diff --git a/src/ai/mcp/base.py b/src/ai/mcp/base.py
index 770ae8c..d375176 100644
--- a/src/ai/mcp/base.py
+++ b/src/ai/mcp/base.py
@@ -89,7 +89,9 @@ class MCPServer:
         
         handler = self.tools[name]
         logger.info(
-            f"MCP工具调用开始: server={self.name}, tool={name}, args={json.dumps(arguments, ensure_ascii=False)}"
+            "MCP工具调用开始: "
+            f"server={self.name}, tool={name}, "
+            f"args={json.dumps(arguments, ensure_ascii=False, default=str)}"
         )
         try:
             result = await handler(**arguments)