docs: replace vague provenance prose with recorded facts

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: ba0fa456593e598b6532c10ef2390bbd55f3a486
-README.zh.md: 581da5c8621e5653f57edce38ac9816da7a40d40
+README.md: 73d32d09d880b0d27b80a7aeecc1eb75bf03f8dd
+README.zh.md: e140d76c940ac605ddc6dedad8a9f2f16457fde0

packages/core/agent/README.md

@@ -115,5 +115,5 @@ Prefix-stable while an agent's scoped registrations are unchanged. Setup or relo
 - **Inter-agent channels beyond delegation** — shared state, streaming child output, and background/poll semantics remain outside the current synchronous `ctx.subagents` seam.
 - **`agent/session-start` cannot gate startup** — it remains a synchronous, veto-less notification; async composition that must finish before publication belongs in the factory's `setup(agentCtx)` transaction instead.
 - **`cancel()` clears the inbox by default** — it aborts the in-flight turn plus queued and steering work; `cancel(cause, { keepInbox: true })` aborts only the turn and preserves pending items. There is still no step-only abort that keeps the in-flight turn running ([stop-surface Agent Note](../../../.agents/notes/implemented/simplification/2026-06-20-public-agent-stop-surface.md)).
-- **Each additional `UserMessage` carries exactly one `MessageSource`** — contributions from several plugins merged onto one tool call collapse under one source; mixed provenance is unrepresentable.
+- **Each additional `UserMessage` carries exactly one `MessageSource`** — contributions from several plugins merged onto one tool call collapse under one source, so the message cannot name several producers.
 - **`SessionStartSource` reserves `'clear'`/`'compact'` with no emitter yet** — only `'startup'`/`'resume'` occur until the driving subsystems land (`TODO(compaction)`).

packages/core/agent/README.zh.md

@@ -115,5 +115,5 @@ inbox 的实时通知刻意采用逐消息的最小载荷：`agent/inbox/inserte
 - **委派以外的 agent 间通道**：共享状态、流式子输出和后台／轮询语义仍在当前同步 `ctx.subagents` seam 之外。
 - **`agent/session-start` 不能为启动设置门禁**：它仍是同步且不可 veto 的通知；必须在发布前完成的异步组合属于工厂的 `setup(agentCtx)` 事务。
 - **`cancel()` 默认清空 inbox**：它会中止正在处理的轮次以及排队和 steering 工作；`cancel(cause, { keepInbox: true })` 只中止轮次并保留待处理项。仍不存在只中止步骤、同时让正在处理的轮次继续运行的操作（[关于停止操作接口的 Agent Note](../../../.agents/notes/implemented/simplification/2026-06-20-public-agent-stop-surface.md)）。
-- **每条附加 `UserMessage` 恰好携带一个 `MessageSource`**：多个插件合并到一次工具调用上的贡献会归入一个来源；无法表示混合来源。
+- **每条附加 `UserMessage` 恰好携带一个 `MessageSource`**：多个插件合并到一次工具调用上的贡献会归入同一来源，因此该消息无法列出多个生产者。
 - **`SessionStartSource` 预留 `'clear'`/`'compact'`，但还没有发出方**：在驱动子系统落地前，只会出现 `'startup'`/`'resume'`（`TODO(compaction)`）。

packages/core/agent/src/types.ts

@@ -109,7 +109,7 @@ export interface Agent {
    * cancel leaves it parked. A wake submitted while already idle always opens
    * its turn boundary, even when its message is cleared before the driver
    * claims ([cancel-convergence wake latch](../../../../.agents/notes/implemented/bug-fix/2026-08-07-cancel-convergence-wake-latch.md)).
-   * @param message - identified content and its producer provenance.
+   * @param message - identified content and the source that supplied it.
    * @param target - the preferred next-turn or next-step inbox boundary.
    * @param wakeup - whether delivery may wake the driver.
    */
@@ -118,7 +118,7 @@ export interface Agent {
   /**
    * Queue an ordinary follow-up turn and wake the driver. The item becomes the
    * sole ordinary message of its own turn.
-   * @param message - identified prompt content and its producer provenance.
+   * @param message - identified prompt content and the source that supplied it.
    */
   followup(message: UserMessage): void
 
@@ -127,7 +127,7 @@ export interface Agent {
    * a running driver consumes it at its next step boundary.
    * A rejected step leaves steering parked in the inbox until the next
    * wake; cancellation or disposal may discard pending steering.
-   * @param message - identified steering content and its producer provenance.
+   * @param message - identified steering content and the source that supplied it.
    */
   steer(message: UserMessage): void
 
@@ -137,7 +137,7 @@ export interface Agent {
    * idle drivers leave it pending until follow-up or steering
    * wakes them. It may miss a request whose pre-step already claimed its
    * batch. Cancellation or disposal may discard pending context.
-   * @param message - identified injected context and its producer provenance.
+   * @param message - identified injected context and the source that supplied it.
    */
   inject(message: UserMessage): void
 }