diff --git a/PROGRESS.md b/PROGRESS.md
index d6216ca..217a45c 100644
--- a/PROGRESS.md
+++ b/PROGRESS.md
@@ -182,6 +182,8 @@ 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`
 
+- [2026-07-08] @backend — **✅ QA-CR 后端整改 5 项（TDD，逐 fix 提交）**。**CR-C2**：`chain_runner.run_chain_job` 给 `graph.ainvoke` 传显式 top-level `recursion_limit=count*NODES_PER_CHAPTER+HEADROOM`（防御硬化，命名常量）。**CR-H1**：Kimi OAuth 设备轮询移出 DB 会话——新增 `_poll_for_token`(纯 HTTP)/`_make_persist_work`/`_run_kimi_oauth_poll`，仅最终持久化经 `run_job` 开短会话（防连接池饥饿；删 `_make_poll_work`）。**CR-H2**：请求级 httpx 客户端改**生成器依赖** `_http_client`（`async with ... yield`，请求结束 aclose 修泄漏）；`_default_http_client` 保留供后台裸调；E2E + 端点测试 override 键跟随改 `_http_client`。**CR-H7**：冻结 `TOOLBOX` 为只读 `MappingProxyType`（`_TOOLBOX_BY_KEY` 私有底 dict + `Final[Mapping]`，仿 SPECS）。**CR-H9**：用户请求字符串字段补 `max_length`（providers/generation/projects/style/foreshadow/rules/templates，命名常量无魔数，样本列表长度+每条双上界）+ 新错误码 `ErrorCode.PAYLOAD_TOO_LARGE`(413) + 应用级 `body_size_limit_middleware`(2 MiB，按 Content-Length 拦截自建 413 信封)，`main.py` 注册。**门禁全绿**：ruff/format 干净 · mypy **229 文件**（0 错）· pytest **928**（+23：recursion_limit 1 / poll-no-session 1 / http-gen 1 / toolbox-readonly 1 / input-size 19[17 参数化 + samples 1 + body413 1]）· **无 DDL/无迁移**。记 contracts C3（CR-H9：新增 `maxLength` + `PAYLOAD_TOO_LARGE`）。→ **@frontend 须 `pnpm gen:api`**（请求字段现有 `maxLength`；本 cluster 未代跑）。守不变量 #3/#8/#9。
+
 - [2026-07-06] @backend/@llm/@frontend — **✅ 灵感⑦ 群像按定位配比·缩减版 + §0 归属纠偏（develop 直提）**。角色群像生成支持「按定位配比」下发。**契约变更** `CharacterGenerateRequest` 加 `role_mix:dict[str,int]|None`——`model_validator(mode="after")` 定义与既有 `count` 的关系：在场时校验（非空、每项≥1、总和≤`MAX_GENERATE_COUNT`=12）并把 `count` 归一为各值之和（构造期归一化，忽略客户端 count）；缺省退回单一 `role`+`count`。**§0 归属纠偏**：`build_character_gen_context`+`run_character_gen`（`ww_core/orchestrator/generation_node.py`）确为 **@llm 域**——加末位默认 `role_mix=None` 关键字参，在场时注入「角色定位配比」块（保插入序、确定性、无时间戳，守 #6/#7 assemble 纯函数；覆盖单一 role 行）；`routers/generation.py` 穿 `role_mix=body.role_mix`。`character-gen.md` 加「按配比严格分配 role、各定位之和=总数」纪律 → **regen `prompt_hashes.json`**（仅 character-gen 哈希变，**不进 SPECS→不 bump 计数**）。**前端** `cards.ts` 加 `sanitizeRoleMix`（去空/去重/clamp≥1/按 12 截断）+`roleMixTotal`+`buildCharacterGenerateRequest` 第 4 参 roleMix；`useCharacterGen` `CharacterGenInput.roleMix` 穿参；新 `RoleMixEditor.tsx` + `CharacterGenerator` SegmentedControl 单一/配比双模。**TDD**：schema 校验 7 例（总和≤12/空 dict/非正值拒绝）+ context 注入 2 例 + run 穿参 1 例 + 前端 cards 构造/clamp 5 例 + hook renderHook 1 例。**门禁全绿**：后端 ruff/format 干净 · mypy **222** · pytest **858**（+11）· 无迁移（未动模型，未跑 alembic）；前端 gen:api/lint/typecheck 干净 · vitest **543**（+6）· coverage 95%（cards.ts 100%）· build OK。记 contracts C3。守不变量 #2/#6/#7/#9。**无 DB 迁移**。
 
 - [2026-07-06] @llm/@db/@backend/@frontend — **✅ 灵感③ 人物塑造 advisory 审（develop 直提）**。写→审链新增第五审「人物塑造」：**advisory 单维——仅建议、不阻断验收**（不进 conflicts、不碰 `assert_conflicts_resolved`、**不入 `REVIEW_RESERVED_NAMES`**，D2）；只做人物塑造、不做氛围（氛围噪声大折进 style/pace）。**新 SPEC** `characterization_spec`（`tier="analyst"` 不写 model，`reads=("characters",)` 以人物卡 motive/appearance 为客观锚点，`writes=()` 只读，`prompts/characterization.md` **显式忽略文本长度与辞藻华丽度**、引用逐字片段+置信度对抗 LLM-judge 冗长/辞藻偏见）+ schema `CharacterizationReview{issues:[…character/aspect/where/quote/diagnosis/suggestion/confidence]}`（全字段默认值守解析韧性）+ 注册 `SCHEMA_CATALOG["characterization"]`；**计数三处 22→23**（`specs.py` assert / `test_prompt_loader.py` len / `schema_catalog.py` docstring）+ **regen `prompt_hashes.json`**（仅加一条，无其余漂移）。**DB** `chapter_reviews` 加 1 列 `characterization`（**JSONB nullable**，迁移 `f6a7b8c9d0e1`，nullable 免 backfill）。**契约变更** `ReviewHistoryItem`+`ReviewView` 加 `characterization`；接线链 `graph.py REVIEW_SPECS` 末位追加 + `chain/nodes.py ReviewRecordRepo` + `collect.py {CHARACTERIZATION/extract_characterization/ReviewRecorder/collect_reviews}` + `review_repo.py {Protocol/SqlReviewRepo/_to_view}` + `sse.py {EVENT_CHARACTERIZATION/characterization_event/_section_result_events}`（normalize 按 sorted 键自动纳入，字典序排最前不打乱既有四审断言）。**前端** `lib/review/{sse.ts,history.ts,useReviewStream.ts}` + 新 `CharacterizationPanel.tsx`（advisory 只展示、**无裁决 UI**、按置信度降序 + 低置信度折叠控注意力预算）+ `ReviewReport.tsx` 挂面板 + 双 seed。**门禁全绿**：后端 ruff/format 干净 · mypy **221** · pytest **848**（+核心 char 审 12 + agents spec 11 + api accept 2 等）· alembic 无漂移；前端 gen:api/lint/typecheck 干净 · vitest **536**（+10 含 `test_characterization_does_not_block_accept` 对应前端 reducer/normalize/parse）· coverage 95% · build OK。记 contracts C3+C4。守不变量 #2/#3/#9。依赖 ⑧（motive/appearance 已入 CharacterCard 契约，作客观锚点）。
diff --git a/apps/api/tests/test_input_size_limits.py b/apps/api/tests/test_input_size_limits.py
new file mode 100644
index 0000000..9193b38
--- /dev/null
+++ b/apps/api/tests/test_input_size_limits.py
@@ -0,0 +1,109 @@
+"""CR-H9：用户请求文本字段 max_length 上界 + 应用级请求体大小中间件（防 DoS/成本）。
+
+- 单元：各请求 schema 的字符串字段在 cap 处可构造、cap+1 触发 ValidationError（含样本列表长度
+  与列表项两处上界——最大 DoS 面）。
+- 集成（无 pg）：超大请求体经中间件直接 413（不入路由/DB）。
+"""
+
+from __future__ import annotations
+
+import os
+from dataclasses import dataclass, field
+from typing import Any
+
+import pytest
+from cryptography.fernet import Fernet
+from pydantic import BaseModel, ValidationError
+
+# create_app() 于 import ww_api.main 时构建，需 CREDENTIAL_ENC_KEY——先于任何 main 导入置好。
+os.environ.setdefault("CREDENTIAL_ENC_KEY", Fernet.generate_key().decode())
+
+from ww_api.schemas.foreshadow import ForeshadowRegisterRequest
+from ww_api.schemas.generation import CharacterGenerateRequest, WorldGenerateRequest
+from ww_api.schemas.projects import (
+    AcceptRequest,
+    DraftSaveRequest,
+    ProjectCreateRequest,
+    ReviewRequest,
+)
+from ww_api.schemas.providers import (
+    ProviderCredentialInput,
+    TierRoutingInput,
+)
+from ww_api.schemas.providers import (
+    TestConnectionRequest as _TestConnectionRequest,  # 别名避免 pytest 误采集 Test* 类
+)
+from ww_api.schemas.rules import RuleCreateRequest
+from ww_api.schemas.style import RefineRequest, StyleLearnRequest
+from ww_api.schemas.templates import TemplateCreateRequest
+
+
+@dataclass(frozen=True)
+class _StrCase:
+    """一个字符串字段的上界用例：cap 处可构造、cap+1 触发 ValidationError。"""
+
+    schema: type[BaseModel]
+    field_name: str
+    cap: int
+    case_id: str
+    base: dict[str, Any] = field(default_factory=dict)  # 该 schema 其余必填字段
+
+
+_STR_CASES: list[_StrCase] = [
+    _StrCase(ProviderCredentialInput, "api_key", 512, "api_key<=512", {"provider": "p"}),
+    _StrCase(ProviderCredentialInput, "provider", 64, "provider<=64", {"api_key": "k"}),
+    _StrCase(TierRoutingInput, "model", 128, "model<=128", {"tier": "writer", "provider": "p"}),
+    _StrCase(
+        TierRoutingInput, "provider", 64, "routing-provider<=64", {"tier": "writer", "model": "m"}
+    ),
+    _StrCase(_TestConnectionRequest, "provider", 64, "test-provider<=64"),
+    _StrCase(WorldGenerateRequest, "brief", 10_000, "world-brief<=10000"),
+    _StrCase(CharacterGenerateRequest, "brief", 10_000, "char-brief<=10000"),
+    _StrCase(ProjectCreateRequest, "title", 200, "title<=200"),
+    _StrCase(AcceptRequest, "final_text", 200_000, "final_text<=200000"),
+    _StrCase(DraftSaveRequest, "text", 200_000, "draft-text<=200000"),
+    _StrCase(ReviewRequest, "draft", 200_000, "review-draft<=200000"),
+    _StrCase(RefineRequest, "segment", 20_000, "segment<=20000"),
+    _StrCase(ForeshadowRegisterRequest, "code", 100, "code<=100", {"title": "t"}),
+    _StrCase(ForeshadowRegisterRequest, "title", 500, "foreshadow-title<=500", {"code": "c"}),
+    _StrCase(RuleCreateRequest, "content", 10_000, "rule-content<=10000", {"level": "project"}),
+    _StrCase(TemplateCreateRequest, "title", 200, "template-title<=200", {"body": "b"}),
+    _StrCase(TemplateCreateRequest, "body", 20_000, "template-body<=20000", {"title": "t"}),
+]
+
+
+@pytest.mark.parametrize("case", _STR_CASES, ids=[c.case_id for c in _STR_CASES])
+def test_request_str_fields_reject_over_max_length(case: _StrCase) -> None:
+    # Arrange / Act — 长度 == cap：构造成功。
+    case.schema(**{**case.base, case.field_name: "x" * case.cap})
+    # Assert — 长度 == cap+1：超界即 ValidationError。
+    with pytest.raises(ValidationError):
+        case.schema(**{**case.base, case.field_name: "x" * (case.cap + 1)})
+
+
+def test_style_learn_samples_item_and_list_caps() -> None:
+    # 单条样本 == 20_000 字符 OK；20_001 → ValidationError（最大 DoS 面：每条正文都设上界）。
+    StyleLearnRequest(samples=["x" * 20_000])
+    with pytest.raises(ValidationError):
+        StyleLearnRequest(samples=["x" * 20_001])
+    # 列表 == 20 条 OK；21 条 → ValidationError（同时约束列表长度）。
+    StyleLearnRequest(samples=["s"] * 20)
+    with pytest.raises(ValidationError):
+        StyleLearnRequest(samples=["s"] * 21)
+
+
+def test_oversized_request_body_rejected_413() -> None:
+    """超大请求体经 body-size 中间件直接 413（不入路由/DB）。
+
+    不以 context manager 进入 TestClient → 不跑 lifespan/seed → 不需 Postgres。中间件在
+    路由前拦截，故请求根本不触达任何 DB。
+    """
+    from fastapi.testclient import TestClient
+    from ww_api.main import create_app
+    from ww_api.middleware import MAX_BODY_BYTES
+
+    client = TestClient(create_app())
+    resp = client.post("/projects", content=b"x" * (MAX_BODY_BYTES + 1))
+
+    assert resp.status_code == 413
+    assert resp.json()["error"]["code"] == "PAYLOAD_TOO_LARGE"
diff --git a/apps/api/ww_api/main.py b/apps/api/ww_api/main.py
index e2e78c1..cd4b5dc 100644
--- a/apps/api/ww_api/main.py
+++ b/apps/api/ww_api/main.py
@@ -14,7 +14,11 @@ from ww_db import get_sessionmaker
 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.middleware import (
+    REQUEST_ID_HEADER,
+    body_size_limit_middleware,
+    request_id_middleware,
+)
 from ww_api.routers import (
     chain,
     foreshadow,
@@ -74,6 +78,8 @@ def create_app() -> FastAPI:
         allow_headers=["content-type", "authorization", REQUEST_ID_HEADER],
     )
     app.middleware("http")(request_id_middleware)
+    # 请求体大小守卫（CR-H9）：在路由前拦截超大 body，直接 413。
+    app.middleware("http")(body_size_limit_middleware)
 
     @app.exception_handler(AppError)
     async def _app_error_handler(request: Request, exc: AppError) -> JSONResponse:
diff --git a/apps/api/ww_api/middleware.py b/apps/api/ww_api/middleware.py
index 23102db..8fb5f3c 100644
--- a/apps/api/ww_api/middleware.py
+++ b/apps/api/ww_api/middleware.py
@@ -12,10 +12,14 @@ from collections.abc import Awaitable, Callable
 
 import structlog
 from starlette.requests import Request
-from starlette.responses import Response
+from starlette.responses import JSONResponse, Response
+from ww_shared import ErrorBody, ErrorCode, ErrorEnvelope
 
 REQUEST_ID_HEADER = "x-request-id"
 
+# 请求体大小上限（2 MiB）：超过即 413，防超大 body 撑爆内存/成本（CR-H9）。
+MAX_BODY_BYTES = 2 * 1024 * 1024
+
 # 放行安全字符集（字母数字 . _ -，1–128 位）：覆盖 uuid4().hex、常见 trace id 与客户端
 # 自定义短 id；含空白/控制字符/换行/注入序列/超长的一律丢弃改生成新 uuid——防止把未经
 # 校验的客户端值原样写进日志/响应头（日志注入防护）。
@@ -38,3 +42,29 @@ async def request_id_middleware(
     response = await call_next(request)
     response.headers[REQUEST_ID_HEADER] = request_id
     return response
+
+
+async def body_size_limit_middleware(
+    request: Request, call_next: Callable[[Request], Awaitable[Response]]
+) -> Response:
+    """按 `Content-Length` 拦截超大请求体，超限直接 413（CR-H9）。
+
+    用户中间件跑在 FastAPI 的 AppError 处理器**之外**，故必须自建错误信封响应（不能靠抛
+    AppError）。分块编码（无 `Content-Length`）无法在此拦截——单用户原型可接受的限制。
+    """
+    content_length = request.headers.get("content-length")
+    if content_length is not None:
+        try:
+            size = int(content_length)
+        except ValueError:
+            size = 0  # 非法头防御性视作 0，交由下游正常解析/报错。
+        if size > MAX_BODY_BYTES:
+            envelope = ErrorEnvelope(
+                error=ErrorBody(
+                    code=ErrorCode.PAYLOAD_TOO_LARGE,
+                    message="请求体过大",
+                    request_id=_sanitize_request_id(request.headers.get(REQUEST_ID_HEADER)),
+                )
+            )
+            return JSONResponse(status_code=413, content=envelope.model_dump())
+    return await call_next(request)
diff --git a/apps/api/ww_api/schemas/foreshadow.py b/apps/api/ww_api/schemas/foreshadow.py
index f221514..7626835 100644
--- a/apps/api/ww_api/schemas/foreshadow.py
+++ b/apps/api/ww_api/schemas/foreshadow.py
@@ -11,12 +11,18 @@ from typing import Any
 
 from pydantic import BaseModel, Field
 
+# 请求字符串字段长度上界（CR-H9：防超长入参 DoS/成本）。代号=短标识；标题=一句话。
+_CODE_MAX = 100
+_TITLE_MAX = 500
+
 
 class ForeshadowRegisterRequest(BaseModel):
     """POST /projects/:id/foreshadow：作者显式登记一条伏笔（status 落 OPEN）。"""
 
-    code: str = Field(min_length=1, description="伏笔代号，`(project_id, code)` 唯一")
-    title: str = Field(min_length=1, description="伏笔标题/一句话描述")
+    code: str = Field(
+        min_length=1, max_length=_CODE_MAX, description="伏笔代号，`(project_id, code)` 唯一"
+    )
+    title: str = Field(min_length=1, max_length=_TITLE_MAX, description="伏笔标题/一句话描述")
     planted_at: int | None = Field(default=None, description="埋设章号")
     content: str | None = Field(default=None, description="伏笔正文/线索")
     expected_close_from: int | None = Field(default=None, description="预期回收窗口起始章")
diff --git a/apps/api/ww_api/schemas/generation.py b/apps/api/ww_api/schemas/generation.py
index d527165..d78c8d4 100644
--- a/apps/api/ww_api/schemas/generation.py
+++ b/apps/api/ww_api/schemas/generation.py
@@ -19,6 +19,9 @@ from ww_api.schemas.rules import RuleView
 # 批量生成数量上限（防一次性巨量调用；原型保守值）。
 MAX_GENERATE_COUNT = 12
 
+# 一句话需求文本上界（CR-H9：防超长入参撑爆上下文/成本）。
+_BRIEF_MAX = 10_000
+
 
 # ---- 世界观生成（预览）----
 
@@ -26,7 +29,9 @@ MAX_GENERATE_COUNT = 12
 class WorldGenerateRequest(BaseModel):
     """POST /projects/:id/world/generate：据需求生成世界观实体（预览）。"""
 
-    brief: str = Field(min_length=1, description="世界观生成需求（题材/设定方向/约束）")
+    brief: str = Field(
+        min_length=1, max_length=_BRIEF_MAX, description="世界观生成需求（题材/设定方向/约束）"
+    )
 
 
 class WorldEntityCardView(BaseModel):
@@ -54,7 +59,7 @@ class CharacterGenerateRequest(BaseModel):
     单一 `role` + `count` 语义。
     """
 
-    brief: str = Field(min_length=1, description="角色生成需求")
+    brief: str = Field(min_length=1, max_length=_BRIEF_MAX, description="角色生成需求")
     count: int = Field(
         default=1,
         ge=1,
diff --git a/apps/api/ww_api/schemas/projects.py b/apps/api/ww_api/schemas/projects.py
index d451907..a5f6aa3 100644
--- a/apps/api/ww_api/schemas/projects.py
+++ b/apps/api/ww_api/schemas/projects.py
@@ -11,11 +11,15 @@ from typing import Any, Literal
 
 from pydantic import BaseModel, Field
 
+# 请求文本长度上界（CR-H9：防超长入参 DoS/成本）。标题=标签级；章正文=整章级。
+_TITLE_MAX = 200
+_CHAPTER_TEXT_MAX = 200_000
+
 
 class ProjectCreateRequest(BaseModel):
     """POST /projects：立项向导字段（owner_id 由后端补 stub，不入参）。"""
 
-    title: str = Field(min_length=1)
+    title: str = Field(min_length=1, max_length=_TITLE_MAX)
     genre: str | None = None
     logline: str | None = None
     premise: str | None = None
@@ -120,9 +124,9 @@ class DraftStreamRequest(BaseModel):
     directive: str | None = None
 
 
-# 整章重写输入上界（守 DoS/成本，CR-H9 方向）：意见短、整章草稿大。
+# 整章重写输入上界（守 DoS/成本，CR-H9 方向）：意见短、整章草稿大（复用章正文上界，DRY）。
 _REWRITE_FEEDBACK_MAX = 4000
-_REWRITE_DRAFT_MAX = 200_000
+_REWRITE_DRAFT_MAX = _CHAPTER_TEXT_MAX
 
 
 class RewriteStreamRequest(BaseModel):
@@ -140,7 +144,7 @@ class RewriteStreamRequest(BaseModel):
 class DraftSaveRequest(BaseModel):
     """PUT /projects/:id/chapters/:no/draft：自动保存草稿正文。"""
 
-    text: str
+    text: str = Field(max_length=_CHAPTER_TEXT_MAX)
 
 
 class DraftResponse(BaseModel):
@@ -179,7 +183,7 @@ class ReviewRequest(BaseModel):
     不传 `draft` 时端点回退到已保存的草稿（chapter_repo）。
     """
 
-    draft: str | None = None
+    draft: str | None = Field(default=None, max_length=_CHAPTER_TEXT_MAX)
 
 
 class ReviewConflictView(BaseModel):
@@ -237,7 +241,9 @@ class ConflictDecision(BaseModel):
 class AcceptRequest(BaseModel):
     """POST /projects/:id/chapters/:no/accept：裁决清单 + 可能改过的终稿。"""
 
-    final_text: str = Field(min_length=1, description="作者裁决/改稿后的最终验收文本")
+    final_text: str = Field(
+        min_length=1, max_length=_CHAPTER_TEXT_MAX, description="作者裁决/改稿后的最终验收文本"
+    )
     decisions: list[ConflictDecision] = Field(
         default_factory=list, description="对最近审稿每个冲突的裁决（每冲突必有其一，R5）"
     )
diff --git a/apps/api/ww_api/schemas/providers.py b/apps/api/ww_api/schemas/providers.py
index b428d64..84875f0 100644
--- a/apps/api/ww_api/schemas/providers.py
+++ b/apps/api/ww_api/schemas/providers.py
@@ -8,6 +8,11 @@ from __future__ import annotations
 from pydantic import BaseModel, Field
 from ww_llm_gateway.types import Tier
 
+# 请求字符串字段长度上界（CR-H9：防超长入参 DoS/成本）。
+_PROVIDER_MAX = 64
+_MODEL_MAX = 128
+_API_KEY_MAX = 512
+
 
 class ProviderView(BaseModel):
     """已配置提供商（掩码视图）。"""
@@ -35,8 +40,8 @@ class ProvidersResponse(BaseModel):
 class ProviderCredentialInput(BaseModel):
     """单条提供商凭据写入。"""
 
-    provider: str = Field(min_length=1)
-    api_key: str = Field(min_length=1)  # 明文入站，加密入库，绝不回显
+    provider: str = Field(min_length=1, max_length=_PROVIDER_MAX)
+    api_key: str = Field(min_length=1, max_length=_API_KEY_MAX)  # 明文入站，加密入库，绝不回显
 
 
 class TierRoutingInput(BaseModel):
@@ -44,8 +49,8 @@ class TierRoutingInput(BaseModel):
 
     # tier 限定已知档位 writer/analyst/light；未知档位 → 422（QA MEDIUM：原接受任意字符串）。
     tier: Tier
-    provider: str = Field(min_length=1)
-    model: str = Field(min_length=1)
+    provider: str = Field(min_length=1, max_length=_PROVIDER_MAX)
+    model: str = Field(min_length=1, max_length=_MODEL_MAX)
     fallback: list[str] = Field(default_factory=list)
 
 
@@ -59,7 +64,7 @@ class ProvidersUpsertRequest(BaseModel):
 class TestConnectionRequest(BaseModel):
     """POST /test：最小探测请求。"""
 
-    provider: str = Field(min_length=1)
+    provider: str = Field(min_length=1, max_length=_PROVIDER_MAX)
 
 
 class CapabilitiesView(BaseModel):
diff --git a/apps/api/ww_api/schemas/rules.py b/apps/api/ww_api/schemas/rules.py
index a7ab307..d77cca1 100644
--- a/apps/api/ww_api/schemas/rules.py
+++ b/apps/api/ww_api/schemas/rules.py
@@ -14,8 +14,13 @@ from pydantic import BaseModel, Field, StringConstraints
 
 RuleLevel = Literal["global", "genre", "style", "project"]
 
+# 规则正文长度上界（CR-H9：防超长入参 DoS/成本）。
+_RULE_CONTENT_MAX = 10_000
+
 # 先 strip 再校验长度：纯空白内容（"   "）strip 后为空 → 422（QA MEDIUM：此前被接受入库）。
-RuleContent = Annotated[str, StringConstraints(strip_whitespace=True, min_length=1)]
+RuleContent = Annotated[
+    str, StringConstraints(strip_whitespace=True, min_length=1, max_length=_RULE_CONTENT_MAX)
+]
 
 
 class RuleCreateRequest(BaseModel):
diff --git a/apps/api/ww_api/schemas/style.py b/apps/api/ww_api/schemas/style.py
index 87465fe..26ad154 100644
--- a/apps/api/ww_api/schemas/style.py
+++ b/apps/api/ww_api/schemas/style.py
@@ -7,15 +7,26 @@ snake_case（命名契约，见 memory/gotchas）。前端经 OpenAPI→TS 客
 from __future__ import annotations
 
 import uuid
-from typing import Literal
+from typing import Annotated, Literal
 
-from pydantic import BaseModel, Field
+from pydantic import BaseModel, Field, StringConstraints
+
+# 请求文本长度上界（CR-H9：防超长入参空跑 LLM/DoS）。选段/样本 20k 字符，样本列表 ≤20 条。
+_SEGMENT_MAX = 20_000
+_SAMPLE_MAX = 20_000
+_SAMPLES_LIST_MAX = 20
+# 预检澄清沿用相同选段上界（DRY）；指令短。
+_MAX_CLARIFY_SEGMENT_LEN = _SEGMENT_MAX
+_MAX_CLARIFY_INSTRUCTION_LEN = 2000
 
 
 class StyleLearnRequest(BaseModel):
     """学文风：上传样本正文（前端可读文件转文本）+ 模式（首学 / 更新）。"""
 
-    samples: list[str] = Field(min_length=1)
+    # 同时约束**列表条数**与**每条样本长度**（最大 DoS 面：多条超长正文）。
+    samples: list[Annotated[str, StringConstraints(max_length=_SAMPLE_MAX)]] = Field(
+        min_length=1, max_length=_SAMPLES_LIST_MAX
+    )
     mode: Literal["create", "update"] = "create"
 
 
@@ -47,7 +58,7 @@ class StyleFingerprintResponse(BaseModel):
 class RefineRequest(BaseModel):
     """回炉：重写选中段（可选改写指令）。"""
 
-    segment: str = Field(min_length=1)
+    segment: str = Field(min_length=1, max_length=_SEGMENT_MAX)
     instruction: str | None = None
 
 
@@ -58,11 +69,6 @@ class RefineResponse(BaseModel):
     refined: str
 
 
-# 上界：选段/意见文本长度守卫（防超长入参空跑 LLM；预检只看本段，无需整章）。
-_MAX_CLARIFY_SEGMENT_LEN = 20000
-_MAX_CLARIFY_INSTRUCTION_LEN = 2000
-
-
 class RefineClarifyRequest(BaseModel):
     """润色预检澄清：选段 + 再沟通意见（WFW-9 M1 路线A 两阶段之「问题」阶段）。
 
diff --git a/apps/api/ww_api/schemas/templates.py b/apps/api/ww_api/schemas/templates.py
index 0939d43..ce574b1 100644
--- a/apps/api/ww_api/schemas/templates.py
+++ b/apps/api/ww_api/schemas/templates.py
@@ -12,15 +12,24 @@ from typing import Annotated
 
 from pydantic import BaseModel, Field, StringConstraints
 
+# 长度上界（CR-H9：防超长入参 DoS/成本）。标题=标签级；正文=段落级。
+_TITLE_MAX = 200
+_BODY_MAX = 20_000
+
 # 先去首尾空白再校验长度：纯空白（"   "）strip 后为空 → min_length=1 不满足 → 422。
-NonBlankStr = Annotated[str, StringConstraints(strip_whitespace=True, min_length=1)]
+NonBlankTitle = Annotated[
+    str, StringConstraints(strip_whitespace=True, min_length=1, max_length=_TITLE_MAX)
+]
+NonBlankBody = Annotated[
+    str, StringConstraints(strip_whitespace=True, min_length=1, max_length=_BODY_MAX)
+]
 
 
 class TemplateCreateRequest(BaseModel):
     """POST /templates：新建一条提示词模板。"""
 
-    title: NonBlankStr = Field(description="模板标题（非空，纯空白 → 422）")
-    body: NonBlankStr = Field(description="模板正文（非空，一键填入生成器的 brief/text）")
+    title: NonBlankTitle = Field(description="模板标题（非空，纯空白 → 422）")
+    body: NonBlankBody = Field(description="模板正文（非空，一键填入生成器的 brief/text）")
     category: str | None = Field(default=None, description="可选分类")
     tool_key: str | None = Field(default=None, description="可选关联生成器（NULL=通用）")
 
diff --git a/memory/contracts.md b/memory/contracts.md
index 7060792..8b8d1b5 100644
--- a/memory/contracts.md
+++ b/memory/contracts.md
@@ -374,4 +374,6 @@
 
 - [2026-07-07] @backend/@llm/@frontend 立 C-Rewrite（WFW-8 整章再沟通/重写）：新增 **`POST /projects/{project_id}/chapters/{chapter_no}/rewrite`**（SSE，text/event-stream，复用 token/done/error 帧契约）← `RewriteStreamRequest{feedback:str(1..4000), prior_draft:str(1..200000)}` → 流式重写整章一版。实现：`prompts/rewrite.md` 教条（非 SPEC，仿 write_craft 经 `load_prompt` 读盘，`test_prompt_loader` doctrine 排除集加 `rewrite`）+ `orchestrator/rewrite_node.py`（`build_rewrite_request` 纯函数 system=[rewrite教条,stable_core] cache 前缀 / input=近况+当前草稿+作者意见 断点后，守不变量 #9；`stream_chapter_rewrite`）+ 端点复用 `assemble()` 记忆注入 + `normalize_deltas`。**只读不写库**（HITL：新版停前端，接受才落，不变量 #3）、**工具非写节点**（不破坏 章=f(outline,state) 纯函数，不变量 #7）、项目不存在触网关前 404。**无 DDL/无迁移**。门禁绿：ruff/mypy(224)/pytest(+test_rewrite_node 5 例)/alembic 无漂移。→ 影响 @frontend（已 `pnpm gen:api`；`useChapterRewrite` SSE hook + `ChapterRewritePanel` 版本栈 + Workbench「整章重写」入口）。
 
+- [2026-07-08] @backend 改 C3（CR-H9 输入大小上界 + 请求体守卫）：给用户请求字符串字段补 `max_length`（`Field(...,max_length=)` / `StringConstraints(max_length=)`，保留既有 `min_length`，命名常量无魔数）——`providers.py`{provider≤64,model≤128,api_key≤512}、`generation.py`{brief≤10_000}、`projects.py`{title≤200,final_text/draft/text≤200_000}、`style.py`{segment≤20_000,samples 列表≤20 且每条≤20_000}、`foreshadow.py`{code≤100,title≤500}、`rules.py`{content≤10_000}、`templates.py`{`NonBlankStr`→`NonBlankTitle`(≤200)+`NonBlankBody`(≤20_000)}；`ProjectPlanGenerateRequest`/`RewriteStreamRequest`/`RefineClarifyRequest` 早前已有上界，未动。**新增错误码** `ErrorCode.PAYLOAD_TOO_LARGE`(413)（`ww_shared.errors`，`ErrorBody.code` 为裸 str → **OpenAPI schema 不变**）+ 应用级 `body_size_limit_middleware`（`apps/api/ww_api/middleware.py`，`MAX_BODY_BYTES=2 MiB`，按 `Content-Length` 拦超大 body 直接自建 413 信封——用户中间件跑在 AppError 处理器外；chunked 无 Content-Length 为原型可接受限制）+ `main.py` 在 `request_id_middleware` 后注册。**无 DDL/无迁移**。超界 → 422（字段 ValidationError）/ 413（整体 body）。→ 影响 @frontend：请求字段现有 `maxLength`，须 **`pnpm gen:api`** 重生成 TS 客户端（**本 cluster 不代跑**）。
+
 - [2026-07-08] @backend/@llm/@frontend 立 C-Clarify（WFW-9 M1 refine 侧 AI 反问澄清，路线A 两阶段）：新增 **`POST /projects/{project_id}/chapters/{chapter_no}/refine/clarify`**（**非流式** JSON 预检）← `RefineClarifyRequest{segment:str(1..20000), instruction:str(默认"",0..2000)}` → **`ClarifyDecision`**{need_clarification:bool, questions:[ClarifyQuestion{question, options:[ClarifyOption{label,value}](0..4), allow_free_text:bool}](0或1,v1硬上限1问), verification:str|null}。tier=**analyst**，结构化输出(instructor)，**只读不写库**(末尾 commit 仅记 usage_ledger，不变量 #3)；判别/校验失败**确定性回退 need_clarification=false**(放行)。`ClarifyDecision` 定义在 `ww_agents`(供 producer+端点共用)，注册 `clarify_refine_spec`(SPECS #24)+SCHEMA_CATALOG+金标准。**既有 `POST .../refine`(RefineRequest/RefineResponse)完全未改**。→ 影响 @frontend(已 gen:api；`useClarify` 映射 snake→VM + `ChoiceChips` 选项芯片 + `RefinePanel` 门控预检：意见<10字或点按钮→预检→needClarification 则渲染选项→答案 foldClarifications 折进 instruction→走既有 refine)。**无 DDL/无迁移**。门禁绿：后端 ruff/mypy227/pytest900/alembic；前端 tsc/lint/vitest654/build/cov95.36%。M2(rewrite 侧两阶段)/M3(UX+E2E) 待办。
diff --git a/packages/shared/ww_shared/errors.py b/packages/shared/ww_shared/errors.py
index 1d7eb8f..c8aa2c6 100644
--- a/packages/shared/ww_shared/errors.py
+++ b/packages/shared/ww_shared/errors.py
@@ -12,6 +12,7 @@ class ErrorCode(StrEnum):
     CONFLICT_UNRESOLVED = "CONFLICT_UNRESOLVED"  # 未决冲突禁验收
     LLM_UNAVAILABLE = "LLM_UNAVAILABLE"  # 回退耗尽
     RATE_LIMITED = "RATE_LIMITED"
+    PAYLOAD_TOO_LARGE = "PAYLOAD_TOO_LARGE"  # 请求体超过大小上限（body-size 中间件）
     INTERNAL = "INTERNAL"
 
 
@@ -23,6 +24,7 @@ HTTP_STATUS: dict[ErrorCode, int] = {
     ErrorCode.CONFLICT_UNRESOLVED: 409,
     ErrorCode.LLM_UNAVAILABLE: 503,
     ErrorCode.RATE_LIMITED: 429,
+    ErrorCode.PAYLOAD_TOO_LARGE: 413,
     ErrorCode.INTERNAL: 500,
 }