diff --git a/src/blackboard/operations.py b/src/blackboard/operations.py
index 9de7bf5..0e2611a 100644
--- a/src/blackboard/operations.py
+++ b/src/blackboard/operations.py
@@ -198,6 +198,20 @@ class Blackboard:
         finally:
             conn.close()
 
+    def update_must_haves(self, task_id: str, must_haves: str) -> bool:
+        """更新 Task 的 must_haves 字段（用于 Mail 元数据等）"""
+        conn = self._conn()
+        try:
+            conn.execute("BEGIN IMMEDIATE")
+            conn.execute(
+                "UPDATE tasks SET must_haves=?, updated_at=datetime('now') WHERE id=?",
+                (must_haves, task_id),
+            )
+            conn.commit()
+            return True
+        finally:
+            conn.close()
+
     # ===================================================================
     # Comment
     # ===================================================================