diff --git a/src/daemon/mail_notify.py b/src/daemon/mail_notify.py
index 9e7d632..90b9fc7 100644
--- a/src/daemon/mail_notify.py
+++ b/src/daemon/mail_notify.py
@@ -13,6 +13,12 @@ from src.blackboard.operations import Blackboard
 
 logger = logging.getLogger(__name__)
 
+# 有效 Agent ID 集合（用于校验通知目标）
+_VALID_AGENT_IDS = frozenset({
+    "pangtong-fujunshi", "simayi-challenger", "zhangfei-dev",
+    "guanyu-dev", "zhaoyun-data", "jiangwei-infra",
+})
+
 # 邮件通知正文模板（统一模板，包含所有可能的失败原因和建议）
 _NOTIFY_TEMPLATE = """你的邮件投递失败了。
 
@@ -42,6 +48,7 @@ def notify_mail_failed(db_path: Path, original_mail_id: str,
 
     直接通过 Blackboard 创建 Task，不走 HTTP API。
     防递归：检查原邮件 must_hives.system_notify，为 true 则跳过。
+    发件人不是有效 Agent（如 system）→ 通知庞统代处理，避免广播风暴。
     """
     try:
         bb = Blackboard(db_path)
@@ -67,6 +74,13 @@ def notify_mail_failed(db_path: Path, original_mail_id: str,
             logger.warning("notify_mail_failed: cannot determine sender for mail %s", original_mail_id)
             return
 
+        # 发件人不是有效 Agent（如 system）→ 通知庞统代处理，不触发广播
+        target_agent = from_agent
+        if from_agent not in _VALID_AGENT_IDS:
+            logger.warning("Mail %s: sender '%s' is not a valid agent, routing failure notice to pangtong-fujunshi",
+                           original_mail_id, from_agent)
+            target_agent = "pangtong-fujunshi"
+
         # 构造通知正文
         text = _NOTIFY_TEMPLATE.format(
             title=title,
@@ -90,15 +104,15 @@ def notify_mail_failed(db_path: Path, original_mail_id: str,
             id=notify_id,
             title=f"[投递失败] {title}",
             description=text,
-            assignee=from_agent,
+            assignee=target_agent,
             assigned_by="system",
             must_haves=json.dumps(notify_meta, ensure_ascii=False),
             task_type="mail",
             status="pending",
         )
         bb.create_task(notify_task)
-        logger.info("Mail %s: sent failure notification to %s (reason=%s, notify_id=%s)",
-                     original_mail_id, from_agent, reason, notify_id)
+        logger.info("Mail %s: sent failure notification to %s (original_sender=%s, reason=%s, notify_id=%s)",
+                     original_mail_id, target_agent, from_agent, reason, notify_id)
 
     except Exception as e:
         logger.warning("notify_mail_failed: failed to send notification for mail %s: %s", original_mail_id, e)