MCP error -32602: Invalid arguments for tool

[Janene-Li]

2025-08-02 19:57:03,922 - INFO - HTTP Request: POST https://server.smithery.ai/exa/mcp?config=eyJkZWJ1ZyI6IGZhbHNlfQ==&api_key=3fcdd206-a7b0-43cc-af16-6916514ae32f&profile=shaggy-wombat-pKqPYL "HTTP/1.1 200 OK"
2025-08-02 19:57:03,922 - INFO - Received session ID: eyJpIjoiNjgzMjMzMmE2MGQ2MjgiLCJzIjoiMDE5ODZhYTQtODRmZS03ZjE2LWJiOTAtNTIyNGI0NGZlMzI3IiwidiI6MX0.UetZrQghWu_HjnjMByiQ9oFbRuxkQqZ8B9cPZk29BeY,9e3be9b1-fc3f-4907-9c76-71a27dd08214
2025-08-02 19:57:03,923 - INFO - Negotiated protocol version: 2025-03-26
session初始化成功
server name: exa;
tool name: deep_researcher_start;
tool args:{'instruction': 'What is the first name of the mother of the 15th First Lady of the United States?', 'model': 'exa-research'}

2025-08-02 19:57:04,206 - INFO - HTTP Request: POST https://server.smithery.ai/exa/mcp?config=eyJkZWJ1ZyI6IGZhbHNlfQ==&api_key=3fcdd206-a7b0-43cc-af16-6916514ae32f&profile=shaggy-wombat-pKqPYL "HTTP/1.1 202 Accepted"
2025-08-02 19:57:04,217 - INFO - HTTP Request: GET https://server.smithery.ai/exa/mcp?config=eyJkZWJ1ZyI6IGZhbHNlfQ==&api_key=3fcdd206-a7b0-43cc-af16-6916514ae32f&profile=shaggy-wombat-pKqPYL "HTTP/1.1 200 OK"
2025-08-02 19:57:04,490 - INFO - HTTP Request: POST https://server.smithery.ai/exa/mcp?config=eyJkZWJ1ZyI6IGZhbHNlfQ==&api_key=3fcdd206-a7b0-43cc-af16-6916514ae32f&profile=shaggy-wombat-pKqPYL "HTTP/1.1 200 OK"
2025-08-02 19:57:04,908 - INFO - HTTP Request: DELETE https://server.smithery.ai/exa/mcp?config=eyJkZWJ1ZyI6IGZhbHNlfQ==&api_key=3fcdd206-a7b0-43cc-af16-6916514ae32f&profile=shaggy-wombat-pKqPYL "HTTP/1.1 204 No Content"
调用mcp tools时出错:

• Exception Group Traceback (most recent call last):
  | File "/home/enhan/NAMCP/proxy_server/server.py", line 107, in main
  | sub_mcp_result = await mcp_call_tool(server_name, tool_name, args_json)
  | File "/home/enhan/NAMCP/proxy_server/mcp_client/call_mcp_tool.py", line 83, in mcp_call_tool
  | async with streamablehttp_client(url) as (read, write, _):
  | File "/home/enhan/miniconda3/envs/MCP/lib/python3.10/contextlib.py", line 217, in aexit
  | await self.gen.athrow(typ, value, traceback)
  | File "/home/enhan/miniconda3/envs/MCP/lib/python3.10/site-packages/mcp/client/streamable_http.py", line 474, in streamablehttp_client
  | async with anyio.create_task_group() as tg:
  | File "/home/enhan/miniconda3/envs/MCP/lib/python3.10/site-packages/anyio/_backends/_asyncio.py", line 772, in aexit
  | raise BaseExceptionGroup(
  | exceptiongroup.ExceptionGroup: unhandled errors in a TaskGroup (1 sub-exception)
  +-+---------------- 1 ----------------
  | Exception Group Traceback (most recent call last):
  | File "/home/enhan/miniconda3/envs/MCP/lib/python3.10/site-packages/mcp/client/streamable_http.py", line 498, in streamablehttp_client
  | yield (
  | File "/home/enhan/NAMCP/proxy_server/mcp_client/call_mcp_tool.py", line 84, in mcp_call_tool
  | async with mcp.ClientSession(read, write) as session:
  | File "/home/enhan/miniconda3/envs/MCP/lib/python3.10/site-packages/anyio/_backends/_asyncio.py", line 772, in aexit
  | raise BaseExceptionGroup(
  | exceptiongroup.ExceptionGroup: unhandled errors in a TaskGroup (1 sub-exception)
  +-+---------------- 1 ----------------
  | Traceback (most recent call last):
  | File "/home/enhan/NAMCP/proxy_server/mcp_client/call_mcp_tool.py", line 91, in mcp_call_tool
  | response = await session.call_tool(tool_name, tool_args)
  | File "/home/enhan/miniconda3/envs/MCP/lib/python3.10/site-packages/mcp/client/session.py", line 293, in call_tool
  | result = await self.send_request(
  | File "/home/enhan/miniconda3/envs/MCP/lib/python3.10/site-packages/mcp/shared/session.py", line 286, in send_request
  | raise McpError(response_or_error.error)
  | mcp.shared.exceptions.McpError: MCP error -32602: Invalid arguments for tool deep_researcher_start: [
  | {
  | "code": "invalid_type",
  | "expected": "string",
  | "received": "undefined",
  | "path": [
  | "instructions"
  | ],
  | "message": "Required"
  | }
  | ]
  +------------------------------------

sometimes this error happens， it seems like my args is wrong, but my args seems like in the right format:
{'instruction': 'What is the first name of the mother of the 15th First Lady of the United States?', 'model': 'exa-research'}

here's my code:
async with streamablehttp_client(url) as (read, write, _):
async with mcp.ClientSession(read, write) as session:
await session.initialize()
print(f"server name: {server_name};\n tool name: {tool_name};\n tool args:{tool_args}\n\n")
response = await session.call_tool(tool_name, tool_args)