diff --git a/cloud/scorecard_diff.py b/cloud/scorecard_diff.py
index a88ac23..be1061e 100644
--- a/cloud/scorecard_diff.py
+++ b/cloud/scorecard_diff.py
@@ -90,6 +90,8 @@ from __future__ import annotations
 
 import sqlite3
 
+from cloud.db import connect as _db_connect
+
 TABLES = ("code", "production", "product")
 
 # 停表阈值：测试默认值、未拍板。生产阈值须用户拍板后显式传入。
@@ -297,8 +299,9 @@ class SqliteScorecardGainLedger:
             self._conn = connection
             self._owns_conn = False
         else:
-            self._conn = sqlite3.connect(str(db_path))
-            self._conn.row_factory = sqlite3.Row
+            # 层规则：服务层不得直连驱动，须走 cloud.db.connect
+            # （其 SQLite 路径已设 WAL + busy_timeout + Row）。
+            self._conn = _db_connect(str(db_path))
             self._owns_conn = True
         self._conn.execute(SQLITE_DDL)
         self._conn.commit()