diff --git a/app/services/agent_dispatcher.py b/app/services/agent_dispatcher.py
index 4c2f860..cf34afc 100644
--- a/app/services/agent_dispatcher.py
+++ b/app/services/agent_dispatcher.py
@@ -674,6 +674,11 @@ class AgentDispatcher:
         svc = get_alarm_event_service()
         wechat = get_wechat_service()
 
+        # 检查告警是否存在
+        detail = svc.get_alarm(alarm_id)
+        if not detail:
+            return {"error": f"未找到告警: {alarm_id}"}
+
         # 合并 session 中暂存的图片
         session = get_session_manager().get(user_id)
         if session.pending_images: