diff --git a/src/plugin_runtime/protocol/errors.py b/src/plugin_runtime/protocol/errors.py
index ed19760d..d2b9228b 100644
--- a/src/plugin_runtime/protocol/errors.py
+++ b/src/plugin_runtime/protocol/errors.py
@@ -7,7 +7,7 @@ from enum import Enum
 from typing import Any, Dict, Optional
 
 
-class ErrorCode(Enum):
+class ErrorCode(str, Enum):
     """RPC 错误码枚举"""
 
     # 通用