diff --git a/src/api/toolchain_routes.py b/src/api/toolchain_routes.py
index b22d1fa..5faed9a 100644
--- a/src/api/toolchain_routes.py
+++ b/src/api/toolchain_routes.py
@@ -15,7 +15,7 @@ import logging
 import os
 import time
 from datetime import datetime
-from pathlib import PurePath
+from pathlib import Path, PurePath
 from typing import Any, Dict, List, Optional, Set, Tuple
 
 import httpx
@@ -134,9 +134,8 @@ def _calc_risk_level(changed_files: List[str]) -> str:
 MAIL_PROJECT_ID = "_mail"
 
 
-def _mail_db_path() -> "Path":
+def _mail_db_path() -> Path:
     """获取 Mail 数据库路径，确保目录存在。"""
-    from pathlib import Path as P
     root = get_data_root()
     db = root / MAIL_PROJECT_ID / "blackboard.db"
     db.parent.mkdir(parents=True, exist_ok=True)