diff --git a/.agents/notes/implemented/architecture/2026-07-22-unified-send-and-coalesced-user-messages.i18n.yaml b/.agents/notes/implemented/architecture/2026-07-22-unified-send-and-coalesced-user-messages.i18n.yaml
index 00fe96d2f2..cbf529c8aa 100644
--- a/.agents/notes/implemented/architecture/2026-07-22-unified-send-and-coalesced-user-messages.i18n.yaml
+++ b/.agents/notes/implemented/architecture/2026-07-22-unified-send-and-coalesced-user-messages.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
-2026-07-22-unified-send-and-coalesced-user-messages.md: 61f9775c7b99c783a86e6a0814dc69d548ecbbe1
-2026-07-22-unified-send-and-coalesced-user-messages.zh.md: d9ce4c482203592b8e5aada976debb6f088bb1eb
+2026-07-22-unified-send-and-coalesced-user-messages.md: d88cd60f5c09f7961d7a59dbbd0703abdd26cc1a
+2026-07-22-unified-send-and-coalesced-user-messages.zh.md: d16ed9f763a350e61abc00d3971e4a7711e8f610
diff --git a/.agents/notes/implemented/architecture/2026-07-22-unified-send-and-coalesced-user-messages.md b/.agents/notes/implemented/architecture/2026-07-22-unified-send-and-coalesced-user-messages.md
index 61f9775c7b..d88cd60f5c 100644
--- a/.agents/notes/implemented/architecture/2026-07-22-unified-send-and-coalesced-user-messages.md
+++ b/.agents/notes/implemented/architecture/2026-07-22-unified-send-and-coalesced-user-messages.md
@@ -20,7 +20,9 @@ Separately, `context/message` and `user/message` had converged: the surface proj
 
 **Goal replay disambiguates by round, not type.** A goal state change is a round-zero goal-sourced `user/message` carrying `goal/change` metadata; a positive round is an admitted continuation prompt. `decodeGoalEvent` now takes a `user/message` and still fails loud on goal metadata under a non-goal source or a goal source lacking metadata.
 
-**Three inbox events replace agent/queued.** `agent/inbox/enqueue` (an item entered a FIFO; carries `target`/`wakeup` on `InboxItemInfo`), `agent/inbox/dequeue` (the driver claimed one), and `agent/inbox/discard` (`cancel()` dropped pending items). Injection never touches a FIFO and emits none of these. Every FIFO entry publishes an enqueue, including the loop-authored continuation-reason steer (`agent/turn-continuation` returning `{ action: 'continue', reason }`), so the ledger stays balanced with its later dequeue or discard. The `dsh-agent` invariant companion asserts FIFO conservation: a per-agent outstanding count that dequeue and discard can never drive negative.
+**`send` returns an id.** `send` (and the aliases) return an opaque branded `AgentMessageId` for the accepted message; `send`'s previous return was `void`.
+
+**Three inbox events replace agent/queued.** `agent/inbox/enqueue` (an item entered a FIFO), `agent/inbox/dequeue` (the driver claimed one), and `agent/inbox/discard` (`cancel()` dropped pending items) each carry an `AgentMessage` — the accepted message including its returned `id`, `target`/`wakeup`, source, and contexts — so a caller can correlate a queued item with its lifecycle. Injection never touches a FIFO and emits none of these. Every FIFO entry publishes an enqueue, including the loop-authored continuation-reason steer (`agent/turn-continuation` returning `{ action: 'continue', reason }`), so the ledger stays balanced with its later dequeue or discard. The `dsh-agent` invariant companion asserts FIFO conservation: a per-agent outstanding count that dequeue and discard can never drive negative.
 
 **cancel gains keepInbox.** `cancel(cause?, { keepInbox? })`; when true it aborts the active turn but preserves queued and steering items (no discard event, and un-started work is not dropped).
 
diff --git a/.agents/notes/implemented/architecture/2026-07-22-unified-send-and-coalesced-user-messages.zh.md b/.agents/notes/implemented/architecture/2026-07-22-unified-send-and-coalesced-user-messages.zh.md
index d9ce4c4822..d16ed9f763 100644
--- a/.agents/notes/implemented/architecture/2026-07-22-unified-send-and-coalesced-user-messages.zh.md
+++ b/.agents/notes/implemented/architecture/2026-07-22-unified-send-and-coalesced-user-messages.zh.md
@@ -20,7 +20,9 @@ agent 的对外驱动接口逐渐长出三个近乎平行的动词——`send`
 
 **goal 回放靠轮次而非类型来区分。** 一次 goal 状态变更是一条第 0 轮、来源为 goal 的 `user/message`，携带 `goal/change` 元数据；正数轮次则是一条已准入的继续执行提示词。`decodeGoalEvent` 现在接收一条 `user/message`，并仍会在非 goal 来源携带 goal 元数据、或 goal 来源缺少元数据时立即报错。
 
-**三个 inbox 事件取代 agent/queued。** `agent/inbox/enqueue`（一个队列项进入某个 FIFO；在 `InboxItemInfo` 上携带 `target`/`wakeup`）、`agent/inbox/dequeue`（驱动器认领了一个）和 `agent/inbox/discard`（`cancel()` 丢弃了待处理项）。注入从不触及 FIFO，也不发出这些事件中的任何一个。每一次 FIFO 入队都会发布一个 enqueue 事件，包括由 loop 生成的携带继续原因的 steer（`agent/turn-continuation` 返回 `{ action: 'continue', reason }`），因此账目会与其后的 dequeue 或 discard 保持平衡。`dsh-agent` 的不变量配套断言 FIFO 守恒：一个按 agent 计的未结算计数，dequeue 和 discard 永远无法把它压到负数。
+**`send` 返回一个 id。** `send`（以及其别名）为被接受的消息返回一个不透明的 branded `AgentMessageId`；`send` 此前的返回值是 `void`。
+
+**三个 inbox 事件取代 agent/queued。** `agent/inbox/enqueue`（一个队列项进入某个 FIFO）、`agent/inbox/dequeue`（驱动器认领了一个）和 `agent/inbox/discard`（`cancel()` 丢弃了待处理项）都携带一条 `AgentMessage`——即被接受的消息，包含其返回的 `id`、`target`/`wakeup`、来源和上下文——因此调用方可以把一个排队项与其生命周期关联起来。注入从不触及 FIFO，也不发出这些事件中的任何一个。每一次 FIFO 入队都会发布一个 enqueue 事件，包括由 loop 生成的携带继续原因的 steer（`agent/turn-continuation` 返回 `{ action: 'continue', reason }`），因此账目会与其后的 dequeue 或 discard 保持平衡。`dsh-agent` 的不变量配套断言 FIFO 守恒：一个按 agent 计的未结算计数，dequeue 和 discard 永远无法把它压到负数。
 
 **cancel 新增 keepInbox。** `cancel(cause?, { keepInbox? })`；当其为 true 时，它中止活跃轮次，但保留排队项和 steering 项（不发出 discard 事件，尚未启动的工作也不会被丢弃）。
 
diff --git a/docs/cordis-catalog/events.md b/docs/cordis-catalog/events.md
index 7c9ae4bea8..d61b126661 100644
--- a/docs/cordis-catalog/events.md
+++ b/docs/cordis-catalog/events.md
@@ -32,7 +32,7 @@ Effective broad cancellation was requested, before queued/steering work is clear
 
 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:329`](../../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:269`](../../packages/core/agent/src/types.ts)
+Source: [`packages/core/agent/src/types.ts:293`](../../packages/core/agent/src/types.ts)
 
 ### `agent/disposed` — emit
 
@@ -74,7 +74,7 @@ An agent left the registry; AgentLoop emits this after driver quiescence but bef
 
 Types: [Agent](../core-data-structures/core.md) · [Scoped](../core-data-structures/scope.md)
 
-Source: [`packages/core/agent/src/types.ts:278`](../../packages/core/agent/src/types.ts)
+Source: [`packages/core/agent/src/types.ts:302`](../../packages/core/agent/src/types.ts)
 
 ### `agent/error` — emit
 
@@ -96,7 +96,7 @@ A step or turn errored. The loop reports a failure here (plus the logger) even w
 
 Types: [Agent](../core-data-structures/core.md) · [Scoped](../core-data-structures/scope.md)
 
-Source: [`packages/core/agent/src/types.ts:477`](../../packages/core/agent/src/types.ts)
+Source: [`packages/core/agent/src/types.ts:501`](../../packages/core/agent/src/types.ts)
 
 ### `agent/inbox/dequeue` — emit
 
@@ -108,16 +108,16 @@ The driver claimed one item out of the inbox: a queued item at a turn boundary,
  * boundary, or steering drained between steps. Fires after the item leaves
  * its FIFO and before it becomes a durable message.
  * @param agent - the agent whose inbox item was claimed.
- * @param info - the claimed item's accepted content, source, contexts, steering, and wakeup facts.
+ * @param message - the claimed message (matching the `id` from its `agent/inbox/enqueue`).
  * Scope-filtered dispatch (`@deepseek-ai/dsh-scope`): agent-scoped listeners receive only that agent.
  * @mode emit
  */
-'agent/inbox/dequeue'(this: Scoped<Agent>, agent: Agent, info: InboxItemInfo): void
+'agent/inbox/dequeue'(this: Scoped<Agent>, agent: Agent, message: AgentMessage): void
 ```
 
-Types: [Agent](../core-data-structures/core.md) · [InboxItemInfo](../core-data-structures/core.md) · [Scoped](../core-data-structures/scope.md)
+Types: [Agent](../core-data-structures/core.md) · [AgentMessage](../core-data-structures/core.md) · [Scoped](../core-data-structures/scope.md)
 
-Source: [`packages/core/agent/src/types.ts:309`](../../packages/core/agent/src/types.ts)
+Source: [`packages/core/agent/src/types.ts:333`](../../packages/core/agent/src/types.ts)
 
 ### `agent/inbox/discard` — emit
 
@@ -129,16 +129,16 @@ Source: [`packages/core/agent/src/types.ts:309`](../../packages/core/agent/src/t
  * delivering them. Fires once per effective clearing call with every
  * discarded item, after `agent/cancel-requested` and before the abort.
  * @param agent - the agent whose inbox was cleared.
- * @param items - the discarded items in FIFO order (queued then steering); empty when nothing was pending.
+ * @param messages - the discarded messages in FIFO order (queued then steering); empty when nothing was pending.
  * Scope-filtered dispatch (`@deepseek-ai/dsh-scope`): agent-scoped listeners receive only that agent.
  * @mode emit
  */
-'agent/inbox/discard'(this: Scoped<Agent>, agent: Agent, items: InboxItemInfo[]): void
+'agent/inbox/discard'(this: Scoped<Agent>, agent: Agent, messages: AgentMessage[]): void
 ```
 
-Types: [Agent](../core-data-structures/core.md) · [InboxItemInfo](../core-data-structures/core.md) · [Scoped](../core-data-structures/scope.md)
+Types: [Agent](../core-data-structures/core.md) · [AgentMessage](../core-data-structures/core.md) · [Scoped](../core-data-structures/scope.md)
 
-Source: [`packages/core/agent/src/types.ts:319`](../../packages/core/agent/src/types.ts)
+Source: [`packages/core/agent/src/types.ts:343`](../../packages/core/agent/src/types.ts)
 
 ### `agent/inbox/enqueue` — emit
 
@@ -152,16 +152,16 @@ A detached, frozen item entered the agent's inbox (queued or steering FIFO). Sou
  * is the eventual `user/message`/`steering/message`. Injection
  * (`next-step`/no-wakeup) bypasses the FIFOs and does not emit this.
  * @param agent - the agent whose inbox received the item.
- * @param info - the accepted content, source, contexts, steering, and wakeup facts.
+ * @param message - the accepted message (its returned `id`, content, source, contexts, steering, and wakeup facts).
  * Scope-filtered dispatch (`@deepseek-ai/dsh-scope`): agent-scoped listeners receive only that agent.
  * @mode emit
  */
-'agent/inbox/enqueue'(this: Scoped<Agent>, agent: Agent, info: InboxItemInfo): void
+'agent/inbox/enqueue'(this: Scoped<Agent>, agent: Agent, message: AgentMessage): void
 ```
 
-Types: [Agent](../core-data-structures/core.md) · [InboxItemInfo](../core-data-structures/core.md) · [Scoped](../core-data-structures/scope.md)
+Types: [Agent](../core-data-structures/core.md) · [AgentMessage](../core-data-structures/core.md) · [Scoped](../core-data-structures/scope.md)
 
-Source: [`packages/core/agent/src/types.ts:299`](../../packages/core/agent/src/types.ts)
+Source: [`packages/core/agent/src/types.ts:323`](../../packages/core/agent/src/types.ts)
 
 ### `agent/post-step` — serial
 
@@ -184,7 +184,7 @@ Awaited serial checkpoint after the response, real or synthetic tool results, in
 
 Types: [Agent](../core-data-structures/core.md) · [Scoped](../core-data-structures/scope.md)
 
-Source: [`packages/core/agent/src/types.ts:427`](../../packages/core/agent/src/types.ts)
+Source: [`packages/core/agent/src/types.ts:451`](../../packages/core/agent/src/types.ts)
 
 ### `agent/pre-step` — serial
 
@@ -207,7 +207,7 @@ Awaited serial checkpoint before `step/start`; appends land outside the pending
 
 Types: [Agent](../core-data-structures/core.md) · [Scoped](../core-data-structures/scope.md)
 
-Source: [`packages/core/agent/src/types.ts:358`](../../packages/core/agent/src/types.ts)
+Source: [`packages/core/agent/src/types.ts:382`](../../packages/core/agent/src/types.ts)
 
 ### `agent/prompt-submit` — waterfall
 
@@ -234,7 +234,7 @@ Allow, rewrite, or block one claimed prompt before it becomes a user message. Ca
 
 Types: [Agent](../core-data-structures/core.md) · [ContentBlock](../core-data-structures/core.md) · [MessageSource](../core-data-structures/core.md) · [PromptDecision](../core-data-structures/core.md) · [Scoped](../core-data-structures/scope.md)
 
-Source: [`packages/core/agent/src/types.ts:374`](../../packages/core/agent/src/types.ts)
+Source: [`packages/core/agent/src/types.ts:398`](../../packages/core/agent/src/types.ts)
 
 ### `agent/request` — waterfall
 
@@ -259,7 +259,7 @@ Replace the frozen call configuration. Model-visible content must use logged cha
 
 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:388`](../../packages/core/agent/src/types.ts)
+Source: [`packages/core/agent/src/types.ts:412`](../../packages/core/agent/src/types.ts)
 
 ### `agent/request-error` — waterfall
 
@@ -285,7 +285,7 @@ Recover a model-request failure after its failed step has closed. `retry` opens
 
 Types: [Agent](../core-data-structures/core.md) · [LlmFailure](../core-data-structures/llm-streaming.md) · [RequestError](../core-data-structures/core.md) · [RequestErrorDecision](../core-data-structures/core.md) · [Scoped](../core-data-structures/scope.md)
 
-Source: [`packages/core/agent/src/types.ts:442`](../../packages/core/agent/src/types.ts)
+Source: [`packages/core/agent/src/types.ts:466`](../../packages/core/agent/src/types.ts)
 
 ### `agent/session-prefix` — waterfall
 
@@ -311,7 +311,7 @@ Compose request-only messages placed before derived history. The frozen result i
 
 Types: [Agent](../core-data-structures/core.md) · [Message](../core-data-structures/core.md) · [Scoped](../core-data-structures/scope.md)
 
-Source: [`packages/core/agent/src/types.ts:403`](../../packages/core/agent/src/types.ts)
+Source: [`packages/core/agent/src/types.ts:427`](../../packages/core/agent/src/types.ts)
 
 ### `agent/session-start` — emit
 
@@ -333,7 +333,7 @@ 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:342`](../../packages/core/agent/src/types.ts)
+Source: [`packages/core/agent/src/types.ts:366`](../../packages/core/agent/src/types.ts)
 
 ### `agent/status` — emit
 
@@ -353,7 +353,7 @@ Agent status changed (`idle` ⇄ `running`, or → `disposed`). `send()` does no
 
 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:287`](../../packages/core/agent/src/types.ts)
+Source: [`packages/core/agent/src/types.ts:311`](../../packages/core/agent/src/types.ts)
 
 ### `agent/step-result` — waterfall
 
@@ -376,7 +376,7 @@ Waterfall: post-process the assembled assistant Message before tool dispatch (va
 
 Types: [Agent](../core-data-structures/core.md) · [Message](../core-data-structures/core.md) · [Scoped](../core-data-structures/scope.md)
 
-Source: [`packages/core/agent/src/types.ts:415`](../../packages/core/agent/src/types.ts)
+Source: [`packages/core/agent/src/types.ts:439`](../../packages/core/agent/src/types.ts)
 
 ### `agent/turn-continuation` — waterfall
 
@@ -398,7 +398,7 @@ Override whether the turn continues. The default continues after tool calls or s
 
 Types: [Agent](../core-data-structures/core.md) · [ContinuationDecision](../core-data-structures/core.md) · [Scoped](../core-data-structures/scope.md)
 
-Source: [`packages/core/agent/src/types.ts:453`](../../packages/core/agent/src/types.ts)
+Source: [`packages/core/agent/src/types.ts:477`](../../packages/core/agent/src/types.ts)
 
 ### `agent/turn-stop` — serial
 
@@ -420,7 +420,7 @@ Monotonic terminal-stop checkpoint after continuation and steering are folded; a
 
 Types: [Agent](../core-data-structures/core.md) · [ContinuationStop](../core-data-structures/core.md) · [Scoped](../core-data-structures/scope.md)
 
-Source: [`packages/core/agent/src/types.ts:464`](../../packages/core/agent/src/types.ts)
+Source: [`packages/core/agent/src/types.ts:488`](../../packages/core/agent/src/types.ts)
 
 ## `agent-loop/*`
 
diff --git a/docs/core-data-structures/core.md b/docs/core-data-structures/core.md
index c2d8b56a80..69f917eaad 100644
--- a/docs/core-data-structures/core.md
+++ b/docs/core-data-structures/core.md
@@ -409,16 +409,30 @@ The fixed-preset aliases own `target` and `wakeup`, so they accept only the rema
 type AliasSendOptions = Omit<SendOptions, 'target' | 'wakeup'>
 ```
 
-The `agent/inbox/*` live events carry the resolved facts of one FIFO item; injection bypasses the FIFOs and never appears on them:
+`send` returns the accepted message's opaque `AgentMessageId`, stable across that message's `agent/inbox/*` events:
 
 ```ts type-equiv
 /**
- * The resolved facts of one inbox FIFO item, carried by the `agent/inbox/*`
- * live events. Source defaults are already applied, so these are the exact
- * values the item was accepted with. `steering` is true for a `next-step`
- * item drained between steps; a `next-turn` item is claimed at a turn boundary.
+ * Opaque id assigned to one accepted {@link Agent.send} message; returned by
+ * `send` and carried on its `agent/inbox/*` events for correlation.
  */
-interface InboxItemInfo {
+type AgentMessageId = Branded<'AgentMessageId'>
+```
+
+The `agent/inbox/*` live events carry one accepted message; injection bypasses the FIFOs and never appears on them:
+
+```ts type-equiv
+/**
+ * One accepted {@link Agent.send} message, carried by the `agent/inbox/*` live
+ * events. `id` is the value `send` returned to the caller, stable across this
+ * message's enqueue, dequeue, and discard events. Source defaults are already
+ * applied, so these are the exact values the item was accepted with. `steering`
+ * is true for a `next-step` item drained between steps; a `next-turn` item is
+ * claimed at a turn boundary.
+ */
+interface AgentMessage {
+  /** The id `send` returned for this message. */
+  id: AgentMessageId
   content: ContentBlock[]
   source: MessageSource
   contexts: HookContext[]
@@ -488,8 +502,9 @@ abstract class Agent {
    * input throws synchronously before any notification, enqueue, or append.
    * @param content - the model-facing content blocks to deliver.
    * @param options - target queue, wakeup decision, source, contexts, and meta.
+   * @returns the accepted message's {@link AgentMessageId}, stable across its `agent/inbox/*` events.
    */
-  abstract send(content: ContentBlock[], options?: SendOptions): void
+  abstract send(content: ContentBlock[], options?: SendOptions): AgentMessageId
 
   /**
    * Clear queued and steering work — unless `keepInbox` — and abort the active
@@ -512,9 +527,10 @@ abstract class Agent {
    * ordinary message of its own turn.
    * @param content - the prompt content blocks.
    * @param options - source and attached contexts.
+   * @returns the accepted message's {@link AgentMessageId}.
    */
-  followup(content: ContentBlock[], options?: AliasSendOptions): void {
-    this.send(content, { ...options, target: 'next-turn', wakeup: true })
+  followup(content: ContentBlock[], options?: AliasSendOptions): AgentMessageId {
+    return this.send(content, { ...options, target: 'next-turn', wakeup: true })
   }
 
   /**
@@ -526,9 +542,10 @@ abstract class Agent {
    * Idle steering falls back to a woken follow-up turn.
    * @param content - the steering content blocks.
    * @param options - source and attached contexts.
+   * @returns the accepted message's {@link AgentMessageId}.
    */
-  steer(content: ContentBlock[], options?: AliasSendOptions): void {
-    this.send(content, { ...options, target: 'next-step', wakeup: true })
+  steer(content: ContentBlock[], options?: AliasSendOptions): AgentMessageId {
+    return this.send(content, { ...options, target: 'next-step', wakeup: true })
   }
 
   /**
@@ -541,9 +558,10 @@ abstract class Agent {
    * `agent/error`. An omitted source defaults to `{ kind: 'plugin', plugin: '' }`.
    * @param content - the injected context content blocks.
    * @param options - source and durable model-hidden meta.
+   * @returns the accepted message's {@link AgentMessageId}.
    */
-  inject(content: ContentBlock[], options?: AliasSendOptions): void {
-    this.send(content, { ...options, target: 'next-step', wakeup: false })
+  inject(content: ContentBlock[], options?: AliasSendOptions): AgentMessageId {
+    return this.send(content, { ...options, target: 'next-step', wakeup: false })
   }
 }
 ```
diff --git a/docs/event-producer-consumer.md b/docs/event-producer-consumer.md
index 0825bbf348..2cf7e3a577 100644
--- a/docs/event-producer-consumer.md
+++ b/docs/event-producer-consumer.md
@@ -8,24 +8,24 @@ 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:353`](../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:329`](../packages/core/agent/src/types.ts) | [`agent-loop`](../packages/core/agent-loop) (`emit`) | [`goal-session`](../packages/goal/goal-session) |
-| `agent/created` | `emit` | [`packages/core/agent/src/types.ts:269`](../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:278`](../packages/core/agent/src/types.ts) | [`agent`](../packages/core/agent) (`events.dispatch`) | [`agent-loop`](../packages/core/agent-loop), [`goal-session`](../packages/goal/goal-session), [`tui`](../packages/ui/tui) |
-| `agent/error` | `emit` | [`packages/core/agent/src/types.ts:477`](../packages/core/agent/src/types.ts) | [`agent-loop`](../packages/core/agent-loop) (`emit`) | [`goal-session`](../packages/goal/goal-session), `runtime`, [`tui`](../packages/ui/tui) |
-| `agent/inbox/dequeue` | `emit` | [`packages/core/agent/src/types.ts:309`](../packages/core/agent/src/types.ts) | [`agent-loop`](../packages/core/agent-loop) (`emit`) | [`agent`](../packages/core/agent) |
-| `agent/inbox/discard` | `emit` | [`packages/core/agent/src/types.ts:319`](../packages/core/agent/src/types.ts) | [`agent-loop`](../packages/core/agent-loop) (`emit`) | [`agent`](../packages/core/agent) |
-| `agent/inbox/enqueue` | `emit` | [`packages/core/agent/src/types.ts:299`](../packages/core/agent/src/types.ts) | [`agent-loop`](../packages/core/agent-loop) (`emit`) | [`agent`](../packages/core/agent), [`goal-session`](../packages/goal/goal-session), [`tui`](../packages/ui/tui) |
-| `agent/post-step` | `serial` | [`packages/core/agent/src/types.ts:427`](../packages/core/agent/src/types.ts) | [`agent-loop`](../packages/core/agent-loop) (`serial`) | [`compact-basic`](../packages/compact/compact-basic), [`session-checkpoint-policy`](../packages/session-persistence/session-checkpoint-policy) |
-| `agent/pre-step` | `serial` | [`packages/core/agent/src/types.ts:358`](../packages/core/agent/src/types.ts) | [`agent-loop`](../packages/core/agent-loop) (`serial`) | [`time-context`](../packages/context/time-context), [`user-approval`](../packages/ui/user-approval) |
-| `agent/prompt-submit` | `waterfall` | [`packages/core/agent/src/types.ts:374`](../packages/core/agent/src/types.ts) | [`agent-loop`](../packages/core/agent-loop) (`waterfall`) | [`acp`](../packages/ui/acp), [`goal-session`](../packages/goal/goal-session), [`hooks-claude`](../packages/hooks/hooks-claude), [`hooks-codex`](../packages/hooks/hooks-codex), [`plan-mode`](../packages/plan/plan-mode), [`repeat-tool-guard`](../packages/guard/repeat-tool-guard) |
-| `agent/request` | `waterfall` | [`packages/core/agent/src/types.ts:388`](../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:442`](../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), [`plan-mode`](../packages/plan/plan-mode) |
-| `agent/session-prefix` | `waterfall` | [`packages/core/agent/src/types.ts:403`](../packages/core/agent/src/types.ts) | [`agent-loop`](../packages/core/agent-loop) (`waterfall`) | [`tool-skill`](../packages/skill/tool-skill), [`workspace-context`](../packages/context/workspace-context) |
-| `agent/session-start` | `emit` | [`packages/core/agent/src/types.ts:342`](../packages/core/agent/src/types.ts) | [`agent-loop`](../packages/core/agent-loop) (`emit`) | [`goal`](../packages/goal/goal), [`goal-session`](../packages/goal/goal-session), [`hooks-claude`](../packages/hooks/hooks-claude), [`hooks-codex`](../packages/hooks/hooks-codex) |
-| `agent/status` | `emit` | [`packages/core/agent/src/types.ts:287`](../packages/core/agent/src/types.ts) | [`agent-loop`](../packages/core/agent-loop) (`emit`) | [`agent`](../packages/core/agent), [`goal-session`](../packages/goal/goal-session), `runtime`, [`tui`](../packages/ui/tui) |
-| `agent/step-result` | `waterfall` | [`packages/core/agent/src/types.ts:415`](../packages/core/agent/src/types.ts) | [`agent-loop`](../packages/core/agent-loop) (`waterfall`) | - |
-| `agent/turn-continuation` | `waterfall` | [`packages/core/agent/src/types.ts:453`](../packages/core/agent/src/types.ts) | [`agent-loop`](../packages/core/agent-loop) (`waterfall`) | [`hooks-claude`](../packages/hooks/hooks-claude), [`hooks-codex`](../packages/hooks/hooks-codex), [`plan-mode`](../packages/plan/plan-mode) |
-| `agent/turn-stop` | `serial` | [`packages/core/agent/src/types.ts:464`](../packages/core/agent/src/types.ts) | [`agent-loop`](../packages/core/agent-loop) (`serial`) | [`subagent-inprocess`](../packages/subagent/subagent-inprocess), [`tool-goal`](../packages/goal/tool-goal) |
+| `agent/cancel-requested` | `emit` | [`packages/core/agent/src/types.ts:353`](../packages/core/agent/src/types.ts) | [`agent-loop`](../packages/core/agent-loop) (`emit`) | [`goal-session`](../packages/goal/goal-session) |
+| `agent/created` | `emit` | [`packages/core/agent/src/types.ts:293`](../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:302`](../packages/core/agent/src/types.ts) | [`agent`](../packages/core/agent) (`events.dispatch`) | [`agent-loop`](../packages/core/agent-loop), [`goal-session`](../packages/goal/goal-session), [`tui`](../packages/ui/tui) |
+| `agent/error` | `emit` | [`packages/core/agent/src/types.ts:501`](../packages/core/agent/src/types.ts) | [`agent-loop`](../packages/core/agent-loop) (`emit`) | [`goal-session`](../packages/goal/goal-session), `runtime`, [`tui`](../packages/ui/tui) |
+| `agent/inbox/dequeue` | `emit` | [`packages/core/agent/src/types.ts:333`](../packages/core/agent/src/types.ts) | [`agent-loop`](../packages/core/agent-loop) (`emit`) | [`agent`](../packages/core/agent) |
+| `agent/inbox/discard` | `emit` | [`packages/core/agent/src/types.ts:343`](../packages/core/agent/src/types.ts) | [`agent-loop`](../packages/core/agent-loop) (`emit`) | [`agent`](../packages/core/agent) |
+| `agent/inbox/enqueue` | `emit` | [`packages/core/agent/src/types.ts:323`](../packages/core/agent/src/types.ts) | [`agent-loop`](../packages/core/agent-loop) (`emit`) | [`agent`](../packages/core/agent), [`goal-session`](../packages/goal/goal-session), [`tui`](../packages/ui/tui) |
+| `agent/post-step` | `serial` | [`packages/core/agent/src/types.ts:451`](../packages/core/agent/src/types.ts) | [`agent-loop`](../packages/core/agent-loop) (`serial`) | [`compact-basic`](../packages/compact/compact-basic), [`session-checkpoint-policy`](../packages/session-persistence/session-checkpoint-policy) |
+| `agent/pre-step` | `serial` | [`packages/core/agent/src/types.ts:382`](../packages/core/agent/src/types.ts) | [`agent-loop`](../packages/core/agent-loop) (`serial`) | [`time-context`](../packages/context/time-context), [`user-approval`](../packages/ui/user-approval) |
+| `agent/prompt-submit` | `waterfall` | [`packages/core/agent/src/types.ts:398`](../packages/core/agent/src/types.ts) | [`agent-loop`](../packages/core/agent-loop) (`waterfall`) | [`acp`](../packages/ui/acp), [`goal-session`](../packages/goal/goal-session), [`hooks-claude`](../packages/hooks/hooks-claude), [`hooks-codex`](../packages/hooks/hooks-codex), [`plan-mode`](../packages/plan/plan-mode), [`repeat-tool-guard`](../packages/guard/repeat-tool-guard) |
+| `agent/request` | `waterfall` | [`packages/core/agent/src/types.ts:412`](../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:466`](../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), [`plan-mode`](../packages/plan/plan-mode) |
+| `agent/session-prefix` | `waterfall` | [`packages/core/agent/src/types.ts:427`](../packages/core/agent/src/types.ts) | [`agent-loop`](../packages/core/agent-loop) (`waterfall`) | [`tool-skill`](../packages/skill/tool-skill), [`workspace-context`](../packages/context/workspace-context) |
+| `agent/session-start` | `emit` | [`packages/core/agent/src/types.ts:366`](../packages/core/agent/src/types.ts) | [`agent-loop`](../packages/core/agent-loop) (`emit`) | [`goal`](../packages/goal/goal), [`goal-session`](../packages/goal/goal-session), [`hooks-claude`](../packages/hooks/hooks-claude), [`hooks-codex`](../packages/hooks/hooks-codex) |
+| `agent/status` | `emit` | [`packages/core/agent/src/types.ts:311`](../packages/core/agent/src/types.ts) | [`agent-loop`](../packages/core/agent-loop) (`emit`) | [`agent`](../packages/core/agent), [`goal-session`](../packages/goal/goal-session), `runtime`, [`tui`](../packages/ui/tui) |
+| `agent/step-result` | `waterfall` | [`packages/core/agent/src/types.ts:439`](../packages/core/agent/src/types.ts) | [`agent-loop`](../packages/core/agent-loop) (`waterfall`) | - |
+| `agent/turn-continuation` | `waterfall` | [`packages/core/agent/src/types.ts:477`](../packages/core/agent/src/types.ts) | [`agent-loop`](../packages/core/agent-loop) (`waterfall`) | [`hooks-claude`](../packages/hooks/hooks-claude), [`hooks-codex`](../packages/hooks/hooks-codex), [`plan-mode`](../packages/plan/plan-mode) |
+| `agent/turn-stop` | `serial` | [`packages/core/agent/src/types.ts:488`](../packages/core/agent/src/types.ts) | [`agent-loop`](../packages/core/agent-loop) (`serial`) | [`subagent-inprocess`](../packages/subagent/subagent-inprocess), [`tool-goal`](../packages/goal/tool-goal) |
 | `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/ui/acp) |
 | `commands/change` | `emit` | [`packages/ui/commands/src/index.ts:103`](../packages/ui/commands/src/index.ts) | [`commands`](../packages/ui/commands) (`events.dispatch`) | [`acp`](../packages/ui/acp), [`tui`](../packages/ui/tui) |
 | `fs/edit-intent` | `waterfall` | [`packages/fs/fs/src/index.ts:62`](../packages/fs/fs/src/index.ts) | [`tool-fs`](../packages/fs/tool-fs) (`waterfall`) | [`fs-policy`](../packages/fs/fs-policy) |
diff --git a/packages/context/time-context/tests/time-context.spec.ts b/packages/context/time-context/tests/time-context.spec.ts
index 26bb5d7a9d..c87915dda7 100644
--- a/packages/context/time-context/tests/time-context.spec.ts
+++ b/packages/context/time-context/tests/time-context.spec.ts
@@ -4,7 +4,7 @@ import Loader from '@cordisjs/plugin-loader'
 import { CallId, LlmAdapter } from '@deepseek-ai/dsh-llm'
 import type { GenerateOptions, StreamChunk } from '@deepseek-ai/dsh-llm'
 import { Session, SessionId, type SessionEvent } from '@deepseek-ai/dsh-session'
-import AgentRegistry, { agentEvents, type Agent } from '@deepseek-ai/dsh-agent'
+import AgentRegistry, { agentEvents, AgentMessageId, type Agent } from '@deepseek-ai/dsh-agent'
 import { defineTool } from '@deepseek-ai/dsh-tools'
 import AgentLoop from '@deepseek-ai/dsh-agent-loop'
 import { mountAgentLoopTestDependencies } from '@deepseek-ai/dsh-agent-loop-testkit'
@@ -42,14 +42,15 @@ function sessionAgent(session: Session, id = 'agent'): Agent {
     session,
     status: 'running',
     ctx: new Context(),
-    send() {},
-    followup() {},
-    steer() {},
+    send: () => AgentMessageId('stub'),
+    followup: () => AgentMessageId('stub'),
+    steer: () => AgentMessageId('stub'),
     inject(content, options) {
       session.append('user/message', {
         content,
         source: options?.source ?? { kind: 'user' },
       }, { surfaceOp: 'append' })
+      return AgentMessageId('stub')
     },
     cancel() {},
     whenIdle: () => Promise.resolve(),
diff --git a/packages/context/workspace-context/tests/workspace-context.spec.ts b/packages/context/workspace-context/tests/workspace-context.spec.ts
index c96cee8b38..e04c92fd19 100644
--- a/packages/context/workspace-context/tests/workspace-context.spec.ts
+++ b/packages/context/workspace-context/tests/workspace-context.spec.ts
@@ -7,7 +7,7 @@ import Loader from '@cordisjs/plugin-loader'
 import * as workspaceContext from '@deepseek-ai/dsh-workspace-context'
 import LlmService, { CallId, type Message, type StreamChunk } from '@deepseek-ai/dsh-llm'
 import SessionStore, { Session, SessionId, SESSION_FORMAT_VERSION, type SessionEvent } from '@deepseek-ai/dsh-session'
-import AgentRegistry, { type Agent, type HookContext } from '@deepseek-ai/dsh-agent'
+import AgentRegistry, { AgentMessageId, type Agent, type HookContext } from '@deepseek-ai/dsh-agent'
 import AgentLoop from '@deepseek-ai/dsh-agent-loop'
 import { FileSystem, FsTargetKey, FsVersion } from '@deepseek-ai/dsh-fs'
 import type {
@@ -174,15 +174,16 @@ function stubAgent(cwd?: string, seed: SessionEvent[] = []): Agent {
     options: {},
     session,
     status: 'idle',
-    send() {},
-    followup() {},
-    steer() {},
+    send: () => AgentMessageId('stub'),
+    followup: () => AgentMessageId('stub'),
+    steer: () => AgentMessageId('stub'),
     inject(content, options) {
       session.append('user/message', {
         content,
         source: options?.source ?? { kind: 'user' },
         ...options?.meta !== undefined ? { meta: options.meta } : {},
       }, { surfaceOp: 'append' })
+      return AgentMessageId('stub')
     },
     cancel() {},
     whenIdle: () => Promise.resolve(),
diff --git a/packages/cordis/tool-cordis/src/api-catalog.ts b/packages/cordis/tool-cordis/src/api-catalog.ts
index f5872f5fcc..9e6087a4de 100644
--- a/packages/cordis/tool-cordis/src/api-catalog.ts
+++ b/packages/cordis/tool-cordis/src/api-catalog.ts
@@ -846,22 +846,22 @@ export const EVENT_API: readonly EventApiEntry[] = [
   {
     name: 'agent/inbox/dequeue',
     mode: 'emit',
-    signature: '\'agent/inbox/dequeue\'(this: Scoped<Agent>, agent: Agent, info: InboxItemInfo): void',
-    jsDoc: '/**\n * The driver claimed one item out of the inbox: a queued item at a turn\n * boundary, or steering drained between steps. Fires after the item leaves\n * its FIFO and before it becomes a durable message.\n * @param agent - the agent whose inbox item was claimed.\n * @param info - the claimed item\'s accepted content, source, contexts, steering, and wakeup facts.\n * Scope-filtered dispatch (`@deepseek-ai/dsh-scope`): agent-scoped listeners receive only that agent.\n * @mode emit\n */',
+    signature: '\'agent/inbox/dequeue\'(this: Scoped<Agent>, agent: Agent, message: AgentMessage): void',
+    jsDoc: '/**\n * The driver claimed one item out of the inbox: a queued item at a turn\n * boundary, or steering drained between steps. Fires after the item leaves\n * its FIFO and before it becomes a durable message.\n * @param agent - the agent whose inbox item was claimed.\n * @param message - the claimed message (matching the `id` from its `agent/inbox/enqueue`).\n * Scope-filtered dispatch (`@deepseek-ai/dsh-scope`): agent-scoped listeners receive only that agent.\n * @mode emit\n */',
     summary: 'The driver claimed one item out of the inbox: a queued item at a turn boundary, or steering drained between steps.',
   },
   {
     name: 'agent/inbox/discard',
     mode: 'emit',
-    signature: '\'agent/inbox/discard\'(this: Scoped<Agent>, agent: Agent, items: InboxItemInfo[]): void',
-    jsDoc: '/**\n * `cancel()` (without `keepInbox`) dropped pending inbox items without\n * delivering them. Fires once per effective clearing call with every\n * discarded item, after `agent/cancel-requested` and before the abort.\n * @param agent - the agent whose inbox was cleared.\n * @param items - the discarded items in FIFO order (queued then steering); empty when nothing was pending.\n * Scope-filtered dispatch (`@deepseek-ai/dsh-scope`): agent-scoped listeners receive only that agent.\n * @mode emit\n */',
+    signature: '\'agent/inbox/discard\'(this: Scoped<Agent>, agent: Agent, messages: AgentMessage[]): void',
+    jsDoc: '/**\n * `cancel()` (without `keepInbox`) dropped pending inbox items without\n * delivering them. Fires once per effective clearing call with every\n * discarded item, after `agent/cancel-requested` and before the abort.\n * @param agent - the agent whose inbox was cleared.\n * @param messages - the discarded messages in FIFO order (queued then steering); empty when nothing was pending.\n * Scope-filtered dispatch (`@deepseek-ai/dsh-scope`): agent-scoped listeners receive only that agent.\n * @mode emit\n */',
     summary: '`cancel()` (without `keepInbox`) dropped pending inbox items without delivering them.',
   },
   {
     name: 'agent/inbox/enqueue',
     mode: 'emit',
-    signature: '\'agent/inbox/enqueue\'(this: Scoped<Agent>, agent: Agent, info: InboxItemInfo): void',
-    jsDoc: '/**\n * A detached, frozen item entered the agent\'s inbox (queued or steering\n * FIFO). Source defaults are already applied, so `info` holds the exact\n * accepted values. This is the enqueue-time live signal; the durable record\n * is the eventual `user/message`/`steering/message`. Injection\n * (`next-step`/no-wakeup) bypasses the FIFOs and does not emit this.\n * @param agent - the agent whose inbox received the item.\n * @param info - the accepted content, source, contexts, steering, and wakeup facts.\n * Scope-filtered dispatch (`@deepseek-ai/dsh-scope`): agent-scoped listeners receive only that agent.\n * @mode emit\n */',
+    signature: '\'agent/inbox/enqueue\'(this: Scoped<Agent>, agent: Agent, message: AgentMessage): void',
+    jsDoc: '/**\n * A detached, frozen item entered the agent\'s inbox (queued or steering\n * FIFO). Source defaults are already applied, so `info` holds the exact\n * accepted values. This is the enqueue-time live signal; the durable record\n * is the eventual `user/message`/`steering/message`. Injection\n * (`next-step`/no-wakeup) bypasses the FIFOs and does not emit this.\n * @param agent - the agent whose inbox received the item.\n * @param message - the accepted message (its returned `id`, content, source, contexts, steering, and wakeup facts).\n * Scope-filtered dispatch (`@deepseek-ai/dsh-scope`): agent-scoped listeners receive only that agent.\n * @mode emit\n */',
     summary: 'A detached, frozen item entered the agent\'s inbox (queued or steering FIFO).',
   },
   {
diff --git a/packages/core/agent-loop/src/agent.ts b/packages/core/agent-loop/src/agent.ts
index 670945a8fa..2ce1928af2 100644
--- a/packages/core/agent-loop/src/agent.ts
+++ b/packages/core/agent-loop/src/agent.ts
@@ -6,15 +6,16 @@
  * @module dsh-agent-loop/agent
  */
 
+import { randomUUID } from 'node:crypto'
 import type { Context } from 'cordis'
-import { agentEvents } from '@deepseek-ai/dsh-agent'
+import { agentEvents, AgentMessageId } from '@deepseek-ai/dsh-agent'
 import { Agent } from '@deepseek-ai/dsh-agent'
 import type { AgentCancelCause, AgentOptions, AgentStatus, CancelOptions, HookContext, SendOptions } from '@deepseek-ai/dsh-agent'
 import { deepFreeze, errorChain } from '@deepseek-ai/dsh-llm'
 import type { ContentBlock, MessageSource } from '@deepseek-ai/dsh-llm'
 import { snapshotJsonValue, type Session, type SessionId } from '@deepseek-ai/dsh-session'
 import { DISPOSED_INTERRUPT_REASON, TurnCancellation } from './cancellation.ts'
-import { Inbox, inboxInfo, type InboxMessage } from './inbox.ts'
+import { Inbox, agentMessage, type InboxMessage } from './inbox.ts'
 import { isTurnOpen, lastTurnNumber, runLoop } from './loop.ts'
 
 /** Sessions already claimed by a concrete driver construction. */
@@ -196,9 +197,11 @@ export class ReactLoopAgent extends Agent {
    * materialization reads every nested field once; deep freeze prevents later
    * caller mutation before an inbox or deferred-injection queue drains it.
    */
-  private acceptMessage(content: ContentBlock[], source: MessageSource, wakeup: boolean, options?: SendOptions): InboxMessage {
+  private acceptMessage(
+    id: AgentMessageId, content: ContentBlock[], source: MessageSource, wakeup: boolean, options?: SendOptions,
+  ): InboxMessage {
     const contexts = options?.contexts ?? []
-    const accepted = snapshotJsonValue({ content, source, contexts, wakeup })
+    const accepted = snapshotJsonValue({ id, content, source, contexts, wakeup })
     if (accepted === undefined) {
       throw new TypeError('agent message content, source, and contexts must be losslessly JSON-serializable')
     }
@@ -219,23 +222,25 @@ export class ReactLoopAgent extends Agent {
     if (this._status === 'disposed') throw new Error(`agent "${this.id}" is disposed`)
   }
 
-  send(content: ContentBlock[], options?: SendOptions): void {
+  send(content: ContentBlock[], options?: SendOptions): AgentMessageId {
     this.assertNotDisposed()
+    const id = AgentMessageId(randomUUID())
     const target = options?.target ?? 'next-turn'
     const wakeup = options?.wakeup ?? true
     // next-step/no-wakeup is injection: durable context without running the model.
-    if (target === 'next-step' && !wakeup) { this.injectContext(content, options); return }
+    if (target === 'next-step' && !wakeup) { this.injectContext(content, options); return id }
     // next-step/wakeup is steering into the running turn; idle falls back to a
     // woken follow-up turn (there is no active turn to attach to).
     const steering = target === 'next-step' && this._status === 'running'
     const source = options?.source ?? { kind: 'user' }
-    const accepted = this.acceptMessage(content, source, wakeup, options)
+    const accepted = this.acceptMessage(id, content, source, wakeup, options)
     if (steering) {
       this.#inbox.steer(accepted)
     } else {
       this.#inbox.enqueue(accepted, wakeup)
     }
-    agentEvents(this.loopCtx, this).emit('agent/inbox/enqueue', inboxInfo(accepted, steering))
+    agentEvents(this.loopCtx, this).emit('agent/inbox/enqueue', agentMessage(accepted, steering))
+    return id
   }
 
   /** The `next-step`/no-wakeup injection path: durable context, no FIFO, no run. */
@@ -346,7 +351,7 @@ export class ReactLoopAgent extends Agent {
       // Clear work already present before abort observers run.
       this.#inbox.clear()
       if (discarded.length > 0) {
-        const items = discarded.map(({ message, steering }) => inboxInfo(message, steering))
+        const items = discarded.map(({ message, steering }) => agentMessage(message, steering))
         agentEvents(this.loopCtx, this).emit('agent/inbox/discard', items)
       }
     }
diff --git a/packages/core/agent-loop/src/inbox.ts b/packages/core/agent-loop/src/inbox.ts
index e6bbbcfb7f..fd2810ea9a 100644
--- a/packages/core/agent-loop/src/inbox.ts
+++ b/packages/core/agent-loop/src/inbox.ts
@@ -7,10 +7,11 @@
  */
 
 import type { ContentBlock, MessageSource } from '@deepseek-ai/dsh-llm'
-import type { HookContext, InboxItemInfo } from '@deepseek-ai/dsh-agent'
+import type { AgentMessage, AgentMessageId, HookContext } from '@deepseek-ai/dsh-agent'
 
-/** One message waiting in an agent's inbox. */
+/** One message waiting in an agent's inbox; `id` is the value `send` returned. */
 export interface InboxMessage {
+  id: AgentMessageId
   content: ContentBlock[]
   source: MessageSource
   contexts: HookContext[]
@@ -22,10 +23,10 @@ export interface InboxMessage {
  * Build the `agent/inbox/*` event payload for one inbox item.
  * @param message - the accepted inbox record.
  * @param steering - whether the item is in the steering FIFO (`next-step`).
- * @returns the live-event facts for enqueue/dequeue/discard.
+ * @returns the live-event message for enqueue/dequeue/discard.
  */
-export function inboxInfo(message: InboxMessage, steering: boolean): InboxItemInfo {
-  return { content: message.content, source: message.source, contexts: message.contexts, steering, wakeup: message.wakeup }
+export function agentMessage(message: InboxMessage, steering: boolean): AgentMessage {
+  return { id: message.id, content: message.content, source: message.source, contexts: message.contexts, steering, wakeup: message.wakeup }
 }
 
 /**
diff --git a/packages/core/agent-loop/src/loop.ts b/packages/core/agent-loop/src/loop.ts
index 11733b17e8..6b57f87e74 100644
--- a/packages/core/agent-loop/src/loop.ts
+++ b/packages/core/agent-loop/src/loop.ts
@@ -5,11 +5,12 @@
  * @module dsh-agent-loop/loop
  */
 
+import { randomUUID } from 'node:crypto'
 import type { Context } from 'cordis'
 import type { ContentBlock, FinishReason, GenerateOptions, LlmCallConfig, LlmFailure, Message } from '@deepseek-ai/dsh-llm'
 import { isDeepStrictEqual } from 'node:util'
 import { BlockAssembler, HarnessError, LlmError, assertNever, deepFreeze, errorChain, llmFailureOf, markAgentLoopRequest } from '@deepseek-ai/dsh-llm'
-import { agentEvents, agentInterruptReasonOf, assembleContextFor } from '@deepseek-ai/dsh-agent'
+import { agentEvents, agentInterruptReasonOf, assembleContextFor, AgentMessageId } from '@deepseek-ai/dsh-agent'
 import type { AgentEventDispatch, ContinuationDecision, HookContext, PromptDecision, RequestError, RequestErrorDecision } from '@deepseek-ai/dsh-agent'
 import { canonicalHeader } from '@deepseek-ai/dsh-session'
 import type { PromptMessageData, Session, TurnEndReason, TurnTrigger } from '@deepseek-ai/dsh-session'
@@ -19,7 +20,7 @@ import { renderPrompt } from '@deepseek-ai/dsh-system-prompt'
 import type { PromptAssembly } from '@deepseek-ai/dsh-system-prompt'
 import type {} from '@deepseek-ai/dsh-tools'
 import { executeToolCalls } from './tool-calls.ts'
-import { inboxInfo, type Inbox, type InboxMessage } from './inbox.ts'
+import { agentMessage, type Inbox, type InboxMessage } from './inbox.ts'
 import type { TurnCancellation } from './cancellation.ts'
 
 /** Normalize thrown values while preserving an existing error code. */
@@ -279,7 +280,7 @@ async function runTurn(
   const drainSteering = (): boolean => {
     const messages = handle.inbox.drainSteering()
     for (const message of messages) {
-      events.emit('agent/inbox/dequeue', inboxInfo(message, true))
+      events.emit('agent/inbox/dequeue', agentMessage(message, true))
       const prepared = preparePromptMessage(message.content, message.source, message.contexts)
       session.append('steering/message', { turn, ...prepared.data }, { surfaceOp: 'append' })
       for (const context of prepared.separateContexts) {
@@ -297,7 +298,7 @@ async function runTurn(
   const message = handle.inbox.dequeueQueued()
   /* v8 ignore next 3 -- invariant guard: runLoop only calls runTurn when hasQueued */
   if (!message) throw new Error('runTurn invariant violated: no queued message at turn start')
-  events.emit('agent/inbox/dequeue', inboxInfo(message, false))
+  events.emit('agent/inbox/dequeue', agentMessage(message, false))
   const trigger: TurnTrigger = { kind: 'message', source: message.source }
 
   let reason: TurnEndReason = { kind: 'completed' }
@@ -542,9 +543,12 @@ async function runTurn(
       // enqueue event a public steer would, so the inbox ledger stays balanced
       // (every FIFO entry has a matching enqueue before its dequeue/discard).
       if (decision.action === 'continue' && decision.reason) {
-        const item: InboxMessage = { content: decision.reason.content, source: decision.reason.source, contexts: [], wakeup: true }
+        const item: InboxMessage = {
+          id: AgentMessageId(randomUUID()), content: decision.reason.content,
+          source: decision.reason.source, contexts: [], wakeup: true,
+        }
         handle.inbox.steer(item)
-        events.emit('agent/inbox/enqueue', inboxInfo(item, true))
+        events.emit('agent/inbox/enqueue', agentMessage(item, true))
       }
       let shouldContinue = decision.action === 'continue'
 
diff --git a/packages/core/agent-loop/tests/inbox.spec.ts b/packages/core/agent-loop/tests/inbox.spec.ts
index 91858e7050..791eae3bda 100644
--- a/packages/core/agent-loop/tests/inbox.spec.ts
+++ b/packages/core/agent-loop/tests/inbox.spec.ts
@@ -1,8 +1,9 @@
 import { describe, expect, it } from 'vitest'
+import { AgentMessageId } from '@deepseek-ai/dsh-agent'
 import { Inbox } from '../src/inbox.ts'
 
 function message(text: string) {
-  return { content: [{ type: 'text' as const, text }], source: { kind: 'user' as const }, contexts: [], wakeup: true }
+  return { id: AgentMessageId(text), content: [{ type: 'text' as const, text }], source: { kind: 'user' as const }, contexts: [], wakeup: true }
 }
 
 function resolverPair() {
diff --git a/packages/core/agent/README.md b/packages/core/agent/README.md
index 06a7e618f9..ebb756b139 100644
--- a/packages/core/agent/README.md
+++ b/packages/core/agent/README.md
@@ -56,7 +56,7 @@ Turn and step boundaries and the model token stream are durable `session/event`
 
 The handle every plugin programs against:
 
-- `agent.send(content, options?)` — the one delivery primitive over the (`target` × `wakeup`) matrix; `Agent` is an abstract class whose `followup`/`steer`/`inject` aliases are fixed-preset delegates to it. `target: 'next-turn'` (default) queues one independent FIFO item that, if claimed, becomes the sole ordinary message in its turn; `wakeup` (default `true`) wakes a parked driver, while `wakeup: false` queues without waking. `target: 'next-step'` with `wakeup: true` submits steering, and with `wakeup: false` injects durable context without running the model. Omitting `options.source` attests direct human input as `{ kind: 'user' }` (injection defaults to `{ kind: 'plugin', plugin: '' }`) and may authorize policy consumers, so plugins, schedulers, and other non-human producers provide their own source. Content, resolved source, and `options.contexts` become one detached, deeply frozen lossless-JSON record before `agent/inbox/enqueue` and enqueue; invalid data throws synchronously, and caller or notification-listener in-place mutation cannot change the log or model input. After admission, separate contexts become injected `user/message` events, while prompt-prefix contexts are baked before the effective request in the same `user/message`; a block or replacement of the default additional-context decision can discard them. The [one-send-one-turn Agent Note](../../../.agents/notes/implemented/simplification/2026-07-17-one-send-one-turn.md) owns the turn rationale.
+- `agent.send(content, options?)` — the one delivery primitive over the (`target` × `wakeup`) matrix; `Agent` is an abstract class whose `followup`/`steer`/`inject` aliases are fixed-preset delegates to it. It returns the accepted message's opaque `AgentMessageId`, which the message's `agent/inbox/enqueue`/`dequeue`/`discard` events carry so a caller can correlate a queued item with its lifecycle. `target: 'next-turn'` (default) queues one independent FIFO item that, if claimed, becomes the sole ordinary message in its turn; `wakeup` (default `true`) wakes a parked driver, while `wakeup: false` queues without waking. `target: 'next-step'` with `wakeup: true` submits steering, and with `wakeup: false` injects durable context without running the model. Omitting `options.source` attests direct human input as `{ kind: 'user' }` (injection defaults to `{ kind: 'plugin', plugin: '' }`) and may authorize policy consumers, so plugins, schedulers, and other non-human producers provide their own source. Content, resolved source, and `options.contexts` become one detached, deeply frozen lossless-JSON record before `agent/inbox/enqueue` and enqueue; invalid data throws synchronously, and caller or notification-listener in-place mutation cannot change the log or model input. After admission, separate contexts become injected `user/message` events, while prompt-prefix contexts are baked before the effective request in the same `user/message`; a block or replacement of the default additional-context decision can discard them. The [one-send-one-turn Agent Note](../../../.agents/notes/implemented/simplification/2026-07-17-one-send-one-turn.md) owns the turn rationale.
 - `agent.followup(content, options?)` — the `next-turn`/wakeup preset of `send()`: queue an ordinary follow-up turn and wake the driver.
 - `agent.steer(content, options?)` — the `next-step`/wakeup preset: while running, queue steering for the next checkpoint without dispatching `agent/prompt-submit`; when idle, delegate to a woken follow-up. Attached contexts remain in the same frozen record; separate contexts append immediately after the steering event, while prompt-prefix contexts are baked into that steering event. Both survive late-steering conversion to queued input and disappear with their message on cancellation or terminal discard. Policy can still stop before another step; after turn close and its checkpoint, remaining steering becomes later queued input unless terminal turn policy, cancellation, or disposal discards it.
 - `agent.inject(content, options?)` — the `next-step`/no-wakeup preset: accept detached in-session context without running the model; the next request sees its `user/message` (default plugin source) with `content` rendered verbatim as a user-role message. `options.meta` persists opaque JSON state without rendering it. While a turn is open it joins that turn, deferring FIFO while the current tool batch executes and draining before turn close if execution is interrupted; while idle it is wrapped in a one-shot `injection` turn and durability checkpoint ([the turn-enclosure invariant](../../../.agents/notes/implemented/architecture/2026-06-15-turn-enclosure-invariant.md)). Injection bypasses the FIFOs and emits no `agent/inbox/*` event.
diff --git a/packages/core/agent/src/types.ts b/packages/core/agent/src/types.ts
index f04c999cb6..e7d733c920 100644
--- a/packages/core/agent/src/types.ts
+++ b/packages/core/agent/src/types.ts
@@ -6,6 +6,7 @@
  */
 
 import type { Context } from 'cordis'
+import type { Branded } from '@deepseek-ai/dsh-brand'
 import type { Scoped } from '@deepseek-ai/dsh-scope'
 import type { ContentBlock, LlmCallConfig, LlmFailure, Message, MessageSource } from '@deepseek-ai/dsh-llm'
 import type { JsonValue, Session, SessionId } from '@deepseek-ai/dsh-session'
@@ -68,12 +69,31 @@ export interface SendOptions {
 export type AliasSendOptions = Omit<SendOptions, 'target' | 'wakeup'>
 
 /**
- * The resolved facts of one inbox FIFO item, carried by the `agent/inbox/*`
- * live events. Source defaults are already applied, so these are the exact
- * values the item was accepted with. `steering` is true for a `next-step`
- * item drained between steps; a `next-turn` item is claimed at a turn boundary.
+ * Opaque id assigned to one accepted {@link Agent.send} message; returned by
+ * `send` and carried on its `agent/inbox/*` events for correlation.
  */
-export interface InboxItemInfo {
+export type AgentMessageId = Branded<'AgentMessageId'>
+
+/**
+ * Brand a string as an {@link AgentMessageId}.
+ * @param id - the generated message id.
+ * @returns the same string, branded; no validation is performed.
+ */
+export function AgentMessageId(id: string): AgentMessageId {
+  return id as AgentMessageId
+}
+
+/**
+ * One accepted {@link Agent.send} message, carried by the `agent/inbox/*` live
+ * events. `id` is the value `send` returned to the caller, stable across this
+ * message's enqueue, dequeue, and discard events. Source defaults are already
+ * applied, so these are the exact values the item was accepted with. `steering`
+ * is true for a `next-step` item drained between steps; a `next-turn` item is
+ * claimed at a turn boundary.
+ */
+export interface AgentMessage {
+  /** The id `send` returned for this message. */
+  id: AgentMessageId
   content: ContentBlock[]
   source: MessageSource
   contexts: HookContext[]
@@ -194,8 +214,9 @@ export abstract class Agent {
    * input throws synchronously before any notification, enqueue, or append.
    * @param content - the model-facing content blocks to deliver.
    * @param options - target queue, wakeup decision, source, contexts, and meta.
+   * @returns the accepted message's {@link AgentMessageId}, stable across its `agent/inbox/*` events.
    */
-  abstract send(content: ContentBlock[], options?: SendOptions): void
+  abstract send(content: ContentBlock[], options?: SendOptions): AgentMessageId
 
   /**
    * Clear queued and steering work — unless `keepInbox` — and abort the active
@@ -218,9 +239,10 @@ export abstract class Agent {
    * ordinary message of its own turn.
    * @param content - the prompt content blocks.
    * @param options - source and attached contexts.
+   * @returns the accepted message's {@link AgentMessageId}.
    */
-  followup(content: ContentBlock[], options?: AliasSendOptions): void {
-    this.send(content, { ...options, target: 'next-turn', wakeup: true })
+  followup(content: ContentBlock[], options?: AliasSendOptions): AgentMessageId {
+    return this.send(content, { ...options, target: 'next-turn', wakeup: true })
   }
 
   /**
@@ -232,9 +254,10 @@ export abstract class Agent {
    * Idle steering falls back to a woken follow-up turn.
    * @param content - the steering content blocks.
    * @param options - source and attached contexts.
+   * @returns the accepted message's {@link AgentMessageId}.
    */
-  steer(content: ContentBlock[], options?: AliasSendOptions): void {
-    this.send(content, { ...options, target: 'next-step', wakeup: true })
+  steer(content: ContentBlock[], options?: AliasSendOptions): AgentMessageId {
+    return this.send(content, { ...options, target: 'next-step', wakeup: true })
   }
 
   /**
@@ -247,9 +270,10 @@ export abstract class Agent {
    * `agent/error`. An omitted source defaults to `{ kind: 'plugin', plugin: '' }`.
    * @param content - the injected context content blocks.
    * @param options - source and durable model-hidden meta.
+   * @returns the accepted message's {@link AgentMessageId}.
    */
-  inject(content: ContentBlock[], options?: AliasSendOptions): void {
-    this.send(content, { ...options, target: 'next-step', wakeup: false })
+  inject(content: ContentBlock[], options?: AliasSendOptions): AgentMessageId {
+    return this.send(content, { ...options, target: 'next-step', wakeup: false })
   }
 }
 
@@ -292,31 +316,31 @@ declare module 'cordis' {
      * is the eventual `user/message`/`steering/message`. Injection
      * (`next-step`/no-wakeup) bypasses the FIFOs and does not emit this.
      * @param agent - the agent whose inbox received the item.
-     * @param info - the accepted content, source, contexts, steering, and wakeup facts.
+     * @param message - the accepted message (its returned `id`, content, source, contexts, steering, and wakeup facts).
      * Scope-filtered dispatch (`@deepseek-ai/dsh-scope`): agent-scoped listeners receive only that agent.
      * @mode emit
      */
-    'agent/inbox/enqueue'(this: Scoped<Agent>, agent: Agent, info: InboxItemInfo): void
+    'agent/inbox/enqueue'(this: Scoped<Agent>, agent: Agent, message: AgentMessage): void
     /**
      * The driver claimed one item out of the inbox: a queued item at a turn
      * boundary, or steering drained between steps. Fires after the item leaves
      * its FIFO and before it becomes a durable message.
      * @param agent - the agent whose inbox item was claimed.
-     * @param info - the claimed item's accepted content, source, contexts, steering, and wakeup facts.
+     * @param message - the claimed message (matching the `id` from its `agent/inbox/enqueue`).
      * Scope-filtered dispatch (`@deepseek-ai/dsh-scope`): agent-scoped listeners receive only that agent.
      * @mode emit
      */
-    'agent/inbox/dequeue'(this: Scoped<Agent>, agent: Agent, info: InboxItemInfo): void
+    'agent/inbox/dequeue'(this: Scoped<Agent>, agent: Agent, message: AgentMessage): void
     /**
      * `cancel()` (without `keepInbox`) dropped pending inbox items without
      * delivering them. Fires once per effective clearing call with every
      * discarded item, after `agent/cancel-requested` and before the abort.
      * @param agent - the agent whose inbox was cleared.
-     * @param items - the discarded items in FIFO order (queued then steering); empty when nothing was pending.
+     * @param messages - the discarded messages in FIFO order (queued then steering); empty when nothing was pending.
      * Scope-filtered dispatch (`@deepseek-ai/dsh-scope`): agent-scoped listeners receive only that agent.
      * @mode emit
      */
-    'agent/inbox/discard'(this: Scoped<Agent>, agent: Agent, items: InboxItemInfo[]): void
+    'agent/inbox/discard'(this: Scoped<Agent>, agent: Agent, messages: AgentMessage[]): void
     /**
      * Effective broad cancellation was requested, before queued/steering work
      * is cleared or the active turn is aborted. This observe-only notification
diff --git a/packages/core/agent/tests/agent.spec.ts b/packages/core/agent/tests/agent.spec.ts
index d157eeab57..aefa739dde 100644
--- a/packages/core/agent/tests/agent.spec.ts
+++ b/packages/core/agent/tests/agent.spec.ts
@@ -4,6 +4,7 @@ import type { Events } from 'cordis'
 import { Session, SessionId } from '@deepseek-ai/dsh-session'
 import AgentRegistry, {
   Agent,
+  AgentMessageId,
   agentEvents,
   agentInterruptReasonOf,
 } from '@deepseek-ai/dsh-agent'
@@ -20,7 +21,7 @@ function stubAgent(rawId: string, overrides: Partial<Agent> = {}): Agent {
     session: new Session(id),
     status: 'idle',
     ctx: new Context(),
-    send() {},
+    send: () => AgentMessageId('stub'),
     cancel() {},
     whenIdle() { return Promise.resolve() },
     ...overrides,
diff --git a/packages/core/agent/tests/invariant.spec.ts b/packages/core/agent/tests/invariant.spec.ts
index b850e8743a..453752c402 100644
--- a/packages/core/agent/tests/invariant.spec.ts
+++ b/packages/core/agent/tests/invariant.spec.ts
@@ -1,6 +1,6 @@
 import { describe, expect, it } from 'vitest'
 import { Context } from 'cordis'
-import type { Agent } from '@deepseek-ai/dsh-agent'
+import { AgentMessageId, type Agent } from '@deepseek-ai/dsh-agent'
 import * as AgentInvariant from '@deepseek-ai/dsh-agent/invariant'
 import { scopeTarget } from '@deepseek-ai/dsh-scope'
 import InvariantService from '@deepseek-ai/dsh-invariants'
@@ -58,7 +58,7 @@ describe('agent status invariants', () => {
 })
 
 describe('agent inbox invariants', () => {
-  const info = (steering: boolean) => ({ content: [], source: { kind: 'user' as const }, contexts: [], steering, wakeup: true })
+  const info = (steering: boolean) => ({ id: AgentMessageId('m'), content: [], source: { kind: 'user' as const }, contexts: [], steering, wakeup: true })
 
   it('accepts a dequeue and a discard covered by prior enqueues', async () => {
     const ctx = await setup()
diff --git a/packages/core/scope/tests/invariant.spec.ts b/packages/core/scope/tests/invariant.spec.ts
index bcb3944cbd..ca0841165b 100644
--- a/packages/core/scope/tests/invariant.spec.ts
+++ b/packages/core/scope/tests/invariant.spec.ts
@@ -1,7 +1,7 @@
 import { describe, expect, it } from 'vitest'
 import { Context } from 'cordis'
 import type { Events } from 'cordis'
-import type { Agent } from '@deepseek-ai/dsh-agent'
+import { AgentMessageId, type Agent } from '@deepseek-ai/dsh-agent'
 import { scopeTarget } from '@deepseek-ai/dsh-scope'
 import * as ScopeInvariant from '@deepseek-ai/dsh-scope/invariant'
 import InvariantService from '@deepseek-ai/dsh-invariants'
@@ -42,8 +42,8 @@ describe('scoped-dispatch invariants', () => {
       'agent/created': [agent],
       'agent/disposed': [agent],
       'agent/status': [agent, 'idle'],
-      'agent/inbox/enqueue': [agent, { content: [], source: { kind: 'user' }, contexts: [], steering: false, wakeup: true }],
-      'agent/inbox/dequeue': [agent, { content: [], source: { kind: 'user' }, contexts: [], steering: false, wakeup: true }],
+      'agent/inbox/enqueue': [agent, { id: AgentMessageId('m'), content: [], source: { kind: 'user' }, contexts: [], steering: false, wakeup: true }],
+      'agent/inbox/dequeue': [agent, { id: AgentMessageId('m'), content: [], source: { kind: 'user' }, contexts: [], steering: false, wakeup: true }],
       'agent/inbox/discard': [agent, []],
       'agent/cancel-requested': [agent, { kind: 'user' }],
       'agent/session-start': [agent, 'startup'],
diff --git a/packages/goal/command-goal/tests/command-goal.spec.ts b/packages/goal/command-goal/tests/command-goal.spec.ts
index 6ea767e091..8964d02df2 100644
--- a/packages/goal/command-goal/tests/command-goal.spec.ts
+++ b/packages/goal/command-goal/tests/command-goal.spec.ts
@@ -1,7 +1,7 @@
 import { describe, expect, it, vi } from 'vitest'
 import { Context } from 'cordis'
 import Loader from '@cordisjs/plugin-loader'
-import AgentRegistry from '@deepseek-ai/dsh-agent'
+import AgentRegistry, { AgentMessageId } from '@deepseek-ai/dsh-agent'
 import type { Agent, AgentStatus, AliasSendOptions } from '@deepseek-ai/dsh-agent'
 import CommandService from '@deepseek-ai/dsh-commands'
 import GoalService from '@deepseek-ai/dsh-goal'
@@ -48,10 +48,10 @@ function stubAgent(id: string): { agent: Agent; session: Session } {
     session,
     ctx: new Context(),
     get status() { return status },
-    send() {},
-    followup() {},
-    steer() {},
-    inject(content, options) { appendInjection(session, content, options) },
+    send: () => AgentMessageId('stub'),
+    followup: () => AgentMessageId('stub'),
+    steer: () => AgentMessageId('stub'),
+    inject(content, options) { appendInjection(session, content, options); return AgentMessageId('stub') },
     cancel() { status = 'idle' },
     whenIdle() { return Promise.resolve() },
   }
diff --git a/packages/goal/goal-session/tests/goal-session.spec.ts b/packages/goal/goal-session/tests/goal-session.spec.ts
index e323180e88..d4994466f9 100644
--- a/packages/goal/goal-session/tests/goal-session.spec.ts
+++ b/packages/goal/goal-session/tests/goal-session.spec.ts
@@ -488,7 +488,7 @@ describe('same-session goal driving', () => {
       if (options?.source?.kind === 'goal' && (options.target ?? 'next-turn') === 'next-turn') {
         throw new Error('queue rejected')
       }
-      realSend(content, options)
+      return realSend(content, options)
     })
     test.ctx.goals.create(test.agent, { objective: 'handle queue failure' })
 
@@ -510,7 +510,7 @@ describe('same-session goal driving', () => {
         test.ctx.goals.disarm(test.agent)
         throw new Error('queue rejected after disarm')
       }
-      realSend(content, options)
+      return realSend(content, options)
     })
     test.ctx.goals.create(test.agent, { objective: 'preserve the newer activation state' })
 
diff --git a/packages/goal/goal/tests/goal.spec.ts b/packages/goal/goal/tests/goal.spec.ts
index 18f8d5dfe2..4f6e4e2cfc 100644
--- a/packages/goal/goal/tests/goal.spec.ts
+++ b/packages/goal/goal/tests/goal.spec.ts
@@ -1,6 +1,6 @@
 import { describe, expect, it, vi } from 'vitest'
 import { Context } from 'cordis'
-import AgentRegistry, { agentEvents } from '@deepseek-ai/dsh-agent'
+import AgentRegistry, { agentEvents, AgentMessageId } from '@deepseek-ai/dsh-agent'
 import type { Agent, AgentStatus, AliasSendOptions } from '@deepseek-ai/dsh-agent'
 import { HarnessError, type ContentBlock, type MessageSource } from '@deepseek-ai/dsh-llm'
 import SessionStore, { Session, SessionId } from '@deepseek-ai/dsh-session'
@@ -64,12 +64,13 @@ function stubAgentForSession(session: Session): StubAgent {
     session,
     ctx: new Context(),
     get status() { return status },
-    send() {},
-    followup() {},
-    steer() {},
+    send: () => AgentMessageId('stub'),
+    followup: () => AgentMessageId('stub'),
+    steer: () => AgentMessageId('stub'),
     inject(content, options) {
       if (shouldDefer) deferred.push({ content, options })
       else appendInjection(session, content, options)
+      return AgentMessageId('stub')
     },
     cancel() {},
     whenIdle() { return Promise.resolve() },
@@ -476,7 +477,7 @@ describe('GoalService mutations', () => {
     let reject = true
     stub.agent.inject = (content, options) => {
       if (reject) throw new Error('injection rejected')
-      append(content, options)
+      return append(content, options)
     }
     ctx.agents.register(stub.agent)
 
diff --git a/packages/goal/tool-goal/tests/tool-goal.spec.ts b/packages/goal/tool-goal/tests/tool-goal.spec.ts
index 171fe1c0ef..a4f21392a3 100644
--- a/packages/goal/tool-goal/tests/tool-goal.spec.ts
+++ b/packages/goal/tool-goal/tests/tool-goal.spec.ts
@@ -1,7 +1,7 @@
 import { describe, expect, it } from 'vitest'
 import { Context } from 'cordis'
 import Loader from '@cordisjs/plugin-loader'
-import AgentRegistry, { agentEvents } from '@deepseek-ai/dsh-agent'
+import AgentRegistry, { agentEvents, AgentMessageId } from '@deepseek-ai/dsh-agent'
 import type { Agent, AgentStatus, AliasSendOptions } from '@deepseek-ai/dsh-agent'
 import GoalService, { GoalId } from '@deepseek-ai/dsh-goal'
 import type { GoalRef } from '@deepseek-ai/dsh-goal'
@@ -31,9 +31,9 @@ function stubAgent(rawId: string, supplied?: Session): StubAgent {
     session,
     get status() { return status },
     ctx: new Context(),
-    send() {},
-    followup() {},
-    steer() {},
+    send: () => AgentMessageId('stub'),
+    followup: () => AgentMessageId('stub'),
+    steer: () => AgentMessageId('stub'),
     inject(content: ContentBlock[], options?: AliasSendOptions) {
       const source = options?.source ?? { kind: 'plugin', plugin: '' }
       session.append('user/message', {
@@ -41,6 +41,7 @@ function stubAgent(rawId: string, supplied?: Session): StubAgent {
         source,
         ...options?.meta === undefined ? {} : { meta: options.meta },
       }, { surfaceOp: 'append' })
+      return AgentMessageId('stub')
     },
     cancel() {},
     whenIdle() { return Promise.resolve() },
diff --git a/packages/pty/pty-local/tests/index.spec.ts b/packages/pty/pty-local/tests/index.spec.ts
index 360b71c3f8..dffd80dfbd 100644
--- a/packages/pty/pty-local/tests/index.spec.ts
+++ b/packages/pty/pty-local/tests/index.spec.ts
@@ -3,7 +3,7 @@ import type { IPty, IPtyForkOptions } from 'node-pty'
 import { Context } from 'cordis'
 import Loader from '@cordisjs/plugin-loader'
 import { Session, SessionId } from '@deepseek-ai/dsh-session'
-import type { Agent } from '@deepseek-ai/dsh-agent'
+import { AgentMessageId, type Agent } from '@deepseek-ai/dsh-agent'
 import SandboxProvider from '@deepseek-ai/dsh-sandbox'
 import type { ConfinedArgv, SandboxPolicy } from '@deepseek-ai/dsh-sandbox'
 import SandboxPolicyService from '@deepseek-ai/dsh-sandbox-policy'
@@ -42,7 +42,7 @@ function agent(ctx: Context): Agent {
   const id = SessionId('agent')
   return {
     id, options: {}, session: new Session(id), status: 'idle', ctx,
-    send() {}, followup() {}, steer() {}, inject() {}, cancel() {}, whenIdle: () => Promise.resolve(),
+    send: () => AgentMessageId('stub'), followup: () => AgentMessageId('stub'), steer: () => AgentMessageId('stub'), inject: () => AgentMessageId('stub'), cancel() {}, whenIdle: () => Promise.resolve(),
   }
 }
 
diff --git a/packages/pty/pty-local/tests/local.spec.ts b/packages/pty/pty-local/tests/local.spec.ts
index ad463a0352..512c84c6eb 100644
--- a/packages/pty/pty-local/tests/local.spec.ts
+++ b/packages/pty/pty-local/tests/local.spec.ts
@@ -4,7 +4,7 @@ import { join } from 'node:path'
 import { afterEach, describe, expect, it } from 'vitest'
 import { Context } from 'cordis'
 import { Session, SessionId } from '@deepseek-ai/dsh-session'
-import AgentRegistry from '@deepseek-ai/dsh-agent'
+import AgentRegistry, { AgentMessageId } from '@deepseek-ai/dsh-agent'
 import type { Agent } from '@deepseek-ai/dsh-agent'
 import PtyService from '@deepseek-ai/dsh-pty'
 import SandboxProvider from '@deepseek-ai/dsh-sandbox'
@@ -34,7 +34,7 @@ function stubAgent(ctx: Context, rawId: string): Agent {
   const scope = ctx.plugin(() => {})
   return {
     id, options: {}, session: new Session(id), status: 'idle', ctx: scope.ctx,
-    send() {}, followup() {}, steer() {}, inject() {}, cancel() {}, whenIdle: () => Promise.resolve(),
+    send: () => AgentMessageId('stub'), followup: () => AgentMessageId('stub'), steer: () => AgentMessageId('stub'), inject: () => AgentMessageId('stub'), cancel() {}, whenIdle: () => Promise.resolve(),
   }
 }
 
diff --git a/packages/pty/pty/tests/service.spec.ts b/packages/pty/pty/tests/service.spec.ts
index 4a690ed520..91842173c8 100644
--- a/packages/pty/pty/tests/service.spec.ts
+++ b/packages/pty/pty/tests/service.spec.ts
@@ -1,7 +1,7 @@
 import { describe, expect, expectTypeOf, it } from 'vitest'
 import { Context } from 'cordis'
 import { Session, SessionId } from '@deepseek-ai/dsh-session'
-import AgentRegistry from '@deepseek-ai/dsh-agent'
+import AgentRegistry, { AgentMessageId } from '@deepseek-ai/dsh-agent'
 import type { Agent } from '@deepseek-ai/dsh-agent'
 import PtyService, { PtyError, PtySessionId } from '@deepseek-ai/dsh-pty'
 import type {
@@ -27,10 +27,10 @@ function stubAgent(ctx: Context, rawId: string): Agent {
     session: new Session(id),
     status: 'idle',
     ctx: scopeFiber.ctx,
-    send() {},
-    followup() {},
-    steer() {},
-    inject() {},
+    send: () => AgentMessageId('stub'),
+    followup: () => AgentMessageId('stub'),
+    steer: () => AgentMessageId('stub'),
+    inject: () => AgentMessageId('stub'),
     cancel() {},
     whenIdle: () => Promise.resolve(),
   }
diff --git a/packages/pty/tool-pty/tests/loader-composition.spec.ts b/packages/pty/tool-pty/tests/loader-composition.spec.ts
index f71a637928..cf096ebb70 100644
--- a/packages/pty/tool-pty/tests/loader-composition.spec.ts
+++ b/packages/pty/tool-pty/tests/loader-composition.spec.ts
@@ -8,7 +8,7 @@ import Loader from '@cordisjs/plugin-loader'
 import Include from '@cordisjs/plugin-include'
 import { CallId } from '@deepseek-ai/dsh-llm'
 import { Session, SessionId } from '@deepseek-ai/dsh-session'
-import AgentRegistry from '@deepseek-ai/dsh-agent'
+import AgentRegistry, { AgentMessageId } from '@deepseek-ai/dsh-agent'
 import type { Agent } from '@deepseek-ai/dsh-agent'
 import SystemPrompt from '@deepseek-ai/dsh-system-prompt'
 import ToolRegistry from '@deepseek-ai/dsh-tools'
@@ -40,7 +40,7 @@ function agent(ctx: Context): Agent {
   const id = SessionId('pty-loader-agent')
   const value: Agent = {
     id, options: {}, session: new Session(id), status: 'idle', ctx: scope.ctx,
-    send() {}, followup() {}, steer() {}, inject() {}, cancel() {}, whenIdle: () => Promise.resolve(),
+    send: () => AgentMessageId('stub'), followup: () => AgentMessageId('stub'), steer: () => AgentMessageId('stub'), inject: () => AgentMessageId('stub'), cancel() {}, whenIdle: () => Promise.resolve(),
   }
   ctx.agents.register(value)
   return value
diff --git a/packages/pty/tool-pty/tests/tools.spec.ts b/packages/pty/tool-pty/tests/tools.spec.ts
index 0439e5f876..b0da3adb27 100644
--- a/packages/pty/tool-pty/tests/tools.spec.ts
+++ b/packages/pty/tool-pty/tests/tools.spec.ts
@@ -2,7 +2,7 @@ import { describe, expect, it } from 'vitest'
 import { Context } from 'cordis'
 import { CallId } from '@deepseek-ai/dsh-llm'
 import { Session, SessionId } from '@deepseek-ai/dsh-session'
-import AgentRegistry from '@deepseek-ai/dsh-agent'
+import AgentRegistry, { AgentMessageId } from '@deepseek-ai/dsh-agent'
 import type { Agent } from '@deepseek-ai/dsh-agent'
 import SystemPrompt from '@deepseek-ai/dsh-system-prompt'
 import ToolRegistry from '@deepseek-ai/dsh-tools'
@@ -17,7 +17,7 @@ function fakeAgent(ctx: Context, rawId: string): Agent {
   const id = SessionId(rawId)
   const agent: Agent = {
     id, options: {}, session: new Session(id), status: 'idle', ctx: scope.ctx,
-    send() {}, followup() {}, steer() {}, inject() {}, cancel() {}, whenIdle: () => Promise.resolve(),
+    send: () => AgentMessageId('stub'), followup: () => AgentMessageId('stub'), steer: () => AgentMessageId('stub'), inject: () => AgentMessageId('stub'), cancel() {}, whenIdle: () => Promise.resolve(),
   }
   ctx.agents.register(agent)
   return agent
diff --git a/packages/tasks/tasks/tests/tasks.spec.ts b/packages/tasks/tasks/tests/tasks.spec.ts
index b4d57191a2..cb72658968 100644
--- a/packages/tasks/tasks/tests/tasks.spec.ts
+++ b/packages/tasks/tasks/tests/tasks.spec.ts
@@ -1,7 +1,7 @@
 import { describe, expect, expectTypeOf, it, vi } from 'vitest'
 import { Context } from 'cordis'
 import { Session, SessionId } from '@deepseek-ai/dsh-session'
-import AgentRegistry from '@deepseek-ai/dsh-agent'
+import AgentRegistry, { AgentMessageId } from '@deepseek-ai/dsh-agent'
 import type { Agent } from '@deepseek-ai/dsh-agent'
 import TaskService, { TaskId } from '@deepseek-ai/dsh-tasks'
 import type { TaskHooks, TaskKind, TaskOutcome, TaskSnapshot, TaskStart } from '@deepseek-ai/dsh-tasks'
@@ -23,10 +23,10 @@ function stubAgent(ctx: Context, rawId: string): Agent {
     session: new Session(id),
     status: 'idle' as const,
     ctx: scopeFiber.ctx,
-    send() {},
-    followup() {},
-    steer() {},
-    inject() {},
+    send: () => AgentMessageId('stub'),
+    followup: () => AgentMessageId('stub'),
+    steer: () => AgentMessageId('stub'),
+    inject: () => AgentMessageId('stub'),
     cancel() {},
     whenIdle() { return Promise.resolve() },
   }
diff --git a/packages/ui/tui/tests/harness.ts b/packages/ui/tui/tests/harness.ts
index c8755e4bb3..243f492d2c 100644
--- a/packages/ui/tui/tests/harness.ts
+++ b/packages/ui/tui/tests/harness.ts
@@ -1,6 +1,7 @@
 import { Context } from 'cordis'
 import type { Terminal } from '@earendil-works/pi-tui'
 import AgentRegistry, {
+  AgentMessageId,
   type Agent,
   type AgentCancelCause,
   type AgentOptions,
@@ -152,16 +153,19 @@ export async function createTuiTestHarness<TerminalType extends Terminal, Exit e
     send(content, options) {
       sent.push(content)
       sentOptions.push(options)
+      return AgentMessageId('stub')
     },
     followup(content, options) {
       sent.push(content)
       sentOptions.push(options)
+      return AgentMessageId('stub')
     },
     steer(content, options) {
       steered.push(content)
       steeredOptions.push(options)
+      return AgentMessageId('stub')
     },
-    inject() {},
+    inject: () => AgentMessageId('stub'),
     cancel(cause = { kind: 'user' }) {
       cancelled.push(cause)
     },
diff --git a/packages/ui/tui/tests/tui.spec.ts b/packages/ui/tui/tests/tui.spec.ts
index b45b7a826f..23e297783c 100644
--- a/packages/ui/tui/tests/tui.spec.ts
+++ b/packages/ui/tui/tests/tui.spec.ts
@@ -3,7 +3,7 @@ import { join, resolve } from 'node:path'
 import { describe, expect, it, vi } from 'vitest'
 import { Context } from 'cordis'
 import { CombinedAutocompleteProvider, type Terminal } from '@earendil-works/pi-tui'
-import AgentRegistry, { agentEvents, assembleContextFor, type Agent } from '@deepseek-ai/dsh-agent'
+import AgentRegistry, { agentEvents, assembleContextFor, AgentMessageId, type Agent } from '@deepseek-ai/dsh-agent'
 import { type LlmCallConfig } from '@deepseek-ai/dsh-llm'
 import CommandService, { type CommandInvocation } from '@deepseek-ai/dsh-commands'
 import SessionStore, { SessionId, type JsonValue, type SessionHeader } from '@deepseek-ai/dsh-session'
@@ -552,7 +552,7 @@ describe('pi-tui chat lifecycle and transcript', () => {
     expect(result.terminal.output).not.toContain('queued')
 
     const queueSteering = (text: string): void => {
-      result.ctx.emit('agent/inbox/enqueue', result.agent, { content: [{ type: 'text', text }], source: { kind: 'user' }, contexts: [], steering: true, wakeup: true })
+      result.ctx.emit('agent/inbox/enqueue', result.agent, { id: AgentMessageId('stub'), content: [{ type: 'text', text }], source: { kind: 'user' }, contexts: [], steering: true, wakeup: true })
     }
     const drainSteering = (text: string): void => {
       result.session.append('steering/message', { turn: 1, content: [{ type: 'text', text }], source: { kind: 'user' } }, { surfaceOp: 'append' })
@@ -561,7 +561,7 @@ describe('pi-tui chat lifecycle and transcript', () => {
     // A steering queue for a different agent never touches this status line.
     const other = { ...result.agent, id: SessionId('other') } as unknown as Agent
     result.terminal.output = ''
-    result.ctx.emit('agent/inbox/enqueue', other, { content: [{ type: 'text', text: 'elsewhere' }], source: { kind: 'user' }, contexts: [], steering: true, wakeup: true })
+    result.ctx.emit('agent/inbox/enqueue', other, { id: AgentMessageId('stub'), content: [{ type: 'text', text: 'elsewhere' }], source: { kind: 'user' }, contexts: [], steering: true, wakeup: true })
     await tick()
     expect(result.terminal.output).not.toContain('queued')
 
@@ -574,7 +574,7 @@ describe('pi-tui chat lifecycle and transcript', () => {
 
     // A non-steering queue (an idle-style send) leaves the badge untouched.
     result.terminal.output = ''
-    result.ctx.emit('agent/inbox/enqueue', result.agent, { content: [{ type: 'text', text: 'sent' }], source: { kind: 'user' }, contexts: [], steering: false, wakeup: true })
+    result.ctx.emit('agent/inbox/enqueue', result.agent, { id: AgentMessageId('stub'), content: [{ type: 'text', text: 'sent' }], source: { kind: 'user' }, contexts: [], steering: false, wakeup: true })
     drainSteering('first')
     await tick()
     expect(result.terminal.output).toContain('1 queued')
@@ -628,7 +628,7 @@ describe('pi-tui chat lifecycle and transcript', () => {
     const idle = await setup()
     // A steering queue arriving while idle has no status line to badge, so the
     // refresh is a no-op beyond requesting a render.
-    idle.ctx.emit('agent/inbox/enqueue', idle.agent, { content: [{ type: 'text', text: 'early' }], source: { kind: 'user' }, contexts: [], steering: true, wakeup: true })
+    idle.ctx.emit('agent/inbox/enqueue', idle.agent, { id: AgentMessageId('stub'), content: [{ type: 'text', text: 'early' }], source: { kind: 'user' }, contexts: [], steering: true, wakeup: true })
     idle.session.append('tool/call', { turn: 1, step: 0, callId: 'pre' as never, name: 'bash', arguments: '{}' })
     await tick()
     expect(idle.terminal.output).not.toContain('Executing tools')
@@ -2208,7 +2208,7 @@ describe('terminal mounting', () => {
     const session = ctx.sessions.create(SessionId('main'))
     ctx.agents.register({
       id: session.id, options: {}, session, status: 'idle', ctx,
-      send() {}, followup() {}, steer() {}, inject() {}, cancel() {}, whenIdle: () => Promise.resolve(),
+      send: () => AgentMessageId('stub'), followup: () => AgentMessageId('stub'), steer: () => AgentMessageId('stub'), inject: () => AgentMessageId('stub'), cancel() {}, whenIdle: () => Promise.resolve(),
     })
     const terminal = new FakeTerminal()
     mountTui(ctx, { color: false }, { terminal, exit: vi.fn() })
@@ -2232,7 +2232,7 @@ describe('terminal mounting', () => {
     const session = ctx.sessions.create(SessionId('main'))
     ctx.agents.register({
       id: session.id, options: {}, session, status: 'idle', ctx,
-      send() {}, followup() {}, steer() {}, inject() {}, cancel() {}, whenIdle: () => Promise.resolve(),
+      send: () => AgentMessageId('stub'), followup: () => AgentMessageId('stub'), steer: () => AgentMessageId('stub'), inject: () => AgentMessageId('stub'), cancel() {}, whenIdle: () => Promise.resolve(),
     })
     const terminal = new FakeTerminal()
     // Mirror dsh-tui's own inject (minus loader, the absence under test).
@@ -2266,14 +2266,14 @@ describe('terminal mounting', () => {
     const otherSession = ctx.sessions.create(SessionId('other-session'))
     ctx.agents.register({
       id: otherSession.id, options: {}, session: otherSession, status: 'idle', ctx,
-      send() {}, followup() {}, steer() {}, inject() {}, cancel() {}, whenIdle: () => Promise.resolve(),
+      send: () => AgentMessageId('stub'), followup: () => AgentMessageId('stub'), steer: () => AgentMessageId('stub'), inject: () => AgentMessageId('stub'), cancel() {}, whenIdle: () => Promise.resolve(),
     })
     expect(terminal.started).toBe(0)
 
     const session = ctx.sessions.create(SessionId('late-session'))
     const agent = {
       id: session.id, options: {}, session, status: 'idle', ctx,
-      send() {}, followup() {}, steer() {}, inject() {}, cancel() {}, whenIdle: () => Promise.resolve(),
+      send: () => AgentMessageId('stub'), followup: () => AgentMessageId('stub'), steer: () => AgentMessageId('stub'), inject: () => AgentMessageId('stub'), cancel() {}, whenIdle: () => Promise.resolve(),
     } as Agent
     ctx.agents.register(agent)
     await tick()
@@ -2303,7 +2303,7 @@ describe('terminal mounting', () => {
     const session = ctx.sessions.create(SessionId('main-session'))
     ctx.agents.register({
       id: session.id, options: {}, session, status: 'idle', ctx,
-      send() {}, followup() {}, steer() {}, inject() {}, cancel() {}, whenIdle: () => Promise.resolve(),
+      send: () => AgentMessageId('stub'), followup: () => AgentMessageId('stub'), steer: () => AgentMessageId('stub'), inject: () => AgentMessageId('stub'), cancel() {}, whenIdle: () => Promise.resolve(),
     })
     await tick()
     expect(terminal.started).toBe(0)
@@ -2345,7 +2345,7 @@ describe('terminal mounting', () => {
     session.append('step/start', { turn: 1, step: 1 })
     ctx.agents.register({
       id: session.id, options: {}, session, status: 'running', ctx,
-      send() {}, followup() {}, steer() {}, inject() {}, cancel() {}, whenIdle: () => Promise.resolve(),
+      send: () => AgentMessageId('stub'), followup: () => AgentMessageId('stub'), steer: () => AgentMessageId('stub'), inject: () => AgentMessageId('stub'), cancel() {}, whenIdle: () => Promise.resolve(),
     })
     const terminal = new FakeTerminal()
     terminal.start = () => { throw new Error('terminal startup failed') }
diff --git a/scripts/gen-cordis-catalog.ts b/scripts/gen-cordis-catalog.ts
index 2eee7e0bb0..800f59c22e 100644
--- a/scripts/gen-cordis-catalog.ts
+++ b/scripts/gen-cordis-catalog.ts
@@ -35,8 +35,9 @@ export const LINK_MAP: Record<string, string> = {
   ContinuationDecision: 'core.md',
   ContinuationStop: 'core.md',
   GenerateOptions: 'core.md',
+  AgentMessage: 'core.md',
+  AgentMessageId: 'core.md',
   HookContext: 'core.md',
-  InboxItemInfo: 'core.md',
   LlmCallConfig: 'core.md',
   LlmModelContext: 'core.md',
   LlmFailure: 'llm-streaming.md',
diff --git a/scripts/type-equiv.manifest.json b/scripts/type-equiv.manifest.json
index 5014148504..45c08e494a 100644
--- a/scripts/type-equiv.manifest.json
+++ b/scripts/type-equiv.manifest.json
@@ -83,7 +83,12 @@
     },
     {
       "doc": "docs/core-data-structures/core.md",
-      "symbol": "InboxItemInfo",
+      "symbol": "AgentMessageId",
+      "source": "packages/core/agent/src/types.ts"
+    },
+    {
+      "doc": "docs/core-data-structures/core.md",
+      "symbol": "AgentMessage",
       "source": "packages/core/agent/src/types.ts"
     },
     {