docs: align runtime-context contracts

docs/architecture.i18n.yaml

@@ -2,5 +2,5 @@
 # side as of the last confirmed-consistent state. Both languages carry equal authority;
 # after editing either side, bring the other along and re-record with:
 #   pnpm run verify-translation-pairing --write docs/architecture.md
-architecture.md: c6e14fac6436b2401509aaf8bb20ccaf29aeeafc
-architecture.zh.md: 2e85f25eb3f40f58c8ffbfa7691bb793638c8b37
+architecture.md: 461a1eee94be28ced65e320286bab98773f78337
+architecture.zh.md: 9dd3b4aed1b3bb0af14f7c53b7c8d51dfd75cd99

docs/architecture.md

@@ -93,7 +93,8 @@ forever:
     STEP loop:
       agent/step
       drain injected context and steering (steering bypasses prompt-submit)
-      assemble system prompt and tool schemas
+      assemble system prompt and tools
+      materialize changed runtime context as sourced 'user/message'
       snapshot the derived messages (the reconstruction boundary)
       'step/start'
       agent/request (config only) -> prepare adapter defaults/provenance under turn signal -> log request/header -> llm/stream (frozen, registration-bound)
@@ -145,7 +146,7 @@ Each agent owns scoped `agent.ctx`; shared storage overlays its tool, prompt, an
 
 The session log is authoritative. `deriveMessages()` projects model history; raw `assistant/chunk` events preserve replay and UI fidelity. Fork, resume, transcript rendering, telemetry, and persistence derive from this stream.
 
-**Model-visible ⟺ logged**: messages at `step/start` plus the folded `request/header` reconstruct every request; the header also marks adapter-materialized defaults so the next proposal can discard them and resolve the selected route without losing explicit conversation settings. Package-owned `dsh-agent-loop/invariant` can assert reconstructability through `ctx.invariants` ([reconstructability](../.agents/notes/implemented/architecture/2026-07-05-reconstructable-requests.md)).
+**Model-visible ⟺ logged**: before `step/start`, the loop appends the full current runtime-context snapshot as a sourced `user/message`, then snapshots derived messages. Those messages and the folded `request/header` reconstruct each request. The header marks adapter defaults so later proposals discard them and re-resolve the route without losing explicit settings. `dsh-agent-loop/invariant` asserts this through `ctx.invariants` ([reconstructability](../.agents/notes/implemented/architecture/2026-07-05-reconstructable-requests.md)).
 
 Durability is a plugin concern. Backends eagerly drain synchronous `session/event` notifications. `session/flush` barriers precede each request and top-level tool dispatch, then follow `turn/end` before another queued turn or idle observation. `SessionPersistence` stores `SessionEvent` directly and metadata in `SessionHeader`; JSONL defaults to checksummed Zstandard, while SQLite shares the contract ([decision](../.agents/notes/implemented/bug-fix/2026-07-21-semantic-session-checkpoints.md)).
 

docs/architecture.zh.md

@@ -93,7 +93,8 @@ forever:
     STEP loop:
       agent/step
       drain injected context and steering (steering bypasses prompt-submit)
-      assemble system prompt and tool schemas
+      assemble system prompt and tools
+      materialize changed runtime context as sourced 'user/message'
       snapshot the derived messages (the reconstruction boundary)
       'step/start'
       agent/request (config only) -> prepare adapter defaults/provenance under turn signal -> log request/header -> llm/stream (frozen, registration-bound)
@@ -145,7 +146,7 @@ idle inject:
 
 会话日志是权威依据。`deriveMessages()` 投影出模型历史；原始 `assistant/chunk` 事件保证回放和 UI 保真。fork、恢复、transcript（文本记录）渲染、遥测和持久化均派生自该事件流。
 
-**模型可见 ⟺ 已记录**：`step/start` 时的消息与折叠后的 `request/header` 可以重建每个请求；该 header 还会标记适配器填入的默认值，使下一次提议可以丢弃这些值并解析所选路由，同时不丢失显式对话设置。该包的 `dsh-agent-loop/invariant` 可通过 `ctx.invariants` 断言可重建性（[可重建性](../.agents/notes/implemented/architecture/2026-07-05-reconstructable-requests.md)）。
+**模型可见 ⟺ 已记录**：在 `step/start` 之前，循环会将完整的当前运行时上下文快照作为一条带来源的 `user/message` 追加，随后对派生消息制作快照。这些消息与折叠后的 `request/header` 可以重建每个请求。该 header 会标记适配器默认值，使后续提议丢弃这些值并重新解析路由，同时不丢失显式设置。`dsh-agent-loop/invariant` 通过 `ctx.invariants` 断言这一点（[可重建性](../.agents/notes/implemented/architecture/2026-07-05-reconstructable-requests.md)）。
 
 持久性由插件负责。后端会尽快排空同步的 `session/event` 通知。`session/flush` 屏障位于每次请求与顶层工具分发之前，并在 `turn/end` 之后、处理另一个已排队轮次或观察到空闲状态之前执行。`SessionPersistence` 直接存储 `SessionEvent`，并将元数据存入 `SessionHeader`；JSONL 默认采用带校验和的 Zstandard，SQLite 遵循同一契约（[决策](../.agents/notes/implemented/bug-fix/2026-07-21-semantic-session-checkpoints.md)）。