diff --git a/apps/application/flow/tools.py b/apps/application/flow/tools.py
index 149eafaa0..bde1d0ed4 100644
--- a/apps/application/flow/tools.py
+++ b/apps/application/flow/tools.py
@@ -290,26 +290,60 @@ async def _yield_mcp_response(chat_model, message_list, mcp_servers, mcp_output_
         agent = create_react_agent(chat_model, tools)
         response = agent.astream({"messages": message_list}, stream_mode='messages')
 
-        # 用于存储工具调用信息
+        # 用于存储工具调用信息（按 tool_id）以及按 index 聚合分片
         tool_calls_info = {}
+        _tool_fragments = {}  # index -> {'id':..., 'name':..., 'arguments':...}
 
         async for chunk in response:
             if isinstance(chunk[0], AIMessageChunk):
                 tool_calls = chunk[0].additional_kwargs.get('tool_calls', [])
                 for tool_call in tool_calls:
-                    tool_id = tool_call.get('id', '')
-                    if tool_id:
-                        # 保存工具调用的输入
-                        tool_calls_info[tool_id] = {
-                            'name': tool_call.get('function', {}).get('name', ''),
-                            'input': tool_call.get('function', {}).get('arguments', '')
-                        }
+                    idx = tool_call.get('index')
+                    if idx is None:
+                        continue
+                    entry = _tool_fragments.setdefault(idx, {'id': '', 'name': '', 'arguments': ''})
+
+                    # 更新 id 与 name（如果有）
+                    if tool_call.get('id'):
+                        entry['id'] = tool_call.get('id')
+
+                    func = tool_call.get('function', {})
+                    # arguments 可能在 function.arguments 或顶层 arguments
+                    part_args = ''
+                    if isinstance(func, dict) and 'arguments' in func:
+                        part_args = func.get('arguments') or ''
+                        if func.get('name'):
+                            entry['name'] = func.get('name')
+                    else:
+                        part_args = tool_call.get('arguments', '') or ''
+
+                    # 统一为字符串
+                    if not isinstance(part_args, str):
+                        try:
+                            part_args = json.dumps(part_args, ensure_ascii=False)
+                        except Exception:
+                            part_args = str(part_args)
+
+                    entry['arguments'] += part_args
+
+                    # 尝试判断 JSON 是否完整（若 arguments 是 JSON），完整则提交到 tool_calls_info
+                    try:
+                        json.loads(entry['arguments'])
+                        if entry['id']:
+                            tool_calls_info[entry['id']] = {
+                                'name': entry.get('name', ''),
+                                'input': entry['arguments']
+                            }
+                            _tool_fragments.pop(idx, None)
+                    except Exception:
+                        # 如果不是完整 JSON，继续等待后续片段
+                        pass
+
                 yield chunk[0]
 
             if mcp_output_enable and isinstance(chunk[0], ToolMessage):
                 tool_id = chunk[0].tool_call_id
                 if tool_id in tool_calls_info:
-                    # 合并输入和输出
                     tool_info = tool_calls_info[tool_id]
                     content = generate_tool_message_complete(
                         tool_info['name'],
@@ -335,6 +369,7 @@ async def _yield_mcp_response(chat_model, message_list, mcp_servers, mcp_output_
         raise RuntimeError(error_msg) from None
 
 
+
 def mcp_response_generator(chat_model, message_list, mcp_servers, mcp_output_enable=True):
     """使用全局事件循环，不创建新实例"""
     result_queue = queue.Queue()