diff --git a/apps/api/tests/test_input_size_limits.py b/apps/api/tests/test_input_size_limits.py
index 9193b38..a787602 100644
--- a/apps/api/tests/test_input_size_limits.py
+++ b/apps/api/tests/test_input_size_limits.py
@@ -23,6 +23,7 @@ from ww_api.schemas.generation import CharacterGenerateRequest, WorldGenerateReq
 from ww_api.schemas.projects import (
     AcceptRequest,
     DraftSaveRequest,
+    DraftStreamRequest,
     ProjectCreateRequest,
     ReviewRequest,
 )
@@ -64,6 +65,8 @@ _STR_CASES: list[_StrCase] = [
     _StrCase(DraftSaveRequest, "text", 200_000, "draft-text<=200000"),
     _StrCase(ReviewRequest, "draft", 200_000, "review-draft<=200000"),
     _StrCase(RefineRequest, "segment", 20_000, "segment<=20000"),
+    _StrCase(RefineRequest, "instruction", 2_000, "refine-instruction<=2000", {"segment": "s"}),
+    _StrCase(DraftStreamRequest, "directive", 20_000, "directive<=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"}),
diff --git a/apps/api/ww_api/schemas/projects.py b/apps/api/ww_api/schemas/projects.py
index a5f6aa3..2e7d587 100644
--- a/apps/api/ww_api/schemas/projects.py
+++ b/apps/api/ww_api/schemas/projects.py
@@ -14,6 +14,7 @@ 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
+_DIRECTIVE_MAX = 20_000  # CR-H9 收尾：本章指令喂 LLM，加上界（正文级 body 中间件仍兜底）
 
 
 class ProjectCreateRequest(BaseModel):
@@ -121,7 +122,7 @@ class DraftStreamRequest(BaseModel):
     后端只入 volatile（守缓存前缀不变量 #9）。无 body 时退化为纯按大纲生成（向后兼容）。
     """
 
-    directive: str | None = None
+    directive: str | None = Field(default=None, max_length=_DIRECTIVE_MAX)
 
 
 # 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）。
diff --git a/apps/api/ww_api/schemas/style.py b/apps/api/ww_api/schemas/style.py
index 26ad154..c63bab0 100644
--- a/apps/api/ww_api/schemas/style.py
+++ b/apps/api/ww_api/schemas/style.py
@@ -59,7 +59,8 @@ class RefineRequest(BaseModel):
     """回炉：重写选中段（可选改写指令）。"""
 
     segment: str = Field(min_length=1, max_length=_SEGMENT_MAX)
-    instruction: str | None = None
+    # CR-H9 收尾：再沟通意见喂 LLM，加上界（与 clarify instruction 同口径 2000）。
+    instruction: str | None = Field(default=None, max_length=_MAX_CLARIFY_INSTRUCTION_LEN)
 
 
 class RefineResponse(BaseModel):