merge: 多章工作流链（LangGraph cyclic 链图 + interrupt-on-conflict + checkpointer）

逐学科多 agent 实施 + 3 路对抗交叉评审 + 修复 1 CRITICAL/5 HIGH。
后端门禁绿：mypy 194 · alembic 无漂移 · pytest 608 passed。

PROGRESS.md

@@ -111,6 +111,7 @@ T0.1 monorepo 骨架 ✅ @devops · T0.2 16 MVP 表迁移（无漂移，users st
 
 > 格式：`- [YYYY-MM-DD] @skill 完成/进展 Txx — 一句话结果 + 影响的契约/文件`
 
+- [2026-06-23] @backend — **✅ Chain Workflow C2（多章链 服务+端点+schema+checkpointer 接线，分支 `feat/chain-workflow`）**。承 C1(@llm)链图（`build_chain_graph` §3.3），落地服务/端点壳：① **3 端点**`routers/chain.py`（`POST .../chains/{key}/run`→202 `ChainRunAccepted`；`POST .../chains/runs/{job_id}/resume`→202；`GET /jobs/{id}` 复用）。校验：count 1..50→422、未知 chain_key→404、项目不存在→404、resume job 不存在→404、resume 非 awaiting→**409 新码 `CONFLICT`**、无凭据→503。② **schema**`schemas/chain.py`（`ChainRunRequest/ChainRunAccepted/ChainResumeRequest`，`ConflictDecision` 复用）。③ **服务**`services/chain_runner.py`（`run_chain_job` 仿 `run_job` 壳自建独立 session 驱动链图：set_running→ainvoke→据 `__interrupt__` 置 `awaiting_input` 或 `done`/`failed`；`build_accept_op` 在 apps/api 装配验收事务闭包注入图节点，守 #3/#4；token 不入 result/日志）+ `services/chain_deps.py`（`get_checkpointer_factory`：运行时 `AsyncPostgresSaver` 上下文 / 测试 MemorySaver）。④ **零迁移**（§7）：复用 `jobs`，新增 `status="awaiting_input"` + `JobRepo.set_awaiting`，awaiting 章经 `result.awaiting_chapter`；新错误码 `ErrorCode.CONFLICT`(409)。⑤ **新网关缝**`project_deps.build_chain_gateway`/`get_chain_gateway`（按请求 tier writer/analyst/light 分派——单档网关恒返该档会错路由 review/digest，见 gotcha）+ `get_digest_gateway_builder`。**单测**`apps/api/tests/test_chain.py` 12 用例（mock 网关 + MemorySaver + fake session/accept_op，无 DB/无网络/无真 LLM）：run→202、resume→202、未知 key 404、count 越界(>50/0) 422、resume 非 awaiting 409、项目/ job 不存在 404、run_chain_job 无冲突→done+written 满、冲突→awaiting→resume→done、错误脱敏、accept_op 冲突缺判→CONFLICT_UNRESOLVED。**全仓门禁绿**：ruff/format 干净、mypy **193 Success**、alembic **无漂移**（无 ORM 变更）、pytest **600 passed**。守不变量 #1/#3/#4/#5/#9。记 contracts C-Chain 稳定 + 2 decision + 3 gotcha。**唯一新增 DDL（langgraph 检查点表）= C3 迁移；前端链 UI = 契约稳定后 @frontend follow-up（本期非目标）。**
 - [2026-06-22] @orchestrator — **🎉 T6 创作工具箱（通用生成器框架）全工具箱交付 + 独立复核（分支 `feat/t6-creation-toolbox`）**。多 agent 并行波次：Wave 0（@llm T6.5 ‖ @backend 描述符类型 ‖ P2 收尾）→ Wave A（@backend T6.2+T6.3 TOOLBOX+端点合龙，契约稳定点）→ Wave B（@frontend T6.6 ‖ @qa T6.4）→ Wave C 收口，目录单写者零写冲突、契约先行、零返工。**@llm T6.5**：`ww_agents` +7 输出 schema + 7 spec（book-title/blurb/name/golden-finger/glossary/opening/fine-outline，只声明 tier #2）+ `build_outline_chapter_context`（with_outline_chapter 策略）。**@frontend T6.6**：`gen:api` 纳入 3 端点；`app/projects/[id]/toolbox/page.tsx`(RSC) + `components/toolbox/{ToolboxPage,ToolCard,GeneratorRunner}` + `lib/toolbox/*`（声明驱动纯函数，按 `input_fields` 渲染表单、按 `output_kind` 渲染预览、可入库者复用 `ConflictAdjudication` 走 409→ack）+ LeftNav「工具箱」+ ⌘K `nav-toolbox`/`action-gen-*`；legacy 3 跳现页不回归。**@qa T6.4**：`tests/test_t6_toolbox_e2e.py` 5 用例真 pg + mock 网关零 token，**未发现端点 bug**。**P2 收尾**：限流→`decisions.md` 记延后（单用户原型）；noopener/Committable 经查本分支早已修；`provider_deps.py` 残留 `type:ignore` 为 SDK 私有属性探活、load-bearing 保留。**最终独立复跑全仓门禁绿**：后端 ruff/format 干净、mypy **195 Success**、alembic **无漂移**（descriptor 在代码、复用既有表，零建表迁移）、pytest **583 passed**；前端 gen:api/lint/tsc/vitest **279**/build OK。守不变量 #2（只声明 tier）/#3（预览不写库、入库经验收 gate）/#9（system_prompt 进缓存前块）。**"加生成器=加一份声明" 经实证（8 个新生成器复用同一通用执行器 + 同一前端组件）。** **实景 browse 复验（工具箱卡片栅格→脑洞预览→词条入库）待做。** 后续可选 P5：封面图像轨道 / 自定义 skill 运行期 schema / 收敛已有 3 竖井。
 - [2026-06-20] UX计划 B0(可控版)+F1(控件) — **✅ 本章注入透明 可控版（分支 `feat/ux-b0-controllable-injection`，提交 `0d473e7` 后端 + `6449c31` 前端，未合 develop）**。在 B0 读端点之上加作者微调，守不变量 #6「确定性选择」的作者兜底。**后端**(@backend/@db)：`PUT /projects/{id}/chapters/{no}/injection` ← `InjectionOverrideRequest{pinned,excluded,recent_n(1..20→422)}` → `InjectionResponse`（新增回显 `pinned`/`excluded`，`selected[].reasons` 可含新值 **`author_pin`**）；`select_relevant_entities` 加 `pinned/excluded` frozenset 入参（pin 强制纳入加 author_pin / excluded 强制剔除且**优先于 pin**）；`assemble` 加 `override` 关键字参（recent_n 覆盖回看章数）；**GET injection + PUT + draft 流式端点同读同一覆盖**（看到的=写章用的）。持久化：**新表 `chapter_injection`**（迁移 `ad2c4c663daf`，唯一 `(project_id,chapter_no)`；复用 outline 行污染 beats 已否决）+ 新 `domain/injection_repo.py`（`InjectionOverride`/`EntityRef`/`SqlInjectionOverrideRepo`，upsert 只 flush 端点 commit）。**前端**(@frontend)：`gen:api` 纳入 PUT + 新 schema；`lib/workbench/injection.ts` override 纯函数（`currentOverride`/`withPinToggled`/`withExcluded`/`withRestored`/`withRecentN`/`isPinned`，钳 1..20）；`useInjection` 加 `saving` 态 + `togglePin/exclude/restore/setRecentN`（PUT 后以服务端确定结果为准、写失败可读文案不改本地态）；`ChapterAssistant` 每实体 📌置顶/✕排除 + 「近 N 章」步进器 + 「已排除」恢复区。**全仓门禁绿**：后端 ruff/format/mypy **163**/alembic 无漂移/pytest **476**；前端 lint/tsc/vitest **183**/build。记 contracts C3 再扩。**实景 browse 复验待做。** UX 计划余项：R1/R2/R3 审稿人体学 + Tier4。
 - [2026-06-20] UX计划 M1+M2 — **✅ 移动端可用（纯前端，分支 `feat/ux-m1-m2-mobile` 提交 9b893a6）**。救活手机端（390px）写→审主路径。**M1 导航响应式抽屉**：抽出纯逻辑 `lib/nav/items.ts`（`GLOBAL_NAV_ITEMS`/`projectNavItems`/`isNavItemActive` + `ActiveNav` 类型，6 vitest），桌面静态侧栏与移动抽屉共用避免漂移；新增通用 `Drawer`（遮罩点击/Esc 关闭/打开聚焦面板，复用 `CommandPalette` a11y 模式，`lg:hidden`）+ `NavDrawer`（汉堡 `aria-label=打开导航` + 左抽屉）+ `NavItems`；`LeftNav` 改 `hidden lg:block`，`AppShell` 顶栏加汉堡。**M2 工具条不溢出 + 移动可达**：`Workbench` 工具条改 `flex-wrap`（390px 不再横切「尚未保存」）；`ChapterList`/`ChapterAssistant` 抽出 `ChapterListContent`/`AssistantContent`，`Workbench` 经左/右 `Drawer` 在 `<lg` 触达目录/助手。**实景 390px 复验（browse）**：汉堡显示 + 静态导航 `display:none`、抽屉开合（聚焦 + Esc 关闭）、工具条两行无横向溢出、助手抽屉真注入面板。前端门禁绿：lint/typecheck 干净 · vitest **177**(171→+6) · build OK。无后端/契约变更。文件：`lib/nav/{items,items.test}.ts`(新) · `components/{Drawer,NavDrawer,NavItems}.tsx`(新) · `components/{AppShell,LeftNav}.tsx` · `components/workbench/{Workbench,ChapterList,ChapterAssistant}.tsx`。**UX 计划余项**：B0 可控版(PUT override) + F1 控件 + R1/R2/R3 审稿人体学 + Tier4。

apps/api/tests/fakes_projects.py

@@ -23,6 +23,7 @@ from ww_core.domain.foreshadow_state import (
 )
 from ww_core.domain.job_repo import (
     PROGRESS_COMPLETE,
+    STATUS_AWAITING,
     STATUS_DONE,
     STATUS_FAILED,
     STATUS_QUEUED,
@@ -413,7 +414,13 @@ class FakeJobRepo:
         self.rows: dict[uuid.UUID, JobView] = {}
 
     async def create(self, project_id: uuid.UUID | None, kind: str) -> JobView:
-        view = JobView(id=uuid.uuid4(), kind=kind, status=STATUS_QUEUED, progress=0)
+        view = JobView(
+            id=uuid.uuid4(),
+            project_id=project_id,
+            kind=kind,
+            status=STATUS_QUEUED,
+            progress=0,
+        )
         self.rows[view.id] = view
         return view
 
@@ -434,6 +441,22 @@ class FakeJobRepo:
         self.rows[job_id] = view
         return view
 
+    async def set_awaiting(self, job_id: uuid.UUID, result: dict[str, Any]) -> JobView:
+        view = self.rows[job_id].model_copy(
+            update={"status": STATUS_AWAITING, "result": dict(result)}
+        )
+        self.rows[job_id] = view
+        return view
+
+    async def claim_awaiting_to_running(self, job_id: uuid.UUID) -> JobView | None:
+        """原子抢占 awaiting→running（内存替身：仅当现态 awaiting 才抢到，否则 None）。"""
+        current = self.rows.get(job_id)
+        if current is None or current.status != STATUS_AWAITING:
+            return None
+        view = current.model_copy(update={"status": STATUS_RUNNING})
+        self.rows[job_id] = view
+        return view
+
     async def fail(self, job_id: uuid.UUID, error: str) -> JobView:
         view = self.rows[job_id].model_copy(update={"status": STATUS_FAILED, "error": error})
         self.rows[job_id] = view

apps/api/tests/test_chain.py

@@ -0,0 +1,653 @@
+"""C2 多章链端点 + 服务层单测（chain-workflow §6/§10）——内存替身，无 DB/无网络/无真 LLM。
+
+覆盖：
+- 端点契约（HTTP 层，`run_chain_job` 被 no-op 替换以隔离调度逻辑）：
+  run → 202 `{job_id,...}`；resume → 202；未知 chain_key → 404；count 越界（>50 / 0）→ 422；
+  resume 非 awaiting 态 → 409；项目不存在 → 404；resume job 不存在 → 404。
+- 服务层 `run_chain_job`（mock 网关 + MemorySaver + fake session_factory + fake accept_op）：
+  无冲突全跑 → job done + result.written 满；有冲突 → interrupt → job awaiting_input；
+  resume 续跑 → done；token 绝不入 job result。
+- `build_accept_op`：冲突缺判 → CONFLICT_UNRESOLVED；无冲突章正常落库（经 fake op 桩验证）。
+"""
+
+from __future__ import annotations
+
+import uuid
+from collections.abc import AsyncIterator
+from contextlib import asynccontextmanager
+from typing import Any
+
+import httpx
+import pytest
+from fakes_projects import FakeJobRepo, FakeProjectRepo
+from fastapi import FastAPI
+from langgraph.checkpoint.memory import MemorySaver
+from pydantic import BaseModel
+from ww_agents import Conflict, ContinuityReview
+from ww_api.schemas.projects import ConflictDecision
+from ww_api.services.chain_runner import build_accept_op, run_chain_job
+from ww_core.domain.job_repo import STATUS_AWAITING, STATUS_DONE
+from ww_core.domain.project_repo import ProjectCreate
+from ww_llm_gateway.types import LlmRequest, LlmResponse, ServedBy, Usage
+
+PROJECT_OWNER = uuid.UUID(int=1)
+USER = uuid.UUID("00000000-0000-0000-0000-0000000000aa")
+
+
+# ---- 共享替身 ----
+
+
+def _usage() -> Usage:
+    return Usage(
+        provider="fake", model="fake", input_tokens=1, output_tokens=1, cost_minor=0, currency="USD"
+    )
+
+
+class _FakeChainGateway:
+    """链网关 mock：write（无 output_schema）回固定正文；审稿按 schema 回 parsed。"""
+
+    def __init__(self, *, conflicts: list[Conflict]) -> None:
+        self._continuity = ContinuityReview(conflicts=conflicts)
+        from ww_agents import foreshadow_spec, pace_spec, style_drift_spec
+
+        self._by_schema: dict[type, BaseModel] = {}
+        for spec in (foreshadow_spec, pace_spec, style_drift_spec):
+            schema = spec.output_schema
+            assert schema is not None
+            self._by_schema[schema] = schema()
+
+    async def run(self, req: LlmRequest) -> LlmResponse:
+        schema = req.output_schema
+        if schema is None:
+            return LlmResponse(
+                text="第 N 章正文。",
+                parsed=None,
+                usage=_usage(),
+                served_by=ServedBy(provider="fake", model="fake"),
+            )
+        parsed = self._continuity if schema is ContinuityReview else self._by_schema[schema]
+        return LlmResponse(
+            text=parsed.model_dump_json(),
+            parsed=parsed,
+            usage=_usage(),
+            served_by=ServedBy(provider="fake", model="fake"),
+        )
+
+
+class _FakeDraftView:
+    def __init__(self, content: str) -> None:
+        self.content = content
+
+
+class _FakeChapterRepo:
+    def __init__(self, store: dict[int, str]) -> None:
+        self._store = store
+
+    async def save_draft(
+        self, project_id: uuid.UUID, chapter_no: int, *, text: str, volume: int = 1
+    ) -> Any:
+        self._store[chapter_no] = text
+        return _FakeDraftView(text)
+
+    async def get_draft(self, project_id: uuid.UUID, chapter_no: int) -> Any:
+        content = self._store.get(chapter_no)
+        return _FakeDraftView(content) if content is not None else None
+
+
+class _FakeReviewRecord:
+    def __init__(self, chapter_no: int, conflicts: list[dict[str, Any]]) -> None:
+        self.id = uuid.uuid4()
+        self.chapter_no = chapter_no
+        self.conflicts = conflicts
+
+
+class _FakeReviewRepo:
+    def __init__(self, records: dict[int, list[_FakeReviewRecord]]) -> None:
+        self._records = records
+
+    async def record(
+        self,
+        project_id: uuid.UUID,
+        chapter_no: int,
+        *,
+        chapter_version: int | None = None,
+        conflicts: list[dict[str, Any]],
+        foreshadow_sug: list[dict[str, Any]] | None = None,
+        style: dict[str, Any] | None = None,
+        pace: dict[str, Any] | None = None,
+        health_score: int | None = None,
+    ) -> Any:
+        rec = _FakeReviewRecord(chapter_no, list(conflicts))
+        self._records.setdefault(chapter_no, []).insert(0, rec)
+        return rec
+
+    async def list_for_chapter(self, project_id: uuid.UUID, chapter_no: int) -> list[Any]:
+        return list(self._records.get(chapter_no, []))
+
+
+class _FakeSession:
+    def __init__(self) -> None:
+        self.commits = 0
+
+    async def commit(self) -> None:
+        self.commits += 1
+
+
+@asynccontextmanager
+async def _session_cm() -> AsyncIterator[Any]:
+    yield _FakeSession()
+
+
+def _session_factory() -> Any:
+    """fake 独立 session 工厂（满足 `SessionFactory` 形：`()` → async-CM）。
+
+    返回 Any 避开 AsyncSession 不变型校验（同 test_job_runner 的 `__call__ -> Any` 纪律）。
+    """
+    return _session_cm()
+
+
+@asynccontextmanager
+async def _memsaver_ctx(saver: MemorySaver) -> AsyncIterator[Any]:
+    yield saver
+
+
+def _async_returning(gateway: Any) -> Any:
+    """构造「按 session 建网关」的 builder 替身：忽略 session，恒返给定 mock 网关（绝不联网）。
+
+    链节点经 `gateway_builder(session)` 现建网关（不变量 #1）；测试里 ledger 不落库（fake
+    session），故 builder 只需把 mock 网关交回即可。
+    """
+
+    async def _build(_session: Any) -> Any:
+        return gateway
+
+    return _build
+
+
+class _FakeContext:
+    stable_core = "## 世界观硬规则\n灵气可凝丹"
+    volatile = "## 写作指令\n写第 N 章"
+
+
+# ---- 端点契约（HTTP 层，run_chain_job no-op）----
+
+
+def _app(project_repo: FakeProjectRepo, job_repo: FakeJobRepo) -> FastAPI:
+    import os
+
+    from cryptography.fernet import Fernet
+
+    os.environ.setdefault("CREDENTIAL_ENC_KEY", Fernet.generate_key().decode())
+    from ww_api.main import create_app
+    from ww_api.services.chain_deps import get_checkpointer_factory
+    from ww_api.services.project_deps import (
+        get_chain_gateway,
+        get_chain_gateway_builder,
+        get_digest_gateway_builder,
+        get_job_repo,
+        get_project_repo,
+        get_session_factory,
+    )
+    from ww_db import get_session
+
+    app = create_app()
+    app.dependency_overrides[get_project_repo] = lambda: project_repo
+    app.dependency_overrides[get_job_repo] = lambda: job_repo
+    app.dependency_overrides[get_session] = lambda: _FakeSession()
+    app.dependency_overrides[get_session_factory] = lambda: _session_factory
+    app.dependency_overrides[get_chain_gateway] = lambda: _FakeChainGateway(conflicts=[])
+    app.dependency_overrides[get_chain_gateway_builder] = lambda: _async_returning(
+        _FakeChainGateway(conflicts=[])
+    )
+    saver = MemorySaver()
+    app.dependency_overrides[get_checkpointer_factory] = lambda: lambda: _memsaver_ctx(saver)
+    app.dependency_overrides[get_digest_gateway_builder] = lambda: lambda _s: None
+    return app
+
+
+def _client(app: FastAPI) -> httpx.AsyncClient:
+    transport = httpx.ASGITransport(app=app, raise_app_exceptions=False)
+    return httpx.AsyncClient(transport=transport, base_url="http://test")
+
+
+async def _seed_project(repo: FakeProjectRepo) -> uuid.UUID:
+    view = await repo.create(PROJECT_OWNER, ProjectCreate(title="测试作品", genre="玄幻"))
+    return uuid.UUID(str(view.id))
+
+
+@pytest.fixture
+def _noop_run_chain_job(monkeypatch: pytest.MonkeyPatch) -> list[dict[str, Any]]:
+    """把端点登记的 `run_chain_job` 换成记录调用的 no-op（隔离调度逻辑，不真跑图）。"""
+    calls: list[dict[str, Any]] = []
+
+    async def _fake(*args: Any, **kwargs: Any) -> None:
+        calls.append({"args": args, "kwargs": kwargs})
+
+    monkeypatch.setattr("ww_api.routers.chain.run_chain_job", _fake)
+    return calls
+
+
+async def test_run_chain_returns_202_and_schedules_job(
+    _noop_run_chain_job: list[dict[str, Any]],
+) -> None:
+    project_repo = FakeProjectRepo()
+    job_repo = FakeJobRepo()
+    pid = await _seed_project(project_repo)
+    app = _app(project_repo, job_repo)
+
+    async with _client(app) as client:
+        resp = await client.post(
+            f"/projects/{pid}/chains/draft_volume/run",
+            json={"start_chapter_no": 1, "count": 3},
+        )
+
+    assert resp.status_code == 202
+    body = resp.json()
+    assert body["chain_key"] == "draft_volume"
+    assert body["start_chapter_no"] == 1
+    assert body["count"] == 3
+    assert uuid.UUID(body["job_id"])
+    # job 行已落（queued）+ 调度了一次后台任务
+    assert len(job_repo.rows) == 1
+    assert len(_noop_run_chain_job) == 1
+
+
+async def test_run_chain_unknown_key_returns_404(
+    _noop_run_chain_job: list[dict[str, Any]],
+) -> None:
+    project_repo = FakeProjectRepo()
+    job_repo = FakeJobRepo()
+    pid = await _seed_project(project_repo)
+    app = _app(project_repo, job_repo)
+
+    async with _client(app) as client:
+        resp = await client.post(
+            f"/projects/{pid}/chains/unknown_chain/run",
+            json={"start_chapter_no": 1, "count": 2},
+        )
+
+    assert resp.status_code == 404
+    assert resp.json()["error"]["code"] == "NOT_FOUND"
+    assert len(_noop_run_chain_job) == 0  # 未调度
+
+
+async def test_run_chain_count_over_50_returns_422(
+    _noop_run_chain_job: list[dict[str, Any]],
+) -> None:
+    project_repo = FakeProjectRepo()
+    job_repo = FakeJobRepo()
+    pid = await _seed_project(project_repo)
+    app = _app(project_repo, job_repo)
+
+    async with _client(app) as client:
+        resp = await client.post(
+            f"/projects/{pid}/chains/draft_volume/run",
+            json={"start_chapter_no": 1, "count": 51},
+        )
+
+    assert resp.status_code == 422
+
+
+async def test_run_chain_count_zero_returns_422(
+    _noop_run_chain_job: list[dict[str, Any]],
+) -> None:
+    project_repo = FakeProjectRepo()
+    job_repo = FakeJobRepo()
+    pid = await _seed_project(project_repo)
+    app = _app(project_repo, job_repo)
+
+    async with _client(app) as client:
+        resp = await client.post(
+            f"/projects/{pid}/chains/draft_volume/run",
+            json={"start_chapter_no": 1, "count": 0},
+        )
+
+    assert resp.status_code == 422
+
+
+async def test_run_chain_project_not_found_returns_404(
+    _noop_run_chain_job: list[dict[str, Any]],
+) -> None:
+    project_repo = FakeProjectRepo()
+    job_repo = FakeJobRepo()
+    app = _app(project_repo, job_repo)
+
+    async with _client(app) as client:
+        resp = await client.post(
+            f"/projects/{uuid.uuid4()}/chains/draft_volume/run",
+            json={"start_chapter_no": 1, "count": 2},
+        )
+
+    assert resp.status_code == 404
+
+
+async def test_resume_chain_awaiting_returns_202(
+    _noop_run_chain_job: list[dict[str, Any]],
+) -> None:
+    project_repo = FakeProjectRepo()
+    job_repo = FakeJobRepo()
+    pid = await _seed_project(project_repo)
+    # 预置一个 awaiting_input 的链 job
+    job = await job_repo.create(pid, "chain")
+    await job_repo.set_awaiting(job.id, {"awaiting_chapter": 1})
+    app = _app(project_repo, job_repo)
+
+    async with _client(app) as client:
+        resp = await client.post(
+            f"/projects/{pid}/chains/runs/{job.id}/resume",
+            json={"decisions": [{"conflict_index": 0, "verdict": "ignore"}]},
+        )
+
+    assert resp.status_code == 202
+    assert resp.json()["job_id"] == str(job.id)
+    assert len(_noop_run_chain_job) == 1
+
+
+async def test_resume_chain_non_awaiting_returns_409(
+    _noop_run_chain_job: list[dict[str, Any]],
+) -> None:
+    project_repo = FakeProjectRepo()
+    job_repo = FakeJobRepo()
+    pid = await _seed_project(project_repo)
+    job = await job_repo.create(pid, "chain")  # queued（非 awaiting）
+    app = _app(project_repo, job_repo)
+
+    async with _client(app) as client:
+        resp = await client.post(
+            f"/projects/{pid}/chains/runs/{job.id}/resume",
+            json={"decisions": []},
+        )
+
+    assert resp.status_code == 409
+    assert resp.json()["error"]["code"] == "CONFLICT"
+    assert len(_noop_run_chain_job) == 0
+
+
+async def test_resume_chain_job_not_found_returns_404(
+    _noop_run_chain_job: list[dict[str, Any]],
+) -> None:
+    project_repo = FakeProjectRepo()
+    job_repo = FakeJobRepo()
+    pid = await _seed_project(project_repo)
+    app = _app(project_repo, job_repo)
+
+    async with _client(app) as client:
+        resp = await client.post(
+            f"/projects/{pid}/chains/runs/{uuid.uuid4()}/resume",
+            json={"decisions": []},
+        )
+
+    assert resp.status_code == 404
+
+
+async def test_resume_chain_wrong_project_returns_404(
+    _noop_run_chain_job: list[dict[str, Any]],
+) -> None:
+    """所有权校验（审评 #4）：job 属项目 A，从项目 B 路径 resume → 404（同案，不枚举）。"""
+    project_repo = FakeProjectRepo()
+    job_repo = FakeJobRepo()
+    pid_a = await _seed_project(project_repo)
+    pid_b = uuid.UUID(
+        str((await project_repo.create(PROJECT_OWNER, ProjectCreate(title="作品B"))).id)
+    )
+    job = await job_repo.create(pid_a, "chain")  # job 属 A
+    await job_repo.set_awaiting(job.id, {"awaiting_chapter": 1})
+    app = _app(project_repo, job_repo)
+
+    async with _client(app) as client:
+        resp = await client.post(
+            f"/projects/{pid_b}/chains/runs/{job.id}/resume",  # 从 B 续 A 的 job
+            json={"decisions": []},
+        )
+
+    assert resp.status_code == 404
+    assert len(_noop_run_chain_job) == 0  # 未调度
+
+
+async def test_resume_chain_concurrent_claim_returns_409(
+    _noop_run_chain_job: list[dict[str, Any]],
+) -> None:
+    """原子抢占（审评 #3）：第一个 resume 已把 awaiting→running，第二个抢不到 → 409。"""
+    project_repo = FakeProjectRepo()
+    job_repo = FakeJobRepo()
+    pid = await _seed_project(project_repo)
+    job = await job_repo.create(pid, "chain")
+    await job_repo.set_awaiting(job.id, {"awaiting_chapter": 1})
+    # 模拟并发：第一个 resume 已抢占 awaiting→running。
+    claimed = await job_repo.claim_awaiting_to_running(job.id)
+    assert claimed is not None
+    app = _app(project_repo, job_repo)
+
+    async with _client(app) as client:
+        resp = await client.post(
+            f"/projects/{pid}/chains/runs/{job.id}/resume",
+            json={"decisions": []},
+        )
+
+    # job 现态 running（非 awaiting）→ 守卫先在 status 检查处 409（CONFLICT）。
+    assert resp.status_code == 409
+    assert resp.json()["error"]["code"] == "CONFLICT"
+    assert len(_noop_run_chain_job) == 0
+
+
+# ---- 服务层 run_chain_job（直接 await，注入全 fake；job 状态由 fake SqlJobRepo 替身记录）----
+
+
+class _RecordingJobRepo:
+    """run_chain_job 内部 `SqlJobRepo(session)` 的替身（monkeypatch）：记录状态流转。"""
+
+    state: dict[uuid.UUID, dict[str, Any]] = {}
+
+    def __init__(self, session: Any) -> None:
+        pass
+
+    async def set_running(self, job_id: uuid.UUID) -> Any:
+        _RecordingJobRepo.state.setdefault(job_id, {})["status"] = "running"
+        return None
+
+    async def complete(self, job_id: uuid.UUID, result: dict[str, Any]) -> Any:
+        _RecordingJobRepo.state[job_id] = {"status": STATUS_DONE, "result": result}
+        return None
+
+    async def set_awaiting(self, job_id: uuid.UUID, result: dict[str, Any]) -> Any:
+        _RecordingJobRepo.state[job_id] = {"status": STATUS_AWAITING, "result": result}
+        return None
+
+    async def fail(self, job_id: uuid.UUID, error: str) -> Any:
+        _RecordingJobRepo.state[job_id] = {"status": "failed", "error": error}
+        return None
+
+
+def _chain_runner_fakes() -> dict[str, Any]:
+    draft_store: dict[int, str] = {}
+    review_store: dict[int, list[_FakeReviewRecord]] = {}
+    accepted: list[dict[str, Any]] = []
+
+    async def accept_op(
+        *, project_id: uuid.UUID, chapter_no: int, user_id: uuid.UUID, decisions: list[Any]
+    ) -> None:
+        accepted.append({"chapter_no": chapter_no, "decisions": list(decisions)})
+
+    return {
+        "draft_store": draft_store,
+        "review_store": review_store,
+        "accepted": accepted,
+        "accept_op": accept_op,
+        "chapter_repo_factory": lambda _s: _FakeChapterRepo(draft_store),
+        "review_repo_factory": lambda _s: _FakeReviewRepo(review_store),
+    }
+
+
+@pytest.fixture
+def _patched_runner(monkeypatch: pytest.MonkeyPatch) -> None:
+    """把 run_chain_job 里的 SqlJobRepo + assemble + sql_memory_repos 换成 fake（不触 DB）。"""
+    _RecordingJobRepo.state = {}
+    monkeypatch.setattr("ww_api.services.chain_runner.SqlJobRepo", _RecordingJobRepo)
+
+    async def _fake_assemble(
+        repos: Any, project_id: uuid.UUID, chapter_no: int, *a: Any, **k: Any
+    ) -> _FakeContext:
+        return _FakeContext()
+
+    monkeypatch.setattr("ww_api.services.chain_runner.assemble", _fake_assemble)
+    monkeypatch.setattr("ww_api.services.chain_runner.sql_memory_repos", lambda _s: object())
+
+
+async def test_run_chain_job_no_conflict_completes_done(_patched_runner: None) -> None:
+    fakes = _chain_runner_fakes()
+    gateway = _FakeChainGateway(conflicts=[])
+    job_id = uuid.uuid4()
+    saver = MemorySaver()
+
+    await run_chain_job(
+        _session_factory,
+        job_id,
+        project_id=uuid.uuid4(),
+        user_id=USER,
+        chain_key="draft_volume",
+        start_chapter_no=1,
+        count=2,
+        chain_gateway_builder=_async_returning(gateway),
+        checkpointer_ctx=lambda: _memsaver_ctx(saver),
+        accept_op=fakes["accept_op"],
+        chapter_repo_factory=fakes["chapter_repo_factory"],
+        review_repo_factory=fakes["review_repo_factory"],
+    )
+
+    rec = _RecordingJobRepo.state[job_id]
+    assert rec["status"] == STATUS_DONE
+    assert rec["result"]["written"] == [1, 2]
+    assert rec["result"]["completed"] is True
+    assert rec["result"]["awaiting_chapter"] is None
+    # token 不入 result：只含章号/标志，无正文/prompt
+    assert "第 N 章正文" not in str(rec["result"])
+    assert [a["chapter_no"] for a in fakes["accepted"]] == [1, 2]
+
+
+async def test_run_chain_job_conflict_sets_awaiting_then_resume_done(
+    _patched_runner: None,
+) -> None:
+    fakes = _chain_runner_fakes()
+    conflict = Conflict(type="性格漂移", where="第3段", suggestion="统一主角姓名")
+    gateway = _FakeChainGateway(conflicts=[conflict])
+    job_id = uuid.uuid4()
+    saver = MemorySaver()  # 同 saver 跨 run/resume 两次调用
+    project_id = uuid.uuid4()
+
+    # 初始 run：第 1 章四审报冲突 → interrupt → job awaiting_input。
+    await run_chain_job(
+        _session_factory,
+        job_id,
+        project_id=project_id,
+        user_id=USER,
+        chain_key="draft_volume",
+        start_chapter_no=1,
+        count=1,
+        chain_gateway_builder=_async_returning(gateway),
+        checkpointer_ctx=lambda: _memsaver_ctx(saver),
+        accept_op=fakes["accept_op"],
+        chapter_repo_factory=fakes["chapter_repo_factory"],
+        review_repo_factory=fakes["review_repo_factory"],
+    )
+
+    rec = _RecordingJobRepo.state[job_id]
+    assert rec["status"] == STATUS_AWAITING
+    assert rec["result"]["awaiting_chapter"] == 1
+    assert fakes["accepted"] == []  # 尚未验收
+
+    # resume：作者裁决 → 续跑 accept → done。
+    decisions = [ConflictDecision(conflict_index=0, verdict="ignore", note="笔误")]
+    await run_chain_job(
+        _session_factory,
+        job_id,
+        project_id=project_id,
+        user_id=USER,
+        chain_key="draft_volume",
+        start_chapter_no=1,
+        count=1,
+        chain_gateway_builder=_async_returning(gateway),
+        checkpointer_ctx=lambda: _memsaver_ctx(saver),
+        accept_op=fakes["accept_op"],
+        chapter_repo_factory=fakes["chapter_repo_factory"],
+        review_repo_factory=fakes["review_repo_factory"],
+        resume_decisions=decisions,
+    )
+
+    rec = _RecordingJobRepo.state[job_id]
+    assert rec["status"] == STATUS_DONE
+    assert rec["result"]["written"] == [1]
+    assert [a["chapter_no"] for a in fakes["accepted"]] == [1]
+    assert fakes["accepted"][0]["decisions"] == [
+        {"conflict_index": 0, "verdict": "ignore", "note": "笔误"}
+    ]
+
+
+async def test_run_chain_job_error_marks_failed_safely(_patched_runner: None) -> None:
+    """work 抛 → job failed + 脱敏文案（不泄 str(exc)），异常不冒泡。"""
+    fakes = _chain_runner_fakes()
+    job_id = uuid.uuid4()
+
+    class _BoomGateway:
+        async def run(self, req: LlmRequest) -> LlmResponse:
+            raise RuntimeError("boom secret=/internal/path")
+
+    await run_chain_job(
+        _session_factory,
+        job_id,
+        project_id=uuid.uuid4(),
+        user_id=USER,
+        chain_key="draft_volume",
+        start_chapter_no=1,
+        count=1,
+        chain_gateway_builder=_async_returning(_BoomGateway()),
+        checkpointer_ctx=lambda: _memsaver_ctx(MemorySaver()),
+        accept_op=fakes["accept_op"],
+        chapter_repo_factory=fakes["chapter_repo_factory"],
+        review_repo_factory=fakes["review_repo_factory"],
+    )
+
+    rec = _RecordingJobRepo.state[job_id]
+    assert rec["status"] == "failed"
+    assert rec["error"] == "任务执行失败"
+    assert "secret" not in rec["error"]
+
+
+# ---- build_accept_op：冲突缺判 gate ----
+
+
+async def test_build_accept_op_missing_decision_raises_conflict_unresolved(
+    monkeypatch: pytest.MonkeyPatch,
+) -> None:
+    from ww_shared import AppError, ErrorCode
+
+    review_store: dict[int, list[_FakeReviewRecord]] = {
+        1: [_FakeReviewRecord(1, [{"type": "矛盾", "where": "第1段"}])]
+    }
+
+    class _Session:
+        async def commit(self) -> None: ...
+
+    @asynccontextmanager
+    async def _sf_cm() -> AsyncIterator[Any]:
+        yield _Session()
+
+    def _sf() -> Any:
+        return _sf_cm()
+
+    # 桩出 accept_op 依赖：链 accept 节点重读审稿、跑 gate（缺判应在 gate 拦下，不触 digest/事务）。
+    monkeypatch.setattr(
+        "ww_api.services.chain_runner.SqlChapterRepo", lambda _s: _FakeChapterRepo({1: "正文"})
+    )
+    monkeypatch.setattr(
+        "ww_api.services.chain_runner.SqlReviewRepo", lambda _s: _FakeReviewRepo(review_store)
+    )
+    monkeypatch.setattr("ww_api.services.chain_runner.SqlDigestAppendRepo", lambda _s: object())
+
+    async def _digest_builder(_s: Any) -> Any:
+        return object()
+
+    accept_op = build_accept_op(session_factory=_sf, digest_gateway_builder=_digest_builder)
+
+    with pytest.raises(AppError) as exc:
+        await accept_op(project_id=uuid.uuid4(), chapter_no=1, user_id=USER, decisions=[])
+    assert exc.value.code == ErrorCode.CONFLICT_UNRESOLVED

apps/api/ww_api/main.py

@@ -16,6 +16,7 @@ from ww_shared import AppError, ErrorBody, ErrorCode, ErrorEnvelope
 from ww_api.logging_config import configure_logging, get_logger
 from ww_api.middleware import REQUEST_ID_HEADER, request_id_middleware
 from ww_api.routers import (
+    chain,
     foreshadow,
     generation,
     health,
@@ -117,6 +118,7 @@ def create_app() -> FastAPI:
     app.include_router(generation.router)
     app.include_router(generation.skills_router)
     app.include_router(toolbox.router)
+    app.include_router(chain.router)
     app.include_router(settings_providers.router)
     app.include_router(kimi_oauth.router)
     return app

apps/api/ww_api/routers/chain.py

@@ -0,0 +1,264 @@
+"""多章工作流链端点（chain-workflow 设计 §6）——发起 / 续跑，进度走 `GET /jobs/{id}`。
+
+三端点：
+- `POST /projects/{pid}/chains/{chain_key}/run` → 202 `ChainRunAccepted{job_id,...}`：
+  写一行 jobs(queued, kind=chain) 立即返 202，链经 BackgroundTask `run_chain_job` 跑
+  （**自建独立 session**，请求 session 已关闭）。无凭据 → 流前 `LLM_UNAVAILABLE`（503，
+  调度 job 前拦下）。未知 chain_key → 404；`count` 1..50 越界 → 422（schema Field 约束）。
+- `GET /jobs/{job_id}`：复用现有 jobs 端点轮询进度/awaiting（不在本 router）。
+- `POST /projects/{pid}/chains/runs/{job_id}/resume` → 202：仅当 job=awaiting_input；
+  带裁决经 BackgroundTask resume 续跑。非 awaiting 态 → 409。
+
+不变量：链是**编排**新增、非业务重写——复用同一 `assemble`/审稿 spec/`run_accept_transaction`
+（经 `accept_op` 闭包注入），守 #1/#3/#4/#5/#9。token 绝不入 job result/状态/日志（§5）。
+"""
+
+from __future__ import annotations
+
+import uuid
+from typing import Annotated, Any
+
+from fastapi import APIRouter, BackgroundTasks, Depends, Request, Response
+from sqlalchemy.ext.asyncio import AsyncSession
+from ww_core.domain import JobRepo, ProjectRepo
+from ww_core.domain.job_repo import STATUS_AWAITING
+from ww_db import get_session
+from ww_llm_gateway import Gateway
+from ww_shared import AppError, ErrorCode, ErrorEnvelope
+
+from ww_api.logging_config import get_logger
+from ww_api.schemas.chain import (
+    ChainResumeAccepted,
+    ChainResumeRequest,
+    ChainRunAccepted,
+    ChainRunRequest,
+)
+from ww_api.services.chain_deps import (
+    CheckpointerFactory,
+    get_checkpointer_factory,
+)
+from ww_api.services.chain_runner import (
+    JOB_KIND_CHAIN,
+    build_accept_op,
+    run_chain_job,
+)
+from ww_api.services.credentials import STUB_OWNER_ID
+from ww_api.services.foreshadow_scan import SessionFactory
+from ww_api.services.project_deps import (
+    GatewayChainBuilder,
+    GatewayDigestBuilder,
+    get_chain_gateway,
+    get_chain_gateway_builder,
+    get_digest_gateway_builder,
+    get_job_repo,
+    get_project_repo,
+    get_session_factory,
+)
+
+log = get_logger("ww.api.chain")
+
+router = APIRouter(prefix="/projects", tags=["chain"])
+
+# 本期唯一内置链（§1.3/§3）。未知 key → 404（系统边界，fail fast）。
+SUPPORTED_CHAINS = frozenset({"draft_volume"})
+
+ProjectRepoDep = Annotated[ProjectRepo, Depends(get_project_repo)]
+JobRepoDep = Annotated[JobRepo, Depends(get_job_repo)]
+ChainGatewayDep = Annotated[Gateway, Depends(get_chain_gateway)]
+SessionDep = Annotated[AsyncSession, Depends(get_session)]
+SessionFactoryDep = Annotated[SessionFactory, Depends(get_session_factory)]
+CheckpointerFactoryDep = Annotated[CheckpointerFactory, Depends(get_checkpointer_factory)]
+DigestBuilderDep = Annotated[GatewayDigestBuilder, Depends(get_digest_gateway_builder)]
+ChainBuilderDep = Annotated[GatewayChainBuilder, Depends(get_chain_gateway_builder)]
+
+_RUN_ERRORS: dict[int | str, dict[str, Any]] = {
+    404: {"model": ErrorEnvelope, "description": "项目或链 key 不存在"},
+    422: {"model": ErrorEnvelope, "description": "请求参数非法（count 越界等）"},
+    503: {"model": ErrorEnvelope, "description": "无可用 LLM 凭据"},
+}
+_RESUME_ERRORS: dict[int | str, dict[str, Any]] = {
+    404: {"model": ErrorEnvelope, "description": "项目或 job 不存在"},
+    409: {"model": ErrorEnvelope, "description": "job 非 awaiting_input 态，不可续跑"},
+}
+
+
+async def _require_project(project_repo: ProjectRepo, project_id: uuid.UUID) -> None:
+    if await project_repo.get(STUB_OWNER_ID, project_id) is None:
+        raise AppError(ErrorCode.NOT_FOUND, f"project not found: {project_id}")
+
+
+@router.post(
+    "/{project_id}/chains/{chain_key}/run",
+    status_code=202,
+    responses=_RUN_ERRORS,
+)
+async def run_chain(
+    project_id: uuid.UUID,
+    chain_key: str,
+    body: ChainRunRequest,
+    request: Request,
+    response: Response,
+    background_tasks: BackgroundTasks,
+    project_repo: ProjectRepoDep,
+    job_repo: JobRepoDep,
+    gateway: ChainGatewayDep,  # 凭据探测（无凭据 → dep 解析阶段 503）；不用于实际 LLM 调用
+    session: SessionDep,
+    session_factory: SessionFactoryDep,
+    checkpointer_factory: CheckpointerFactoryDep,
+    digest_gateway_builder: DigestBuilderDep,
+    chain_gateway_builder: ChainBuilderDep,
+) -> ChainRunAccepted:
+    """发起多章链：写一行 job 返 202，链经 BackgroundTask 异步跑。
+
+    项目不存在 → 404；未知 chain_key → 404；无凭据 → 503（dep 解析阶段拦下）；
+    `count` 越界由 schema Field 在解析阶段 → 422。`gateway` 仅做请求阶段凭据探测——
+    链本体在 BackgroundTask 里用独立 session 重建网关跑（请求 session 即将关闭）。
+    """
+    request_id = getattr(request.state, "request_id", None)
+
+    await _require_project(project_repo, project_id)
+    if chain_key not in SUPPORTED_CHAINS:
+        raise AppError(ErrorCode.NOT_FOUND, f"unknown chain key: {chain_key}")
+
+    job = await job_repo.create(project_id, JOB_KIND_CHAIN)
+    await session.commit()  # job 行须在 202 返回前持久化（供前端立即轮询）。
+
+    accept_op = build_accept_op(
+        session_factory=session_factory,
+        digest_gateway_builder=digest_gateway_builder,
+        request_id=request_id,
+    )
+    background_tasks.add_task(
+        run_chain_job,
+        session_factory,
+        job.id,
+        project_id=project_id,
+        user_id=STUB_OWNER_ID,
+        chain_key=chain_key,
+        start_chapter_no=body.start_chapter_no,
+        count=body.count,
+        chain_gateway_builder=chain_gateway_builder,
+        checkpointer_ctx=checkpointer_factory,
+        accept_op=accept_op,
+        chapter_repo_factory=_chapter_repo_factory,
+        review_repo_factory=_review_repo_factory,
+        request_id=request_id,
+    )
+
+    log.info(
+        "chain_run_scheduled",
+        project_id=str(project_id),
+        request_id=request_id,
+        job_id=str(job.id),
+        chain_key=chain_key,
+        start_chapter_no=body.start_chapter_no,
+        count=body.count,
+    )
+    response.status_code = 202
+    return ChainRunAccepted(
+        job_id=job.id,
+        chain_key=chain_key,
+        start_chapter_no=body.start_chapter_no,
+        count=body.count,
+    )
+
+
+@router.post(
+    "/{project_id}/chains/runs/{job_id}/resume",
+    status_code=202,
+    responses=_RESUME_ERRORS,
+)
+async def resume_chain(
+    project_id: uuid.UUID,
+    job_id: uuid.UUID,
+    body: ChainResumeRequest,
+    request: Request,
+    response: Response,
+    background_tasks: BackgroundTasks,
+    project_repo: ProjectRepoDep,
+    job_repo: JobRepoDep,
+    gateway: ChainGatewayDep,  # 凭据探测（无凭据 → dep 解析阶段 503）；不用于实际 LLM 调用
+    session: SessionDep,
+    session_factory: SessionFactoryDep,
+    checkpointer_factory: CheckpointerFactoryDep,
+    digest_gateway_builder: DigestBuilderDep,
+    chain_gateway_builder: ChainBuilderDep,
+) -> ChainResumeAccepted:
+    """裁决续跑：仅当 job=awaiting_input，带裁决经 BackgroundTask resume。
+
+    项目不存在 → 404；job 不存在 / 不属于该项目 → 404（同案，不枚举）；非 awaiting 态 →
+    409（CONFLICT）。`awaiting→running` 在 HTTP 处理器内**原子抢占**（条件 UPDATE），避免两个
+    并发 resume 都过守卫后双 `Command(resume=...)` 损坏图（审评 #3）；抢不到（已被并发抢走/非
+    awaiting）→ 409。resume 经 `Command(resume=decisions)` 从 interrupt 续跑（同 thread_id）。
+    """
+    request_id = getattr(request.state, "request_id", None)
+
+    await _require_project(project_repo, project_id)
+    job = await job_repo.get(job_id)
+    # 所有权校验（审评 #4）：job 不存在 **或** 不属于该项目 → 404（同案，避免跨项目枚举 job）。
+    if job is None or job.project_id != project_id:
+        raise AppError(ErrorCode.NOT_FOUND, f"job not found: {job_id}")
+    if job.status != STATUS_AWAITING:
+        raise AppError(
+            ErrorCode.CONFLICT,
+            f"job {job_id} 非 awaiting_input 态（当前 {job.status}），不可续跑",
+            {"job_status": job.status},
+        )
+
+    # 原子抢占 awaiting→running（审评 #3）：抢不到（并发竞态/已非 awaiting）→ 409，绝不调度。
+    claimed = await job_repo.claim_awaiting_to_running(job_id)
+    await session.commit()  # 抢占须在 202 返回前持久化（防并发 resume 双调度）。
+    if claimed is None:
+        raise AppError(
+            ErrorCode.CONFLICT,
+            f"job {job_id} 已被并发续跑抢占或非 awaiting_input 态，不可重复续跑",
+        )
+
+    chain_key = claimed.kind if claimed.kind in SUPPORTED_CHAINS else "draft_volume"
+
+    accept_op = build_accept_op(
+        session_factory=session_factory,
+        digest_gateway_builder=digest_gateway_builder,
+        request_id=request_id,
+    )
+    background_tasks.add_task(
+        run_chain_job,
+        session_factory,
+        job_id,
+        project_id=project_id,
+        user_id=STUB_OWNER_ID,
+        chain_key=chain_key,
+        start_chapter_no=1,  # resume 不重置区间：图从检查点续，初值不再使用。
+        count=1,
+        chain_gateway_builder=chain_gateway_builder,
+        checkpointer_ctx=checkpointer_factory,
+        accept_op=accept_op,
+        chapter_repo_factory=_chapter_repo_factory,
+        review_repo_factory=_review_repo_factory,
+        resume_decisions=body.decisions,
+        request_id=request_id,
+    )
+
+    log.info(
+        "chain_resume_scheduled",
+        project_id=str(project_id),
+        request_id=request_id,
+        job_id=str(job_id),
+        decision_count=len(body.decisions),
+    )
+    response.status_code = 202
+    return ChainResumeAccepted(job_id=job_id, chain_key=chain_key)
+
+
+def _chapter_repo_factory(session: AsyncSession) -> object:
+    """链节点（review 重读草稿）按 session 建 chapter draft repo。"""
+    from ww_core.domain.chapter_repo import SqlChapterRepo
+
+    return SqlChapterRepo(session)
+
+
+def _review_repo_factory(session: AsyncSession) -> object:
+    """链节点（review 落留痕 / decide 重读）按 session 建审稿 repo。"""
+    from ww_core.domain.review_repo import SqlReviewRepo
+
+    return SqlReviewRepo(session)

apps/api/ww_api/schemas/chain.py

@@ -0,0 +1,64 @@
+"""多章工作流链端点的请求/响应 schema（chain-workflow 设计 §6）。
+
+snake_case（命名契约，见 memory/gotchas）。前端经 OpenAPI→TS 客户端消费——改字段
+须 `pnpm gen:api` 重生成。
+
+- `ChainRunRequest`：发起一条链（起始章 + 章数）。`count` 1..50（系统边界校验，fail fast）。
+- `ChainRunAccepted`：202 受理回执（job_id + 回显请求参数，供前端轮询 `GET /jobs/{id}`）。
+- `ChainResumeRequest`：裁决续跑（复用 `ConflictDecision`，对 awaiting 章的冲突逐条裁决）。
+"""
+
+from __future__ import annotations
+
+import uuid
+
+from pydantic import BaseModel, Field
+
+from ww_api.schemas.projects import ConflictDecision
+
+# 链一次最多写 K 章（系统边界，避免一条 run 无界占用；§6 校验）。
+MAX_CHAIN_COUNT = 50
+MIN_CHAIN_COUNT = 1
+
+
+class ChainRunRequest(BaseModel):
+    """发起多章链：从 `start_chapter_no` 起循环写 `count` 章（区间含两端）。
+
+    `count` 1..50（>50 → 422 VALIDATION，由 Field 约束在边界拦下，不进 BackgroundTask）；
+    `start_chapter_no >= 1`。
+    """
+
+    start_chapter_no: int = Field(ge=1, description="起始章号（含），>=1")
+    count: int = Field(
+        ge=MIN_CHAIN_COUNT,
+        le=MAX_CHAIN_COUNT,
+        description="本 run 连续写的章数（1..50，含起始章）",
+    )
+
+
+class ChainRunAccepted(BaseModel):
+    """链受理回执（202）：job_id + 回显请求参数（前端走 `GET /jobs/{id}` 轮询进度/awaiting）。"""
+
+    job_id: uuid.UUID
+    chain_key: str
+    start_chapter_no: int
+    count: int
+
+
+class ChainResumeRequest(BaseModel):
+    """裁决续跑：对 awaiting 章最近审稿的每个冲突逐条裁决（复用 `ConflictDecision`）。"""
+
+    decisions: list[ConflictDecision] = Field(
+        default_factory=list,
+        description="对 awaiting 章冲突的裁决清单（采纳/忽略/手改）",
+    )
+
+
+class ChainResumeAccepted(BaseModel):
+    """resume 受理回执（202）：job_id + chain_key（前端走 `GET /jobs/{id}` 轮询续跑进度）。
+
+    续跑无独立区间（图从检查点续），故不回显 start/count（会是无意义哨兵值）——只回 job 标识。
+    """
+
+    job_id: uuid.UUID
+    chain_key: str

apps/api/ww_api/services/chain_deps.py

@@ -0,0 +1,44 @@
+"""多章链的 checkpointer 注入缝（chain-workflow 设计 §4）——激活休眠资产。
+
+`get_checkpointer()` 是可注入缝：
+- **运行时**：返 `AsyncPostgresSaver`（`langgraph.checkpoint.postgres.aio`），连 `DATABASE_URL`，
+  持久控制流位置 + pending handle（跨小时可恢复）。检查点表由迁移/CI 调 `setup_checkpointer`
+  建（C3），本缝**绝不**触碰 DDL（CLAUDE.md「LangGraph」：`setup()` 只在 migrations/CI）。
+- **测试**：经 `app.dependency_overrides[get_checkpointer]` 注 `MemorySaver`（同进程跨两次
+  invoke 可恢复 interrupt），绝不连真 Postgres、绝不真 LLM。
+
+注：`AsyncPostgresSaver.from_conn_string` 是 async 上下文管理器——其连接生命周期须横跨整条
+链 run（含 interrupt 暂停后的 resume）。故 `run_chain_job` 在自身 task 内打开/关闭 saver
+上下文（见 `chain_runner`），本缝只提供「按需建一个 saver 上下文管理器」的工厂。
+"""
+
+from __future__ import annotations
+
+from collections.abc import Callable
+from contextlib import AbstractAsyncContextManager
+from typing import TYPE_CHECKING, Any
+
+from ww_config import get_settings
+
+if TYPE_CHECKING:
+    from langgraph.checkpoint.base import BaseCheckpointSaver
+
+# checkpointer 工厂：`()` → async 上下文管理器，进入得一个 `BaseCheckpointSaver`。
+# 运行时 = Postgres saver 上下文（连接随上下文开/关）；测试注一个产 MemorySaver 的工厂。
+CheckpointerFactory = Callable[[], AbstractAsyncContextManager[Any]]
+
+
+def get_checkpointer_factory() -> CheckpointerFactory:
+    """运行时 checkpointer 工厂：建连 `DATABASE_URL` 的 `AsyncPostgresSaver` 上下文。
+
+    `from_conn_string` 返回的 async-CM 在 `run_chain_job` 内 `async with` 打开——其连接
+    存活整条链（含 interrupt→resume）；run 结束关闭。测试经 dep 覆盖注 MemorySaver 工厂。
+    """
+
+    def _factory() -> AbstractAsyncContextManager[BaseCheckpointSaver[Any]]:
+        from langgraph.checkpoint.postgres.aio import AsyncPostgresSaver
+
+        # langgraph 的 Postgres saver 走 psycopg(同步驱动串)；用 sync 串建连接。
+        return AsyncPostgresSaver.from_conn_string(get_settings().database_url_sync)
+
+    return _factory

apps/api/ww_api/services/chain_runner.py

@@ -0,0 +1,312 @@
+"""多章链长任务 runner（chain-workflow 设计 §5）——`run_chain_job` 在 jobs 壳里跑链图。
+
+复用 `run_job` 的生命周期心智（set_running → work → complete/fail），但链多一态：
+**interrupt 命中 → `awaiting_input`**（等作者裁决续跑）。故不直接复用 `run_job`，而是
+仿其壳自建独立 session 写 job 状态，work 本体 = 驱动 LangGraph 链图。
+
+纪律（守不变量）：
+- **#1/#5**：图节点各自短事务落领域表（`chapters`/`chapter_reviews`/`chapter_digests`）；
+  checkpointer 只存控制流；resume 重读领域表。本 runner 不持业务事务。
+- **#3/#4**：`accept_op`（apps/api 注入）跑冲突 gate → 终稿提炼 digest → 单原子验收事务 →
+  伏笔到期扫描，唯一正文写经此。
+- **token 不泄漏**：job result/status/日志只记章号/计数/标志，绝不含 prompt/正文/token。
+- **错误脱敏**：复用 `_classify_job_error`（AppError 透传安全文案，其余通用文案，P0-3）。
+
+可测性：`session_factory`/`gateway`/`checkpointer`/`accept_op` 全可注入——单测直接 `await`
+它，注 fake session 工厂 + mock 网关 + MemorySaver + fake accept_op（绝不联网/真 DB/真 LLM）。
+"""
+
+from __future__ import annotations
+
+import uuid
+from collections.abc import Awaitable, Callable, Sequence
+from contextlib import AbstractAsyncContextManager
+from typing import Any
+
+import structlog
+from langchain_core.runnables import RunnableConfig
+from langgraph.types import Command
+from ww_core.domain.chapter_repo import ChapterRepo, SqlChapterRepo
+from ww_core.domain.digest_repo import SqlDigestAppendRepo
+from ww_core.domain.job_repo import SqlJobRepo
+from ww_core.domain.review_repo import SqlReviewRepo
+from ww_core.memory import assemble
+from ww_core.memory.sql_repositories import sql_memory_repos
+from ww_core.orchestrator import REVIEW_SPECS
+from ww_core.orchestrator.chain import build_chain_graph, initial_chain_state
+from ww_llm_gateway import Gateway
+
+from ww_api.schemas.projects import ConflictDecision
+from ww_api.services.accept_service import (
+    assert_conflicts_resolved,
+    run_accept_transaction,
+)
+from ww_api.services.digest_extraction import extract_digest_facts
+from ww_api.services.foreshadow_scan import SessionFactory, run_overdue_scan
+from ww_api.services.job_runner import _classify_job_error
+
+log = structlog.get_logger(__name__)
+
+# 链 job 的 kind（jobs.kind 自由 Text 列，零迁移复用；§7）。
+JOB_KIND_CHAIN = "chain"
+
+
+# 「按 session 建 digest 网关」缝：accept 节点在自建短事务里需 light 档网关跑终稿提炼。
+DigestGatewayBuilder = Callable[[Any], Awaitable[Gateway]]
+
+# 「按 session 建链网关」缝：write/review 节点在自建短事务里现建网关（ledger 绑节点 session，
+# 不变量 #1）。BackgroundTask 跑时请求 session 已关闭，故必须用节点 session 重建网关。
+GatewayChainBuilder = Callable[[Any], Awaitable[Gateway]]
+
+
+def build_accept_op(
+    *,
+    session_factory: SessionFactory,
+    digest_gateway_builder: DigestGatewayBuilder,
+    request_id: str | None = None,
+) -> AcceptOp:
+    """组装单章验收落库闭包（apps/api，守不变量 #3/#4）。
+
+    链 `accept_chapter` 节点经此闭包把作者裁决落库——每章**独立短事务**（自建 session）：
+    重读最近审稿 → 冲突 gate（缺判 → `CONFLICT_UNRESOLVED`，链失败）→ 终稿(=已存草稿)提炼
+    digest（事务外）→ `run_accept_transaction` 单原子提交 → 提交后伏笔到期扫描（自建 session）。
+
+    自动链无作者改稿：`final_text` = `chapters` 里该章草稿正文（write 节点所落）。
+    `decisions` 为 dict 清单（interrupt 恢复值 / 无冲突 []），此处校验为 `ConflictDecision`。
+    """
+
+    async def accept_op(
+        *,
+        project_id: uuid.UUID,
+        chapter_no: int,
+        user_id: uuid.UUID,
+        decisions: list[Any],
+    ) -> None:
+        parsed_decisions = [
+            d if isinstance(d, ConflictDecision) else ConflictDecision.model_validate(d)
+            for d in (decisions or [])
+        ]
+        async with session_factory() as session:
+            chapter_repo: ChapterRepo = SqlChapterRepo(session)
+            review_repo = SqlReviewRepo(session)
+            digest_repo = SqlDigestAppendRepo(session)
+
+            history = await review_repo.list_for_chapter(project_id, chapter_no)
+            latest_review = history[0] if history else None
+            # 冲突 gate（R5，事务前拦截，不写库；缺判 → CONFLICT_UNRESOLVED 抛，链失败）。
+            assert_conflicts_resolved(latest_review, parsed_decisions)
+
+            draft = await chapter_repo.get_draft(project_id, chapter_no)
+            final_text = draft.content if draft is not None else ""
+
+            gateway = await digest_gateway_builder(session)
+            # R2：终稿 digest 提炼在开原子事务之前（别在持开事务里跨网络调 LLM）。
+            digest_facts = await extract_digest_facts(
+                gateway,
+                final_text=final_text,
+                user_id=user_id,
+                project_id=project_id,
+                chapter_no=chapter_no,
+            )
+            await run_accept_transaction(
+                session=session,
+                chapter_repo=chapter_repo,
+                digest_repo=digest_repo,
+                review_repo=review_repo,
+                project_id=project_id,
+                chapter_no=chapter_no,
+                final_text=final_text,
+                digest_facts=digest_facts,
+                latest_review=latest_review,
+                decisions=parsed_decisions,
+            )
+        # 验收提交后伏笔到期扫描（自建独立 session，§6.2；与单章端点同纪律）。
+        await run_overdue_scan(
+            session_factory,
+            project_id=project_id,
+            chapter_no=chapter_no,
+            request_id=request_id,
+        )
+
+    return accept_op
+
+
+# `()` → async-CM，进入得一个 langgraph checkpointer（Postgres 运行时 / MemorySaver 测试）。
+CheckpointerCtx = Callable[[], AbstractAsyncContextManager[Any]]
+
+#: apps/api 注入的「按 session 建 chapter draft repo」工厂（review 节点重读草稿用）。
+ChapterRepoFactory = Callable[[Any], Any]
+#: apps/api 注入的「按 session 建审稿留痕 repo」工厂（review/decide 节点用）。
+ReviewRepoFactory = Callable[[Any], Any]
+#: 单章验收落库闭包（apps/api 组装：冲突 gate + digest + 验收事务 + 到期扫描）。
+AcceptOp = Callable[..., Awaitable[None]]
+
+
+def _chain_result(state: dict[str, Any], *, awaiting_chapter: int | None) -> dict[str, Any]:
+    """从图 state 取非密进度摘要（绝不含正文/token；§5）。
+
+    `awaiting_chapter` 非 None = interrupt 命中该章待裁决；None 且 completed = 全跑完。
+    """
+    written = list(state.get("written") or [])
+    return {
+        "chain_key": state.get("chain_key"),
+        "written": written,
+        "completed": awaiting_chapter is None,
+        "awaiting_chapter": awaiting_chapter,
+    }
+
+
+def _extract_awaiting_chapter(final: dict[str, Any]) -> int | None:
+    """从图返回值判 interrupt：有 `__interrupt__` → 取暂停章号；否则 None（跑完）。
+
+    interrupt 载荷 = `{"chapter_no": n}`（见链图 `_accept` 节点）。LangGraph 把它放在
+    `final["__interrupt__"]`（Interrupt 对象列表）。容错读 `.value`/dict 两种形。
+    """
+    interrupts = final.get("__interrupt__")
+    if not interrupts:
+        return None
+    first = interrupts[0]
+    payload = getattr(first, "value", first)
+    if isinstance(payload, dict):
+        chapter_no = payload.get("chapter_no")
+        return int(chapter_no) if chapter_no is not None else None
+    return None
+
+
+async def run_chain_job(
+    session_factory: SessionFactory,
+    job_id: uuid.UUID,
+    *,
+    project_id: uuid.UUID,
+    user_id: uuid.UUID,
+    chain_key: str,
+    start_chapter_no: int,
+    count: int,
+    chain_gateway_builder: GatewayChainBuilder,
+    checkpointer_ctx: CheckpointerCtx,
+    accept_op: AcceptOp,
+    chapter_repo_factory: ChapterRepoFactory,
+    review_repo_factory: ReviewRepoFactory,
+    resume_decisions: list[ConflictDecision] | None = None,
+    review_specs: Sequence[Any] = REVIEW_SPECS,
+    request_id: str | None = None,
+) -> None:
+    """跑/续一条多章链：set_running → 驱动链图 → 据返回置 done/awaiting_input/failed。
+
+    `resume_decisions is None` → 初始 run（`graph.ainvoke(initial_state, config)`）；
+    否则 resume（`graph.ainvoke(Command(resume=decisions), config)`），从 interrupt 续跑。
+    `thread_id = str(job_id)`：同 job 的初始/续跑落同一检查点 thread。
+
+    `chain_gateway_builder`（非具体网关实例）：write/review 节点在自建短事务的**新鲜** session
+    上现建网关，使 usage_ledger 绑节点 session（不变量 #1）。**绝不**把请求阶段建的网关传进来——
+    BackgroundTask 跑时请求 session 已关闭，其 ledger.record() 会落到死 session 上被静默丢弃。
+
+    checkpointer 上下文（Postgres 连接 / MemorySaver）横跨整次 invoke；本 runner 在 task
+    内打开/关闭它。异常一律被吞（后台任务边界），脱敏后置 job failed，不冒泡崩进程。
+    """
+    try:
+        async with checkpointer_ctx() as checkpointer:
+            await _set_running(session_factory, job_id)
+            config: RunnableConfig = {"configurable": {"thread_id": str(job_id)}}
+            graph = build_chain_graph(
+                chain_gateway_builder,
+                session_factory=session_factory,
+                memory_repos_factory=sql_memory_repos,
+                chapter_repo_factory=chapter_repo_factory,
+                review_repo_factory=review_repo_factory,
+                assemble=assemble,
+                accept_op=accept_op,
+                review_specs=review_specs,
+                checkpointer=checkpointer,
+            )
+            if resume_decisions is None:
+                initial = initial_chain_state(
+                    project_id=project_id,
+                    user_id=user_id,
+                    start_chapter_no=start_chapter_no,
+                    count=count,
+                    chain_key=chain_key,
+                )
+                raw_final = await graph.ainvoke(initial, config=config)
+            else:
+                resume_value = [d.model_dump() for d in resume_decisions]
+                raw_final = await graph.ainvoke(Command(resume=resume_value), config=config)
+
+            final: dict[str, Any] = dict(raw_final)
+            awaiting_chapter = _extract_awaiting_chapter(final)
+            result = _chain_result(final, awaiting_chapter=awaiting_chapter)
+            await _finish(session_factory, job_id, result, awaiting=awaiting_chapter is not None)
+        log.info(
+            "chain_job_settled",
+            job_id=str(job_id),
+            request_id=request_id,
+            awaiting_chapter=awaiting_chapter,
+            written_count=len(result["written"]),
+        )
+    except Exception as exc:  # noqa: BLE001 — 后台任务边界：记错误 + 置 job failed，不冒泡。
+        # 日志只记脱敏文案 + 异常类型；绝不记 str(exc)（可能含 API key/连接串/LLM 输出，设计 §5）。
+        stored_error = _classify_job_error(exc)
+        log.error(
+            "chain_job_failed",
+            job_id=str(job_id),
+            request_id=request_id,
+            exc_type=type(exc).__name__,
+            error=stored_error,
+        )
+        await _mark_failed(session_factory, job_id, stored_error, request_id)
+
+
+async def _set_running(session_factory: SessionFactory, job_id: uuid.UUID) -> None:
+    """独立短事务把 job 置 running（图驱动开始前）。"""
+    async with session_factory() as session:
+        await SqlJobRepo(session).set_running(job_id)
+        await session.commit()
+
+
+async def _finish(
+    session_factory: SessionFactory,
+    job_id: uuid.UUID,
+    result: dict[str, Any],
+    *,
+    awaiting: bool,
+) -> None:
+    """据是否 interrupt 把 job 置 awaiting_input（待裁决）或 done（跑完），独立短事务。"""
+    async with session_factory() as session:
+        repo = SqlJobRepo(session)
+        if awaiting:
+            await repo.set_awaiting(job_id, result)
+        else:
+            await repo.complete(job_id, result)
+        await session.commit()
+
+
+async def _mark_failed(
+    session_factory: SessionFactory,
+    job_id: uuid.UUID,
+    error: str,
+    request_id: str | None,
+) -> None:
+    """在**全新** session 里把 job 置 failed（前一事务已因异常作废）。"""
+    try:
+        async with session_factory() as session:
+            await SqlJobRepo(session).fail(job_id, error)
+            await session.commit()
+    except Exception as exc:  # noqa: BLE001 — 置失败态本身再炸只记日志，不冒泡。
+        # 同 §5：不记 str(exc)，只记异常类型（避免泄露内部细节）。
+        log.error(
+            "chain_job_fail_mark_failed",
+            job_id=str(job_id),
+            request_id=request_id,
+            exc_type=type(exc).__name__,
+        )
+
+
+__all__ = [
+    "JOB_KIND_CHAIN",
+    "AcceptOp",
+    "CheckpointerCtx",
+    "DigestGatewayBuilder",
+    "GatewayChainBuilder",
+    "build_accept_op",
+    "run_chain_job",
+]

apps/api/ww_api/services/project_deps.py

@@ -10,7 +10,7 @@
 from __future__ import annotations
 
 from collections.abc import Awaitable, Callable
-from typing import Annotated
+from typing import Annotated, Any
 
 import httpx
 from fastapi import Depends
@@ -399,6 +399,53 @@ async def build_writer_gateway(session: AsyncSession, store: CredentialStore) ->
     return await build_gateway_for_tier(session, store, "writer")
 
 
+# 多章链一条 run 内跨 writer(write)/analyst(review)/light(digest) 三档——单档网关的
+# chain_resolver 恒返该档链、忽略请求 tier，会把 review/digest 错路由到 writer。故链需一个
+# **按请求 tier 分派**的网关：并 union 三档所有 provider 的适配器 + 逐 tier 解析其链。
+_CHAIN_TIERS: tuple[Tier, ...] = ("writer", "analyst", "light")
+
+
+def _chain_for_tier(stored_by_tier: dict[Tier, Any], tier: Tier) -> list[Route]:
+    """据该 tier 的 DB 路由行构链；无行则退回全局默认（单 provider，M1 兼容）。"""
+    stored = stored_by_tier.get(tier)
+    if stored is None:
+        return [resolve_route(tier)]
+    primary_spec = f"{stored.provider}:{stored.model}"
+    return chain_from_routing(tier, primary_spec, list(stored.fallback))
+
+
+async def build_chain_gateway(session: AsyncSession, store: CredentialStore) -> Gateway:
+    """装配多章链网关：按请求 tier（writer/analyst/light）分派，union 三档适配器 + 回退链。
+
+    与 `build_gateway_for_tier` 同凭据/适配器装配，但 `chain_resolver` 据 `req.tier` 返回
+    对应档的链（不锁死单档）。至少一个可用适配器，否则 `LLM_UNAVAILABLE`（无任何凭据）。
+    """
+    ledger = SqlAlchemyLedgerSink(session)
+    routing_rows = await store.list_routing()
+    stored_by_tier: dict[Tier, Any] = {r.tier: r for r in routing_rows if r.tier in _CHAIN_TIERS}
+
+    # union 三档链里所有 provider，逐个建可用适配器（未配凭据/未知 base_url 的跳过）。
+    adapters: dict[str, ProviderAdapter] = {}
+    for tier in _CHAIN_TIERS:
+        for route in _chain_for_tier(stored_by_tier, tier):
+            if route.provider in adapters:
+                continue
+            built = await _build_provider_adapter(store, route.provider)
+            if built is not None:
+                adapters[route.provider] = built
+    if not adapters:
+        raise AppError(
+            ErrorCode.LLM_UNAVAILABLE,
+            "多章链无任何已配置凭据的 provider，请先在设置中配置",
+            {"tiers": list(_CHAIN_TIERS)},
+        )
+
+    def _resolver(tier: Tier) -> list[Route]:
+        return _chain_for_tier(stored_by_tier, tier)
+
+    return Gateway(adapters=adapters, ledger=ledger, chain_resolver=_resolver)
+
+
 async def get_writer_gateway(
     session: Annotated[AsyncSession, Depends(get_session)],
 ) -> Gateway:
@@ -451,3 +498,59 @@ async def get_refine_gateway(
     """回炉（writer 档位）的可注入网关缝。测试经 override 注 mock（产纯文本重写段）。"""
     store = SqlCredentialStore(session)
     return await build_gateway_for_tier(session, store, "writer")
+
+
+async def get_chain_gateway(
+    session: Annotated[AsyncSession, Depends(get_session)],
+) -> Gateway:
+    """多章链（write writer + review analyst + digest light，按请求 tier 分派）的可注入网关缝。
+
+    `POST .../chains/{key}/run` 在 dep 解析阶段构建网关 → 无凭据时这里抛 `LLM_UNAVAILABLE`
+    （503，调度 job 之前拦下，避免凭空写注定失败的 job）。链本体在 BackgroundTask 里用
+    `run_chain_job` 自建独立 session 重新构网关跑（请求 session 已关闭）；本依赖只做请求阶段
+    凭据探测。测试经 `app.dependency_overrides[get_chain_gateway]` 注 mock（绝不联网）。
+    """
+    store = SqlCredentialStore(session)
+    return await build_chain_gateway(session, store)
+
+
+# 「按 session 建 digest 网关」缝类型（chain accept_op 终稿提炼按节点自建短事务的 session 建）。
+GatewayDigestBuilder = Callable[[AsyncSession], Awaitable[Gateway]]
+
+
+def _digest_gateway_builder(session: AsyncSession) -> Awaitable[Gateway]:
+    """链 accept 节点在自建短事务里建 light 档 digest 网关（终稿提炼）。"""
+    return build_gateway_for_tier(session, SqlCredentialStore(session), "light")
+
+
+def get_digest_gateway_builder() -> GatewayDigestBuilder:
+    """返回「按 session 建 digest 网关」的缝（chain accept_op 终稿提炼用）。
+
+    BackgroundTask 自建短事务 → 节点内据该 session 现建 light 档网关。测试经
+    `app.dependency_overrides[get_digest_gateway_builder]` 注返回 mock 的 builder（绝不联网）。
+    """
+    return _digest_gateway_builder
+
+
+# 「按 session 建链网关」缝类型（链 write/review 节点在 BackgroundTask 自建短事务的 session 建）。
+GatewayChainBuilder = Callable[[AsyncSession], Awaitable[Gateway]]
+
+
+def _chain_gateway_builder(session: AsyncSession) -> Awaitable[Gateway]:
+    """链 write/review 节点在自建短事务里建按请求 tier 分派的链网关。
+
+    关键（守不变量 #1）：网关的 `SqlAlchemyLedgerSink` 必须绑**节点当前的** session——
+    BackgroundTask 跑时请求 session 已关闭，故不能复用请求阶段的网关，必须按节点新 session 现建，
+    否则 `gateway.run()` 的 `usage_ledger` 写会落到已死 session 上被静默丢弃（成本记账断裂）。
+    """
+    return build_chain_gateway(session, SqlCredentialStore(session))
+
+
+def get_chain_gateway_builder() -> GatewayChainBuilder:
+    """返回「按 session 建链网关」的缝（链 write/review 节点在 BackgroundTask 内现建网关用）。
+
+    与 `get_chain_gateway`（请求阶段凭据探测，返单实例，仅做 503 拦截）不同：本缝供
+    `run_chain_job` 在节点自建的**新鲜** session 上重建网关，使 usage_ledger 落到活 session。
+    测试经 `app.dependency_overrides[get_chain_gateway_builder]` 注返 mock 的 builder（绝不联网）。
+    """
+    return _chain_gateway_builder

docs/design/chain-workflow.md

@@ -0,0 +1,211 @@
+# 设计文档 · 多章工作流链（Chain Workflow）
+
+> 状态：设计稿（实施前契约）· 分支 `feat/chain-workflow` · 锚点 ARCHITECTURE §5.2/§5.5、CLAUDE.md 架构不变量 #1/#3/#5/#9、DEV_PLAN §4
+>
+> 本文是实施的**唯一契约源**。所有实施 agent 先读本文，按其中签名/事件/DoD 落地；与现有 spec 冲突时以更具体者为准并回写。
+
+---
+
+## 1. 背景与目标
+
+### 1.1 为什么做
+对标竞品「星月写作」的核心能力是**一键多章工作流**（导语→大纲→细纲→一键十章正文循环），但其纯走量、无一致性闸，靠提示词补"关联前文/不跑偏"。本产品的差异化：**同样的链式量产，但每一章都过 `assemble → write → 四审 → digest` 闭环 → 批量生成而长篇不崩**。这是星月架构上做不到的杀手锏。
+
+### 1.2 为什么用 LangGraph（而非端点+DB 循环）
+多章循环是本项目**第一个真正需要 LangGraph 的场景**：单章流程是线性的（写一发、审一次 `ainvoke`、验收一个事务），无需图；而"写→审→判定→循环/中断、跨小时可恢复、遇冲突暂停交人"是**有环、可持久、可中断**的编排 = LangGraph 本职。本设计借此**激活当前休眠的资产**：`checkpointer`（现恒 `None`）、`interrupt()`（现未实现）、`build_write_graph`（现死代码——将被本链图取代/吸收）。
+
+### 1.3 目标（DoD）
+1. 一条内置链 `draft_volume`：从指定起始章，循环写 K 章，每章 `write → 四审 → 判定 → 验收`，digest 入库。
+2. **杀手锏 interrupt-on-conflict**：链自动跑；某章四审报出冲突 → `interrupt()` 暂停 → 前端取该章冲突交人裁决 → resume 续跑。无冲突章自动 accept。
+3. 跑在 `run_job` 长任务壳里：`POST .../chains/{key}/run` → 202 `{job_id}`；`GET /jobs/{id}` 看进度（"3/10 章已过审"）；`POST .../chains/runs/{job_id}/resume` 带裁决续跑。
+4. **后端门禁绿**（ruff/format/mypy/alembic 无漂移/pytest）+ **E2E**（mock 网关零 token）走通：无冲突全自动两章 + 冲突→interrupt→resume 两路径。
+
+### 1.4 非目标（本期不做）
+- **前端 UI**（链发起页/进度/裁决续跑面板）→ 契约稳定后单独一刀（@frontend follow-up）。
+- **可编辑/可分享的 UGC 链市场**（星月式）→ 需多租户/Auth，已 deferred，单独立项。
+- **续写/扩写 节点** → 可作为链的可选步后补，本期链步固定为 write。
+- 多种 HITL 档位 → 本期只做 `auto`（无冲突自动过、有冲突才停）。
+
+---
+
+## 2. 架构总览
+
+```
+POST .../chains/draft_volume/run {start_chapter_no, count}
+        │  (写 jobs 行 status=queued, kind="chain") → 202 {job_id}
+        ▼  BackgroundTasks → run_chain_job(job_id, resume=None)
+┌──────────────────────── LangGraph ChainGraph (thread_id = job_id) ─────────────────────┐
+│  START → write_chapter → review_chapter → decide ──(无冲突)──→ accept_chapter ─┐        │
+│            ▲                                  │                                 │        │
+│            │                              (有冲突)                              │        │
+│            │                                  ▼                                 │        │
+│            │                            interrupt() ⏸  (job=awaiting_input)     │        │
+│            │                                                                    │        │
+│            └────────────────(还有章: current<=last)──── advance ◄──────────────┘        │
+│                                                          │                              │
+│                                                     (写满 K 章) → END                    │
+└────────────────────────────────────────────────────────────────────────────────────────┘
+        │ checkpointer (Postgres runtime / MemorySaver tests) 持久控制流位置 + pending handle
+        ▼
+POST .../chains/runs/{job_id}/resume {decisions:[...]}
+        │  (Command(resume=decisions)) → 202 → run_chain_job(job_id, resume=decisions)
+        ▼  从 interrupt 续跑：accept_chapter 用 decisions → advance → 下一章…
+```
+
+**关键纪律**：节点做 DB IO 时各自用**短事务、独立 session**（每章 accept 章原子提交，仿 `run_overdue_scan` 自建 session）。checkpointer **只存控制流**（`current_chapter_no` / `written` / `pending`），章正文落 `chapters`、审稿落 `chapter_reviews`——**resume 时重读领域表**为真相（不变量 #5）。
+
+---
+
+## 3. 状态与节点
+
+### 3.1 State 类型 `ChainState`（新增 `orchestrator/chain/state.py`）
+TypedDict（langgraph 状态 = 检查点内容，**只放控制流，不放正文/上下文**）：
+
+| 字段 | 类型 | 说明 |
+|---|---|---|
+| `project_id` | `uuid.UUID` | |
+| `user_id` | `uuid.UUID` | STUB_OWNER_ID |
+| `chain_key` | `str` | 固定 `"draft_volume"` |
+| `start_chapter_no` | `int` | 起始章 |
+| `last_chapter_no` | `int` | = start + count - 1（含） |
+| `current_chapter_no` | `int` | 当前处理章；初值 = start |
+| `written` | `list[int]` | 本 run 已验收章号（进度来源） |
+| `has_conflicts` | `bool` | `decide` 节点写入；控制流标志，不存冲突明文 |
+
+> 草稿正文/上下文**不进** state（落 DB）。冲突明文**不进** state（resume 时从 `chapter_reviews` 重读，不变量 #5）。
+
+### 3.2 节点（`orchestrator/chain/nodes.py`，gateway/session_factory 经闭包绑入工厂）
+
+1. **`write_chapter`**：新建读写 session → `assemble(project_id, current_chapter_no)` 组装记忆（确定性，不变量 #6/#9：硬规则+指纹进缓存前缀）→ `gateway.run`（收集版写章，复用 `write_node` 同一 prompt 组装路径，非 SSE）→ `chapter_repo.save_draft` 落 `chapters` draft → commit。State 不变（正文在 DB）。
+2. **`review_chapter`**：复用四审。两种实现取其一（实施者选更省的）：(a) 内联调用 `build_review_graph(gateway, review_repo).ainvoke(review_state)`；(b) 直接 `run_review × REVIEW_SPECS` + `collect_reviews`。落 `chapter_reviews` 留痕（不变量 #3 只读，不写正文）→ commit。
+3. **`decide`**（确定性纯逻辑，无 LLM）：读该章最近审稿留痕 → `has_conflicts = len(conflicts) > 0`。写入 state。
+4. **条件边 `decide → ?`**：
+   - `has_conflicts == True` → `interrupt({chapter_no})`：`interrupt()` 暂停，恢复值 = 该章 `decisions` 列表。恢复后进 `accept_chapter`。
+   - `has_conflicts == False` → 直接进 `accept_chapter`（`decisions = []`）。
+5. **`accept_chapter`**：新建 session → 从 `chapter_reviews` **重读**该章最近审稿（不信 state）→ `assert_conflicts_resolved(latest_review, decisions)`（缺判 → `CONFLICT_UNRESOLVED`，链失败）→ 事务外 `extract_digest_facts`（从终稿）→ `run_accept_transaction(...)` 章原子提交 → 提交后 `run_overdue_scan`（自建 session，伏笔到期）。`written.append(current_chapter_no)`。
+6. **条件边 `accept_chapter → ?`**：`current_chapter_no < last_chapter_no` → `advance`（`current_chapter_no += 1`）→ 回 `write_chapter`；否则 → `END`。
+
+> `advance` 可并入 `accept_chapter` 的返回（`current_chapter_no+1`）+ 一个 `should_continue` 条件边判 START/END，避免独立节点。实施者择简。
+
+### 3.3 图工厂 `build_chain_graph`（`orchestrator/chain/graph.py`）— 契约
+
+```python
+def build_chain_graph(
+    gateway: GatewayRun,                      # 复用 ._protocols.GatewayRun
+    *,
+    session_factory: SessionFactory,          # 节点自建短事务用（services 注入）
+    review_repo_factory,                      # session -> ReviewRecorder
+    checkpointer: BaseCheckpointSaver | None = None,  # 运行时 Postgres；测试 MemorySaver
+) -> CompiledStateGraph[ChainState, None, ChainState, ChainState]: ...
+```
+
+- 节点 DB 依赖经 `session_factory` + `*_repo_factory` 闭包注入（与现有"gateway 闭包绑定"同模式；langgraph 不收 `functools.partial`，用默认参绑定，见 gotcha）。
+- **删除/吸收 `build_write_graph`**：本链图取代它；`write_node` 函数本体保留（被 `write_chapter` 节点复用），删掉无人调用的 `build_write_graph` 工厂（YAGNI，解决审计发现的死代码）。
+
+---
+
+## 4. checkpointer 接线（激活休眠资产）
+
+- **运行时**：`AsyncPostgresSaver`（`langgraph.checkpoint.postgres.aio`）。新增注入缝 `get_checkpointer()`（`services/chain_deps.py`）→ 运行时返 Postgres saver（连 `DATABASE_URL`），测试注 `MemorySaver`。
+- **建表**：`setup_checkpointer(conn_string)`（已存在 `orchestrator/graph.py:106`，迁移本链图后移到 `orchestrator/chain/graph.py` 或保留）。**在 alembic 迁移/CI 跑一次**建 langgraph 检查点表（不变量：DDL 不在 app-runtime）。新增迁移 `xxxx_langgraph_checkpoint_setup`：`op` 内 `await setup_checkpointer(sync_or_async_conn)`（实施者按本仓 alembic async 模式处理；若 alembic 环境不便跑 async saver.setup，则在 CI bootstrap 步骤调用并在迁移注释说明）。
+- `thread_id = str(job_id)`：`config={"configurable": {"thread_id": str(job_id)}}`。初始 run `graph.ainvoke(initial, config)`；resume `graph.ainvoke(Command(resume=decisions), config)`。
+- **测试**：E2E 用**单个进程内 MemorySaver 实例**横跨"初始 run"与"resume run"两次模拟调用（同进程同 saver，故 interrupt 可恢复）；绝不连真 Postgres、绝不真 LLM。
+
+---
+
+## 5. 服务层（`apps/api/ww_api/services/chain_runner.py`）
+
+```python
+async def run_chain_job(
+    session_factory, job_id, *, project_id, chain_key, start_chapter_no, count,
+    gateway, checkpointer, resume_decisions=None, request_id=None,
+) -> None:
+    # 复用 run_job 的生命周期壳：set_running → work → complete/fail。
+    # work: 构 build_chain_graph(...) → config{thread_id=job_id}
+    #   - resume_decisions is None → graph.ainvoke(initial_state, config)
+    #   - else → graph.ainvoke(Command(resume=resume_decisions), config)
+    # 返回值/进度: 从图最终 state 取 {written, last_chapter_no} → job.result
+    #   {"chain_key","written":[...],"completed":bool,"awaiting_chapter":int|None}
+    # interrupt 命中 → graph 返回带 __interrupt__ → job 置 status="awaiting_input"
+    #   (jobs 复用现有状态机 + 新增/复用一个 awaiting 态，见 §7 数据)
+```
+
+- **进度**：每验收一章可经 `job_repo.set_progress`（若有）更新 `progress`；否则 result 里 `written` 长度即进度。
+- **错误脱敏**：复用 `run_job` 的 `_classify_job_error`（AppError 透传安全文案，其余通用文案，不泄 `str(exc)`，P0-3）。
+- **token 不泄漏**：job result/status/日志绝不含 prompt/正文/token（只记章号、长度、计数）。
+
+---
+
+## 6. API 契约（@backend；改 OpenAPI → 记 contracts + 前端 follow-up `pnpm gen:api`）
+
+| 端点 | 方法 | 请求 | 响应 | 说明 |
+|---|---|---|---|---|
+| `/projects/{pid}/chains/{chain_key}/run` | POST | `ChainRunRequest{start_chapter_no:int>=1, count:int 1..50}` | 202 `ChainRunAccepted{job_id, chain_key, start_chapter_no, count}` | 写 jobs(queued,kind=chain) + BackgroundTask `run_chain_job` |
+| `/jobs/{job_id}` | GET | — | 现有 `JobView` + `result{chain_key,written[],completed,awaiting_chapter}` | 复用现有 jobs 端点；轮询进度/awaiting |
+| `/projects/{pid}/chains/runs/{job_id}/resume` | POST | `ChainResumeRequest{decisions: list[ConflictDecision]}` | 202 `ChainRunAccepted` | 仅当 job=awaiting_input；BackgroundTask resume |
+
+- 校验（系统边界，fail fast）：`count` 1..50（>50 → 422 VALIDATION）；`start_chapter_no >= 1`；`chain_key` 未知 → 404；resume 非 awaiting 态 → 409。
+- `ConflictDecision` 复用 `schemas/projects.py` 既有（`conflict_index/verdict/note`）。
+- schemas 新增 `schemas/chain.py`：`ChainRunRequest/ChainRunAccepted/ChainResumeRequest`。
+
+---
+
+## 7. 数据模型
+
+- **无新业务表**。章正文 → `chapters`；审稿 → `chapter_reviews`；digest → `chapter_digests`；运行 → `jobs`。
+- `jobs`：复用。新增 `kind` 值 `"chain"`（若 `kind` 列已存在则直接用；若无则本设计**允许**一个最小迁移加 `jobs.kind TEXT` + `jobs.status` 增态 `awaiting_input`——实施者先查现表，能复用就零迁移）。
+- **langgraph 检查点表**：由 `setup_checkpointer` 在迁移/CI 建（§4）。这是唯一新增 DDL。
+
+> 实施者 MUST 先查 `packages/db/ww_db/models.py` 的 `jobs` 现有列（是否已有 `kind`/`progress`/`result`/能否表达 awaiting）再决定是否需要迁移；优先零迁移方案（如用 `result.awaiting_chapter` 表达待裁决，`status` 复用现有枚举）。
+
+---
+
+## 8. 不变量符合性（逐条核对）
+
+- **#1 DB 即单一真源**：链节点只经领域表通信；节点间不互调。✅
+- **#3 四审只读 + 验收 HITL 闸**：`review_chapter` 只写 `chapter_reviews`；唯一正文写经 `accept_chapter`→`run_accept_transaction`；有冲突必 `interrupt()` 交人，`assert_conflicts_resolved` 缺判即拦。✅
+- **#4 digest 从终稿提炼**：`accept_chapter` 事务外 `extract_digest_facts(final_text)`。✅
+- **#5 checkpoint 只存控制流**：`ChainState` 只含章号/计数/标志；冲突明文 + 正文重读领域表。✅
+- **#9 缓存前缀稳定**：`write_chapter` 复用 `assemble` 的 stable_core/volatile 切分，硬规则+指纹进前缀、无时间戳/UUID。✅
+- **节点确定性可测**：LLM 非确定性锁在 gateway 后；`decide` 是纯逻辑。✅
+
+---
+
+## 9. 任务拆分（多 agent，契约先行）
+
+| 任务 | skill | 依赖 | 产出 | DoD |
+|---|---|---|---|---|
+| **C1 链图 + 节点 + 单测** | @llm | — | `orchestrator/chain/{state,nodes,graph}.py` + 删 `build_write_graph` + 单测（mock gateway + fake session_factory + MemorySaver；测无冲突全跑 + 有冲突 interrupt + resume→accept；`decide` 纯逻辑测） | `packages/core`+`packages/agents` ruff/format/mypy 干净 + pytest 绿；图可 ainvoke、可 interrupt、可 resume |
+| **C2 服务 + 端点 + schema + checkpointer 接线 + 单测** | @backend | C1 契约 | `services/{chain_runner,chain_deps}.py` + `routers/chain.py` + `schemas/chain.py` + main 注册 + jobs 复用/最小迁移 | `apps/api` 门禁绿；3 端点入 OpenAPI；run→202、resume→202、未知 key 404、count>50 422、resume 非 awaiting 409；token 不入 result/日志 |
+| **C3 检查点建表迁移** | @db/@devops | C1 | alembic 迁移调 `setup_checkpointer`（或 CI bootstrap）+ jobs 最小迁移（如需） | `alembic upgrade head` 应用、`alembic check` 无漂移 |
+| **C4 E2E** | @qa | C2 | `tests/test_chain_workflow_e2e.py`：真 pg + mock 网关零 token：① 两章无冲突全自动→`chapters` 两 accepted 版次 + `chapter_digests` 两行 + job done `written=[n,n+1]`；② 注入冲突→第一章 interrupt→job awaiting→resume 带裁决→续跑→accept；负向：token 不入 job result/状态 | E2E 绿；DB 真源逐项断言 |
+
+**并行性**：C1 是契约源，先行（§3.3 签名 + §6 端点已在本文锁定，故 C2 可对照契约并行起，但建议 C1 先落地图签名）。C3 依赖 C1（用其 `setup_checkpointer`）。C4 依赖 C2。
+
+---
+
+## 10. 测试计划（守 TDD + mock LLM）
+
+- **单元**（C1）：节点函数直接调用（不起图运行时）：`write_chapter`（fake gateway 返固定文 + fake session 断言 save_draft）、`decide`（构造有/无冲突的 review → 断 `has_conflicts`）、`accept_chapter`（fake repos 断 promote/digest/decisions + 冲突缺判抛 CONFLICT_UNRESOLVED）。**流程**：MemorySaver 跑全图，断无冲突→END 且 written 满、有冲突→`__interrupt__`、resume→END。
+- **集成/E2E**（C4）：FastAPI 端点 + 真 pg + mock 网关；interrupt+resume 在**单进程单 MemorySaver**（经依赖覆盖注入）内横跨两次端点调用。
+- **绝不**：真 LLM、真 Postgres 检查点联网、把正文/token 写进断言外的日志。
+
+---
+
+## 11. 风险与回退
+
+| 风险 | 缓解 |
+|---|---|
+| alembic 跑 async `saver.setup()` 不便 | 退路：CI/bootstrap 脚本调 `setup_checkpointer`，迁移注释指明；E2E 用 MemorySaver 不依赖该表 |
+| 一条 run 内多章长事务/连接占用 | 节点**各自短事务**，不跨章共享 session；图运行本身无 DB 事务，只 checkpointer 写 |
+| MemorySaver 跨请求不持久 | 仅测试用（同进程）；运行时强制 Postgres saver，文档标注 |
+| 链中途崩溃 | checkpointer 持久 → 可经 resume/重跑同 thread_id 续；job 置 failed 带脱敏文案 |
+| 与既有单章 `draft/review/accept` 端点重复逻辑 | 复用同一 `run_accept_transaction`/`assemble`/审稿 spec，不复制；链是**编排**新增、非业务重写 |
+
+---
+
+## 12. 文档回写（实施完成后）
+- `ARCHITECTURE.md §5.2`：补"多章链图（cyclic + interrupt + Postgres checkpointer）"，并更正现状描述（写章直连流式、单章 accept 为事务、链图首次启用 checkpointer）。
+- `memory/contracts.md`：登记 C-Chain 契约（图签名 + 3 端点）。
+- `memory/decisions.md`：记"多章编排选 LangGraph 链图而非端点循环"的理由。
+- `PROGRESS.md`：拉入"Chain Workflow"阶段台账。

memory/contracts.md

@@ -313,9 +313,24 @@
 
 ---
 
+## C-Chain · 多章工作流链端点 + 服务层　owner @backend / @llm(图)　状态: 稳定（C2, 2026-06-23）
+> 设计真源：`docs/design/chain-workflow.md`。C1(@llm) 图签名 §3.3；C2(@backend) 端点/schema/服务接线。
+- **3 端点**（`routers/chain.py`，挂 `/projects` 前缀）：
+  - `POST /projects/{pid}/chains/{chain_key}/run` ← `ChainRunRequest{start_chapter_no:int>=1, count:int 1..50}` → 202 `ChainRunAccepted{job_id, chain_key, start_chapter_no, count}`。写一行 `jobs(queued, kind="chain")` 返 202，链经 BackgroundTask `run_chain_job` 跑（自建独立 session）。未知 chain_key→404（仅 `draft_volume`）；count 越界→422（schema Field）；项目不存在→404；无凭据→503。
+  - `GET /jobs/{job_id}`（**复用**现有）：轮询进度/awaiting。链 job `result = {chain_key, written:[int], completed:bool, awaiting_chapter:int|null}`；interrupt 命中时 `status="awaiting_input"` + `result.awaiting_chapter`。
+  - `POST /projects/{pid}/chains/runs/{job_id}/resume` ← `ChainResumeRequest{decisions:[ConflictDecision]}` → 202 `ChainRunAccepted`。仅当 job=`awaiting_input`；非该态→**409 `CONFLICT`**；job 不存在→404。带裁决 `Command(resume=...)` 续跑。
+- **schema**（`schemas/chain.py`）：`ChainRunRequest`/`ChainRunAccepted`/`ChainResumeRequest`；`ConflictDecision` 复用 `schemas/projects.py`（conflict_index/verdict/note）。
+- **零迁移**（§7）：复用 `jobs`（kind/status/progress/result 全已存）；新增 `status` 值 `"awaiting_input"`（jobs.status 自由 Text 列，无 DDL）；awaiting 章经 `result.awaiting_chapter` 表达。`JobRepo` 加 `set_awaiting(job_id, result)`。**唯一新增 DDL = langgraph 检查点表（C3 迁移建，本任务未引入）。**
+- **新增错误码**（`ww_shared/errors.py`）：`ErrorCode.CONFLICT`→409（资源状态冲突，如对非 awaiting 链 job 续跑；与 `CONFLICT_UNRESOLVED` 区分）。
+- **新网关缝**（`project_deps.py`）：`get_chain_gateway`（`build_chain_gateway`：按请求 tier writer/analyst/light 分派、union 三档适配器+回退链——单档网关 chain_resolver 恒返该档会错路由 review/digest，故链需多档分派）；`get_digest_gateway_builder`（accept 节点自建短事务建 light 档 digest 网关）。`get_checkpointer_factory`（`services/chain_deps.py`：运行时 `AsyncPostgresSaver.from_conn_string(database_url_sync)` 上下文；测试注 MemorySaver 工厂）。
+- **token 纪律**：job result/status/日志只记章号/计数/标志，绝不含 prompt/正文/token（§5，已断言）。
+- → 影响 @frontend（链发起页/进度/裁决续跑面板，**非目标本期不做**，契约稳定后 follow-up `pnpm gen:api`）；@db/@devops C3（检查点建表迁移 + 可选 jobs 注释）。
+
 ## 契约变更日志（append-only）
 > 格式：`- [date] @skill 改 Cx：<改了什么> → 影响 <依赖方/任务>`
 
+- [2026-06-23] @backend 立 C-Chain（C2）：3 端点 + `schemas/chain.py` + `services/{chain_runner,chain_deps}.py` + `jobs` 零迁移复用（加 `status="awaiting_input"` + `JobRepo.set_awaiting`）+ 新 `ErrorCode.CONFLICT`(409) + `project_deps` 加 `build_chain_gateway`/`get_chain_gateway`/`get_digest_gateway_builder`/`get_checkpointer_factory`。OpenAPI 含 2 新 POST（GET /jobs 复用）。门禁绿：ruff/format/mypy(193) 干净 + pytest 600 passed + alembic 无漂移。→ 影响 @frontend（follow-up `pnpm gen:api`）、@db/@devops C3（检查点迁移）。
+
 - [2026-06-20] @backend 扩 C3：新增 **`GET /projects/{project_id}/chapters/{chapter_no}/injection`**（本章注入透明，B0 读端点）→ `InjectionResponse{project_id, chapter_no, selected:[InjectionEntity{kind,name,reasons[]}], recent_n}`（`schemas/injection.py`，snake_case）。实现仅调既有 `assemble()` 回放确定性 `SelectionTrace`——**无 LLM、无 commit、无 DDL**；项目不存在→404，无大纲→`selected:[]`。reasons 取值同 `SelectionReason`（explicit_beat/main_character/recent_digest/foreshadow_window）。→ 影响 @frontend（已 `pnpm gen:api` + `ChapterAssistant` 消费）。**B0 可控版（PUT override + `select_relevant_entities` 加 pinned/excluded/recent_n + draft 端点同读 override + 持久化）尚未实现，届时再扩本契约。**
 
 - [2026-06-20] @backend 再扩 C3（B0 **可控版**，接上条）：新增 **`PUT /projects/{project_id}/chapters/{chapter_no}/injection`** ← `InjectionOverrideRequest{pinned:[{kind,name}], excluded:[{kind,name}], recent_n:int|null(1..20)}` → 返回 `InjectionResponse`（同上，**新增回显字段 `pinned`/`excluded`**，`selected[].reasons` 可含新值 **`author_pin`**）。语义：pin 强制纳入并加 `author_pin` 理由 / excluded 强制剔除（**优先于 pin**）/ recent_n 覆盖近况回看章数。GET injection 与 **draft 流式端点**均先读同一覆盖再 `assemble(override=...)`，故「看到的=写章用的」（不变量 #6 作者兜底）。持久化：**新表 `chapter_injection`**（迁移 `ad2c4c663daf`，唯一 `(project_id,chapter_no)`，复用 outline 行已否决）；`select_relevant_entities` 加 `pinned/excluded` frozenset 入参、`assemble` 加 `override` 关键字参；新 `domain/injection_repo.py`（`InjectionOverride`/`EntityRef`/`SqlInjectionOverrideRepo`，upsert 只 flush 端点 commit）。→ 影响 @frontend（已 `pnpm gen:api`；F1 加 pin/排除控件 + recent_n 步进器）。

memory/decisions.md

@@ -149,3 +149,9 @@
 - 选择：把实现落在已是 workspace member、且承载「编排/写库 apply 层」的 `ww_core.domain`（`skill_registry.py` + `skill_permissions.py`，经 `ww_core.domain` 导出）。`ARCHITECTURE §5.6` 明确「强制点在编排/写库层」=ww_core，语义上也吻合。`packages/skills/ww_skills/__init__.py` 留**再导出门面**（import 自 ww_core），保留稳定「skills」导入名。
 - 理由 / 取舍：非阻塞、门禁可干净覆盖（ruff/mypy/pytest 全跑）、不越权改根配置；代价是物理位置与任务文档措辞略偏，但功能/契约（C8）完整。待 @devops 把 `packages/skills` 纳入 workspace + mypy_path 后，可平滑迁移实现到 `ww_skills` 而不动调用方（只改门面方向）。
 - 影响：消费方 import `ww_core.domain` 的 `SkillRegistry`/`filter_reads`/`partition_writes`/`validate_declaration`（或经 `ww_skills` 门面）。若 @devops 后续纳入 workspace，迁移由届时的 @backend/@llm 执行。
+
+## [2026-06-23] @backend C2（多章链）服务/端点接线：零迁移表达 awaiting + 多档分派网关
+- 决策 1（**零迁移表达 awaiting**）：链 interrupt 暂停态不新建 jobs 列/枚举——`jobs.status` 是自由 Text 列（无 DB CHECK），直接新增值 `"awaiting_input"` + `JobRepo.set_awaiting`；待裁决章号经 `result.awaiting_chapter` 表达。`jobs.kind="chain"` 同理零迁移。唯一新增 DDL（langgraph 检查点表）归 C3 迁移。理由：设计 §7 优先零迁移；result 已是 JSONB 足以承载非密进度。
+- 决策 2（**多档分派网关 `build_chain_gateway`**）：一条链 run 跨 writer(write)/analyst(review)/light(digest) 三档，但 `build_gateway_for_tier(tier)` 装出的网关 `chain_resolver` 恒返该单档链、忽略 `req.tier`——会把 review/digest 错路由到 writer。故链需一个**按请求 tier 分派**的网关：union 三档所有 provider 适配器 + `chain_resolver` 据 `req.tier` 返回对应档链。digest 在 accept 节点自建短事务内按 session 现建 light 档网关（`get_digest_gateway_builder`）。
+- 决策 3（**accept_op 在 apps/api 装配**）：链编排（图/节点）在 `ww_core`，但具体验收事务（`run_accept_transaction`/冲突 gate/digest 提炼/伏笔到期扫描）属 apps/api——经 `build_accept_op` 闭包注入图节点，守目录所有权 + 不变量 #3/#4。自动链无作者改稿，`final_text` = `chapters` 该章草稿正文（write 节点所落）。
+- 决策 4（**新错误码 `CONFLICT`**）：resume 非 awaiting 态须 409，但既有 409 码 `CONFLICT_UNRESOLVED` 语义专指「未决冲突禁验收」，不宜复用。新增通用 `ErrorCode.CONFLICT`→409（资源状态冲突）。

memory/gotchas.md

@@ -84,3 +84,6 @@
 - [2026-06-19] @llm **Kimi Code coding API 伪造头真源 = `ooojustin/opencode-kimi`（`src/headers.ts`+`src/constants.ts`，1:1 镜像 kimi-cli v1.37.0），发完整 7 头、UA `KimiCLI/1.37.0`**（K1.2 校正，推翻上方 pi-kimi-coder UA-only 那条）：`picassio/pi-kimi-coder` 是分歧/错误参考（只发 UA），照它裁成 UA-only 是误修，已回退。`kimi_code_headers()` 发 `User-Agent=KimiCLI/1.37.0` + `X-Msh-Platform=kimi_cli`（字面常量，非 OS 名）+ `X-Msh-Version=1.37.0`（==UA 版本）+ `X-Msh-Device-Name`（`socket.gethostname()` ASCII 化）+ `X-Msh-Device-Model`（macOS=`f"macOS {platform.mac_ver()[0]} {platform.machine()}"`，`machine()` 原样 `arm64`/`x86_64` 不归一化）+ `X-Msh-Os-Version`（`platform.version()`）+ `X-Msh-Device-Id`（稳定 32 位无连字符 `uuid4().hex`：env `KIMI_DEVICE_ID` 优先→否则读/建 `~/.kimi/device_id` 复用，**绝不每次随机**，否则 Kimi 侧每次当新设备）。源码若与此有出入以源码为准（本次核对 master 一致）。⚠️ HTTP 头值含非 ASCII 会被底层 fetch/httpx 拒，host 派生值（Device-Name/Model/Os-Version）须 ASCII 化（`asciiHeaderValue`：裁 `\x20-\x7e` 之外 + trim，空回退 `unknown`）。单测用 env `KIMI_DEVICE_ID` 注入固定 id 保 CI 确定（不触真 ~/.kimi）。ruff E501 按显示宽度算（中文占 2 列），含中文 docstring/注释的行别贴边 100。
 - [2026-06-19] @backend `assemble`（C5）此前只从 world_entities/characters/style/rules + cards/foreshadow/digests/outline.beats 组装，**从不含项目 premise/logline/theme/title，也无「写章」指令** → 全新项目（只有 premise、无世界观/角色/大纲）产出 `stable_core=""`+`volatile=""`，writer 的 user message 为空，LLM 回 `400 "the message at position 0 with role 'user' must not be empty"`。修复：`MemoryRepos` 加第 8 个 repo `project:ProjectSpecRepo`（`spec(project_id)->ProjectSpecView{title,logline?,premise?,theme?}`，按 project_id 读 `projects`，无 owner 过滤——owner 隔离归路由层）；`assemble` 把「作品蓝本」放进 `stable_core` 首段（书级 spec=定型→缓存前缀，不违 #9），并让 `volatile` 始终含 `请创作第 {chapter_no} 章的正文。`（易变指令）。⚠️ 任何手搓 `MemoryRepos(...)` 的地方（含测试 fake）现在**必须**补 `project=` 字段，否则 dataclass 缺参报错。无 DDL 变更（只读既有 projects 列），无迁移。
 - [2026-06-22] @frontend/@orchestrator T6 创作工具箱通用端点的两处契约边界（加新生成器时注意）：① `ToolGenerateRequest` 是**固定字段并集** `{brief, chapter_no?, count?, kind?}`——`GeneratorRunner` 只映射落在此集合内的 `input_field` 名；新生成器若声明了集合外的 `input_field`，前端会**静默忽略**该字段。新工具的 `input_fields` 须落在 `brief/chapter_no/count/kind` 内，否则需先扩 `ToolGenerateRequest` 契约（+`pnpm gen:api`）。② `ToolInputFieldView.type` 是自由字符串，后端可声明 `"select"` 但 descriptor **无 `options` 字段** → 前端把 select 当 text 输入渲染。若某工具需要真下拉选项，须先给 `InputField`/`ToolInputFieldView` 加 `options` 再改前端 `GeneratorRunner`。
+- [2026-06-23] @backend 多章链网关（C2）：**单档 `build_gateway_for_tier(tier)` 网关不能驱动跨档链**。其 `chain_resolver`/`_resolver` 闭包恒返该 tier 的链、**忽略入参 `req.tier`**，故拿它跑 review(analyst)/digest(light) 会全部错路由到 writer 档的 provider/model。链/任何跨档编排须用 `build_chain_gateway`（union 三档适配器 + `chain_resolver` 据 `req.tier` 分派）。测试用 mock 网关按 `req.output_schema` 路由（无 schema=write，有=review），不受此影响。
+- [2026-06-23] @backend langgraph `CompiledStateGraph.ainvoke` 的 mypy 重载：`config` 必须是 `RunnableConfig`（`from langchain_core.runnables import RunnableConfig`），裸 `dict[str,dict[str,str]]` 不匹配任何重载 → call-overload 错。返回值是 `dict[str,Any] | Any`，传给取 `__interrupt__`/`written` 的 helper 前先 `dict(raw_final)` 收敛为 `dict[str,Any]`。interrupt 命中时返回值含 `__interrupt__`（Interrupt 对象列表），载荷读 `getattr(first,"value",first)`（兼容 dict）。
+- [2026-06-23] @backend 改 `JobRepo` Protocol 加方法（如 `set_awaiting`）= 契约变更：**所有 fake 实现都要同步补**，否则 mypy 报 Protocol 缺成员（本次漏了 `packages/core/tests/test_job_repo.py::FakeJobRepo` + `apps/api/tests/fakes_projects.py::FakeJobRepo`）。grep `class Fake.*JobRepo` 全仓再补。

packages/core/tests/test_chain_graph.py

@@ -0,0 +1,380 @@
+"""多章链图单测（chain-workflow 设计 §3 / §10）——节点纯逻辑 + 全图 MemorySaver 流程。
+
+全部注入 mock 网关 + fake session_factory + fake repos + MemorySaver，无真 LLM、无真
+Postgres。验：① 无冲突全跑到 END 且 written 满；② 有冲突 → `__interrupt__`；③ resume
+（`Command(resume=decisions)`）→ accept → END；④ `decide` 纯逻辑；⑤ accept 推进章号。
+asyncio_mode=auto。
+"""
+
+from __future__ import annotations
+
+import uuid
+from collections.abc import AsyncIterator
+from contextlib import asynccontextmanager
+from typing import Any
+
+from langchain_core.runnables import RunnableConfig
+from langgraph.checkpoint.memory import MemorySaver
+from langgraph.types import Command
+from pydantic import BaseModel
+from ww_agents import Conflict, ContinuityReview
+from ww_core.orchestrator.chain import (
+    accept_chapter,
+    build_chain_graph,
+    decide,
+    has_conflicts,
+    initial_chain_state,
+    write_chapter,
+)
+from ww_llm_gateway.types import LlmRequest, LlmResponse, ServedBy, Usage
+
+PROJECT = uuid.UUID("00000000-0000-0000-0000-000000000001")
+USER = uuid.UUID("00000000-0000-0000-0000-0000000000aa")
+
+
+# ---- 测试替身 ----
+
+
+def _usage() -> Usage:
+    return Usage(
+        provider="fake",
+        model="fake",
+        input_tokens=1,
+        output_tokens=1,
+        cost_minor=0,
+        currency="USD",
+    )
+
+
+class FakeChainGateway:
+    """链网关 mock：write（无 output_schema）回固定正文；审稿按 `output_schema` 回 parsed。
+
+    `conflicts`：注给 continuity 审的冲突清单（空 = 无冲突章）。其余审 schema 回各自空实例。
+    """
+
+    def __init__(
+        self,
+        *,
+        draft_text: str,
+        conflicts: list[Conflict],
+        by_schema: dict[type, BaseModel],
+    ) -> None:
+        self._draft = draft_text
+        self._continuity = ContinuityReview(conflicts=conflicts)
+        self._by_schema = by_schema
+        self.write_calls = 0
+        self.review_calls = 0
+
+    async def run(self, req: LlmRequest) -> LlmResponse:
+        schema: type[BaseModel] | None = req.output_schema
+        if schema is None:
+            self.write_calls += 1
+            return LlmResponse(
+                text=self._draft,
+                parsed=None,
+                usage=_usage(),
+                served_by=ServedBy(provider="fake", model="fake"),
+            )
+        self.review_calls += 1
+        parsed: BaseModel = (
+            self._continuity if schema is ContinuityReview else self._by_schema[schema]
+        )
+        return LlmResponse(
+            text=parsed.model_dump_json(),
+            parsed=parsed,
+            usage=_usage(),
+            served_by=ServedBy(provider="fake", model="fake"),
+        )
+
+
+class FakeDraftView:
+    def __init__(self, content: str) -> None:
+        self.content = content
+
+
+class FakeChapterRepo:
+    """内存章草稿 repo：save_draft 存正文，get_draft 回读。"""
+
+    def __init__(self, store: dict[int, str]) -> None:
+        self._store = store
+
+    async def save_draft(
+        self, project_id: uuid.UUID, chapter_no: int, *, text: str, volume: int = 1
+    ) -> Any:
+        self._store[chapter_no] = text
+        return FakeDraftView(text)
+
+    async def get_draft(self, project_id: uuid.UUID, chapter_no: int) -> Any:
+        content = self._store.get(chapter_no)
+        return FakeDraftView(content) if content is not None else None
+
+
+class FakeReviewRecord:
+    def __init__(self, chapter_no: int, conflicts: list[dict[str, Any]]) -> None:
+        self.id = uuid.uuid4()
+        self.chapter_no = chapter_no
+        self.conflicts = conflicts
+
+
+class FakeReviewRepo:
+    """内存审稿 repo：record 追加留痕，list_for_chapter 回新→旧。"""
+
+    def __init__(self, records: dict[int, list[FakeReviewRecord]]) -> None:
+        self._records = records
+
+    async def record(
+        self,
+        project_id: uuid.UUID,
+        chapter_no: int,
+        *,
+        chapter_version: int | None = None,
+        conflicts: list[dict[str, Any]],
+        foreshadow_sug: list[dict[str, Any]] | None = None,
+        style: dict[str, Any] | None = None,
+        pace: dict[str, Any] | None = None,
+        health_score: int | None = None,
+    ) -> Any:
+        rec = FakeReviewRecord(chapter_no, list(conflicts))
+        self._records.setdefault(chapter_no, []).insert(0, rec)
+        return rec
+
+    async def list_for_chapter(self, project_id: uuid.UUID, chapter_no: int) -> list[Any]:
+        return list(self._records.get(chapter_no, []))
+
+
+class FakeSession:
+    def __init__(self) -> None:
+        self.commits = 0
+
+    async def commit(self) -> None:
+        self.commits += 1
+
+
+class FakeContext:
+    def __init__(self) -> None:
+        self.stable_core = "## 世界观硬规则\n灵气可凝丹"
+        self.volatile = "## 写作指令\n写第 N 章"
+
+
+@asynccontextmanager
+async def _session_factory() -> AsyncIterator[FakeSession]:
+    """fake 短事务 session（每次新建；满足 SessionFactory）。"""
+    yield FakeSession()
+
+
+def _empty_by_schema() -> dict[type, BaseModel]:
+    """非 continuity 审（pace/style/foreshadow）的空 parsed——按各 spec 的 output_schema。"""
+    from ww_agents import foreshadow_spec, pace_spec, style_drift_spec
+
+    out: dict[type, BaseModel] = {}
+    for spec in (foreshadow_spec, pace_spec, style_drift_spec):
+        schema = spec.output_schema
+        assert schema is not None
+        out[schema] = schema()
+    return out
+
+
+def _make_harness(*, conflicts: list[Conflict]) -> dict[str, Any]:
+    """造一套共享内存态 + 工厂闭包 + accept 间谍，供图/节点测试复用。"""
+    draft_store: dict[int, str] = {}
+    review_store: dict[int, list[FakeReviewRecord]] = {}
+    accepted: list[dict[str, Any]] = []
+
+    gateway = FakeChainGateway(
+        draft_text="第 N 章正文。", conflicts=conflicts, by_schema=_empty_by_schema()
+    )
+
+    async def gateway_builder(session: Any) -> Any:
+        """按节点 session 建网关的替身（不变量 #1）：忽略 session，恒返同一 mock 网关。"""
+        return gateway
+
+    def memory_repos_factory(session: Any) -> Any:
+        return object()  # assemble 被 fake 替换，不实际用 repos
+
+    def chapter_repo_factory(session: Any) -> Any:
+        return FakeChapterRepo(draft_store)
+
+    def review_repo_factory(session: Any) -> Any:
+        return FakeReviewRepo(review_store)
+
+    async def assemble(repos: Any, project_id: uuid.UUID, chapter_no: int) -> Any:
+        return FakeContext()
+
+    async def accept_op(
+        *,
+        project_id: uuid.UUID,
+        chapter_no: int,
+        user_id: uuid.UUID,
+        decisions: list[Any],
+    ) -> None:
+        accepted.append({"chapter_no": chapter_no, "decisions": list(decisions)})
+
+    return {
+        "gateway": gateway,
+        "gateway_builder": gateway_builder,
+        "session_factory": _session_factory,
+        "memory_repos_factory": memory_repos_factory,
+        "chapter_repo_factory": chapter_repo_factory,
+        "review_repo_factory": review_repo_factory,
+        "assemble": assemble,
+        "accept_op": accept_op,
+        "accepted": accepted,
+        "draft_store": draft_store,
+        "review_store": review_store,
+    }
+
+
+def _build(h: dict[str, Any], checkpointer: Any) -> Any:
+    return build_chain_graph(
+        h["gateway_builder"],
+        session_factory=h["session_factory"],
+        memory_repos_factory=h["memory_repos_factory"],
+        chapter_repo_factory=h["chapter_repo_factory"],
+        review_repo_factory=h["review_repo_factory"],
+        assemble=h["assemble"],
+        accept_op=h["accept_op"],
+        checkpointer=checkpointer,
+    )
+
+
+# ---- decide 纯逻辑 ----
+
+
+async def test_decide_no_conflicts_sets_false() -> None:
+    review_store: dict[int, list[FakeReviewRecord]] = {1: [FakeReviewRecord(1, [])]}
+
+    def review_repo_factory(session: Any) -> Any:
+        return FakeReviewRepo(review_store)
+
+    out = await decide(
+        {"project_id": PROJECT, "user_id": USER, "current_chapter_no": 1},
+        session_factory=_session_factory,
+        review_repo_factory=review_repo_factory,
+    )
+
+    assert out == {"has_conflicts": False}
+
+
+async def test_decide_with_conflicts_sets_true() -> None:
+    review_store: dict[int, list[FakeReviewRecord]] = {
+        1: [FakeReviewRecord(1, [{"kind": "x", "detail": "矛盾"}])]
+    }
+
+    def review_repo_factory(session: Any) -> Any:
+        return FakeReviewRepo(review_store)
+
+    out = await decide(
+        {"project_id": PROJECT, "user_id": USER, "current_chapter_no": 1},
+        session_factory=_session_factory,
+        review_repo_factory=review_repo_factory,
+    )
+
+    assert out == {"has_conflicts": True}
+
+
+def test_has_conflicts_reads_flag() -> None:
+    assert has_conflicts({"has_conflicts": True}) is True
+    assert has_conflicts({"has_conflicts": False}) is False
+    assert has_conflicts({}) is False
+
+
+# ---- accept 节点：推进章号 + 追加 written + 透传裁决 ----
+
+
+async def test_accept_chapter_advances_and_records_decisions() -> None:
+    accepted: list[dict[str, Any]] = []
+
+    async def accept_op(
+        *,
+        project_id: uuid.UUID,
+        chapter_no: int,
+        user_id: uuid.UUID,
+        decisions: list[Any],
+    ) -> None:
+        accepted.append({"chapter_no": chapter_no, "decisions": list(decisions)})
+
+    out = await accept_chapter(
+        {
+            "project_id": PROJECT,
+            "user_id": USER,
+            "current_chapter_no": 3,
+            "written": [1, 2],
+            "last_chapter_no": 5,
+        },
+        decisions=[{"conflict_index": 0, "verdict": "ignore"}],
+        accept_op=accept_op,
+    )
+
+    assert out["current_chapter_no"] == 4
+    assert out["written"] == [1, 2, 3]
+    assert out["has_conflicts"] is False
+    assert accepted == [
+        {"chapter_no": 3, "decisions": [{"conflict_index": 0, "verdict": "ignore"}]}
+    ]
+
+
+# ---- write 节点：收集版（非流式）落稿 ----
+
+
+async def test_write_chapter_saves_collected_draft() -> None:
+    h = _make_harness(conflicts=[])
+    state = initial_chain_state(project_id=PROJECT, user_id=USER, start_chapter_no=1, count=1)
+
+    out = await write_chapter(
+        state,
+        gateway_builder=h["gateway_builder"],
+        session_factory=h["session_factory"],
+        memory_repos_factory=h["memory_repos_factory"],
+        chapter_repo_factory=h["chapter_repo_factory"],
+        assemble=h["assemble"],
+    )
+
+    assert out == {}  # state 不变（正文在 DB）
+    assert h["draft_store"][1] == "第 N 章正文。"
+    # 收集版：write 走非流式 run
+    assert h["gateway"].write_calls == 1
+
+
+# ---- 全图（MemorySaver）：无冲突全自动跑满 ----
+
+
+async def test_chain_runs_all_chapters_when_no_conflicts() -> None:
+    h = _make_harness(conflicts=[])
+    graph = _build(h, MemorySaver())
+    config: RunnableConfig = {"configurable": {"thread_id": "chain-noconflict"}}
+    initial = initial_chain_state(project_id=PROJECT, user_id=USER, start_chapter_no=1, count=2)
+
+    final = await graph.ainvoke(initial, config=config)
+
+    assert "__interrupt__" not in final
+    assert final["written"] == [1, 2]
+    assert final["current_chapter_no"] == 3  # last(2) + 1，越界 → END
+    assert [a["chapter_no"] for a in h["accepted"]] == [1, 2]
+    assert h["accepted"][0]["decisions"] == []  # 无冲突章 decisions=[]
+
+
+# ---- 全图：有冲突 → interrupt → resume → accept → END ----
+
+
+async def test_chain_interrupts_on_conflict_then_resumes() -> None:
+    conflict = Conflict(type="性格漂移", where="第3段", suggestion="统一主角姓名为张三")
+    h = _make_harness(conflicts=[conflict])
+    saver = MemorySaver()  # 同进程同 saver 跨两次 invoke → interrupt 可恢复
+    graph = _build(h, saver)
+    config: RunnableConfig = {"configurable": {"thread_id": "chain-conflict"}}
+    initial = initial_chain_state(project_id=PROJECT, user_id=USER, start_chapter_no=1, count=1)
+
+    # 初始 run：第 1 章四审报冲突 → interrupt 暂停。
+    interrupted = await graph.ainvoke(initial, config=config)
+
+    assert "__interrupt__" in interrupted
+    assert h["accepted"] == []  # 尚未验收
+
+    # resume：作者裁决该冲突 → 续跑 accept → END。
+    decisions = [{"conflict_index": 0, "verdict": "ignore", "note": "笔误，后续统一"}]
+    final = await graph.ainvoke(Command(resume=decisions), config=config)
+
+    assert "__interrupt__" not in final
+    assert final["written"] == [1]
+    assert [a["chapter_no"] for a in h["accepted"]] == [1]
+    assert h["accepted"][0]["decisions"] == decisions  # 裁决透传给 accept_op

packages/core/tests/test_job_repo.py

@@ -15,6 +15,7 @@ import pytest
 from pydantic import ValidationError
 from ww_core.domain.job_repo import (
     PROGRESS_COMPLETE,
+    STATUS_AWAITING,
     STATUS_DONE,
     STATUS_FAILED,
     STATUS_QUEUED,
@@ -93,6 +94,20 @@ class FakeJobRepo:
         row.result = dict(result)
         return _view(row)
 
+    async def set_awaiting(self, job_id: uuid.UUID, result: dict[str, Any]) -> JobView:
+        row = self._require(job_id)
+        row.status = STATUS_AWAITING
+        row.result = dict(result)
+        return _view(row)
+
+    async def claim_awaiting_to_running(self, job_id: uuid.UUID) -> JobView | None:
+        """原子抢占 awaiting→running（内存替身：仅当现态 awaiting 才抢到，否则 None）。"""
+        row = next((r for r in self.rows if r.id == job_id), None)
+        if row is None or row.status != STATUS_AWAITING:
+            return None
+        row.status = STATUS_RUNNING
+        return _view(row)
+
     async def fail(self, job_id: uuid.UUID, error: str) -> JobView:
         row = self._require(job_id)
         row.status = STATUS_FAILED
@@ -166,6 +181,39 @@ async def test_fail_sets_failed_and_error() -> None:
     assert failed.error == "boom"
 
 
+# ---- 原子抢占 awaiting → running（防并发 resume 竞态，审评 #3）----
+
+
+async def test_claim_awaiting_to_running_succeeds_once() -> None:
+    repo: JobRepo = _repo()
+    job = await repo.create(PROJECT, KIND)
+    await repo.set_awaiting(job.id, {"awaiting_chapter": 1})
+    claimed = await repo.claim_awaiting_to_running(job.id)
+    assert claimed is not None
+    assert claimed.status == STATUS_RUNNING
+
+
+async def test_claim_awaiting_second_call_returns_none() -> None:
+    repo: JobRepo = _repo()
+    job = await repo.create(PROJECT, KIND)
+    await repo.set_awaiting(job.id, {"awaiting_chapter": 1})
+    first = await repo.claim_awaiting_to_running(job.id)
+    second = await repo.claim_awaiting_to_running(job.id)  # 已 running → 抢不到
+    assert first is not None
+    assert second is None
+
+
+async def test_claim_non_awaiting_returns_none() -> None:
+    repo: JobRepo = _repo()
+    job = await repo.create(PROJECT, KIND)  # queued（非 awaiting）
+    assert await repo.claim_awaiting_to_running(job.id) is None
+
+
+async def test_claim_absent_job_returns_none() -> None:
+    repo: JobRepo = _repo()
+    assert await repo.claim_awaiting_to_running(uuid.uuid4()) is None
+
+
 # ---- progress (clamped) ----
 
 

packages/core/tests/test_orchestrator.py

@@ -8,15 +8,11 @@ from __future__ import annotations
 import uuid
 
 from fakes_orchestrator import FakeStreamGateway, RaisingGateway
-from langchain_core.runnables import RunnableConfig
-from langgraph.checkpoint.memory import MemorySaver
 from ww_core.orchestrator import (
     EVENT_DONE,
     EVENT_ERROR,
     EVENT_TOKEN,
-    WRITE_NODE,
     ChapterState,
-    build_write_graph,
     build_write_request,
     normalize_deltas,
     stream_chapter_draft,
@@ -135,31 +131,5 @@ async def test_normalize_deltas_maps_unexpected_error_to_internal() -> None:
     assert events[0].data["code"] == ErrorCode.INTERNAL
 
 
-# ---- 图编译：装节点 + checkpointer（MemorySaver，不连真 Postgres） ----
+# 单 `write` 节点图 `build_write_graph` 已删（链图取代，见 chain-workflow 设计 §3.3）；
-
+# write 节点本体 `write_node` 仍由上面的 stream/run 用例直接覆盖（注入 mock 网关，无需图运行时）。
-
-def test_build_write_graph_compiles_with_checkpointer() -> None:
-    gateway = FakeStreamGateway(["x"])
-
-    graph = build_write_graph(gateway, checkpointer=MemorySaver())
-
-    assert WRITE_NODE in graph.get_graph().nodes
-    assert graph.checkpointer is not None
-
-
-async def test_compiled_graph_runs_write_node_end_to_end() -> None:
-    gateway = FakeStreamGateway(["云", "深"])
-    graph = build_write_graph(gateway, checkpointer=MemorySaver())
-    config: RunnableConfig = {"configurable": {"thread_id": "t-1"}}
-    initial: ChapterState = {
-        "project_id": PROJECT,
-        "chapter_no": 1,
-        "user_id": USER,
-        "stable_core": STABLE,
-        "volatile": VOLATILE,
-        "draft": "",
-    }
-
-    final = await graph.ainvoke(initial, config=config)
-
-    assert final["draft"] == "云深"

packages/core/ww_core/domain/job_repo.py

@@ -28,6 +28,8 @@ STATUS_QUEUED = "queued"
 STATUS_RUNNING = "running"
 STATUS_DONE = "done"
 STATUS_FAILED = "failed"
+# 多章链 interrupt 命中：暂停等作者裁决（chain-workflow §7，零迁移复用 jobs.status 自由 Text 列）。
+STATUS_AWAITING = "awaiting_input"
 PROGRESS_COMPLETE = 100
 
 
@@ -37,6 +39,7 @@ class JobView(BaseModel):
     model_config = {"frozen": True}
 
     id: uuid.UUID
+    project_id: uuid.UUID | None = None
     kind: str
     status: str
     progress: int = 0
@@ -63,6 +66,15 @@ class JobRepo(Protocol):
         """置 status=done, progress=100, result=<dict>。"""
         ...
 
+    async def set_awaiting(self, job_id: uuid.UUID, result: dict[str, Any]) -> JobView:
+        """置 status=awaiting_input, result=<dict>（多章链 interrupt 暂停等裁决；chain §5/§7）。"""
+        ...
+
+    async def claim_awaiting_to_running(self, job_id: uuid.UUID) -> JobView | None:
+        """**原子**抢占 awaiting_input → running，返回抢到的 JobView；未抢到（不存在/非
+        awaiting/已被并发抢走）返 None。供 resume 端点防并发 resume 竞态（chain §3/审评 #3）。"""
+        ...
+
     async def fail(self, job_id: uuid.UUID, error: str) -> JobView:
         """置 status=failed, error=<str>。"""
         ...
@@ -79,6 +91,7 @@ class JobRepo(Protocol):
 def _to_view(row: Job) -> JobView:
     return JobView(
         id=row.id,
+        project_id=row.project_id,
         kind=row.kind,
         status=row.status,
         progress=row.progress,
@@ -144,6 +157,42 @@ class SqlJobRepo:
         await self._s.refresh(row)
         return _to_view(row)
 
+    async def set_awaiting(self, job_id: uuid.UUID, result: dict[str, Any]) -> JobView:
+        row = await self._require(job_id)
+        row.status = STATUS_AWAITING
+        row.result = dict(result)
+        await self._s.flush()
+        await self._s.refresh(row)
+        return _to_view(row)
+
+    async def claim_awaiting_to_running(self, job_id: uuid.UUID) -> JobView | None:
+        """原子 `awaiting_input → running`（条件 UPDATE，returning 行）。
+
+        防并发 resume 竞态（审评 #3）：两个并发 resume 仅一个能把 awaiting→running，另一个
+        UPDATE 命中 0 行 → 返 None（端点据此返 409）。避免「两个 resume 都过 awaiting 守卫 →
+        同 thread_id 双 `Command(resume=...)` → 图损坏」。提交交调用方（端点事务）。
+        """
+        result = await self._s.execute(
+            update(Job)
+            .where(Job.id == job_id, Job.status == STATUS_AWAITING)
+            .values(status=STATUS_RUNNING)
+            .returning(
+                Job.id, Job.project_id, Job.kind, Job.status, Job.progress, Job.result, Job.error
+            )
+        )
+        row = result.one_or_none()
+        if row is None:
+            return None
+        return JobView(
+            id=row.id,
+            project_id=row.project_id,
+            kind=row.kind,
+            status=row.status,
+            progress=row.progress,
+            result=row.result,
+            error=row.error,
+        )
+
     async def fail(self, job_id: uuid.UUID, error: str) -> JobView:
         row = await self._require(job_id)
         row.status = STATUS_FAILED

packages/core/ww_core/orchestrator/__init__.py

@@ -1,6 +1,6 @@
 """编排器（C4 / ARCH §5.2）——写章图 + 审稿子图 + SSE 归一 + Postgres checkpointer。
 
-- M1：单 `write` 节点（`build_write_graph`）。
+- write 节点本体 `write_node`（被多章链 `chain` 复用；M1 单节点图 `build_write_graph` 已删）。
 - M2：并行审子图（`build_review_graph`：START→各审并行→collect 落 `chapter_reviews`）+
   审稿 SSE（`section`/`conflict` 事件 + `normalize_review`）。
 - accept（验收事务/`interrupt_before`）不在本图——属 T2.4（确定性代码读领域表，R3）。
@@ -37,7 +37,6 @@ from .graph import (
     REVIEW_SPECS,
     WRITE_NODE,
     build_review_graph,
-    build_write_graph,
     setup_checkpointer,
 )
 from .outline_node import build_outline_request, run_outline
@@ -115,7 +114,6 @@ __all__ = [
     "build_review_request",
     "build_style_extract_request",
     "build_worldbuilder_context",
-    "build_write_graph",
     "build_write_request",
     "collect_reviews",
     "conflict_event",

packages/core/ww_core/orchestrator/chain/__init__.py

@@ -0,0 +1,56 @@
+"""多章工作流链（chain-workflow 设计）——`write → review → decide → accept` 有环图。
+
+第一个真正需要 LangGraph 的场景（有环 + 可持久 + 可中断）：批量量产 K 章，每章过
+`assemble → write → 四审 → digest` 闭环，遇冲突 `interrupt()` 暂停交人裁决，resume 续跑。
+激活休眠资产（checkpointer + interrupt）。详见 docs/design/chain-workflow.md。
+"""
+
+from __future__ import annotations
+
+from .graph import (
+    ACCEPT_CHAPTER,
+    DECIDE,
+    REVIEW_CHAPTER,
+    WRITE_CHAPTER,
+    build_chain_graph,
+    initial_chain_state,
+)
+from .nodes import (
+    AcceptChapterOp,
+    AssembleContext,
+    AssembleFn,
+    ChapterDraftRepo,
+    GatewayBuilder,
+    MemoryReposFactory,
+    ReviewRecordRepo,
+    SessionFactory,
+    accept_chapter,
+    decide,
+    has_conflicts,
+    review_chapter,
+    write_chapter,
+)
+from .state import ChainState
+
+__all__ = [
+    "ACCEPT_CHAPTER",
+    "DECIDE",
+    "REVIEW_CHAPTER",
+    "WRITE_CHAPTER",
+    "AcceptChapterOp",
+    "AssembleContext",
+    "AssembleFn",
+    "ChainState",
+    "ChapterDraftRepo",
+    "GatewayBuilder",
+    "MemoryReposFactory",
+    "ReviewRecordRepo",
+    "SessionFactory",
+    "accept_chapter",
+    "build_chain_graph",
+    "decide",
+    "has_conflicts",
+    "initial_chain_state",
+    "review_chapter",
+    "write_chapter",
+]

packages/core/ww_core/orchestrator/chain/graph.py

@@ -0,0 +1,172 @@
+"""多章链图工厂 `build_chain_graph`（chain-workflow 设计 §3.3）。
+
+链 = LangGraph 有环图：`write → review → decide →(无冲突)→ accept →(还有章)→ write`，
+`decide →(有冲突)→ interrupt ⏸ → accept`，写满 K 章 → END。本图**激活休眠资产**：
+checkpointer（持久控制流 + pending handle，跨小时可恢复）+ interrupt（遇冲突暂停交人）。
+
+依赖注入纪律（与现有「gateway 闭包绑定」同模式）：节点 DB 依赖经 `session_factory` +
+`*_repo_factory` + `accept_op` 闭包绑入图节点。langgraph 不收 `functools.partial`，故用
+**默认参绑定**（见 memory/gotchas.md）。
+
+checkpointer 纪律（CLAUDE.md「LangGraph」）：`setup()` 只在 migrations/CI 跑（`setup_checkpointer`
+在 `orchestrator/graph.py`，迁移/CI 调一次），build 函数绝不触碰 DDL；单测注 `MemorySaver`。
+"""
+
+from __future__ import annotations
+
+import uuid
+from collections.abc import Callable, Sequence
+from typing import TYPE_CHECKING, Any
+
+from langgraph.graph import END, START, StateGraph
+from langgraph.types import interrupt
+from ww_agents import AgentSpec
+
+from ..graph import REVIEW_SPECS
+from . import nodes
+from .nodes import (
+    AcceptChapterOp,
+    AssembleFn,
+    ChapterDraftRepo,
+    GatewayBuilder,
+    MemoryReposFactory,
+    ReviewRecordRepo,
+    SessionFactory,
+)
+from .state import ChainState
+
+if TYPE_CHECKING:
+    from langgraph.checkpoint.base import BaseCheckpointSaver
+    from langgraph.graph.state import CompiledStateGraph
+
+WRITE_CHAPTER = "write_chapter"
+REVIEW_CHAPTER = "review_chapter"
+DECIDE = "decide"
+ACCEPT_CHAPTER = "accept_chapter"
+
+
+def build_chain_graph(
+    gateway_builder: GatewayBuilder,
+    *,
+    session_factory: SessionFactory,
+    memory_repos_factory: MemoryReposFactory,
+    chapter_repo_factory: Callable[[Any], ChapterDraftRepo],
+    review_repo_factory: Callable[[Any], ReviewRecordRepo],
+    assemble: AssembleFn,
+    accept_op: AcceptChapterOp,
+    review_specs: Sequence[AgentSpec] = REVIEW_SPECS,
+    checkpointer: BaseCheckpointSaver[Any] | None = None,
+) -> CompiledStateGraph[ChainState, None, ChainState, ChainState]:
+    """构建并编译 `draft_volume` 多章链图。
+
+    节点（`write_chapter`/`review_chapter`/`decide`/`accept_chapter`）经默认参绑定把
+    `gateway_builder`/`session_factory`/各 repo 工厂/`assemble`/`accept_op` 闭包绑入。
+    `gateway_builder` 而非具体网关实例：write/review 节点在自建 session 上现建网关，使
+    usage_ledger 绑节点 session（不变量 #1，修复请求网关 session 已关闭致记账丢失的缺陷）。
+    条件边：`decide` 命中冲突 → `accept_chapter` 内 `interrupt()` 暂停交人；
+    `accept_chapter` 后判 `current_chapter_no <= last_chapter_no` 回 `write_chapter` 或 END。
+
+    `checkpointer`：运行时传 Postgres saver；单测传 `MemorySaver`（同进程跨 invoke 可恢复）。
+    """
+
+    async def _write(state: ChainState) -> dict[str, Any]:
+        return await nodes.write_chapter(
+            state,
+            gateway_builder=gateway_builder,
+            session_factory=session_factory,
+            memory_repos_factory=memory_repos_factory,
+            chapter_repo_factory=chapter_repo_factory,
+            assemble=assemble,
+        )
+
+    async def _review(state: ChainState) -> dict[str, Any]:
+        return await nodes.review_chapter(
+            state,
+            gateway_builder=gateway_builder,
+            session_factory=session_factory,
+            memory_repos_factory=memory_repos_factory,
+            chapter_repo_factory=chapter_repo_factory,
+            review_repo_factory=review_repo_factory,
+            assemble=assemble,
+            review_specs=review_specs,
+        )
+
+    async def _decide(state: ChainState) -> dict[str, Any]:
+        return await nodes.decide(
+            state,
+            session_factory=session_factory,
+            review_repo_factory=review_repo_factory,
+        )
+
+    async def _accept(state: ChainState) -> dict[str, Any]:
+        # interrupt 放节点**起始**（CLAUDE.md「LangGraph」）：有冲突 → 暂停交人，恢复值 =
+        # 该章裁决清单；无冲突 → decisions=[]，直接验收。恢复后 accept_op 落库（不变量 #3）。
+        decisions: list[Any] = []
+        if nodes.has_conflicts(state):
+            resumed = interrupt({"chapter_no": state["current_chapter_no"]})
+            decisions = list(resumed or [])
+        return await nodes.accept_chapter(state, decisions=decisions, accept_op=accept_op)
+
+    builder: StateGraph[ChainState, None, ChainState, ChainState] = StateGraph(ChainState)
+    builder.add_node(WRITE_CHAPTER, _write)
+    builder.add_node(REVIEW_CHAPTER, _review)
+    builder.add_node(DECIDE, _decide)
+    builder.add_node(ACCEPT_CHAPTER, _accept)
+
+    builder.add_edge(START, WRITE_CHAPTER)
+    builder.add_edge(WRITE_CHAPTER, REVIEW_CHAPTER)
+    builder.add_edge(REVIEW_CHAPTER, DECIDE)
+    # decide 后无论有无冲突都进 accept；interrupt（若有冲突）在 accept 节点起始处暂停。
+    builder.add_edge(DECIDE, ACCEPT_CHAPTER)
+    # accept 后条件边：还有章 → 回 write 续跑；写满 K 章 → END。
+    builder.add_conditional_edges(
+        ACCEPT_CHAPTER,
+        _should_continue,
+        {WRITE_CHAPTER: WRITE_CHAPTER, END: END},
+    )
+    return builder.compile(checkpointer=checkpointer)
+
+
+def _should_continue(state: ChainState) -> str:
+    """accept 后路由：`current_chapter_no <= last_chapter_no` → 续写下一章；否则 END。
+
+    `accept_chapter` 已把 `current_chapter_no += 1`，故此处直接比较即判「是否还有章」。
+    纯函数，便于单测。
+    """
+    if state["current_chapter_no"] <= state["last_chapter_no"]:
+        return WRITE_CHAPTER
+    return END
+
+
+def initial_chain_state(
+    *,
+    project_id: uuid.UUID,
+    user_id: uuid.UUID,
+    start_chapter_no: int,
+    count: int,
+    chain_key: str = "draft_volume",
+) -> ChainState:
+    """构造初始 `ChainState`（区间 [start, start+count-1]，current=start，written=[]）。
+
+    纯函数：服务层 / 测试构初值用，集中区间换算（last = start + count - 1，含）。
+    """
+    return {
+        "project_id": project_id,
+        "user_id": user_id,
+        "chain_key": chain_key,
+        "start_chapter_no": start_chapter_no,
+        "last_chapter_no": start_chapter_no + count - 1,
+        "current_chapter_no": start_chapter_no,
+        "written": [],
+        "has_conflicts": False,
+    }
+
+
+__all__ = [
+    "ACCEPT_CHAPTER",
+    "DECIDE",
+    "REVIEW_CHAPTER",
+    "WRITE_CHAPTER",
+    "build_chain_graph",
+    "initial_chain_state",
+]

packages/core/ww_core/orchestrator/chain/nodes.py

@@ -0,0 +1,324 @@
+"""多章链节点（chain-workflow 设计 §3.2）——write → review → decide → accept 循环。
+
+节点是**小确定性单元**：LLM 非确定性锁在网关后；`decide` 是纯逻辑。每个做 DB IO 的
+节点用**短事务、独立 session**（每章 accept 原子提交，仿 `run_overdue_scan` 自建 session）。
+checkpoint 只存控制流，正文/审稿落领域表——resume 时重读领域表为真相（不变量 #1/#3/#5）。
+
+依赖注入：本模块的节点是裸异步函数（显式关键字依赖），供直接单测注入 fake；图工厂
+（`graph.py`）用默认参绑定把依赖闭包绑进图节点（langgraph 不收 functools.partial，见 gotcha）。
+"""
+
+from __future__ import annotations
+
+import uuid
+from collections.abc import Awaitable, Callable, Sequence
+from contextlib import AbstractAsyncContextManager
+from typing import Any, Protocol
+
+import structlog
+from ww_agents import AgentSpec
+
+from .._protocols import GatewayRun
+from ..collect import collect_reviews
+from ..review_node import build_review_context, run_review
+from ..state import ChapterState
+from ..write_node import build_write_request
+from .state import ChainState
+
+log = structlog.get_logger(__name__)
+
+# ---- 注入缝（图工厂经默认参绑定，单测直接注 fake）----
+
+#: `session -> Repo`：节点自建短事务里从 session 造 repo（仿端点依赖工厂）。
+SessionFactory = Callable[[], AbstractAsyncContextManager[Any]]
+
+#: `session -> Gateway`：按**节点当前 session** 建网关（不变量 #1）。
+#: 关键：网关的 ledger sink 绑节点 session，节点末尾 `commit()` 一并持久 usage_ledger 行——
+#: 绝不能复用请求阶段建好的网关（其 session 在 BackgroundTask 跑时已关闭，记账行会被静默丢弃）。
+GatewayBuilder = Callable[[Any], Awaitable[GatewayRun]]
+
+
+class AssembleContext(Protocol):
+    """`assemble` 产出的最小读形——只需 stable_core/volatile（构造写章/审稿请求）。"""
+
+    stable_core: str
+    volatile: str
+
+
+#: `(repos, project_id, chapter_no) -> AssembledContext`：组装记忆（确定性，不变量 #6/#9）。
+AssembleFn = Callable[[Any, uuid.UUID, int], Awaitable[AssembleContext]]
+
+
+class MemoryReposFactory(Protocol):
+    """`session -> MemoryRepos`（assemble 所需 8 repo 捆绑）。"""
+
+    def __call__(self, session: Any) -> Any: ...
+
+
+class DraftView(Protocol):
+    """章草稿读形最小依赖——只需 `content`（重读正文构审稿上下文）。"""
+
+    content: str
+
+
+class ChapterDraftRepo(Protocol):
+    """章草稿 repo 最小依赖：write 落稿 `save_draft` + review 重读 `get_draft`（只 flush）。"""
+
+    async def save_draft(
+        self, project_id: uuid.UUID, chapter_no: int, *, text: str, volume: int = 1
+    ) -> Any: ...
+
+    async def get_draft(self, project_id: uuid.UUID, chapter_no: int) -> DraftView | None: ...
+
+
+class ReviewRecordRepo(Protocol):
+    """review/accept 节点对审稿 repo 的最小依赖：collect 留痕 + accept 重读最近审稿。"""
+
+    async def record(
+        self,
+        project_id: uuid.UUID,
+        chapter_no: int,
+        *,
+        chapter_version: int | None = None,
+        conflicts: list[dict[str, Any]],
+        foreshadow_sug: list[dict[str, Any]] | None = None,
+        style: dict[str, Any] | None = None,
+        pace: dict[str, Any] | None = None,
+        health_score: int | None = None,
+    ) -> Any: ...
+
+    async def list_for_chapter(self, project_id: uuid.UUID, chapter_no: int) -> list[Any]: ...
+
+
+class CommitSession(Protocol):
+    """节点短事务对 session 的最小依赖——只需 `commit()`（write/review 节点末尾提交）。"""
+
+    async def commit(self) -> None: ...
+
+
+#: accept 步：把作者裁决落库（晋升终稿 + digest + 裁决留痕 + 伏笔到期），各自独立 session。
+#: 编排（链）在 core；具体验收事务（apps/api）经此闭包注入，守目录所有权 + 不变量 #3/#4。
+#: 入参 `decisions` 为裁决清单（`accept_chapter` 节点经 interrupt 恢复值拿到，无冲突=[]）。
+AcceptChapterOp = Callable[..., Awaitable[None]]
+
+
+# ---- 节点本体（裸函数，显式依赖；图工厂绑定闭包）----
+
+
+async def write_chapter(
+    state: ChainState,
+    *,
+    gateway_builder: GatewayBuilder,
+    session_factory: SessionFactory,
+    memory_repos_factory: MemoryReposFactory,
+    chapter_repo_factory: Callable[[Any], ChapterDraftRepo],
+    assemble: AssembleFn,
+) -> dict[str, Any]:
+    """write 节点：组装记忆 → 收集版写章（非 SSE）→ 落 `chapters` draft → commit。
+
+    短事务、独立 session（不跨章共享）。state 不变（正文在 DB）。返回空增量。
+    收集版写章复用 `build_write_request` 同一 prompt 组装路径（stream=False → `gateway.run`），
+    守不变量 #9（stable_core 进缓存前缀）；不确定性锁在网关后，注 mock 即可单测。
+
+    网关经 `gateway_builder(session)` 按**本节点 session** 现建（不变量 #1）：其 ledger sink
+    绑此 session，末尾 `commit()` 一并持久 usage_ledger——绝不复用请求阶段已关闭 session 的网关。
+    """
+    project_id = state["project_id"]
+    chapter_no = state["current_chapter_no"]
+    user_id = state["user_id"]
+    async with session_factory() as session:
+        gateway = await gateway_builder(session)
+        repos = memory_repos_factory(session)
+        context = await assemble(repos, project_id, chapter_no)
+        req = build_write_request(
+            stable_core=context.stable_core,
+            volatile=context.volatile,
+            user_id=user_id,
+            project_id=project_id,
+        )
+        # 收集版：非流式，一次 run 拿全文（链批量量产不走 SSE）。
+        collect_req = req.model_copy(update={"stream": False})
+        resp = await gateway.run(collect_req)
+        chapter_repo = chapter_repo_factory(session)
+        await chapter_repo.save_draft(project_id, chapter_no, text=resp.text)
+        await _commit(session)
+    log.info(
+        "chain_write_chapter",
+        project_id=str(project_id),
+        chapter_no=chapter_no,
+        draft_len=len(resp.text),
+    )
+    return {}
+
+
+async def review_chapter(
+    state: ChainState,
+    *,
+    gateway_builder: GatewayBuilder,
+    session_factory: SessionFactory,
+    memory_repos_factory: MemoryReposFactory,
+    chapter_repo_factory: Callable[[Any], ChapterDraftRepo],
+    review_repo_factory: Callable[[Any], ReviewRecordRepo],
+    assemble: AssembleFn,
+    review_specs: Sequence[AgentSpec],
+) -> dict[str, Any]:
+    """review 节点：复用四审 → 落 `chapter_reviews` 留痕（不变量 #3 只读、不写正文）→ commit。
+
+    复用现有 `run_review × specs` + `collect_reviews`（直接顺序跑各审，非起子图——链节点本身
+    已是图节点，无需嵌套图）。从 DB 重读本章草稿构审稿上下文（真相在表，不信 state）。
+
+    网关经 `gateway_builder(session)` 按**本节点 session** 现建（不变量 #1）：四审各调的
+    usage_ledger 行随节点末尾 `commit()` 一并持久——绝不复用请求阶段已关闭 session 的网关。
+    """
+    project_id = state["project_id"]
+    chapter_no = state["current_chapter_no"]
+    user_id = state["user_id"]
+    async with session_factory() as session:
+        gateway = await gateway_builder(session)
+        repos = memory_repos_factory(session)
+        context = await assemble(repos, project_id, chapter_no)
+        chapter_repo = chapter_repo_factory(session)
+        draft_view = await _read_draft(chapter_repo, project_id, chapter_no)
+        review_context = build_review_context(
+            draft=draft_view,
+            stable_core=context.stable_core,
+            volatile=context.volatile,
+        )
+        review_state: ChapterState = {
+            "project_id": project_id,
+            "chapter_no": chapter_no,
+            "user_id": user_id,
+            "review_context": review_context,
+        }
+        reviews: dict[str, Any] = {}
+        for spec in review_specs:
+            part = await run_review(spec, review_state, gateway=gateway)
+            reviews.update(part.get("reviews", {}))
+        review_state["reviews"] = reviews
+        review_repo = review_repo_factory(session)
+        await collect_reviews(review_state, review_repo=review_repo)
+        await _commit(session)
+    log.info(
+        "chain_review_chapter",
+        project_id=str(project_id),
+        chapter_no=chapter_no,
+        reviews=sorted(reviews.keys()),
+    )
+    return {}
+
+
+async def decide(
+    state: ChainState,
+    *,
+    session_factory: SessionFactory,
+    review_repo_factory: Callable[[Any], ReviewRecordRepo],
+) -> dict[str, Any]:
+    """decide 节点（确定性纯逻辑，无 LLM）：读最近审稿留痕 → `has_conflicts`。
+
+    冲突明文**不入** state（不变量 #5）；只写控制流标志，accept 时再从领域表重读冲突。
+    """
+    project_id = state["project_id"]
+    chapter_no = state["current_chapter_no"]
+    async with session_factory() as session:
+        review_repo = review_repo_factory(session)
+        history = await review_repo.list_for_chapter(project_id, chapter_no)
+    latest = history[0] if history else None
+    conflicts = _conflicts_of(latest)
+    has_conflicts = len(conflicts) > 0
+    log.info(
+        "chain_decide",
+        project_id=str(project_id),
+        chapter_no=chapter_no,
+        has_conflicts=has_conflicts,
+        conflict_count=len(conflicts),
+    )
+    return {"has_conflicts": has_conflicts}
+
+
+async def accept_chapter(
+    state: ChainState,
+    *,
+    decisions: list[Any],
+    accept_op: AcceptChapterOp,
+) -> dict[str, Any]:
+    """accept 节点：用裁决落库（晋升终稿 + digest + 裁决留痕 + 伏笔到期），推进章号。
+
+    具体验收事务（重读 `chapter_reviews`、`assert_conflicts_resolved` gate、终稿提炼 digest、
+    `run_accept_transaction`、`run_overdue_scan`）属 apps/api，经 `accept_op` 闭包注入——守目录
+    所有权 + 不变量 #3/#4（缺判 → `CONFLICT_UNRESOLVED` 由 op 抛，链失败）。
+
+    `decisions`：无冲突章 = []；有冲突章 = interrupt 恢复值（作者裁决清单）。
+    返回 `current_chapter_no += 1` + `written` 追加本章——推进控制流（不可变增量）。
+    """
+    project_id = state["project_id"]
+    chapter_no = state["current_chapter_no"]
+    user_id = state["user_id"]
+    await accept_op(
+        project_id=project_id,
+        chapter_no=chapter_no,
+        user_id=user_id,
+        decisions=decisions,
+    )
+    written = list(state.get("written") or [])
+    written.append(chapter_no)
+    log.info(
+        "chain_accept_chapter",
+        project_id=str(project_id),
+        chapter_no=chapter_no,
+        written_count=len(written),
+    )
+    return {
+        "current_chapter_no": chapter_no + 1,
+        "written": written,
+        "has_conflicts": False,
+    }
+
+
+# ---- 辅助（纯函数 / 小工具）----
+
+
+def _conflicts_of(latest_review: Any) -> list[dict[str, Any]]:
+    """从最近审稿留痕取冲突清单（兼容 ReviewView Pydantic 与内存 fake dict）。"""
+    if latest_review is None:
+        return []
+    conflicts = getattr(latest_review, "conflicts", None)
+    if conflicts is None and isinstance(latest_review, dict):
+        conflicts = latest_review.get("conflicts")
+    return list(conflicts or [])
+
+
+async def _read_draft(
+    chapter_repo: ChapterDraftRepo, project_id: uuid.UUID, chapter_no: int
+) -> str:
+    """从 repo 重读本章草稿正文（真相在表，不信 state）。"""
+    view = await chapter_repo.get_draft(project_id, chapter_no)
+    return view.content if view is not None else ""
+
+
+async def _commit(session: CommitSession) -> None:
+    """提交短事务（session 满足 `CommitSession`：只需 `commit()`）。"""
+    await session.commit()
+
+
+# decide 暴露给条件边的辅助（纯判定，便于单测）。
+def has_conflicts(state: ChainState) -> bool:
+    """条件边读 state 的冲突标志（缺省 False）。"""
+    return bool(state.get("has_conflicts"))
+
+
+__all__ = [
+    "AcceptChapterOp",
+    "AssembleContext",
+    "AssembleFn",
+    "ChainState",
+    "ChapterDraftRepo",
+    "MemoryReposFactory",
+    "ReviewRecordRepo",
+    "SessionFactory",
+    "GatewayBuilder",
+    "accept_chapter",
+    "decide",
+    "has_conflicts",
+    "review_chapter",
+    "write_chapter",
+]

packages/core/ww_core/orchestrator/chain/state.py

@@ -0,0 +1,36 @@
+"""多章工作流链状态 `ChainState`（chain-workflow 设计 §3.1）。
+
+不变量 #5：langgraph 检查点 = state 内容，**只放控制流**——章号/计数/已验收清单/
+冲突标志。草稿正文/上下文/冲突明文**不进** state（落 `chapters`/`chapter_reviews`，
+resume 时从领域表重读为真相）。
+
+`ChainState` 用 TypedDict（LangGraph 原生状态形态），字段全 snake_case。
+"""
+
+from __future__ import annotations
+
+import uuid
+from typing import TypedDict
+
+
+class ChainState(TypedDict, total=False):
+    """`draft_volume` 链的控制流状态（检查点内容）。
+
+    - `project_id` / `user_id`：定位 + 调用作用域（原型单用户 stub）。
+    - `chain_key`：固定 `"draft_volume"`（本期唯一内置链）。
+    - `start_chapter_no` / `last_chapter_no`：本 run 区间 [start, last]（含）。
+    - `current_chapter_no`：当前处理章；初值 = start，每验收一章 +1。
+    - `written`：本 run 已验收章号（进度来源；resume 后累积）。
+    - `has_conflicts`：`decide` 节点写入的控制流标志（不存冲突明文，不变量 #5）。
+
+    `total=False`：初始 invoke 只需填区间字段，`written`/`has_conflicts` 由节点逐步填。
+    """
+
+    project_id: uuid.UUID
+    user_id: uuid.UUID
+    chain_key: str
+    start_chapter_no: int
+    last_chapter_no: int
+    current_chapter_no: int
+    written: list[int]
+    has_conflicts: bool

packages/core/ww_core/orchestrator/graph.py

@@ -27,37 +27,17 @@ from ._protocols import GatewayRun
 from .collect import ReviewRecorder, collect_reviews
 from .review_node import run_review
 from .state import ChapterState
-from .write_node import GatewayStream, write_node
 
 if TYPE_CHECKING:
     from langgraph.checkpoint.base import BaseCheckpointSaver
     from langgraph.graph.state import CompiledStateGraph
 
+# write 节点名（write_node 本体保留，被多章链 `chain.nodes.write_chapter` 复用；M1 的
+# `build_write_graph` 单节点图已删——链图取代之，YAGNI，见 chain-workflow 设计 §3.3）。
 WRITE_NODE = "write"
 COLLECT_NODE = "collect"
 
 
-def build_write_graph(
-    gateway: GatewayStream,
-    *,
-    checkpointer: BaseCheckpointSaver[Any] | None = None,
-) -> CompiledStateGraph[ChapterState, None, ChapterState, ChapterState]:
-    """构建并编译单 `write` 节点图。
-
-    `gateway` 经闭包绑进节点（节点对图只暴露 `(state)->dict`，确定性可单测）。
-    `checkpointer`：运行时传 Postgres saver；单测传 `MemorySaver` 或不传。
-    """
-
-    async def _write(state: ChapterState) -> dict[str, str]:
-        return await write_node(state, gateway=gateway)
-
-    builder: StateGraph[ChapterState, None, ChapterState, ChapterState] = StateGraph(ChapterState)
-    builder.add_node(WRITE_NODE, _write)
-    builder.add_edge(START, WRITE_NODE)
-    builder.add_edge(WRITE_NODE, END)
-    return builder.compile(checkpointer=checkpointer)
-
-
 # M4：四审齐（continuity + foreshadow + pace + style）。第四审 = 文风漂移打分轨。
 REVIEW_SPECS: tuple[AgentSpec, ...] = (
     continuity_spec,

packages/db/migrations/env.py

@@ -20,9 +20,27 @@ if config.config_file_name is not None:
 config.set_main_option("sqlalchemy.url", get_settings().database_url)
 target_metadata = Base.metadata
 
+# langgraph 检查点表由 langgraph 自管 schema（迁移 d3e4f5a6b7c8 调其 setup() 建表），
+# 不在 Base.metadata。autogenerate/check 须忽略它们，否则会误报"待 drop"漂移。
+_LANGGRAPH_TABLES = frozenset(
+    {"checkpoints", "checkpoint_blobs", "checkpoint_writes", "checkpoint_migrations"}
+)
+
+
+def include_object(
+    obj: object, name: str | None, type_: str, reflected: bool, compare_to: object
+) -> bool:
+    if type_ == "table" and name in _LANGGRAPH_TABLES:
+        return False
+    return True
+
 
 def do_run_migrations(connection: Connection) -> None:
-    context.configure(connection=connection, target_metadata=target_metadata)
+    context.configure(
+        connection=connection,
+        target_metadata=target_metadata,
+        include_object=include_object,
+    )
     with context.begin_transaction():
         context.run_migrations()
 

packages/db/migrations/versions/d3e4f5a6b7c8_langgraph_checkpoint_setup.py

@@ -0,0 +1,75 @@
+"""langgraph checkpoint setup (multi-chapter chain workflow)
+
+Revision ID: d3e4f5a6b7c8
+Revises: c2b3d4e5f6a7
+Create Date: 2026-06-23 10:00:00.000000
+
+多章工作流链（docs/design/chain-workflow.md §4/§7）唯一新增 DDL：langgraph
+检查点表（`checkpoints` / `checkpoint_blobs` / `checkpoint_writes` /
+`checkpoint_migrations`）。这些表**不在** ``Base.metadata``（由 langgraph 自己
+管理 schema），故迁移直接调用 langgraph 的一次性 ``setup()`` 建表，而非 ORM
+``op.create_table``。env.py 的 ``include_object`` 过滤这些表，避免 ``alembic
+check`` 误报漂移（要 drop 这些"非 metadata"表）。
+
+实现说明（CLAUDE.md「LangGraph」+ 设计 §11 回退）：
+- DDL 只在 **migrations/CI** 跑（绝不在 app-runtime）——本迁移即该入口。
+- ``upgrade()`` 跑在 alembic 的**同步**迁移上下文里（``connection.run_sync``
+  下已有 event loop 在跑 async 迁移），故**不能**调 async ``setup_checkpointer``
+  /``asyncio.run``（会嵌套 loop 报错）。改用 langgraph 同步 ``PostgresSaver``
+  （psycopg），用一条从 ``database_url`` 派生的 psycopg conn string 自建连接，
+  与 alembic 的 asyncpg 连接解耦。``setup()`` 幂等（langgraph 内部 migration 版本表）。
+- **关键**：langgraph ``setup()`` 跑 ``CREATE INDEX CONCURRENTLY``，它不能在
+  事务块内执行，且会等 alembic 那条仍开着事务（持 ``alembic_version`` 锁）的连接
+  → 死锁（§11 风险落地）。故用 ``op.get_context().autocommit_block()`` 把 alembic
+  的事务先提交、退出事务块，再让 langgraph 在独立 autocommit 连接里建表/建索引。
+
+jobs 表：C2 判定零迁移复用（用 ``result.awaiting_chapter`` 表达待裁决，
+``status`` 复用现有枚举），故本迁移不动 jobs。
+"""
+
+from __future__ import annotations
+
+from collections.abc import Sequence
+
+revision: str = "d3e4f5a6b7c8"
+down_revision: str | None = "c2b3d4e5f6a7"
+branch_labels: str | Sequence[str] | None = None
+depends_on: str | Sequence[str] | None = None
+
+# langgraph 检查点表（langgraph.checkpoint.postgres.base 的 MIGRATIONS 建的全部表）
+_CHECKPOINT_TABLES: tuple[str, ...] = (
+    "checkpoint_writes",
+    "checkpoint_blobs",
+    "checkpoints",
+    "checkpoint_migrations",
+)
+
+
+def _psycopg_conn_string() -> str:
+    """从 settings.database_url 派生 psycopg（同步）conn string。
+
+    settings 用 asyncpg URL（``postgresql+asyncpg://…``）；langgraph 的同步
+    ``PostgresSaver`` 走 psycopg，需去掉 SQLAlchemy 的 ``+asyncpg`` 驱动后缀。
+    """
+    from ww_config import get_settings
+
+    return get_settings().database_url.replace("+asyncpg", "")
+
+
+def upgrade() -> None:
+    from alembic import op
+    from langgraph.checkpoint.postgres import PostgresSaver
+
+    # 退出 alembic 事务块（提交 alembic_version 更新，释放其锁），langgraph 的
+    # CREATE INDEX CONCURRENTLY 才能在独立连接里跑而不死锁。
+    with op.get_context().autocommit_block():
+        with PostgresSaver.from_conn_string(_psycopg_conn_string()) as saver:
+            saver.setup()
+
+
+def downgrade() -> None:
+    import psycopg
+
+    with psycopg.connect(_psycopg_conn_string()) as conn:
+        conn.execute("DROP TABLE IF EXISTS " + ", ".join(_CHECKPOINT_TABLES) + " CASCADE")
+        conn.commit()

packages/shared/ww_shared/errors.py

@@ -8,6 +8,7 @@ from enum import StrEnum
 class ErrorCode(StrEnum):
     NOT_FOUND = "NOT_FOUND"
     VALIDATION = "VALIDATION"
+    CONFLICT = "CONFLICT"  # 资源状态冲突（如对非 awaiting 链 job 续跑）
     CONFLICT_UNRESOLVED = "CONFLICT_UNRESOLVED"  # 未决冲突禁验收
     LLM_UNAVAILABLE = "LLM_UNAVAILABLE"  # 回退耗尽
     RATE_LIMITED = "RATE_LIMITED"
@@ -18,6 +19,7 @@ class ErrorCode(StrEnum):
 HTTP_STATUS: dict[ErrorCode, int] = {
     ErrorCode.NOT_FOUND: 404,
     ErrorCode.VALIDATION: 422,
+    ErrorCode.CONFLICT: 409,
     ErrorCode.CONFLICT_UNRESOLVED: 409,
     ErrorCode.LLM_UNAVAILABLE: 503,
     ErrorCode.RATE_LIMITED: 429,

tests/test_chain_workflow_e2e.py

@@ -0,0 +1,461 @@
+"""C4 多章工作流链 端到端（chain-workflow §9 C4 / §10）——真 pg + mock 网关零 token。
+
+证明杀手锏闭环（不变量 #1/#3/#4/#5/#9）：批量量产，但每章过 `write→四审→decide→accept`，
+遇冲突 interrupt 交人裁决再 resume 续跑——星月架构做不到的一致性闸。
+
+  用例 1 · 两章无冲突全自动
+    `POST /projects` → `POST .../chains/draft_volume/run {start=1,count=2}` → 202 {job_id}；
+    BackgroundTask `run_chain_job` 自建独立 session 驱动链图（mock 网关零冲突）→ 两章
+    `write→四审(无冲突)→accept` 自动跑完。DB 真源逐项断言：
+      - `chapters` 第 1/2 章各一行 `accepted`（write 落 draft → accept 晋升终稿）；
+      - `chapter_digests` 两行（digest 从终稿提炼，不变量 #4）；
+      - `GET /jobs/{id}` status=done，result.written=[1,2]、completed=True、awaiting_chapter=None。
+    负向：job result/状态绝不含正文/prompt/token（§5）。
+
+  用例 2 · 注入冲突 → interrupt → awaiting → resume → accept
+    续审第 1 章报冲突 → `decide` 命中 → `accept` 节点 `interrupt()` 暂停 → job=awaiting_input、
+    result.awaiting_chapter=1、`chapters` 第 1 章仍 `draft`（未晋升）、`chapter_digests` 空。
+    `POST .../chains/runs/{job_id}/resume {decisions:[...]}` → 202 → resume 续跑 → accept →
+    job done、第 1 章 `accepted`、digest 一行。
+    interrupt+resume 横跨**两次端点调用**，靠单进程单 `MemorySaver`（经依赖覆盖注入
+    `get_checkpointer_factory` 的同一 saver 实例）持久控制流位置 + pending handle。
+
+确定性 & 零成本（同 M3/M4）：真 `Gateway` + 假适配器（据 `req.output_schema` 分支返固定
+parsed/text，绝不联网）+ 真 `SqlAlchemyLedgerSink`。检查点用 MemorySaver（绝不连真 Postgres
+检查点）。无 pg → skip。
+
+坑（见 memory/gotchas）：
+- `get_checkpointer_factory` 必 override 成产**同一** MemorySaver 的工厂——run 与 resume 两次
+  端点调用须落同一 thread_id 的同一检查点存储，否则 resume 找不到 interrupt 现场。
+- `get_session_factory` 必 override → `e2e_sm`（真 sessionmaker，同测试 engine/loop）；
+  BackgroundTask 在请求 session 关闭后才跑。
+- `get_digest_gateway_builder` 必 override → 返「按 session 建真 Gateway 包假适配器」的 builder
+  （链 accept 节点终稿提炼用 light 档），否则会从空凭据建真 OpenAI 适配器。
+- ASGITransport 下 `await client.post` 等 ASGI app（含 background task）跑完才返回。
+"""
+
+from __future__ import annotations
+
+import uuid
+from collections.abc import AsyncIterator, Awaitable, Callable
+from contextlib import AbstractAsyncContextManager, asynccontextmanager
+from typing import Annotated, Any
+
+import httpx
+import pytest
+from asgi_lifespan import LifespanManager
+from fastapi import Depends
+from langgraph.checkpoint.memory import MemorySaver
+from sqlalchemy import delete, select
+from sqlalchemy.ext.asyncio import AsyncSession, async_sessionmaker
+from ww_agents import (
+    Conflict,
+    ContinuityReview,
+    ForeshadowReview,
+    PaceReview,
+    StyleDriftReview,
+)
+from ww_api.services.digest_extraction import ChapterDigestFacts
+from ww_db import get_session, get_sessionmaker
+from ww_db.models import (
+    Chapter,
+    ChapterDigest,
+    ChapterReview,
+    Job,
+    Project,
+    UsageLedger,
+)
+from ww_llm_gateway import Gateway, SqlAlchemyLedgerSink, resolve_route
+from ww_llm_gateway.adapters.base import (
+    Capabilities,
+    ProviderResult,
+    ProviderUsage,
+    StreamChunk,
+)
+from ww_llm_gateway.types import LlmRequest
+
+# 三档（writer/analyst/light）默认都路由 deepseek（config.tier_defaults）。
+_PROVIDER = "deepseek"
+
+# 链写章收集版正文（非 SSE，经 gateway.run → adapter.complete，output_schema is None）。
+_CHAPTER_TEXT = "灵气如潮，少年握剑而立，山门之上风雷大作。"
+
+# 各档假用量（喂记账；证明各档调用各落一条 usage_ledger）。
+_USAGE = ProviderUsage(input_tokens=13, output_tokens=7)
+
+# 三审固定无冲突产物（让四审图跑通；continuity 的冲突由 fixture 参数注入）。
+_FORESHADOW_REVIEW = ForeshadowReview(planted=[], resolved=[])
+_PACE_REVIEW = PaceReview(water=[], hook=True, beat_map=[1, 2, 3])
+_STYLE_DRIFT = StyleDriftReview(score=88, segments=[])
+
+
+class _FakeChainAdapter:
+    """实现 `ProviderAdapter`：据 `req.output_schema` 分支返 parsed/text，绝不联网。
+
+    - `output_schema is None` → 链写章收集版纯文本（writer 档，`gateway.run`）。
+    - 四审 schema → 各审 parsed（continuity 注入冲突，其余无冲突）。
+    - `ChapterDigestFacts` → 终稿 digest 提炼（light 档）。
+    `stream()` 实现但链不走（收集版量产非 SSE）。
+    """
+
+    provider = _PROVIDER
+
+    def __init__(self, *, continuity_conflicts: list[Conflict]) -> None:
+        self._continuity = ContinuityReview(conflicts=continuity_conflicts)
+
+    def capabilities(self) -> Capabilities:
+        return Capabilities(structured_output=True)
+
+    async def complete(self, req: LlmRequest, model: str) -> ProviderResult:
+        schema = req.output_schema
+        if schema is None:
+            return ProviderResult(text=_CHAPTER_TEXT, parsed=None, usage=_USAGE)
+        if schema is ContinuityReview:
+            return ProviderResult(
+                text=self._continuity.model_dump_json(), parsed=self._continuity, usage=_USAGE
+            )
+        if schema is ForeshadowReview:
+            return ProviderResult(
+                text=_FORESHADOW_REVIEW.model_dump_json(), parsed=_FORESHADOW_REVIEW, usage=_USAGE
+            )
+        if schema is PaceReview:
+            return ProviderResult(
+                text=_PACE_REVIEW.model_dump_json(), parsed=_PACE_REVIEW, usage=_USAGE
+            )
+        if schema is StyleDriftReview:
+            return ProviderResult(
+                text=_STYLE_DRIFT.model_dump_json(), parsed=_STYLE_DRIFT, usage=_USAGE
+            )
+        # 否则视为终稿 digest 提炼（ChapterDigestFacts）。
+        facts = ChapterDigestFacts(summary="终稿摘要", events=["少年出山"], locations=["山门"])
+        return ProviderResult(text=facts.model_dump_json(), parsed=facts, usage=_USAGE)
+
+    async def stream(self, req: LlmRequest, model: str) -> AsyncIterator[StreamChunk]:
+        yield StreamChunk(text=_CHAPTER_TEXT)
+        yield StreamChunk(usage=_USAGE)
+
+
+@pytest.fixture
+async def e2e_sm() -> AsyncIterator[async_sessionmaker[AsyncSession]]:
+    """真 DB session 工厂；无 pg 时跳过（每测试清缓存重建 engine、结束 dispose）。"""
+    get_sessionmaker.cache_clear()
+    maker = get_sessionmaker()
+    try:
+        async with maker() as probe:
+            await probe.execute(select(1))
+    except Exception:
+        pytest.skip("postgres not reachable")
+    yield maker
+    await maker.kw["bind"].dispose()
+    get_sessionmaker.cache_clear()
+
+
+def _gateway_for(adapter: _FakeChainAdapter, session: AsyncSession) -> Gateway:
+    """真 Gateway + 给定假适配器 + 真 ledger（绑给定 session）。"""
+    return Gateway(
+        adapters={_PROVIDER: adapter},
+        ledger=SqlAlchemyLedgerSink(session),
+        resolver=resolve_route,
+    )
+
+
+def _chain_gateway_override(
+    adapter: _FakeChainAdapter,
+) -> Callable[[AsyncSession], Gateway]:
+    """`get_chain_gateway` 覆盖：请求阶段凭据探测 → 真 Gateway 包假适配器（绕过 503）。"""
+
+    def _override(session: Annotated[AsyncSession, Depends(get_session)]) -> Gateway:
+        return _gateway_for(adapter, session)
+
+    return _override
+
+
+def _digest_builder_override(
+    adapter: _FakeChainAdapter,
+) -> Callable[[], Callable[[AsyncSession], Awaitable[Gateway]]]:
+    """`get_digest_gateway_builder` 覆盖：返「按 session 建真 Gateway 包假适配器」的 builder。
+
+    链 accept 节点在自建短事务里据该 session 现建 light 档 digest 网关（终稿提炼）。
+    """
+
+    def _get_builder() -> Callable[[AsyncSession], Awaitable[Gateway]]:
+        async def _build(session: AsyncSession) -> Gateway:
+            return _gateway_for(adapter, session)
+
+        return _build
+
+    return _get_builder
+
+
+def _memsaver_override(
+    saver: MemorySaver,
+) -> Callable[[], Callable[[], AbstractAsyncContextManager[MemorySaver]]]:
+    """`get_checkpointer_factory` 覆盖：返产**同一** saver 的工厂（run/resume 跨调用共用）。"""
+
+    @asynccontextmanager
+    async def _ctx() -> AsyncIterator[MemorySaver]:
+        yield saver
+
+    return lambda: lambda: _ctx()
+
+
+async def _cleanup(e2e_sm: async_sessionmaker[AsyncSession], project_uuid: uuid.UUID) -> None:
+    """按 FK 顺序清理（多数子表 FK CASCADE；显式删保独立）。"""
+    async with e2e_sm() as cleanup:
+        await cleanup.execute(delete(UsageLedger).where(UsageLedger.project_id == project_uuid))
+        await cleanup.execute(delete(Job).where(Job.project_id == project_uuid))
+        await cleanup.execute(delete(ChapterDigest).where(ChapterDigest.project_id == project_uuid))
+        await cleanup.execute(delete(ChapterReview).where(ChapterReview.project_id == project_uuid))
+        await cleanup.execute(delete(Chapter).where(Chapter.project_id == project_uuid))
+        await cleanup.execute(delete(Project).where(Project.id == project_uuid))
+        await cleanup.commit()
+
+
+def _build_app(adapter: _FakeChainAdapter, saver: MemorySaver, e2e_sm: Any) -> Any:
+    """组装注入了全 fake 缝的 app（凭据探测/session 工厂/checkpointer/digest builder）。"""
+    from ww_api.main import create_app
+    from ww_api.services.chain_deps import get_checkpointer_factory
+    from ww_api.services.project_deps import (
+        get_chain_gateway,
+        get_chain_gateway_builder,
+        get_digest_gateway_builder,
+        get_session_factory,
+    )
+
+    app = create_app()
+    app.dependency_overrides[get_chain_gateway] = _chain_gateway_override(adapter)
+    # 链 write/review 节点经 builder 在节点 session 上现建网关（ledger 绑节点 session，不变量 #1）。
+    app.dependency_overrides[get_chain_gateway_builder] = _digest_builder_override(adapter)
+    app.dependency_overrides[get_session_factory] = lambda: e2e_sm
+    app.dependency_overrides[get_checkpointer_factory] = _memsaver_override(saver)
+    app.dependency_overrides[get_digest_gateway_builder] = _digest_builder_override(adapter)
+    return app
+
+
+async def test_chain_two_chapters_no_conflict_full_auto(
+    e2e_sm: async_sessionmaker[AsyncSession],
+) -> None:
+    """用例 1：两章无冲突全自动 → 两 accepted 章 + 两 digest 行 + job done written=[1,2]。"""
+    adapter = _FakeChainAdapter(continuity_conflicts=[])  # 零冲突 → 全自动
+    saver = MemorySaver()
+    app = _build_app(adapter, saver, e2e_sm)
+
+    transport = httpx.ASGITransport(app=app)
+    project_uuid: uuid.UUID | None = None
+    try:
+        async with LifespanManager(app):
+            async with httpx.AsyncClient(transport=transport, base_url="http://test") as client:
+                create_resp = await client.post("/projects", json={"title": "链 E2E 无冲突作品"})
+                assert create_resp.status_code == 201
+                project_id = create_resp.json()["id"]
+                project_uuid = uuid.UUID(project_id)
+
+                run_resp = await client.post(
+                    f"/projects/{project_id}/chains/draft_volume/run",
+                    json={"start_chapter_no": 1, "count": 2},
+                )
+                assert run_resp.status_code == 202
+                run_body = run_resp.json()
+                assert run_body["chain_key"] == "draft_volume"
+                job_id = run_body["job_id"]
+
+                # 链经 BackgroundTask 已跑完（ASGITransport 等其完成）→ job done。
+                job_resp = await client.get(f"/jobs/{job_id}")
+                assert job_resp.status_code == 200
+                job = job_resp.json()
+                assert job["status"] == "done", job
+                assert job["kind"] == "chain"
+                result = job["result"]
+                assert result["written"] == [1, 2]
+                assert result["completed"] is True
+                assert result["awaiting_chapter"] is None
+                # 负向：job result 绝不含正文/token（只章号/计数/标志）。
+                assert _CHAPTER_TEXT not in str(result)
+                assert "终稿摘要" not in str(result)
+
+        # DB 真源逐项断言。
+        assert project_uuid is not None
+        async with e2e_sm() as verify:
+            chapters = (
+                (
+                    await verify.execute(
+                        select(Chapter)
+                        .where(Chapter.project_id == project_uuid)
+                        .order_by(Chapter.chapter_no, Chapter.version)
+                    )
+                )
+                .scalars()
+                .all()
+            )
+            # 第 1/2 章各晋升一个 accepted 版次。
+            accepted = [c for c in chapters if c.status == "accepted"]
+            assert {c.chapter_no for c in accepted} == {1, 2}
+            assert all(c.content == _CHAPTER_TEXT for c in accepted)
+
+            digests = (
+                (
+                    await verify.execute(
+                        select(ChapterDigest)
+                        .where(ChapterDigest.project_id == project_uuid)
+                        .order_by(ChapterDigest.chapter_no)
+                    )
+                )
+                .scalars()
+                .all()
+            )
+            assert [d.chapter_no for d in digests] == [1, 2]
+
+            # 回归守卫（审评 #1）：链每次 gateway.run 都应落 usage_ledger 行——证明网关 ledger
+            # 绑节点活 session、节点 commit 持久化。
+            # 修复前：请求网关 session 已关闭，行被静默丢弃。
+            ledger_rows = (
+                (
+                    await verify.execute(
+                        select(UsageLedger).where(UsageLedger.project_id == project_uuid)
+                    )
+                )
+                .scalars()
+                .all()
+            )
+            # 两章 × (1 写 + 四审 + 1 digest)；至少应有若干条，绝不为空。
+            assert len(ledger_rows) > 0, "chain usage_ledger 行不应为空（成本记账断裂回归守卫）"
+
+            # 每审过一章应在 chapter_reviews 留痕（不变量 #3 只读留痕；审评 #7b）。
+            review_rows = (
+                (
+                    await verify.execute(
+                        select(ChapterReview)
+                        .where(ChapterReview.project_id == project_uuid)
+                        .order_by(ChapterReview.chapter_no)
+                    )
+                )
+                .scalars()
+                .all()
+            )
+            assert {r.chapter_no for r in review_rows} == {1, 2}
+
+            job_rows = (
+                (await verify.execute(select(Job).where(Job.project_id == project_uuid)))
+                .scalars()
+                .all()
+            )
+            assert len(job_rows) == 1
+            assert job_rows[0].status == "done"
+            assert job_rows[0].kind == "chain"
+            # 负向（DB 真源）：job result 列不含正文/token。
+            assert _CHAPTER_TEXT not in str(job_rows[0].result)
+    finally:
+        if project_uuid is not None:
+            await _cleanup(e2e_sm, project_uuid)
+
+
+async def test_chain_conflict_interrupts_then_resume_accepts(
+    e2e_sm: async_sessionmaker[AsyncSession],
+) -> None:
+    """用例 2：注入冲突 → interrupt → job awaiting → resume 带裁决 → 续跑 → accept。
+
+    interrupt+resume 横跨两次端点调用，靠单进程单 MemorySaver（同一 thread_id 检查点）。
+    """
+    conflict = Conflict(type="性格漂移", where="第2段", suggestion="统一主角姓名为「萧寒」")
+    adapter = _FakeChainAdapter(continuity_conflicts=[conflict])
+    saver = MemorySaver()  # 单实例横跨 run + resume 两次端点调用
+    app = _build_app(adapter, saver, e2e_sm)
+
+    transport = httpx.ASGITransport(app=app)
+    project_uuid: uuid.UUID | None = None
+    try:
+        async with LifespanManager(app):
+            async with httpx.AsyncClient(transport=transport, base_url="http://test") as client:
+                create_resp = await client.post("/projects", json={"title": "链 E2E 冲突作品"})
+                assert create_resp.status_code == 201
+                project_id = create_resp.json()["id"]
+                project_uuid = uuid.UUID(project_id)
+
+                # 1) 发起：第 1 章四审报冲突 → interrupt → job awaiting_input。
+                run_resp = await client.post(
+                    f"/projects/{project_id}/chains/draft_volume/run",
+                    json={"start_chapter_no": 1, "count": 1},
+                )
+                assert run_resp.status_code == 202
+                job_id = run_resp.json()["job_id"]
+
+                job = (await client.get(f"/jobs/{job_id}")).json()
+                assert job["status"] == "awaiting_input", job
+                assert job["result"]["awaiting_chapter"] == 1
+                assert job["result"]["completed"] is False
+                assert job["result"]["written"] == []
+
+                # awaiting 时第 1 章仍 draft（未经 accept 晋升），无 digest。
+                async with e2e_sm() as mid:
+                    mid_chapters = (
+                        (
+                            await mid.execute(
+                                select(Chapter).where(Chapter.project_id == project_uuid)
+                            )
+                        )
+                        .scalars()
+                        .all()
+                    )
+                    assert all(c.status == "draft" for c in mid_chapters)
+                    assert mid_chapters != []
+                    mid_digests = (
+                        (
+                            await mid.execute(
+                                select(ChapterDigest).where(
+                                    ChapterDigest.project_id == project_uuid
+                                )
+                            )
+                        )
+                        .scalars()
+                        .all()
+                    )
+                    assert mid_digests == []
+
+                # 2) resume：作者裁决冲突 → 续跑 accept → done。
+                resume_resp = await client.post(
+                    f"/projects/{project_id}/chains/runs/{job_id}/resume",
+                    json={
+                        "decisions": [
+                            {"conflict_index": 0, "verdict": "ignore", "note": "笔误，忽略"}
+                        ]
+                    },
+                )
+                assert resume_resp.status_code == 202
+
+                job = (await client.get(f"/jobs/{job_id}")).json()
+                assert job["status"] == "done", job
+                assert job["result"]["written"] == [1]
+                assert job["result"]["completed"] is True
+                assert job["result"]["awaiting_chapter"] is None
+
+        # DB 真源断言：resume 后第 1 章 accepted + digest 一行。
+        assert project_uuid is not None
+        async with e2e_sm() as verify:
+            chapters = (
+                (await verify.execute(select(Chapter).where(Chapter.project_id == project_uuid)))
+                .scalars()
+                .all()
+            )
+            accepted = [c for c in chapters if c.status == "accepted"]
+            assert {c.chapter_no for c in accepted} == {1}
+
+            digests = (
+                (
+                    await verify.execute(
+                        select(ChapterDigest).where(ChapterDigest.project_id == project_uuid)
+                    )
+                )
+                .scalars()
+                .all()
+            )
+            assert [d.chapter_no for d in digests] == [1]
+
+            # 负向：job 状态/result 不含正文/裁决正文外的 token/prompt。
+            job_row = (
+                await verify.execute(select(Job).where(Job.project_id == project_uuid))
+            ).scalar_one()
+            assert _CHAPTER_TEXT not in str(job_row.result)
+            assert job_row.status == "done"
+    finally:
+        if project_uuid is not None:
+            await _cleanup(e2e_sm, project_uuid)