diff --git a/aibox_sophon_adapter/edge_app_controller.py b/aibox_sophon_adapter/edge_app_controller.py
index d1662c8..976fbba 100644
--- a/aibox_sophon_adapter/edge_app_controller.py
+++ b/aibox_sophon_adapter/edge_app_controller.py
@@ -161,7 +161,7 @@ async def _cmd_alg_media_fetch(payload: dict) -> dict | None:
         print(f"[alg_media_fetch]Response from internal_mqtt: {resp}")
 
         if resp is None:
-            return _reply(-5, "获取媒体信息超时或失败")
+            return _reply(-5, "获取算法媒体信息失败（内部请求无响应）")
         return resp
 
 async def _cmd_alg_task_fetch(payload: dict) -> dict | None:
@@ -171,7 +171,12 @@ async def _cmd_alg_task_fetch(payload: dict) -> dict | None:
     请求: {"Event": "/alg_task_fetch", "BoardId": "..."}
     返回: {"board_id": ..., "tasks": [...]}
     """
-    from .global_var import db
+    from .global_var import (
+        db,
+        internal_mqtt,
+        internal_request_topic,
+        internal_response_topic,
+    )
 
     board_id = payload.get("BoardId")
     if not board_id:
@@ -182,6 +187,8 @@ async def _cmd_alg_task_fetch(payload: dict) -> dict | None:
 
     if db is None:
         return _reply(-5, "数据库未初始化")
+    if internal_mqtt is None:
+        return _reply(-5, "internal_mqtt 未初始化")
 
     async with db.get_session() as session:
         from .models.orm import BoardHeartbeat
@@ -195,18 +202,15 @@ async def _cmd_alg_task_fetch(payload: dict) -> dict | None:
             print(f"[alg_task_fetch]Board {board_id} not found in database.")
             return _reply(-4, f"设备 {board_id} 不在数据库中")
 
-        import json
-        ping_data = {}
-        try:
-            ping_data = json.loads(record.ping_data) if record.ping_data else {}
-        except json.JSONDecodeError:
-            pass
-
-        return {
-            "board_id": board_id,
-            "tasks": ping_data.get("Tasks", []),
-        }
+        
+        resp = await internal_mqtt.request(
+            request_topic=internal_request_topic,
+            response_topic=internal_response_topic,
+            payload=payload,
+            timeout=5
+        )
 
+        return resp
 
 # 命令注册表：command -> async handler(payload) -> data（返回 None 表示不回复）
 _COMMANDS: dict[str, Callable[[dict], Coroutine[Any, Any, Any]]] = {