diff --git a/apps/api/ww_api/routers/projects.py b/apps/api/ww_api/routers/projects.py
index 30daa56..3258833 100644
--- a/apps/api/ww_api/routers/projects.py
+++ b/apps/api/ww_api/routers/projects.py
@@ -105,6 +105,13 @@ _ACCEPT_ERRORS: dict[int | str, dict[str, Any]] = {
     409: {"model": ErrorEnvelope, "description": "存在未裁决冲突"},
     503: {"model": ErrorEnvelope, "description": "LLM 不可用"},
 }
+# SSE 端点：如实声明 200 的 media type 为 text/event-stream（否则 OpenAPI 误标 json）。
+_SSE_RESPONSE: dict[int | str, dict[str, Any]] = {
+    200: {
+        "description": "SSE 事件流（`event: <name>\\ndata: <json>`，见 memory/contracts.md）",
+        "content": {"text/event-stream": {}},
+    }
+}
 
 ProjectRepoDep = Annotated[ProjectRepo, Depends(get_project_repo)]
 ChapterRepoDep = Annotated[ChapterRepo, Depends(get_chapter_repo)]
@@ -256,7 +263,7 @@ def _encode_sse(event: SseEvent) -> str:
     return f"event: {event.event}\ndata: {payload}\n\n"
 
 
-@router.post("/{project_id}/chapters/{chapter_no}/draft")
+@router.post("/{project_id}/chapters/{chapter_no}/draft", responses=_SSE_RESPONSE)
 async def stream_draft(
     project_id: uuid.UUID,
     chapter_no: int,
@@ -319,7 +326,7 @@ async def stream_draft(
     )
 
 
-@router.post("/{project_id}/chapters/{chapter_no}/rewrite")
+@router.post("/{project_id}/chapters/{chapter_no}/rewrite", responses=_SSE_RESPONSE)
 async def stream_rewrite(
     project_id: uuid.UUID,
     chapter_no: int,
@@ -532,7 +539,7 @@ async def _resolve_review_draft(
     return saved.content
 
 
-@router.post("/{project_id}/chapters/{chapter_no}/review")
+@router.post("/{project_id}/chapters/{chapter_no}/review", responses=_SSE_RESPONSE)
 async def review_chapter(
     project_id: uuid.UUID,
     chapter_no: int,