fix: handle non-JSON-serializable objects in MCP tool calls (#150)

Co-authored-by: 越鸿 <nishenghao.nsh@oceanbase.com>

Author: niiish32x

packages/derisk-serve/src/derisk_serve/agent/resource/tool/mcp_utils.py

@@ -22,6 +22,45 @@
     GptsToolMessages,
 )
 
+
+def _make_json_serializable(obj: Any) -> Any:
+    """将对象转换为 JSON 可序列化的格式。
+
+    处理包括 AgentFileSystem 等非序列化对象，将其转换为字符串或字典表示。
+    """
+    if obj is None:
+        return None
+    if isinstance(obj, (str, int, float, bool)):
+        return obj
+    if isinstance(obj, (list, tuple)):
+        return [_make_json_serializable(item) for item in obj]
+    if isinstance(obj, dict):
+        return {k: _make_json_serializable(v) for k, v in obj.items()}
+
+    # 处理 AgentFileSystem 和其他常见非序列化类型
+    type_name = type(obj).__name__
+
+    # AgentFileSystem 类型 - 转换为字符串表示
+    if type_name == "AgentFileSystem":
+        return f"<AgentFileSystem: {getattr(obj, 'root_path', str(obj))}>"
+
+    # Pydantic 模型 - 使用 model_dump 或 dict
+    if hasattr(obj, "model_dump"):
+        return _make_json_serializable(obj.model_dump())
+    if hasattr(obj, "dict"):
+        return _make_json_serializable(obj.dict())
+
+    # dataclass - 使用 asdict
+    if hasattr(obj, "__dataclass_fields__"):
+        from dataclasses import asdict
+        return _make_json_serializable(asdict(obj))
+
+    # 其他对象 - 尝试转换为字符串
+    try:
+        return str(obj)
+    except Exception:
+        return f"<{type_name}: unserializable>"
+
 logger = logging.getLogger(__name__)
 tool_cache = TTLCache(maxsize=200, ttl=300)
 gpts_tool_messages_dao = GptsToolMessagesDao()
@@ -184,12 +223,15 @@ async def call_mcp_tool(
         tool_id = str(uuid.uuid4())
 
     async def call_tool(server: str, arguments: dict):
+        # 将参数转换为 JSON 可序列化格式，处理 AgentFileSystem 等对象
+        serializable_arguments = _make_json_serializable(arguments)
+
         gpts_tool_messages = GptsToolMessages(
             tool_id=tool_id,
             name=mcp_name,
             sub_name=tool_name,
             type="MCP",
-            input=json.dumps(arguments, ensure_ascii=False),
+            input=json.dumps(serializable_arguments, ensure_ascii=False),
             success=1,
             trace_id=trace_id,
         )
@@ -213,7 +255,7 @@ async def call_tool(server: str, arguments: dict):
             ) as (read, write):
                 async with ClientSession(read, write) as session:
                     await session.initialize()
-                    result = await session.call_tool(tool_name, arguments=arguments)
+                    result = await session.call_tool(tool_name, arguments=serializable_arguments)
                     end_time = int(datetime.now().timestamp() * 1000)
                     LOGGER.info(
                         f"[DIGEST][tools/call]mcp_server=[{mcp_name}],sse=[{mcp_server}],success=[Y],err_msg=[],tool=[{tool_name}],costMs=[{end_time - start_time}],result_length=[{len(str(result.json()))}],headers=[{headers}],result:[{result.json()}]"