
@@ -239,7 +243,7 @@ export type InputEvent =
   | { readonly type: 'paste-upgrade'; readonly attemptId: number; readonly span: TokenSpan; readonly reference: ReferenceInsert }
   /** Shell-observed attempt killers the machine cannot see itself (caret/selection ops, Slash interaction updates). */
   | { readonly type: 'invalidate-paste' }
-  | { readonly type: 'enter' }
+  | { readonly type: 'enter'; readonly mode: InputSubmitMode }
   | { readonly type: 'adjudicated'; readonly attempt: SubmitAttempt; readonly outcome: PickOutcome }
   | { readonly type: 'adjudication-failed'; readonly attempt: SubmitAttempt; readonly message: string }
   | { readonly type: 'submit-settled'; readonly attempt: SubmitAttempt; readonly ok: boolean; readonly outcome?: SubmitOutcome; readonly message?: string }
@@ -258,5 +262,5 @@ export type InputEvent =
 export type InputEffect =
   | { readonly type: 'adjudicate'; readonly attempt: SubmitAttempt; readonly draft: string }
   | { readonly type: 'begin-submit'; readonly attempt: SubmitAttempt; readonly claim: CommandClaim; readonly args: string }
-  | { readonly type: 'default-sink'; readonly draft: string }
+  | { readonly type: 'default-sink'; readonly draft: string; readonly mode: InputSubmitMode }
   | { readonly type: 'notice'; readonly level: 'info' | 'error'; readonly text: string }

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()

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)
       },

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 }]
       : []
   }
 

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.
+  }
+}

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',
@@ -89,8 +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',
@@ -123,6 +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',
@@ -189,8 +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',

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>

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.

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}`)
     }
   }

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;
+}

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>
+  )
+}

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) {
@@ -178,23 +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 => {

packages/client/ui-conversation/tests/chat-apply.spec.tsx

@@ -37,6 +37,7 @@ async function bench() {
   await runtime.root.declare({
     'conversation': { kind: 'single', scope: 'session-maybe' },
     'details': { kind: 'single', scope: 'session' },
+    'settings.general.item': { kind: 'list', scope: 'root' },
   }, (_p: { renderSlot?: unknown }) => null)
 
   const feature = await runtime.mount({ inject: [...inject], apply })
@@ -85,6 +86,7 @@ describe('apply wiring', () => {
     // The hero workspace picker hole rides the conversation entry's children
     // declaration (the empty-state occupant is gone).
     expect(b.slots.spec('conversation.hero.workspace')).toEqual({ kind: 'single', scope: 'root' })
+    expect(b.slots.entries('settings.general.item').map(entry => entry.options.id)).toEqual(['composer-enter'])
     await b.runtime.dispose()
   })
 
@@ -112,6 +114,7 @@ describe('apply wiring', () => {
     expect(b.slots.entries('conversation.chat.toolview')).toHaveLength(0)
     expect(b.slots.spec('conversation.chat.toolview')).toBeUndefined()
     expect(b.slots.entries('details')).toHaveLength(0)
+    expect(b.slots.entries('settings.general.item')).toHaveLength(0)
     expect(b.runtime.ctx.get('conversation')).toBeUndefined()
     await b.runtime.dispose()
   })

packages/client/ui-conversation/tests/chat-branch-tails.spec.tsx

@@ -102,18 +102,28 @@ describe('MessageItem arms', () => {
     fireEvent.click(screen.getByRole('button', { name: '复制' }))
   })
 
-  it('steering bubbles render text and non-text rest blocks, without user actions or a badge', () => {
+  it('consumed steering renders copy and branch actions without a badge', () => {
+    const writeText = vi.fn().mockResolvedValue(undefined)
+    Object.defineProperty(navigator, 'clipboard', {
+      configurable: true,
+      value: { writeText },
+    })
+    const fork = vi.fn()
     const view = render(
       <MessageItem t={t} node={{
-        kind: 'steering', seq: 2, turn: 1, source: null,
+        kind: 'steering', messageId: 'steer-message', seq: 2, time: 1_000, turn: 1, source: null,
         content: [{ type: 'text', text: 'steer!' }, { type: 'image', data: 'x' }] as never,
       } as never}
+      onFork={fork}
       />,
     )
     expect(view.queryByText('插话')).toBeNull()
     expect(view.getByText('steer!')).toBeTruthy()
     expect(view.getByText(/附加内容块/)).toBeTruthy()
-    expect(view.queryByRole('button', { name: '复制' })).toBeNull()
+    fireEvent.click(view.getByRole('button', { name: '复制' }))
+    expect(writeText).toHaveBeenCalledWith('steer!')
+    fireEvent.click(view.getByRole('button', { name: '在新对话中分支' }))
+    expect(fork).toHaveBeenCalledWith(2)
   })
 
   it('context uses the Tool calls disclosure chrome and keeps its JSON collapsed by default', () => {

packages/client/ui-conversation/tests/chat-view.spec.tsx

@@ -251,6 +251,87 @@ describe('ChatView', () => {
     expect(view.getByText('run a')).toBeTruthy()
   })
 
+  it('renders Host-pending steering at the flow tail and hands off to the durable node', () => {
+    const writeText = vi.fn().mockResolvedValue(undefined)
+    Object.defineProperty(navigator, 'clipboard', {
+      configurable: true,
+      value: { writeText },
+    })
+    const pending = {
+      id: 'steer-occurrence' as never,
+      messageId: 'steer-message' as never,
+      placement: 'steering' as const,
+      content: [{ type: 'text' as const, text: 'interrupt now' }],
+      preview: 'interrupt now',
+      text: 'interrupt now',
+    }
+    const queued = {
+      id: 'queued-occurrence' as never,
+      messageId: 'queued-message' as never,
+      placement: 'queued' as const,
+      content: [{ type: 'text' as const, text: 'later' }],
+      preview: 'later',
+      text: 'later',
+    }
+    const h = makeHarness({ nodes: [assistant(1, 'working')], queue: [queued, pending], running: true })
+    const view = render(<h.ChatView {...h.props} />)
+
+    expect(view.getByText('interrupt now').closest('[data-pending-steering]')).not.toBeNull()
+    expect(view.queryByText('later')).toBeNull()
+    const pendingBubble = view.getByText('interrupt now').closest('[data-pending-steering]')
+    expect(pendingBubble).not.toBeNull()
+    fireEvent.click(within(pendingBubble as HTMLElement).getByRole('button', { name: '复制' }))
+    expect(writeText).toHaveBeenCalledWith('interrupt now')
+    expect(within(pendingBubble as HTMLElement).queryByRole('button', { name: '在新对话中分支' })).toBeNull()
+    expect(view.getByRole('status').compareDocumentPosition(view.getByText('interrupt now'))
+      & Node.DOCUMENT_POSITION_FOLLOWING).not.toBe(0)
+
+    act(() => {
+      h.set({
+        queue: [queued],
+        nodes: [
+          assistant(1, 'working'),
+          {
+            kind: 'steering', messageId: pending.messageId,
+            seq: 2, time: 2_000, turn: 1,
+            content: [{ type: 'text', text: 'interrupt now' }], source: null,
+          },
+        ],
+      })
+    })
+    expect(view.getAllByText('interrupt now')).toHaveLength(1)
+    expect(view.container.querySelector('[data-pending-steering]')).toBeNull()
+    expect(view.getAllByRole('button', { name: '复制' })).toHaveLength(2)
+    const branchButtons = view.getAllByRole('button', { name: '在新对话中分支' })
+    expect(branchButtons).toHaveLength(2)
+    fireEvent.click(branchButtons[1]!)
+    expect(h.forkAt).toHaveBeenCalledWith(2)
+  })
+
+  it('keeps a later pending occurrence visible when it reuses a durable MessageId', () => {
+    const pending = {
+      id: 'steer-occurrence-later' as never,
+      messageId: 'shared-steer-message' as never,
+      placement: 'steering' as const,
+      content: [{ type: 'text' as const, text: 'same steering' }],
+      preview: 'same steering',
+      text: 'same steering',
+    }
+    const h = makeHarness({
+      queue: [pending],
+      nodes: [{
+        kind: 'steering', messageId: pending.messageId,
+        seq: 2, time: 2_000, turn: 1,
+        content: pending.content, source: null,
+      }],
+      running: true,
+    })
+    const view = render(<h.ChatView {...h.props} />)
+
+    expect(view.getAllByText('same steering')).toHaveLength(2)
+    expect(view.container.querySelectorAll('[data-pending-steering]')).toHaveLength(1)
+  })
+
   it('animates only the latest unresolved model retry', () => {
     const retryNode = retry(2)
     const nextRetry = { ...retry(3), turn: 2, retry: 2 }

packages/client/ui-conversation/tests/enter-behavior-row.spec.tsx

@@ -0,0 +1,67 @@
+// @vitest-environment jsdom
+import { afterEach, describe, expect, it, vi } from 'vitest'
+import { act, cleanup, fireEvent, render, screen } from '@testing-library/react'
+import { bindSnapshotSelector } from '@deepseek-ai/dsh-client-web-react'
+import { createSnapshotStore, type SessionListState, type WorkspaceListState } from '@deepseek-ai/dsh-client-runtime/client'
+import { makeTranslate } from '@deepseek-ai/dsh-client-test-runtime'
+import { EnterBehaviorRow } from '../src/client/settings/EnterBehaviorRow.tsx'
+import type { EnterBehaviorRowProps } from '../src/client/settings/EnterBehaviorRow.tsx'
+import { ComposerSubmissionPolicy } from '../src/client/input/submission-policy.ts'
+import { en } from '../src/client/locales.ts'
+
+afterEach(() => {
+  cleanup()
+  localStorage.clear()
+})
+
+function emptySessions() {
+  return bindSnapshotSelector(createSnapshotStore<SessionListState>({
+    ids: [], byId: {}, current: undefined, phase: 'ready', subagentsByParent: {}, currentAddress: undefined,
+  }))
+}
+
+function emptyWorkspaces() {
+  return bindSnapshotSelector(createSnapshotStore<WorkspaceListState>({
+    items: [], archivedSessionIds: [], state: 'idle', phase: 'ready', error: null,
+    baselinesReady: true, recentWorkspaceId: undefined,
+  }))
+}
+
+function mount() {
+  const policy = new ComposerSubmissionPolicy()
+  const setBusyEnter = vi.fn((behavior: 'queue' | 'steer') => { policy.setBusyEnter(behavior) })
+  const props: EnterBehaviorRowProps = {
+    useSessions: emptySessions(),
+    useWorkspaces: emptyWorkspaces(),
+    useBusyEnter: bindSnapshotSelector(policy.busyEnter),
+    setBusyEnter,
+    t: makeTranslate(en),
+  }
+  render(<EnterBehaviorRow {...props} />)
+  return { policy, setBusyEnter }
+}
+
+describe('EnterBehaviorRow', () => {
+  it('explains the busy-only scope and shows Queue by default', () => {
+    mount()
+    expect(screen.getByText('Enter behavior while busy')).toBeDefined()
+    expect(screen.getByText('Busy only; Cmd/Ctrl+Enter uses the other behavior')).toBeDefined()
+    expect(screen.getByRole('button', { name: /Queue/ }).getAttribute('aria-expanded')).toBe('false')
+  })
+
+  it('selects Steer, follows later preference changes, and closes outside', () => {
+    const b = mount()
+    const trigger = screen.getByRole('button', { name: /Queue/ })
+    fireEvent.click(trigger)
+    fireEvent.click(screen.getByRole('menuitem', { name: 'Steer' }))
+    expect(b.setBusyEnter).toHaveBeenCalledWith('steer')
+    expect(screen.getByRole('button', { name: /Steer/ })).toBeDefined()
+
+    act(() => { b.policy.setBusyEnter('queue') })
+    const queueTrigger = screen.getByRole('button', { name: /Queue/ })
+    fireEvent.click(queueTrigger)
+    expect(screen.getByRole('menuitem', { name: 'Steer' })).toBeDefined()
+    fireEvent.pointerDown(document.body)
+    expect(screen.queryByRole('menuitem', { name: 'Steer' })).toBeNull()
+  })
+})

packages/client/ui-conversation/tests/input-bar.spec.tsx

@@ -1,6 +1,6 @@
 // @vitest-environment jsdom
 // InputBar behavior over the machine wiring: Enter-send semantics (IME guard,
-// shift newline, ctrl/meta insert, repeat suppression), queue-cut-1 running
+// Shift newline, busy Enter policy, Ctrl/Meta steering, repeat suppression), running
 // semantics (input stays free; primary turns stop), the machine pending lock,
 // decoration backdrop, error/notice strips, and the focus-keeping mousedown.
 
@@ -53,6 +53,7 @@ interface BenchOptions {
   leftItems?: React.ReactNode
   rightItems?: React.ReactNode
   commandMenuOpen?: boolean
+  busyEnter?: 'queue' | 'steer'
   toggleCommandMenu?: (selection: { start: number; end: number }) => void
 }
 
@@ -107,6 +108,11 @@ function bench(over?: BenchOptions) {
     useInput: bindSnapshotSelector(shell.state),
     inputActions: shell.actions,
     keyboard: shell,
+    resolveSubmitMode: (running, gesture, steeringAvailable) => {
+      if (!running || !steeringAvailable) return 'queue'
+      const preferred = over?.busyEnter ?? 'queue'
+      return gesture === 'enter' ? preferred : preferred === 'queue' ? 'steer' : 'queue'
+    },
     toggleCommandMenu: over?.toggleCommandMenu ?? vi.fn(),
     useNotices: bindSnapshotSelector(shell.notices),
     useLexicon: bindSnapshotSelector(shell.lexicon),
@@ -137,7 +143,7 @@ describe('Enter semantics', () => {
   it('plain Enter submits queue mode through the machine; repeat and empty are suppressed', () => {
     const { textarea, sink } = bench({ draft: 'hello' })
     fireEvent.keyDown(textarea, { key: 'Enter' })
-    expect(sink).toHaveBeenCalledWith('hello')
+    expect(sink).toHaveBeenCalledWith('hello', 'queue')
     fireEvent.keyDown(textarea, { key: 'Enter', repeat: true })
     expect(sink).toHaveBeenCalledTimes(1)
     const empty = bench({ draft: '   ' })
@@ -159,12 +165,18 @@ describe('Enter semantics', () => {
     expect(sink).not.toHaveBeenCalled() // and not preventDefault'd: native newline
   })
 
-  it('Ctrl/Meta+Enter inserts a newline through the machine (no browser execCommand)', () => {
-    const { textarea, shell, sink } = bench({ draft: 'hello' })
-    textarea.setSelectionRange(5, 5)
-    fireEvent.keyDown(textarea, { key: 'Enter', ctrlKey: true })
-    expect(shell.snapshot.draft).toBe('hello\n')
-    expect(sink).not.toHaveBeenCalled()
+  it('Ctrl/Meta+Enter sends normally while idle and steers while running', () => {
+    const idle = bench({ draft: 'hello' })
+    fireEvent.keyDown(idle.textarea, { key: 'Enter', metaKey: true })
+    expect(idle.sink).toHaveBeenCalledWith('hello', 'queue')
+
+    const busyCtrl = bench({ running: true, draft: 'steer with ctrl' })
+    fireEvent.keyDown(busyCtrl.textarea, { key: 'Enter', ctrlKey: true })
+    expect(busyCtrl.sink).toHaveBeenCalledWith('steer with ctrl', 'steer')
+
+    const busyMeta = bench({ running: true, draft: 'steer with cmd' })
+    fireEvent.keyDown(busyMeta.textarea, { key: 'Enter', metaKey: true })
+    expect(busyMeta.sink).toHaveBeenCalledWith('steer with cmd', 'steer')
   })
 
   it('platform undo/redo chords route to the machine, never the browser stack', () => {
@@ -205,12 +217,28 @@ describe('running and lock semantics (queue cut 1)', () => {
     expect(textarea.disabled).toBe(false) // running no longer locks
     fireEvent.change(textarea, { target: { value: '排队消息2' } })
     fireEvent.keyDown(textarea, { key: 'Enter' })
-    expect(sink).toHaveBeenCalledWith('排队消息2')
+    expect(sink).toHaveBeenCalledWith('排队消息2', 'queue')
     expect(button.getAttribute('aria-label')).toBe('停止生成')
     fireEvent.click(button)
     expect(stop).toHaveBeenCalledTimes(1)
   })
 
+  it('running plain Enter follows the busy-state Steer preference', () => {
+    const { textarea, sink } = bench({ running: true, busyEnter: 'steer', draft: '直接插话' })
+    fireEvent.keyDown(textarea, { key: 'Enter' })
+    expect(sink).toHaveBeenCalledWith('直接插话', 'steer')
+  })
+
+  it('running Cmd/Ctrl+Enter uses the opposite of the busy-state Enter preference', () => {
+    const meta = bench({ running: true, busyEnter: 'steer', draft: '排到下一轮' })
+    fireEvent.keyDown(meta.textarea, { key: 'Enter', metaKey: true })
+    expect(meta.sink).toHaveBeenCalledWith('排到下一轮', 'queue')
+
+    const ctrl = bench({ running: true, busyEnter: 'steer', draft: 'also queue' })
+    fireEvent.keyDown(ctrl.textarea, { key: 'Enter', ctrlKey: true })
+    expect(ctrl.sink).toHaveBeenCalledWith('also queue', 'queue')
+  })
+
   it('running subagent primary admits a follow-up instead of exposing Stop', () => {
     const { button, sink, stop } = bench({
       running: true,
@@ -226,7 +254,7 @@ describe('running and lock semantics (queue cut 1)', () => {
     })
     expect(button.getAttribute('aria-label')).toBe('发送消息')
     fireEvent.click(button)
-    expect(sink).toHaveBeenCalledWith('后续消息')
+    expect(sink).toHaveBeenCalledWith('后续消息', 'queue')
     expect(stop).not.toHaveBeenCalled()
 
     const empty = bench({
@@ -243,6 +271,24 @@ describe('running and lock semantics (queue cut 1)', () => {
     expect(empty.button.disabled).toBe(true)
   })
 
+  it('keeps both running subagent Enter gestures on Queue transport', () => {
+    const subagent = {
+      address: {
+        parentSessionId: 'parent' as SessionId,
+        childSessionId: SID,
+        mode: 'continuable' as const,
+      },
+      parentAvailable: true,
+    }
+    const plain = bench({ running: true, busyEnter: 'steer', draft: 'plain', subagent })
+    fireEvent.keyDown(plain.textarea, { key: 'Enter' })
+    expect(plain.sink).toHaveBeenCalledWith('plain', 'queue')
+
+    const accelerated = bench({ running: true, draft: 'accelerated', subagent })
+    fireEvent.keyDown(accelerated.textarea, { key: 'Enter', metaKey: true })
+    expect(accelerated.sink).toHaveBeenCalledWith('accelerated', 'queue')
+  })
+
   it('disabled (session removed) locks the textarea and chrome', () => {
     const { textarea, view } = bench({ disabled: true })
     expect(textarea.disabled).toBe(true)
@@ -253,7 +299,7 @@ describe('running and lock semantics (queue cut 1)', () => {
   it('idle primary sends and disables on empty draft', () => {
     const { button, sink } = bench({ draft: 'go' })
     fireEvent.click(button)
-    expect(sink).toHaveBeenCalledWith('go')
+    expect(sink).toHaveBeenCalledWith('go', 'queue')
     const empty = bench()
     expect(empty.button.disabled).toBe(true)
   })

packages/client/ui-conversation/tests/input-machine.spec.ts

@@ -40,9 +40,9 @@ function effectAt<T extends InputEffect['type']>(
 }
 
 /** Drive plain → adjudicating and hand back the minted attempt. */
-function enterAdjudicating(m: InputMachine, draft: string): SubmitAttempt {
+function enterAdjudicating(m: InputMachine, draft: string, mode: 'queue' | 'steer' = 'queue'): SubmitAttempt {
   m.dispatch({ type: 'draft-changed', draft })
-  const fx = m.dispatch({ type: 'enter' })
+  const fx = m.dispatch({ type: 'enter', mode })
   return effectAt(fx, 0, 'adjudicate').attempt
 }
 
@@ -52,35 +52,42 @@ function enterSubmitting(m: InputMachine, name: string, args: string): { attempt
   m.dispatch({ type: 'draft-changed', draft: `/${name.slice(0, 2)}` })
   m.dispatch({ type: 'begin-command', claim, span: spanOf(m, 0, m.state.draft.length) })
   m.dispatch({ type: 'draft-changed', draft: claim.token + args })
-  const fx = m.dispatch({ type: 'enter' })
+  const fx = m.dispatch({ type: 'enter', mode: 'queue' })
   return { attempt: effectAt(fx, 0, 'begin-submit').attempt, claim }
 }
 
 function staleAttempt(): SubmitAttempt {
-  return { seq: 9999, signal: new AbortController().signal, draftSnapshot: '' }
+  return { seq: 9999, signal: new AbortController().signal, draftSnapshot: '', mode: 'queue' }
 }
 
 describe('input-machine: plain × enter', () => {
   it('empty and whitespace-only drafts produce nothing', () => {
     const m = new InputMachine()
-    expect(m.dispatch({ type: 'enter' })).toEqual([])
+    expect(m.dispatch({ type: 'enter', mode: 'queue' })).toEqual([])
     m.dispatch({ type: 'draft-changed', draft: '  \n ' })
-    expect(m.dispatch({ type: 'enter' })).toEqual([])
+    expect(m.dispatch({ type: 'enter', mode: 'queue' })).toEqual([])
     expect(m.state.phase).toBe('plain')
   })
 
   it('non-command text falls to the default sink', () => {
     const m = new InputMachine()
     m.dispatch({ type: 'draft-changed', draft: 'hello world' })
-    expect(m.dispatch({ type: 'enter' }))
-      .toEqual([{ type: 'default-sink', draft: 'hello world' }])
+    expect(m.dispatch({ type: 'enter', mode: 'queue' }))
+      .toEqual([{ type: 'default-sink', draft: 'hello world', mode: 'queue' }])
     expect(m.state.phase).toBe('plain')
   })
 
+  it('retains an explicit steer mode on the default sink effect', () => {
+    const m = new InputMachine()
+    m.dispatch({ type: 'draft-changed', draft: 'steer now' })
+    expect(m.dispatch({ type: 'enter', mode: 'steer' }))
+      .toEqual([{ type: 'default-sink', draft: 'steer now', mode: 'steer' }])
+  })
+
   it('leading "/" enters adjudicating with a minted attempt carrying the draft snapshot', () => {
     const m = new InputMachine()
     m.dispatch({ type: 'draft-changed', draft: '/goal x' })
-    const fx = m.dispatch({ type: 'enter' })
+    const fx = m.dispatch({ type: 'enter', mode: 'queue' })
     const eff = effectAt(fx, 0, 'adjudicate')
     expect(eff.draft).toBe('/goal x')
     expect(eff.attempt.draftSnapshot).toBe('/goal x')
@@ -91,14 +98,14 @@ describe('input-machine: plain × enter', () => {
   it('leading is judged after trim including newlines', () => {
     const m = new InputMachine()
     m.dispatch({ type: 'draft-changed', draft: '\n\n/goal x' })
-    expect(m.dispatch({ type: 'enter' })[0]?.type).toBe('adjudicate')
+    expect(m.dispatch({ type: 'enter', mode: 'queue' })[0]?.type).toBe('adjudicate')
   })
 
   it('a non-whitespace prefix before "/" is not leading — default sink', () => {
     const m = new InputMachine()
     m.dispatch({ type: 'draft-changed', draft: '第一行\n/goal x' })
-    expect(m.dispatch({ type: 'enter' }))
-      .toEqual([{ type: 'default-sink', draft: '第一行\n/goal x' }])
+    expect(m.dispatch({ type: 'enter', mode: 'queue' }))
+      .toEqual([{ type: 'default-sink', draft: '第一行\n/goal x', mode: 'queue' }])
   })
 })
 
@@ -126,9 +133,9 @@ describe('input-machine: adjudication outcomes', () => {
 
   it('undefined outcome falls back to the default sink', () => {
     const m = new InputMachine()
-    const attempt = enterAdjudicating(m, '/unknown thing')
+    const attempt = enterAdjudicating(m, '/unknown thing', 'steer')
     expect(m.dispatch({ type: 'adjudicated', attempt, outcome: undefined }))
-      .toEqual([{ type: 'default-sink', draft: '/unknown thing' }])
+      .toEqual([{ type: 'default-sink', draft: '/unknown thing', mode: 'steer' }])
     expect(m.state.phase).toBe('plain')
   })
 
@@ -152,7 +159,7 @@ describe('input-machine: adjudication outcomes', () => {
   it('enter is a no-op while adjudicating (pending lock)', () => {
     const m = new InputMachine()
     enterAdjudicating(m, '/goal x')
-    expect(m.dispatch({ type: 'enter' })).toEqual([])
+    expect(m.dispatch({ type: 'enter', mode: 'queue' })).toEqual([])
     expect(m.state.phase).toBe('adjudicating')
   })
 
@@ -344,31 +351,6 @@ describe('input-machine: occurrence reconciliation on draft edits', () => {
   })
 })
 
-describe('input-machine: newline transaction (F1)', () => {
-  it('inserts \\n at the caret and shifts trailing occurrences', () => {
-    const m = new InputMachine()
-    m.dispatch({ type: 'draft-changed', draft: 'ab @wor' })
-    m.dispatch({ type: 'insert-ref', reference: refOf('w'), span: spanOf(m, 3, 7) })
-    m.dispatch({ type: 'newline', selection: { start: 2, end: 2 } })
-    expect(m.state.draft).toBe(`ab\n ${P} `)
-    expect(m.state.occurrences[0]?.offset).toBe(4)
-    m.dispatch({ type: 'undo' })
-    expect(m.state.draft).toBe(`ab ${P} `)
-  })
-
-  it('replaces a selection, breaks the claim prefix when leading, and rejects out-of-bounds', () => {
-    const m = new InputMachine()
-    m.dispatch({ type: 'draft-changed', draft: '/go' })
-    m.dispatch({ type: 'begin-command', claim: claimOf('goal'), span: spanOf(m, 0, 3) })
-    expect(m.dispatch({ type: 'newline', selection: { start: 0, end: 99 } })).toEqual([])
-    expect(m.state.phase).toBe('claimed')
-    m.dispatch({ type: 'newline', selection: { start: 0, end: 0 } })
-    expect(m.state.draft).toBe('\n/goal ')
-    expect(m.state.phase).toBe('plain')
-    expect(m.state.claim).toBeUndefined()
-  })
-})
-
 describe('input-machine: consume-token guards', () => {
   it('span guard: CAS pass deletes the token — success observable as a draftRev advance', () => {
     const m = new InputMachine()
@@ -587,7 +569,7 @@ describe('input-machine: paste plane', () => {
 
     const b = new InputMachine()
     b.dispatch({ type: 'paste-begin', text: 'plain text', selection: { start: 0, end: 0 } })
-    b.dispatch({ type: 'enter' })
+    b.dispatch({ type: 'enter', mode: 'queue' })
     expect(b.state.paste).toBeUndefined()
   })
 
@@ -755,7 +737,7 @@ describe('input-machine: submitting transaction', () => {
   it('enter and begin-command are locked; draft-changed is recorded without leaving submitting', () => {
     const m = new InputMachine()
     enterSubmitting(m, 'goal', 'x')
-    expect(m.dispatch({ type: 'enter' })).toEqual([])
+    expect(m.dispatch({ type: 'enter', mode: 'queue' })).toEqual([])
     expect(m.dispatch({ type: 'draft-changed', draft: '/goal y' })).toEqual([])
     expect(m.state).toMatchObject({ phase: 'submitting', draft: '/goal y' })
   })
@@ -768,7 +750,7 @@ describe('input-machine: submitting transaction', () => {
     m.dispatch({ type: 'draft-changed', draft: '/go', editRange: { start: 0, end: 1, insertedLength: 0 } })
     m.dispatch({ type: 'begin-command', claim: claimOf('goal'), span: spanOf(m, 0, 3) })
     m.dispatch({ type: 'draft-changed', draft: '/goal go' })
-    const attempt = effectAt(m.dispatch({ type: 'enter' }), 0, 'begin-submit').attempt
+    const attempt = effectAt(m.dispatch({ type: 'enter', mode: 'queue' }), 0, 'begin-submit').attempt
     const fx = m.dispatch({ type: 'submit-settled', attempt, ok: true, outcome: { kind: 'success', text: 'goal set' } })
     expect(fx).toEqual([{ type: 'notice', level: 'info', text: 'goal set' }])
     expect(m.state).toMatchObject({ phase: 'plain', draft: '', occurrences: [] })
@@ -809,7 +791,7 @@ describe('input-machine: submitting transaction', () => {
     const m = new InputMachine()
     const { attempt: first } = enterSubmitting(m, 'goal', 'x')
     m.dispatch({ type: 'submit-settled', attempt: first, ok: false, message: 'retry' })
-    const second = effectAt(m.dispatch({ type: 'enter' }), 0, 'begin-submit').attempt
+    const second = effectAt(m.dispatch({ type: 'enter', mode: 'queue' }), 0, 'begin-submit').attempt
     expect(second.seq).not.toBe(first.seq)
     expect(m.dispatch({ type: 'submit-settled', attempt: first, ok: true })).toEqual([])
     expect(m.state.phase).toBe('submitting')

packages/client/ui-conversation/tests/input-matrix.spec.tsx

@@ -47,6 +47,7 @@ function mountBar(shell: SessionInputShell, over?: { running?: boolean; disabled
     useInput: bindSnapshotSelector(shell.state),
     inputActions: shell.actions,
     keyboard: shell,
+    resolveSubmitMode: () => 'queue',
     toggleCommandMenu: vi.fn(),
     useNotices: bindSnapshotSelector(shell.notices),
     useLexicon: bindSnapshotSelector(shell.lexicon),
@@ -88,7 +89,7 @@ describe('matrix row: plain', () => {
     fireEvent.change(textarea, { target: { value: '普通消息' } })
     expect(shell.snapshot.claim).toBeUndefined()
     fireEvent.keyDown(textarea, { key: 'Enter' })
-    expect(sink).toHaveBeenCalledWith('普通消息')
+    expect(sink).toHaveBeenCalledWith('普通消息', 'queue')
     expect(shell.snapshot.phase).toBe('plain')
   })
 })
@@ -187,7 +188,7 @@ describe('matrix row: locked (session disabled)', () => {
     expect((textarea).disabled).toBe(false)
     fireEvent.change(textarea, { target: { value: '排队' } })
     fireEvent.keyDown(textarea, { key: 'Enter' })
-    expect(sink).toHaveBeenCalledWith('排队')
+    expect(sink).toHaveBeenCalledWith('排队', 'queue')
   })
 })
 

packages/client/ui-conversation/tests/input-scenarios.spec.tsx

@@ -133,6 +133,7 @@ async function scopedBench(register?: (slash: SlashService) => void) {
     useInput: bindSnapshotSelector(shell.state),
     inputActions: shell.actions,
     keyboard: shell,
+    resolveSubmitMode: () => 'queue',
     toggleCommandMenu: (selection) => {
       const snapshot = shell.snapshot
       controller.toggleSource('command', {
@@ -235,7 +236,7 @@ describe('scenario D: execute-kind /compact', () => {
     act(() => { b2.shell.setDraft('/compact 现在') })
     fireEvent.keyDown(b2.textarea, { key: 'Enter' })
     // execute with trailing → matchEnter answers undefined → default sink.
-    await vi.waitFor(() => { expect(b2.sink).toHaveBeenCalledWith('/compact 现在') })
+    await vi.waitFor(() => { expect(b2.sink).toHaveBeenCalledWith('/compact 现在', 'queue') })
     expect(b2.executed).toHaveLength(0)
   })
 })
@@ -289,7 +290,7 @@ describe('scenario I: unknown /xyz + enter', () => {
     const b = await bench()
     act(() => { b.shell.setDraft('/xyz 干点啥') })
     fireEvent.keyDown(b.textarea, { key: 'Enter' })
-    await vi.waitFor(() => { expect(b.sink).toHaveBeenCalledWith('/xyz 干点啥') })
+    await vi.waitFor(() => { expect(b.sink).toHaveBeenCalledWith('/xyz 干点啥', 'queue') })
     expect(b.shell.snapshot.phase).toBe('plain')
     expect(b.execute).not.toHaveBeenCalled()
   })

packages/client/ui-conversation/tests/queue-dock.spec.tsx

@@ -1,7 +1,7 @@
 // @vitest-environment jsdom
 /**
  * QueueDock rendering and operations: authoritative rows, inline editing,
- * collapse state, removal, failure notices, and live retirement.
+ * collapse state, removal, strict steering, failure notices, and live retirement.
  */
 import { afterEach, describe, expect, it, vi } from 'vitest'
 import { act, cleanup, fireEvent, render, waitFor } from '@testing-library/react'
@@ -23,7 +23,11 @@ const SID = 's1' as SessionId
 const iid = (id: string): QueueItemId => id as QueueItemId
 
 function row(id: string, text: string | null, preview = text ?? '[image]'): QueuedMessage {
-  return { id: iid(id), preview, text }
+  return {
+    id: iid(id), messageId: `message-${id}` as never, placement: 'queued',
+    content: text === null ? [{ type: 'image', data: 'x' } as never] : [{ type: 'text', text }],
+    preview, text,
+  }
 }
 
 function snapshotWith(queue: QueuedMessage[]): ConversationSnapshot {
@@ -85,6 +89,14 @@ describe('QueueDock', () => {
     expect(container.innerHTML).toBe('')
   })
 
+  it('leaves pending steering to the conversation flow', () => {
+    const steering = { ...row('s-1', 'interrupt'), placement: 'steering' as const }
+    const snap = snapshotWith([steering])
+    const source = liveSession(snap)
+    const { container } = render(<QueueDock {...kitFor(snap)} useSession={source.useSession} />)
+    expect(container.innerHTML).toBe('')
+  })
+
   it('renders one row directly and defaults multiple rows to a collapsible count header', () => {
     const single = snapshotWith([row('i-1', 'one')])
     const source = liveSession(single)
@@ -187,10 +199,10 @@ describe('QueueDock', () => {
     fireEvent.click(getByRole('button', { name: '2 条排队消息' }))
     expect([...container.querySelectorAll('li')].map(item => item.textContent))
       .toEqual(['第一条排队消息', 'image [image]'])
-    expect(container.querySelectorAll('button')).toHaveLength(5)
+    expect(container.querySelectorAll('button')).toHaveLength(7)
     expect(container.querySelectorAll('[aria-label="编辑排队消息"]')).toHaveLength(2)
     expect(container.querySelectorAll('[aria-label="删除排队消息"]')).toHaveLength(2)
-    expect(container.querySelectorAll('[aria-label="立即发送排队消息"]')).toHaveLength(0)
+    expect(container.querySelectorAll('[aria-label="插话发送"]')).toHaveLength(2)
     expect((container.querySelectorAll('[aria-label="编辑排队消息"]')[0] as HTMLButtonElement).disabled).toBe(false)
     expect((container.querySelectorAll('[aria-label="编辑排队消息"]')[1] as HTMLButtonElement).disabled).toBe(true)
     expect(container.querySelectorAll('[aria-label="编辑排队消息"]')[1]?.getAttribute('title'))
@@ -273,6 +285,68 @@ describe('QueueDock', () => {
     })
   })
 
+  it('strictly steers complete row content only while the agent is running', async () => {
+    const running = snapshotWith([row('i-steer', null, 'image [image]')])
+    const source = liveSession(running)
+    const updateQueue = vi.fn(() => Promise.resolve())
+    const rendered = render(
+      <QueueDock {...kitFor(running, { updateQueue })} useSession={source.useSession} />,
+    )
+
+    const button = rendered.getByLabelText('插话发送')
+    expect(button).toHaveProperty('disabled', false)
+    fireEvent.click(button)
+    await waitFor(() => {
+      expect(updateQueue).toHaveBeenCalledWith(iid('i-steer'), { kind: 'steer' })
+    })
+
+    act(() => { source.push({ ...running, running: false }) })
+    expect(rendered.getByLabelText('插话发送')).toHaveProperty('disabled', true)
+    expect(rendered.getByLabelText('插话发送').getAttribute('title')).toBe('仅运行中可插话发送')
+  })
+
+  it('renders a session-backed subagent Queue without unsupported actions', () => {
+    const snap = {
+      ...snapshotWith([row('i-subagent', 'pending child follow-up')]),
+      subagent: {
+        address: {
+          parentSessionId: 'parent' as SessionId,
+          childSessionId: SID,
+          mode: 'continuable' as const,
+        },
+        parentAvailable: true,
+      },
+    }
+    const source = liveSession(snap)
+    const view = render(
+      <QueueDock {...kitFor(snap)} useSession={source.useSession} />,
+    )
+
+    expect(view.getByText('pending child follow-up')).toBeTruthy()
+    expect(view.queryByLabelText('编辑排队消息')).toBeNull()
+    expect(view.queryByLabelText('删除排队消息')).toBeNull()
+    expect(view.queryByLabelText('插话发送')).toBeNull()
+  })
+
+  it('keeps the row and reports a genuine steer failure', async () => {
+    const snap = snapshotWith([row('i-steer-race', 'pending steer')])
+    const source = liveSession(snap)
+    const notify = vi.fn()
+    const updateQueue = vi.fn(() => Promise.reject(new Error('transport failed')))
+    const { getByLabelText, getByText } = render(
+      <QueueDock {...kitFor(snap, { updateQueue, notify })} useSession={source.useSession} />,
+    )
+
+    fireEvent.click(getByLabelText('插话发送'))
+    await waitFor(() => {
+      expect(notify).toHaveBeenCalledWith(
+        'error',
+        '插话发送失败，请重试。',
+      )
+    })
+    expect(getByText('pending steer')).toBeTruthy()
+  })
+
   it('keeps the row and surfaces a notice when an operation loses the claim race', async () => {
     const snap = snapshotWith([row('i-race', 'pending')])
     const source = liveSession(snap)

packages/client/ui-conversation/tests/service-orchestration.spec.ts

@@ -50,6 +50,29 @@ describe('ConversationService', () => {
     await expect(b.scoped.send('x')).rejects.toThrow('conversation.send failed: agent-busy: busy')
     b.cancel.mockResolvedValueOnce({ ok: false, error: { code: 'internal', message: 'nope', details: {} } } as never)
     await expect(b.scoped.cancel()).rejects.toThrow('conversation.cancel failed: internal: nope')
+    b.updateQueue.mockResolvedValueOnce({
+      ok: false, error: { code: 'internal', message: 'broken', details: {} },
+    } as never)
+    await expect(b.scoped.updateQueue('item-1' as never, { kind: 'steer' }))
+      .rejects.toThrow('conversation.updateQueue failed: internal: broken')
+    await b.runtime.dispose()
+  })
+
+  it('treats strict-steer races as converged Queue delivery', async () => {
+    const b = await bench()
+    b.updateQueue.mockResolvedValueOnce({
+      ok: false, error: { code: 'steer-unavailable', message: 'closed', details: {} },
+    } as never)
+    await expect(b.scoped.updateQueue('item-1' as never, { kind: 'steer' })).resolves.toBeUndefined()
+    b.updateQueue.mockResolvedValueOnce({
+      ok: false, error: { code: 'queue-item-not-found', message: 'claimed', details: {} },
+    } as never)
+    await expect(b.scoped.updateQueue('item-2' as never, { kind: 'steer' })).resolves.toBeUndefined()
+    b.updateQueue.mockResolvedValueOnce({
+      ok: false, error: { code: 'queue-item-not-found', message: 'claimed', details: {} },
+    } as never)
+    await expect(b.scoped.updateQueue('item-3' as never, { kind: 'remove' }))
+      .rejects.toThrow('conversation.updateQueue failed: queue-item-not-found: claimed')
     await b.runtime.dispose()
   })
 

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

@@ -164,6 +164,7 @@ function mount(
           useInput={useInput}
           inputActions={inputActions}
           keyboard={wiring}
+          resolveSubmitMode={() => 'queue'}
           toggleCommandMenu={vi.fn()}
           useNotices={bindSnapshotSelector(wiring.notices)}
           useLexicon={bindSnapshotSelector(wiring.lexicon)}
@@ -220,7 +221,7 @@ describe('ConversationRoot resident composer', () => {
     fireEvent.change(box, { target: { value: 'ordinary revised' } })
     expect(b.chat.store.getSnapshot().draft).toBe('ordinary revised')
     fireEvent.keyDown(box, { key: 'Enter' })
-    expect(b.sink).toHaveBeenCalledWith('ordinary revised')
+    expect(b.sink).toHaveBeenCalledWith('ordinary revised', 'queue')
     expect((b.view.getByRole('button', { name: 'Child' }) as HTMLButtonElement).disabled).toBe(true)
     expect(b.view.queryByText('Root')).toBeNull()
   })

packages/client/ui-conversation/tests/submission-policy.spec.ts

@@ -0,0 +1,67 @@
+// @vitest-environment jsdom
+import { afterEach, describe, expect, it, vi } from 'vitest'
+import {
+  BUSY_ENTER_STORAGE_KEY, ComposerSubmissionPolicy, DEFAULT_BUSY_ENTER_BEHAVIOR,
+} from '../src/client/input/submission-policy.ts'
+
+afterEach(() => {
+  vi.unstubAllGlobals()
+  localStorage.clear()
+})
+
+describe('ComposerSubmissionPolicy', () => {
+  it('defaults to Queue and only applies the preference while running', () => {
+    const policy = new ComposerSubmissionPolicy()
+    expect(policy.busyEnter.getSnapshot()).toBe(DEFAULT_BUSY_ENTER_BEHAVIOR)
+    expect(policy.resolve(false, 'enter', true)).toBe('queue')
+    expect(policy.resolve(false, 'accelerated', true)).toBe('queue')
+    expect(policy.resolve(true, 'enter', true)).toBe('queue')
+    expect(policy.resolve(true, 'accelerated', true)).toBe('steer')
+    expect(policy.resolve(true, 'enter', false)).toBe('queue')
+    expect(policy.resolve(true, 'accelerated', false)).toBe('queue')
+
+    const changed = vi.fn()
+    policy.busyEnter.subscribe(changed)
+    policy.setBusyEnter('steer')
+    expect(changed).toHaveBeenCalledTimes(1)
+    expect(policy.resolve(true, 'enter', true)).toBe('steer')
+    expect(policy.resolve(true, 'accelerated', true)).toBe('queue')
+    expect(policy.resolve(false, 'enter', true)).toBe('queue')
+    expect(policy.resolve(false, 'accelerated', true)).toBe('queue')
+    expect(localStorage.getItem(BUSY_ENTER_STORAGE_KEY)).toBe('steer')
+  })
+
+  it('restores a valid preference and leaves an identical write untouched', () => {
+    localStorage.setItem(BUSY_ENTER_STORAGE_KEY, 'steer')
+    const write = vi.spyOn(Storage.prototype, 'setItem')
+    const policy = new ComposerSubmissionPolicy()
+    expect(policy.busyEnter.getSnapshot()).toBe('steer')
+    policy.setBusyEnter('steer')
+    expect(write).not.toHaveBeenCalled()
+    write.mockRestore()
+  })
+
+  it('uses Queue for invalid, unavailable, or unreadable storage', () => {
+    localStorage.setItem(BUSY_ENTER_STORAGE_KEY, 'invalid')
+    expect(new ComposerSubmissionPolicy().busyEnter.getSnapshot()).toBe('queue')
+
+    vi.stubGlobal('localStorage', undefined)
+    expect(new ComposerSubmissionPolicy().busyEnter.getSnapshot()).toBe('queue')
+
+    vi.stubGlobal('localStorage', {
+      getItem: () => { throw new Error('blocked') },
+      setItem: vi.fn(),
+    })
+    expect(new ComposerSubmissionPolicy().busyEnter.getSnapshot()).toBe('queue')
+  })
+
+  it('keeps the in-memory preference when persistence throws', () => {
+    vi.stubGlobal('localStorage', {
+      getItem: () => null,
+      setItem: () => { throw new Error('quota') },
+    })
+    const policy = new ComposerSubmissionPolicy()
+    policy.setBusyEnter('steer')
+    expect(policy.busyEnter.getSnapshot()).toBe('steer')
+  })
+})

packages/cordis/tool-cordis/src/api-catalog.ts

@@ -2025,11 +2025,11 @@ export const TYPE_API: readonly TypeApiEntry[] = [
   },
   {
     name: 'InboxAction',
-    declaration: 'export type InboxAction = {\n    readonly kind: \'edit\';\n    readonly content: ContentBlock[];\n} | {\n    readonly kind: \'remove\';\n};',
+    declaration: 'export type InboxAction = {\n    readonly kind: \'edit\';\n    readonly content: ContentBlock[];\n} | {\n    readonly kind: \'remove\';\n} | {\n    readonly kind: \'steer\';\n};',
   },
   {
     name: 'InboxActionResult',
-    declaration: 'export type InboxActionResult = \'applied\' | \'not-found\';',
+    declaration: 'export type InboxActionResult = \'applied\' | \'not-found\' | \'steer-unavailable\';',
   },
   {
     name: 'InboxItemId',

packages/core/agent-loop/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/core/agent-loop/README.md
-README.md: 1662b1076cc116888d048cb6af1be1c7ab8196f6
-README.zh.md: 2fca32a02fdd73961c912c988933e1cd1a1a5817
+README.md: c71b350adfe06a19d4c24cb7e67de895a662bd87
+README.zh.md: d30dfc85e1597a8e193019cc23f4c7c39c991776

packages/core/agent-loop/README.md

@@ -59,7 +59,7 @@ The unified `send()` primitive routes content and source by (`target` × `wakeup
 
 `steer()` attaches a one-shot admission receipt to its exact accepted message. After `agent/step` and asynchronous prompt assembly succeed, the loop commits a stable pending batch as `steering/message`, snapshots derived history, and opens `step/start`; only then does each receipt resolve `admitted` with that turn and step. Later arrivals remain pending. Idle steering enters the ordinary FIFO and uses the first request of its eventual turn as the same admission boundary. A turn-concluding tool result, broad cancellation, disposal, or a claimed idle-steering turn that never reaches a request resolves affected receipts `rejected`; `cancel(..., { keepInbox: true })` and non-terminal routing preserve pending delivery. Open-turn `inject()` still commits after all tool results, including accepted context finalized during an interrupted batch, while steering remains provisional until a request admits it.
 
-Every FIFO acceptance mints an `InboxItemId` and publishes `agent/inbox/enqueue` with the complete occurrence. `updateInbox()` owns the synchronous queued-item boundary: edit freezes replacement content without changing message identity or position, while remove publishes discard. Edit publishes `agent/inbox/update`; steering and claimed occurrences return `not-found`. Claim publishes `agent/inbox/dequeue` and irrevocably removes the live address before prompt admission, so a racing update cannot rewrite durable history; `cancel()` without `keepInbox` publishes `agent/inbox/discard`.
+Every FIFO acceptance mints an `InboxItemId` and publishes `agent/inbox/enqueue` with the complete occurrence. `updateInbox()` owns the synchronous queued-item boundary: edit freezes replacement content without changing message identity or position, remove publishes discard, and strict steer transfers the immutable message into an open next-step window as a new steering occurrence. A closed window returns `steer-unavailable` without mutation; pending steering and claimed occurrences return `not-found`. Claim publishes `agent/inbox/dequeue` and irrevocably removes the live address before prompt admission, so a racing update cannot rewrite durable history; `cancel()` without `keepInbox` publishes `agent/inbox/discard`.
 
 ### Loop lifecycle (`agent.ts`)
 

packages/core/agent-loop/README.zh.md

@@ -59,7 +59,7 @@ interface Config {
 
 `steer()` 会把一次性准入回执附着到其准确的已接收消息。`agent/step` 和异步提示词组装成功后，循环把稳定的待处理批次提交为 `steering/message`、捕获派生历史并开启 `step/start`；只有此时，每个回执才会解析为 `admitted`，并附带轮次与步骤。之后到达的消息继续待处理。空闲 steering 会进入普通 FIFO，并以其最终轮次的首次请求作为相同准入边界。结束轮次的工具结果、广义取消、dispose（资源释放），或已领取 idle-steering 消息却从未到达请求的轮次，会把受影响回执解析为 `rejected`；`cancel(..., { keepInbox: true })` 和非终止型路由会保留待处理投递。活跃轮次内的 `inject()` 仍会在所有工具结果后提交，包括被中断批次中已最终确认的上下文；steering 则保持待准入，直到请求接纳它。
 
-每次 FIFO 接受项时都会铸造一个 `InboxItemId`，并通过 `agent/inbox/enqueue` 发布完整的单次入队项。`updateInbox()` 持有同步 queued 项边界：编辑会冻结替换内容，但不改变消息标识或位置；移除会发布 discard。编辑会发布 `agent/inbox/update`；steering 项和已被认领的项会返回 `not-found`。认领操作会发布 `agent/inbox/dequeue`，并在提示词接纳前不可逆地移除实时寻址标识，因此竞态中的更新无法改写持久历史；`cancel()` 在不带 `keepInbox` 时会发布 `agent/inbox/discard`。
+每次 FIFO 接受项时都会铸造一个 `InboxItemId`，并通过 `agent/inbox/enqueue` 发布完整的单次入队项。`updateInbox()` 持有同步 queued 项边界：编辑会冻结替换内容，但不改变消息标识或位置；移除会发布 discard；严格 steering 会把不可变消息作为新的 steering 单次入队项转移到开放的 next-step 窗口。窗口关闭时返回 `steer-unavailable`，且不做任何变更；待处理 steering 和已被认领的项会返回 `not-found`。认领操作会发布 `agent/inbox/dequeue`，并在提示词接纳前不可逆地移除实时寻址标识，因此竞态中的更新无法改写持久历史；`cancel()` 在不带 `keepInbox` 时会发布 `agent/inbox/discard`。
 
 ### 循环生命周期（`agent.ts`）
 

packages/core/agent-loop/src/agent.ts

@@ -256,6 +256,27 @@ export class ReactLoopAgent implements Agent {
         emitAgentEvent(this.loopCtx, this, 'agent/inbox/discard', [pending.item])
         return 'applied'
       }
+      case 'steer': {
+        if (!this.acceptsNextStep) return 'steer-unavailable'
+        this.queued.splice(queuedIndex, 1)
+        const item: InboxItem = Object.freeze({
+          id: InboxItemId(randomUUID()),
+          message: pending.item.message,
+          placement: 'steering',
+        })
+        this.outbox.push({
+          message: item.message,
+          steering: true,
+          item,
+          ...pending.delivery === undefined ? {} : { delivery: pending.delivery },
+        })
+        // Publish the replacement only after it is owned by the outbox. Its
+        // enqueue precedes the old occurrence's discard so reentrant
+        // cancellation can terminally account for both occurrences.
+        emitAgentEvent(this.loopCtx, this, 'agent/inbox/enqueue', item)
+        emitAgentEvent(this.loopCtx, this, 'agent/inbox/discard', [pending.item])
+        return 'applied'
+      }
       default:
         /* v8 ignore next -- InboxAction is a closed discriminated union. */
         return assertNever(action)

packages/core/agent-loop/tests/contract-regressions.spec.ts

@@ -156,6 +156,106 @@ describe('addressable inbox operations', () => {
         : ''))
       .toEqual(['keep me'])
   })
+
+  it('strictly transfers a queued occurrence into the open turn', async () => {
+    const adapter = new MockAdapter([textResponse('done')])
+    const ctx = await harness(adapter)
+    const agent = ctx.agentLoop.create(SessionId('queue-to-steer'), { provider: 'mock', model: 'mock' })
+    const entered = Promise.withResolvers<undefined>()
+    const decision = Promise.withResolvers<{ kind: 'allow' }>()
+    ctx.on('agent/prompt-submit', async () => {
+      entered.resolve(undefined)
+      return decision.promise
+    })
+
+    const enqueued: InboxItem[] = []
+    const discarded: InboxItem[] = []
+    ctx.on('agent/inbox/enqueue', (subject, item) => {
+      if (subject === agent) enqueued.push(item)
+    })
+    ctx.on('agent/inbox/discard', (subject, items) => {
+      if (subject === agent) discarded.push(...items)
+    })
+
+    const idle = waitForIdle(ctx, agent)
+    send(agent, 'open the turn')
+    const receipt = agent.steer(createUserMessage({
+      content: [{ type: 'text', text: 'steer this message' }],
+      source: { kind: 'user' },
+    }))
+    await entered.promise
+    const queued = enqueued.find(item => inboxText(item) === 'steer this message')!
+
+    expect(agent.updateInbox(queued.id, { kind: 'steer' })).toBe('applied')
+    const steering = enqueued.find(item => item.placement === 'steering')!
+    expect(steering.id).not.toBe(queued.id)
+    expect(steering.message).toBe(queued.message)
+    expect(discarded).toEqual([queued])
+
+    decision.resolve({ kind: 'allow' })
+    await idle
+    expect(agent.session.events.flatMap(event =>
+      event.type === 'steering/message' ? [event.data.message] : [],
+    )).toEqual([queued.message])
+    expect(await receipt.outcome).toEqual({ status: 'admitted', turn: 1, step: 1 })
+    expect(agent.updateInbox(queued.id, { kind: 'steer' })).toBe('not-found')
+  })
+
+  it('keeps a queued occurrence when the next-step window is closed', () => {
+    const ctx = new Context()
+    const session = new Session(SessionId('queue-to-steer-closed'))
+    const agent = new ReactLoopAgent(ctx, session.id, {}, session)
+    const enqueued: InboxItem[] = []
+    const discarded: InboxItem[] = []
+    ctx.on('agent/inbox/enqueue', (_subject, item) => { enqueued.push(item) })
+    ctx.on('agent/inbox/discard', (_subject, items) => { discarded.push(...items) })
+
+    agent.send(
+      createUserMessage({ content: [{ type: 'text', text: 'stay queued' }], source: { kind: 'user' } }),
+      { target: 'next-turn', wakeup: false },
+    )
+    const queued = enqueued[0]!
+    expect(agent.updateInbox(queued.id, { kind: 'steer' })).toBe('steer-unavailable')
+    expect(discarded).toEqual([])
+    expect(agent.updateInbox(queued.id, { kind: 'remove' })).toBe('applied')
+  })
+
+  it('accounts for both occurrences when steering enqueue cancels reentrantly', async () => {
+    const adapter = new MockAdapter([textResponse('unused')])
+    const ctx = await harness(adapter)
+    const agent = ctx.agentLoop.create(SessionId('queue-to-steer-cancel'), { provider: 'mock', model: 'mock' })
+    const entered = Promise.withResolvers<undefined>()
+    const decision = Promise.withResolvers<{ kind: 'allow' }>()
+    ctx.on('agent/prompt-submit', async () => {
+      entered.resolve(undefined)
+      return decision.promise
+    })
+
+    const enqueued: InboxItem[] = []
+    const discarded: InboxItem[] = []
+    ctx.on('agent/inbox/enqueue', (subject, item) => {
+      if (subject !== agent) return
+      enqueued.push(item)
+      if (item.placement === 'steering') agent.cancel({ kind: 'user' })
+    })
+    ctx.on('agent/inbox/discard', (subject, items) => {
+      if (subject === agent) discarded.push(...items)
+    })
+
+    const idle = waitForIdle(ctx, agent)
+    send(agent, 'open the turn')
+    await entered.promise
+    send(agent, 'cancel during conversion')
+    const queued = enqueued.find(item => inboxText(item) === 'cancel during conversion')!
+
+    expect(agent.updateInbox(queued.id, { kind: 'steer' })).toBe('applied')
+    const steering = enqueued.find(item => item.placement === 'steering')!
+    expect(discarded).toEqual([steering, queued])
+
+    decision.resolve({ kind: 'allow' })
+    await idle
+    expect(agent.session.events.some(event => event.type === 'steering/message')).toBe(false)
+  })
 })
 
 describe('assistant replay provenance', () => {

packages/core/agent/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/core/agent/README.md
-README.md: 8a6028352127c4638c0b5e0e3ee85964d1d7d734
-README.zh.md: ffa71ea987ab355ff2f30b6164376199cd5d0170
+README.md: 4c6a6dd95541cfa559e95858fede01d7cd76637f
+README.zh.md: 07bf887c557b410005bbe0fa1a988e63a765ad99

packages/core/agent/README.md

@@ -62,7 +62,7 @@ The handle every plugin programs against:
 
 - `agent.send(message, options)` — the one delivery primitive over the (`target` × `wakeup`) matrix. `message` is an already identified, frozen `UserMessage`; callers normally create it with `createUserMessage()` before routing begins. `SendOptions` owns only the `target` and `wakeup` policy. Each accepted FIFO occurrence receives its own `InboxItemId`, even when callers reuse a `MessageId`; `agent/inbox/enqueue`/`update` and the terminal `dequeue` or `discard` carry that complete `InboxItem`. `target: 'next-turn'` queues one independent FIFO item that, if admitted, becomes the sole ordinary prompt in its turn. `target: 'next-step'` with `wakeup: true` submits steering, while `target: 'next-step'` with `wakeup: false` injects durable context without running the model. The [one-send-one-turn Agent Note](../../../.agents/notes/implemented/simplification/2026-07-17-one-send-one-turn.md) owns the turn rationale.
 - `agent.reserveTurnAdmission()` — synchronously reserve the idle boundary before any queued waking prompt can claim its turn. An accepted prompt, including a same-tick pending wake, has right of way and makes reservation return `undefined`. Later sends keep their ordinary IDs, FIFO placement, and wakeup facts while held; `acceptsNextStep` remains false, `inject()` is not withheld, `whenIdle()` counts the reservation as activity, and the returned release is idempotent. This narrow coordination capability lets standalone durable operations such as manual compaction finish and flush before queued prompts derive from the session.
-- `agent.updateInbox(itemId, action)` — synchronously edits or removes one still-pending queued occurrence. Edit keeps its `MessageId`, `InboxItemId`, source, and FIFO position while replacing frozen content; remove emits the occurrence's terminal discard. Steering and claimed occurrences return `not-found`.
+- `agent.updateInbox(itemId, action)` — synchronously edits, removes, or strictly steers one still-pending queued occurrence. Edit keeps its `MessageId`, `InboxItemId`, source, and FIFO position while replacing frozen content; remove emits the occurrence's terminal discard. Strict steer requires `acceptsNextStep`, ends the queued occurrence, and accepts the same immutable message as a new steering occurrence with a new `InboxItemId`; a closed window returns `steer-unavailable` without mutation. Pending steering and claimed occurrences return `not-found`.
 - `agent.followup(input)` — the `next-turn`/wakeup preset of `send()`: queue an ordinary follow-up turn and wake the driver.
 - `agent.steer(input)` — the `next-step`/wakeup preset: submit one identified message and receive its `SteeringReceipt`. During prompt admission or an open turn, the message stages for the next safe request boundary without dispatching `agent/prompt-submit`; outside that acceptance window, it becomes a woken queued prompt. `receipt.outcome` resolves `admitted` with the turn and step only after the loop logs the message, captures it in immutable request history, and commits `step/start`. A turn-concluding tool result, broad cancellation, disposal, or pre-admission failure resolves it `rejected`; `cancel(..., { keepInbox: true })` and non-terminal routing preserve pending delivery. Reliable callers await the receipt, while best-effort UI steering may ignore it.
 - `agent.inject(input)` — the `next-step`/no-wakeup preset: append model-facing context without running the model; the next request sees a verbatim user-role message whose provenance is carried by the required `input.source`. During prompt admission or an open turn, injection waits in the outbox for the next safe boundary. Outside that acceptance window, it appends immediately without opening a turn; a context-only admission batch takes this fallback if admission closes without a turn, while context staged beside steering remains pending with it. Persistence reacts to `session/event` independently. Injection emits no `agent/inbox/*` event.

packages/core/agent/README.zh.md

@@ -62,7 +62,7 @@ Agent *创建* 由实现 `AgentFactory` 的插件（`dsh-agent-loop`）提供，
 
 - `agent.send(message, options)`：覆盖（`target` × `wakeup`）矩阵的唯一投递原语。`message` 是已有标识且已冻结的 `UserMessage`；调用方通常会在开始路由前使用 `createUserMessage()` 创建它。`SendOptions` 只持有 `target` 与 `wakeup` 策略。每次获准进入 FIFO 的项都会获得独立的 `InboxItemId`，即使调用方复用了同一个 `MessageId`；`agent/inbox/enqueue`／`update` 及终态 `dequeue` 或 `discard` 都会携带这一完整 `InboxItem`。`target: 'next-turn'` 排队一条独立 FIFO 项，获准后成为其轮次中唯一的普通提示词。`target: 'next-step'` 且 `wakeup: true` 提交 steering（中途引导），而 `target: 'next-step'` 且 `wakeup: false` 注入持久上下文，不运行模型。轮次原理由 [one-send-one-turn Agent Note](../../../.agents/notes/implemented/simplification/2026-07-17-one-send-one-turn.md)拥有。
 - `agent.reserveTurnAdmission()`：在任何已排队唤醒提示词认领其轮次之前，同步预留空闲边界。已获接纳的提示词拥有优先权，包括同一 tick 内仍在等待唤醒的项，此时预留返回 `undefined`。预留期间，之后发送的项保留其普通 ID、FIFO 位置与唤醒信息；`acceptsNextStep` 保持 false，`inject()` 不受阻塞，`whenIdle()` 将该预留计为活动，返回的释放函数可幂等调用。这项范围有限的协调能力使手动压缩（compaction）等独立持久操作能够在排队提示词从会话派生内容前完成并 flush。
-- `agent.updateInbox(itemId, action)`：同步编辑或移除一个仍处于待处理状态的 queued 入队项。编辑会替换已冻结的内容，同时保留其 `MessageId`、`InboxItemId`、来源与 FIFO 位置；移除会发出该项的终态 discard。steering 项和已被认领的项会返回 `not-found`。
+- `agent.updateInbox(itemId, action)`：同步编辑、移除一个仍处于待处理状态的 queued 入队项，或对其执行严格 steering。编辑会替换已冻结的内容，同时保留其 `MessageId`、`InboxItemId`、来源与 FIFO 位置；移除会发出该项的终态 discard。严格 steering 要求 `acceptsNextStep` 为 true；它会结束 queued 单次入队项，并把同一条不可变消息接受为新的 steering 单次入队项，后者使用新的 `InboxItemId`。窗口关闭时返回 `steer-unavailable`，且不做任何变更。待处理 steering 和已被认领的项会返回 `not-found`。
 - `agent.followup(input)`：`send()` 的 `next-turn`／wakeup 预设：排队一个普通后续轮次并唤醒驱动器。
 - `agent.steer(input)`：`next-step`／wakeup 预设：提交一条已有标识的消息，并取得其 `SteeringReceipt`。提示词接纳期间或轮次打开时，消息会为下一个安全请求边界暂存，且不分发 `agent/prompt-submit`；该接收窗口之外则成为会唤醒驱动器的排队提示词。只有循环记录消息、将其捕获到不可变请求历史并提交 `step/start` 后，`receipt.outcome` 才会解析为 `admitted`，并附带轮次与步骤。结束轮次的工具结果、广义取消、dispose（资源释放）或准入前故障会使其解析为 `rejected`；`cancel(..., { keepInbox: true })` 和非终止型路由会保留待处理投递。需要可靠投递的调用方应等待回执；尽力执行的 UI steering 可以忽略它。
 - `agent.inject(input)`：`next-step`／不唤醒预设：追加面向模型的上下文而不运行模型；下一次请求会看到一条逐字的 user role 消息，其来源由必填的 `input.source` 携带。提示词接纳期间或轮次打开时，注入会在 outbox 中等待下一个安全边界。该接收窗口之外，它会立即追加而不开启轮次；如果接纳结束却未开启轮次，仅含上下文的接纳批次会采用这一回退，而与 steering 一同暂存的上下文则会随其继续待处理。持久化独立地响应 `session/event`。注入不发出 `agent/inbox/*` 事件。

packages/core/agent/src/types.ts

@@ -54,9 +54,10 @@ export interface InboxItem {
 export type InboxAction =
   | { readonly kind: 'edit'; readonly content: ContentBlock[] }
   | { readonly kind: 'remove' }
+  | { readonly kind: 'steer' }
 
 /** Result of applying an inbox action at the synchronous ownership boundary. */
-export type InboxActionResult = 'applied' | 'not-found'
+export type InboxActionResult = 'applied' | 'not-found' | 'steer-unavailable'
 
 /** Final admission outcome for one call to {@link Agent.steer}. */
 export type SteeringOutcome =
@@ -209,10 +210,13 @@ export interface Agent {
   /**
    * Mutate one still-pending queued occurrence synchronously. Editing preserves
    * the message identity and queue position; removal publishes its terminal
-   * discard. Steering occurrences and driver-claimed items return `not-found`.
+   * discard. Steer strictly transfers the message into the current next-step
+   * window, or returns `steer-unavailable` without changing the queued
+   * occurrence. Steering occurrences and driver-claimed items return
+   * `not-found`.
    * @param id - independently addressable queued occurrence.
-   * @param action - edit or remove operation.
-   * @returns whether the pending occurrence was found and updated.
+   * @param action - edit, remove, or strict steer operation.
+   * @returns the applied outcome or the reason no mutation occurred.
    */
   updateInbox(id: InboxItemId, action: InboxAction): InboxActionResult
 

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: 933b5f6167263545b3bef5ca9fb8f8b945e86ef9
-README.zh.md: f1f1106dbd0c50889eca6f6ae52fbb29d1c4c03f
+README.md: d4af267ef46f327bdabf31429b291ffd04308203
+README.zh.md: f148cfa0c023b54d62016c5211205d391b634544

packages/host/apiproxy/README.md

@@ -22,7 +22,7 @@ Session model routing is a session-domain contract. `session.models` returns the
 
 Generic Agent-bound session, command, and goal operations serve ordinary sessions only. They return `agent-busy` for a session-backed subagent instead of resuming or driving it; explicit-id `session.create` adoption and the attached-only queue controls enforce the same ownership boundary. Subagent conversation reads and continuation use the dedicated `subagent.*` domain, which retains catalog-mode and direct-parent authorization.
 
-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. `session.cancel` aborts only the active turn and preserves pending inbox work; after cancellation reaches quiescence and the closing turn flushes, AgentLoop claims the next waking occurrence in FIFO order. The browser never resends or promotes that occurrence. A driver claim wins races by retiring the address before admission; a later operation returns `queue-item-not-found`. Queue operations query only an attached Agent and never resume a cold session because process-local inbox identities do not survive restart or disposal. The client never infers retirement from turn or status events.
+Pending inbox input is a live control-plane contract, not session history. The gateway mirrors `InboxItem` occurrences from `agent/inbox/*` with their `queued` or `steering` placement and broadcasts authoritative `session/queue` snapshots on every change and reconnect. A steering occurrence remains in this projection until the corresponding durable `steering/message` has been published, preserving the Host's linear event order during the handoff. `session.updateQueue` addresses one `InboxItemId`: edit replaces pending content, remove discards it, and strict steer transfers its complete message into the current next-step window. A closed window returns `steer-unavailable` without changing the row. `session.cancel` aborts only the active turn and preserves pending inbox work; after cancellation reaches quiescence and the closing turn flushes, AgentLoop claims the next waking occurrence in FIFO order. The browser never resends or promotes that occurrence. A driver claim wins races by retiring the address before admission; a later operation returns `queue-item-not-found`. Queue operations query only an attached ordinary-session Agent and never resume 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({ name })` creates a uniquely titled directory under the configured root, while `workspace.create({ path })` adopts an existing canonical directory and permits basename-derived titles to repeat. `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()`. The `session.list` summaries and `host/session-added` frames also carry the optional durable `origin: 'subagent'` classification so navigation can suppress duplicate child rows immediately and after reconnect; that bit is never continuation authority.
 

packages/host/apiproxy/README.zh.md

@@ -22,7 +22,7 @@
 
 绑定到 Agent 的通用会话、命令与目标操作只服务普通会话。对于由会话支撑的 subagent，它们会返回 `agent-busy`，而不是恢复或驱动它；显式 id 的 `session.create` 接纳与仅针对已附加会话的队列控件也会执行同一所有权边界。subagent 对话读取与继续执行使用专用的 `subagent.*` 领域，该领域保留目录 mode 与直接 parent 授权。
 
-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。`session.cancel` 仅中止活动轮次，并保留待处理 inbox 工作；取消达到完全停稳且结束中的轮次完成 flush 后，AgentLoop 按 FIFO 顺序认领下一个可唤醒入队项。浏览器绝不重发或提升该入队项。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`。队列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。
+待处理的 inbox 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 `InboxItem` 入队项及其 `queued` 或 `steering` placement，并在每次变更和重连时广播权威的 `session/queue` 快照。steering 入队项会一直保留在该投影中，直到对应的持久 `steering/message` 已发布，从而在交接期间保持 Host 的线性事件顺序。`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，严格 steering 会把其完整消息转移到当前 next-step 窗口。窗口关闭时返回 `steer-unavailable`，且不改变该行。`session.cancel` 仅中止活动轮次，并保留待处理 inbox 工作；取消达到完全停稳且结束中的轮次完成 flush 后，AgentLoop 按 FIFO 顺序认领下一个可唤醒入队项。浏览器绝不重发或提升该入队项。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`。队列操作只查询当前已挂载的普通会话 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({ name })` 会在配置根目录下创建显示标题唯一的目录，而 `workspace.create({ path })` 会接纳已有的规范目录，并允许由 basename 派生的标题重复。`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.list` 摘要与 `host/session-added` 帧还会携带可选的持久化分类 `origin: 'subagent'`，使导航在实时创建与重连后都能隐藏重复的 child 行；该标记绝不是继续执行的权威依据。
 

packages/host/apiproxy/src/api-proxy.ts

@@ -776,10 +776,11 @@ export function createApiProxy(ctx: Context, defaults: ApiProxyDefaults): ApiPro
   })
 
   /**
-   * Per-session queued-occurrence mirror serving the mux-open queue snapshot
-   * (the same refresh-recovery baseline as pending questions). Each terminal
-   * queue event retires one matching occurrence, so repeated sends of the same
-   * identified message remain visible until every occurrence is claimed.
+   * Per-session pending-occurrence mirror serving live and mux-open
+   * `session/queue` snapshots. It carries both queued and steering placements.
+   * Each terminal inbox event retires one matching occurrence, so repeated
+   * sends of the same identified message remain visible until every occurrence
+   * is claimed.
    */
   const queuedMirror = new Map<SessionId, InboxItem[]>()
   type UnseenQueueEvent =
@@ -818,29 +819,28 @@ export function createApiProxy(ctx: Context, defaults: ApiProxyDefaults): ApiPro
       sessionId,
       items: items.map(item => ({
         id: item.id,
+        placement: item.placement,
         message: item.message,
       })),
     })
   }
   ctx.effect(() => {
-    const retire = (agent: Agent, item: InboxItem): boolean => {
-      const entries = queuedMirror.get(agent.id)
-      if (entries === undefined) {
-        rememberUnseen(agent.id, item.id, { kind: 'terminal' })
-        return false
-      }
-      const index = entries.findIndex(entry => entry.id === item.id)
-      if (index === -1) {
-        rememberUnseen(agent.id, item.id, { kind: 'terminal' })
-        return false
-      }
+    const retireKnown = (sessionId: SessionId, itemId: InboxItemId): boolean => {
+      const entries = queuedMirror.get(sessionId)
+      if (entries === undefined) return false
+      const index = entries.findIndex(entry => entry.id === itemId)
+      if (index === -1) return false
       entries.splice(index, 1)
-      if (entries.length === 0) queuedMirror.delete(agent.id)
+      if (entries.length === 0) queuedMirror.delete(sessionId)
       return true
     }
+    const retire = (agent: Agent, item: InboxItem): boolean => {
+      if (retireKnown(agent.id, item.id)) return true
+      rememberUnseen(agent.id, item.id, { kind: 'terminal' })
+      return false
+    }
     const disposers = [
       ctx.on('agent/inbox/enqueue', (agent: Agent, item: InboxItem) => {
-        if (item.placement !== 'queued') return
         const unseen = takeUnseen(agent.id, item.id)
         if (unseen?.kind === 'terminal') return
         let entries = queuedMirror.get(agent.id)
@@ -866,7 +866,24 @@ export function createApiProxy(ctx: Context, defaults: ApiProxyDefaults): ApiPro
         publishQueue(agent.id)
       }),
       ctx.on('agent/inbox/dequeue', (agent: Agent, item: InboxItem) => {
-        if (retire(agent, item)) publishQueue(agent.id)
+        if (item.placement === 'steering') {
+          // AgentLoop appends the durable steering/message synchronously after
+          // this claim. Retain and retire the mirror row in the following
+          // microtask so any re-entrant snapshot and the Host's linear mux
+          // stream keep it visible until the durable event exists.
+          const present = queuedMirror.get(agent.id)?.some(entry => entry.id === item.id) === true
+          if (!present) {
+            retire(agent, item)
+            return
+          }
+          queueMicrotask(() => {
+            if (retireKnown(agent.id, item.id)) publishQueue(agent.id)
+          })
+        } else if (retire(agent, item)) {
+          // Queued claims have no durable same-message handoff to order.
+          // Publish retirement synchronously as before.
+          publishQueue(agent.id)
+        }
       }),
       ctx.on('agent/inbox/discard', (agent: Agent, items: InboxItem[]) => {
         let changed = false
@@ -1847,13 +1864,28 @@ export function createApiProxy(ctx: Context, defaults: ApiProxyDefaults): ApiPro
         if (agent !== undefined && hasSubagentOwner(agent.session, agent)) {
           return Promise.resolve(err(request, subagentOwnershipError(sessionId)))
         }
-        if (agent === undefined || agent.updateInbox(itemId, action) === 'not-found') {
+        if (agent === undefined) {
           return Promise.resolve(err(request, {
             code: 'queue-item-not-found',
             message: 'queued item is no longer pending',
             details: { itemId },
           }))
         }
+        const result = agent.updateInbox(itemId, action)
+        if (result === 'not-found') {
+          return Promise.resolve(err(request, {
+            code: 'queue-item-not-found',
+            message: 'queued item is no longer pending',
+            details: { itemId },
+          }))
+        }
+        if (result === 'steer-unavailable') {
+          return Promise.resolve(err(request, {
+            code: 'steer-unavailable',
+            message: 'current turn no longer accepts steering',
+            details: { itemId },
+          }))
+        }
         return Promise.resolve(ok(request, { accepted: true as const }))
       },
 
@@ -2494,6 +2526,7 @@ export function createApiProxy(ctx: Context, defaults: ApiProxyDefaults): ApiPro
             sessionId,
             items: items.map(item => ({
               id: item.id,
+              placement: item.placement,
               message: item.message,
             })),
           }))

packages/host/apiproxy/src/api/events.schema.ts

@@ -54,6 +54,7 @@ export const muxFrameSchema = z.discriminatedUnion('type', [
     sessionId: sessionIdSchema,
     items: z.array(z.object({
       id: inboxItemIdSchema,
+      placement: z.union([z.literal('queued'), z.literal('steering')]),
       message: messageSchema,
     })),
   }),

packages/host/apiproxy/src/api/events.ts

@@ -32,10 +32,12 @@ export type ToolEventView =
   | { for: 'call'; view: ToolCallView }
   | { for: 'result'; view: ToolResultView }
 
-/** One pending queued occurrence in an authoritative queue snapshot. */
+/** One pending inbox occurrence in the authoritative `session/queue` snapshot. */
 export interface QueuedInboxItem {
-  /** Agent-owned occurrence identity used by queue mutations. */
+  /** Agent-owned occurrence identity; queue mutations address only `queued` items. */
   id: InboxItemId
+  /** Agent-resolved FIFO placement; clients render queued and steering items on different surfaces. */
+  placement: 'queued' | 'steering'
   /** Complete pending message; it is not durable until the Agent claims it. */
   message: Message
 }
@@ -71,11 +73,12 @@ export type MuxFrame =
   | { type: 'question/requested'; sessionId: SessionId; questions: AskUserQuestionItem[] }
   | { type: 'question/resolved'; sessionId: SessionId; questionRpcId: RpcId; outcome: 'answered' | 'cancelled' }
   /**
-   * Complete transient queue state after every enqueue, mutation, claim, or
+   * Complete transient inbox state after every enqueue, mutation, claim, or
    * discard. Pending work is not model-visible and therefore has no durable
    * session event; the whole snapshot makes edit, deletion, cancel, and
-   * reconnect converge through one authoritative signal. Pending steering is
-   * outside this Web queue projection.
+   * reconnect converge through one authoritative signal. `session/queue`
+   * covers both resolved placements: queued items render
+   * in QueueDock, while pending steering renders at the conversation tail.
    */
   | { type: 'session/queue'; sessionId: SessionId; items: QueuedInboxItem[] }
   /**

packages/host/apiproxy/src/api/rpc.schema.ts

@@ -48,6 +48,7 @@ export const rpcErrorSchema: z.ZodType<RpcError> = z.discriminatedUnion('code',
   z.object({ code: z.literal('directory-picker-unavailable'), message: z.string(), details: z.object({ capability: z.string() }) }),
   z.object({ code: z.literal('agent-busy'), message: z.string(), details: z.object({ reason: z.string() }) }),
   z.object({ code: z.literal('queue-item-not-found'), message: z.string(), details: z.object({ itemId: z.string() }) }),
+  z.object({ code: z.literal('steer-unavailable'), message: z.string(), details: z.object({ itemId: z.string() }) }),
   z.object({ code: z.literal('command-error'), message: z.string(), details: z.object({}) }),
   z.object({ code: z.literal('unknown-command'), message: z.string(), details: z.object({}) }),
   z.object({ code: z.literal('settings-rejected'), message: z.string(), details: z.object({ ns: z.string() }) }),

packages/host/apiproxy/src/api/rpc.ts

@@ -46,6 +46,7 @@ export interface RpcErrorDetailsMap {
   'directory-picker-unavailable': { capability: string }
   'agent-busy': { reason: string }
   'queue-item-not-found': { itemId: InboxItemId }
+  'steer-unavailable': { itemId: InboxItemId }
   /** A known slash command reported a usage/state error; the message is the command's own text. */
   'command-error': {}
   /** A leading-/ prompt named no registered command; the message names the token. */

packages/host/apiproxy/src/api/sessions.schema.ts

@@ -269,6 +269,7 @@ export const sessionUpdateQueueRequestSchema = z.object({
   action: z.discriminatedUnion('kind', [
     z.object({ kind: z.literal('edit'), content: z.array(contentBlockSchema) }),
     z.object({ kind: z.literal('remove') }),
+    z.object({ kind: z.literal('steer') }),
   ]),
 }) as unknown as z.ZodType<RequestPayload<'session.updateQueue'>>
 

packages/host/apiproxy/src/api/sessions.ts

@@ -129,6 +129,7 @@ export interface SessionModels {
 export type QueueAction =
   | { kind: 'edit'; content: ContentBlock[] }
   | { kind: 'remove' }
+  | { kind: 'steer' }
 
 /** Session list entry (v1 builds no index: list does readdir+stat). */
 export interface SessionSummary {
@@ -285,7 +286,7 @@ export interface SessionsApi {
   Promise<RpcResponse<{ accepted: true; command?: { kind: 'success'; text?: string } }>>
 
   /**
-   * Edits or removes one pending queued occurrence on an ordinary session.
+   * Edits, removes, or strictly steers one pending queued occurrence on an ordinary session.
    * Session-backed subagents reject with `agent-busy`.
    */
   updateQueue(request: RpcRequest<{ sessionId: SessionId; itemId: InboxItemId; action: QueueAction }>):

packages/host/apiproxy/tests/api-proxy-commands.spec.ts

@@ -291,13 +291,14 @@ function inboxItem(id: string, message: UserMessage, placement: InboxPlacement):
 }
 
 describe('session.updateQueue', () => {
-  it('routes an addressable action and reports a lost claim race', async () => {
+  it('routes addressable actions and reports strict steer races', async () => {
     const ctx = await harness()
     const agent = stubAgent(ctx)
     const seen: unknown[] = []
     agent.updateInbox = (id, action) => {
       seen.push({ id, action })
-      return id === InboxItemId('present') ? 'applied' : 'not-found'
+      if (id === InboxItemId('present')) return 'applied'
+      return id === InboxItemId('closed') ? 'steer-unavailable' : 'not-found'
     }
     const api = createApiProxy(ctx, DEFAULTS)
 
@@ -319,9 +320,22 @@ describe('session.updateQueue', () => {
       },
     })
     expect(expectErr(missing)).toMatchObject({ code: 'queue-item-not-found' })
+    const closed = await api.sessions.updateQueue({
+      rpcId: RpcId('q-closed'),
+      payload: {
+        sessionId: agent.id,
+        itemId: InboxItemId('closed'),
+        action: { kind: 'steer' },
+      },
+    })
+    expect(expectErr(closed)).toMatchObject({
+      code: 'steer-unavailable',
+      details: { itemId: 'closed' },
+    })
     expect(seen).toEqual([
       { id: 'present', action: { kind: 'edit', content: [{ type: 'text', text: 'edited' }] } },
       { id: 'claimed', action: { kind: 'remove' } },
+      { id: 'closed', action: { kind: 'steer' } },
     ])
   })
 
@@ -365,7 +379,7 @@ describe('session/queue frames', () => {
 
     const liveFrames = (await collected).filter(frame => frame.type === 'session/queue')
     expect(liveFrames.map(frame => frame.items)).toEqual([
-      [{ id: edited.id, message: edited.message }],
+      [{ id: edited.id, placement: edited.placement, message: edited.message }],
     ])
     const replay = new AbortController()
     const replayFrames = await collect<MuxFrame>(
@@ -373,14 +387,41 @@ describe('session/queue frames', () => {
     expect(replayFrames.filter(frame => frame.type === 'session/queue')).toEqual(liveFrames)
   })
 
+  it('expires unmatched mutations after the synchronous re-entry window', async () => {
+    const ctx = await harness()
+    const agent = stubAgent(ctx)
+    const api = createApiProxy(ctx, DEFAULTS)
+    const original = inboxItem('i-stale-edit', inboxMessage('m-stale-edit', 'original'), 'queued')
+    const staleEdit = inboxItem('i-stale-edit', inboxMessage('m-stale-edit', 'stale edit'), 'queued')
+    const staleTerminal = inboxItem('i-stale-terminal', inboxMessage('m-stale-terminal', 'keep me'), 'queued')
+
+    ctx.emit('agent/inbox/update', agent, staleEdit)
+    ctx.emit('agent/inbox/discard', agent, [staleTerminal])
+    await Promise.resolve()
+    ctx.emit('agent/inbox/enqueue', agent, original)
+    ctx.emit('agent/inbox/enqueue', agent, staleTerminal)
+
+    const replay = new AbortController()
+    const frames = await collect<MuxFrame>(
+      api.events.mux({ rpcId: RpcId('t-mux-expired-unseen'), payload: {} }, replay.signal), 2, replay)
+    expect(frames.filter(frame => frame.type === 'session/queue')).toEqual([{
+      type: 'session/queue',
+      sessionId: agent.id,
+      items: [
+        { id: original.id, placement: original.placement, message: original.message },
+        { id: staleTerminal.id, placement: staleTerminal.placement, message: staleTerminal.message },
+      ],
+    }])
+  })
+
   it('publishes complete live snapshots and replays the latest snapshot on reconnect', async () => {
     const ctx = await harness()
     const api = createApiProxy(ctx, DEFAULTS)
     const agent = stubAgent(ctx)
     const live = new AbortController()
     const liveStream = api.events.mux({ rpcId: RpcId('t-mux-live'), payload: {} }, live.signal)
-    // subscribed baseline + one queued snapshot; pending steering stays off this wire.
-    const liveCollected = collect<MuxFrame>(liveStream, 2, live)
+    // subscribed baseline + one snapshot per accepted inbox occurrence.
+    const liveCollected = collect<MuxFrame>(liveStream, 3, live)
 
     const queued = inboxItem('i-1', inboxMessage('m-1', 'queued prompt'), 'queued')
     const steering = inboxItem('i-2', inboxMessage('m-2', 'steering prompt'), 'steering')
@@ -392,7 +433,15 @@ describe('session/queue frames', () => {
       {
         type: 'session/queue',
         sessionId: agent.id,
-        items: [{ id: queued.id, message: queued.message }],
+        items: [{ id: queued.id, placement: 'queued', message: queued.message }],
+      },
+      {
+        type: 'session/queue',
+        sessionId: agent.id,
+        items: [
+          { id: queued.id, placement: 'queued', message: queued.message },
+          { id: steering.id, placement: 'steering', message: steering.message },
+        ],
       },
     ])
 
@@ -400,7 +449,88 @@ describe('session/queue frames', () => {
     const replay = new AbortController()
     const replayFrames = await collect<MuxFrame>(
       api.events.mux({ rpcId: RpcId('t-mux-replay'), payload: {} }, replay.signal), 2, replay)
-    expect(replayFrames.filter(f => f.type === 'session/queue')).toEqual([liveFrames[0]])
+    expect(replayFrames.filter(f => f.type === 'session/queue')).toEqual([liveFrames[1]])
+  })
+
+  it('publishes the durable steering event before retiring its transient row', async () => {
+    const ctx = await harness()
+    const api = createApiProxy(ctx, DEFAULTS)
+    const agent = stubAgent(ctx)
+    const abort = new AbortController()
+    const collected = collect<MuxFrame>(
+      api.events.mux({ rpcId: RpcId('t-steering-order'), payload: {} }, abort.signal), 5, abort)
+    const steering = inboxItem('i-steering', inboxMessage('m-steering', 'interrupt now'), 'steering')
+
+    agent.session.append('turn/start', {
+      turn: 1,
+      trigger: { kind: 'message', source: { kind: 'user' } },
+    })
+    ctx.emit('agent/inbox/enqueue', agent, steering)
+    ctx.emit('agent/inbox/dequeue', agent, steering)
+    agent.session.append('steering/message', {
+      turn: 1,
+      message: steering.message,
+    }, { surfaceOp: 'append' })
+
+    const frames = await collected
+    expect(frames.map(frame => frame.type)).toEqual([
+      'session/subscribed',
+      'session/event',
+      'session/queue',
+      'session/event',
+      'session/queue',
+    ])
+    expect(frames[2]).toMatchObject({
+      type: 'session/queue',
+      items: [{ id: steering.id, placement: 'steering' }],
+    })
+    expect(frames[3]).toMatchObject({
+      type: 'session/event',
+      event: { type: 'steering/message', data: { message: { id: steering.message.id } } },
+    })
+    expect(frames[4]).toMatchObject({ type: 'session/queue', items: [] })
+  })
+
+  it('retains claimed steering in re-entrant snapshots until its durable event', async () => {
+    const ctx = await harness()
+    const api = createApiProxy(ctx, DEFAULTS)
+    const agent = stubAgent(ctx)
+    const steering = inboxItem('i-steering', inboxMessage('m-steering', 'interrupt now'), 'steering')
+    const queued = inboxItem('i-reentrant', inboxMessage('m-reentrant', 'later'), 'queued')
+    ctx.on('agent/inbox/dequeue', (subject, item) => {
+      if (subject === agent && item.id === steering.id) ctx.emit('agent/inbox/enqueue', agent, queued)
+    })
+    const abort = new AbortController()
+    const collected = collect<MuxFrame>(
+      api.events.mux({ rpcId: RpcId('t-steering-reentrant-order'), payload: {} }, abort.signal), 6, abort)
+
+    agent.session.append('turn/start', {
+      turn: 1,
+      trigger: { kind: 'message', source: { kind: 'user' } },
+    })
+    ctx.emit('agent/inbox/enqueue', agent, steering)
+    ctx.emit('agent/inbox/dequeue', agent, steering)
+    agent.session.append('steering/message', {
+      turn: 1,
+      message: steering.message,
+    }, { surfaceOp: 'append' })
+
+    const frames = await collected
+    expect(frames[3]).toMatchObject({
+      type: 'session/queue',
+      items: [
+        { id: steering.id, placement: 'steering' },
+        { id: queued.id, placement: 'queued' },
+      ],
+    })
+    expect(frames[4]).toMatchObject({
+      type: 'session/event',
+      event: { type: 'steering/message', data: { message: { id: steering.message.id } } },
+    })
+    expect(frames[5]).toMatchObject({
+      type: 'session/queue',
+      items: [{ id: queued.id, placement: 'queued' }],
+    })
   })
 
   it('publishes edits in place in the authoritative order', async () => {
@@ -420,10 +550,16 @@ describe('session/queue frames', () => {
 
     const frames = (await collected).filter(frame => frame.type === 'session/queue')
     expect(frames.map(frame => frame.items)).toEqual([
-      [{ id: first.id, message: first.message }],
-      [{ id: first.id, message: first.message }, { id: second.id, message: second.message }],
-      [{ id: first.id, message: first.message }, { id: edited.id, message: edited.message }],
-      [{ id: first.id, message: first.message }],
+      [{ id: first.id, placement: first.placement, message: first.message }],
+      [
+        { id: first.id, placement: first.placement, message: first.message },
+        { id: second.id, placement: second.placement, message: second.message },
+      ],
+      [
+        { id: first.id, placement: first.placement, message: first.message },
+        { id: edited.id, placement: edited.placement, message: edited.message },
+      ],
+      [{ id: first.id, placement: first.placement, message: first.message }],
     ])
   })
 

packages/host/apiproxy/tests/rpc-schemas.spec.ts

@@ -77,6 +77,7 @@ describe('rpcErrorSchema', () => {
     }).code).toBe('model-unavailable')
     expect(rpcErrorSchema.parse({ code: 'agent-busy', message: 'm', details: { reason: 'r' } }).code).toBe('agent-busy')
     expect(rpcErrorSchema.parse({ code: 'queue-item-not-found', message: 'm', details: { itemId: 'i' } }).code).toBe('queue-item-not-found')
+    expect(rpcErrorSchema.parse({ code: 'steer-unavailable', message: 'm', details: { itemId: 'i' } }).code).toBe('steer-unavailable')
     expect(rpcErrorSchema.parse({ code: 'command-error', message: 'm', details: {} }).code).toBe('command-error')
     expect(rpcErrorSchema.parse({ code: 'unknown-command', message: 'm', details: {} }).code).toBe('unknown-command')
     expect(rpcErrorSchema.parse({ code: 'title-invalid', message: 'm', details: { sessionId: 's' } }).code).toBe('title-invalid')
@@ -280,6 +281,9 @@ describe('sessions domain schemas', () => {
     expect(sessionUpdateQueueRequestSchema.parse({
       sessionId: 's1', itemId: 'i1', action: { kind: 'remove' },
     }).action.kind).toBe('remove')
+    expect(sessionUpdateQueueRequestSchema.parse({
+      sessionId: 's1', itemId: 'i1', action: { kind: 'steer' },
+    }).action.kind).toBe('steer')
     expect(() => sessionUpdateQueueRequestSchema.parse({
       sessionId: 's1', itemId: 'i1', action: { kind: 'promote' },
     })).toThrow()
@@ -477,7 +481,7 @@ describe('events frame schemas', () => {
       { type: 'question/requested', sessionId: 's', questions: [{ id: 'q', question: 'Q?', options: [{ label: 'L' }], multiSelect: true }] },
       { type: 'question/resolved', sessionId: 's', questionRpcId: 'r', outcome: 'answered' },
       { type: 'session/queue', sessionId: 's', items: [
-        { id: 'i1', message: { id: 'm1', role: 'user', content: [{ type: 'text', text: 'queued prompt' }], source: { kind: 'user', rpcId: 'r9' } } },
+        { id: 'i1', placement: 'steering', message: { id: 'm1', role: 'user', content: [{ type: 'text', text: 'queued prompt' }], source: { kind: 'user', rpcId: 'r9' } } },
       ] },
       { type: 'session/projection', sessionId: 's', key: 'todos', value: [{ content: 'x', status: 'pending' }], seq: 7 },
       { type: 'stream/error', error: { code: 'internal', message: 'm', details: {} } },