GitHub MCP server doesn't work in Python SDK

[adhikasp]

The @modelcontextprotocol/server-github doesn't work with python SDK. Here is code to reproduce

import os
from mcp import ClientSession, StdioServerParameters
from mcp.client.stdio import stdio_client
import dotenv

dotenv.load_dotenv()

async def main():
    server_params = StdioServerParameters(
        command="npx",
        args=["-y", "@modelcontextprotocol/server-github"],
        env={
            "GITHUB_PERSONAL_ACCESS_TOKEN": os.getenv("GITHUB_PERSONAL_ACCESS_TOKEN"),
            "PATH": os.getenv("PATH")
        }
    )

    async with stdio_client(server_params) as (read, write):
        async with ClientSession(read, write) as session:
            # Initialize the connection
            await session.initialize()

            # Example: Call tool to list repositories
            repos = await session.call_tool(
                "search_repositories",
                arguments={"query": "user:adhikasp"}
            )
            print("Repositories:", repos)

if __name__ == "__main__":
    import asyncio
    asyncio.run(main())

Output

$ python repro_github.py 
GitHub MCP Server running on stdio
Traceback (most recent call last):
  File "/mnt/e/Workspace/mcp-exploration/repro_github.py", line 26, in main
    repos = await session.call_tool(
            ^^^^^^^^^^^^^^^^^^^^^^^^
  File "/mnt/e/Workspace/mcp-exploration/.venv/lib/python3.12/site-packages/mcp/client/session.py", line 163, in call_tool
    return await self.send_request(
           ^^^^^^^^^^^^^^^^^^^^^^^^
  File "/mnt/e/Workspace/mcp-exploration/.venv/lib/python3.12/site-packages/mcp/shared/session.py", line 177, in send_request
    return result_type.model_validate(response_or_error.result)
           ^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^
  File "/mnt/e/Workspace/mcp-exploration/.venv/lib/python3.12/site-packages/pydantic/main.py", line 627, in model_validate
    return cls.__pydantic_validator__.validate_python(
           ^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^
pydantic_core._pydantic_core.ValidationError: 1 validation error for CallToolResult
content
  Field required [type=missing, input_value={'toolResult': {'total_co...ault_branch': 'main'}]}}, input_type=dict]
    For further information visit https://errors.pydantic.dev/2.10/v/missing

The server does work in inspector. Probably it have something to do with the Tool Result (Legacy) and the python sdk cannot parse legacy response?

[dsp-ant]

Thank you for reporting. I take a look

[hemangjoshi37a]

Do we compulsorily need to use the app or we can interface with MCP with python ? this is somewhat confusing

[adhikasp]

@hemangjoshi37a yes you should be able to use MCP servers with python

Example of simple python client in here https://github.com/adhikasp/mcp-client-cli
Right now it only implement the tool calling from the spec, not the resources and other stuff

[hemangjoshi37a]

@adhikasp actually I already tried using with python but it throws so many errors

[adhikasp]

The github servers x python SDK is fixed by modelcontextprotocol/servers#176 👍