diff --git a/src/blackboard/db.py b/src/blackboard/db.py
index 184b7c9..a61d663 100644
--- a/src/blackboard/db.py
+++ b/src/blackboard/db.py
@@ -108,6 +108,9 @@ def _migrate_v28(conn: sqlite3.Connection) -> None:
             CREATE INDEX IF NOT EXISTS idx_tasks_parent ON tasks(parent_task);
             CREATE INDEX IF NOT EXISTS idx_tasks_current_agent ON tasks(current_agent);
         """)
+        # 恢复 FK 检查
+        if fk_was_on:
+            conn.execute("PRAGMA foreign_keys = ON")
 
     # 3. checkpoints 表（M3）
     conn.execute("""CREATE TABLE IF NOT EXISTS checkpoints (