diff --git a/pipeline_bidding/bid_compose_capability.py b/pipeline_bidding/bid_compose_capability.py
index 34b6e2a..b6ab3d6 100644
--- a/pipeline_bidding/bid_compose_capability.py
+++ b/pipeline_bidding/bid_compose_capability.py
@@ -23,18 +23,16 @@ async def _workspace_dir(sor, project_id):
     不走 get_workspace_dir（那个依赖会话当前项目），角色 agent 场景下按项目自身字段解析。
     旧实现自行拼 {base}/{org}/{pipeline_id}/{项目名}（旧平铺口径）导致与项目目录错位，
     2026-09-01 收敛到引擎统一函数根治。
+
+    铁律（输出文件必须在项目空间内）：解析失败绝不回退 /tmp——
+    标书是交付件，写到项目外就违反"输出文件必须在项目空间内"。宁可合成失败。
     """
-    try:
-        from pipeline_service.workspace import get_project_dir_by_id
-        pdir, _ = await get_project_dir_by_id(sor, project_id)
-        if pdir:
-            os.makedirs(pdir, exist_ok=True)
-            return pdir
-    except Exception as e:
-        logger.warning("workspace resolve failed: %s", str(e)[:120])
-    d = os.path.join("/tmp", "pipeline_bidding", project_id)
-    os.makedirs(d, exist_ok=True)
-    return d
+    from pipeline_service.workspace import get_project_dir_by_id
+    pdir, _ = await get_project_dir_by_id(sor, project_id)
+    if pdir:
+        os.makedirs(pdir, exist_ok=True)
+        return pdir
+    return ''
 
 
 def _write_docx(path, title, subtitle, chapters):
@@ -130,6 +128,8 @@ async def compose_bid(project_id, doc_name="", who=None, agent_id=None, task_id=
         ver = to_int(getattr(vrec[0], "v", 0) if vrec else 0) + 1
 
         ws = await _workspace_dir(sor, project_id)
+        if not ws:
+            return False, "无法解析项目工作目录（输出文件必须落项目空间内，已中止合成）"
         title = doc_name or ("%s 投标文件" % (tender.get("title") or proj.get("name") or "项目"))
         subtitle = "投标人：（本单位）　　招标编号：%s" % (tender.get("tender_no") or "-")