mcp-server-motherduck: TypeError main() got an unexpected keyword argument 'result_format'

mcp-server-motherduck: TypeError main() got an unexpected keyword argument 'result_format'

What was going on

Setting up the MotherDuck MCP server with Claude Desktop (access token plus home directory path per the README) wouldnt connect. The Claude log showed the server crashing on startup with TypeError: main() got an unexpected keyword argument 'result_format'. Downgrading to mcp-server-motherduck==0.3.0 made it work, so the bug was in the 0.3.2 release.

The fix that worked

This was a bug in the 0.3.2 release, not your config. The maintainer confirmed it and shipped 0.3.3 the same day fixing the result_format argument mismatch. A reporter confirmed "v 0.3.3 worked!".

Fix: make sure youre on 0.3.3 or newer. If you pinned the version in your Claude config, bump it:

{
  "mcpServers": {
    "motherduck": {
      "command": "uvx",
      "args": ["mcp-server-motherduck@0.3.3", "--db-path", "md:"]
    }
  }
}

Also double check uv itself is installed, since the server runs through uvx.

Where this came from

https://github.com/motherduckdb/mcp-server-motherduck/issues/6

Someone asked: Setting up the MotherDuck MCP server with Claude Desktop (access token plus home directory path per the README) wouldnt connect. The Claude log showed the server crashing on startup with TypeError: main() got an unexpected keyword argument 'result_format'. Downgrading to mcp-server-motherduck==0.3.0 made it work, so the bug was in the 0.3.2 release. The verified resolution: This was a bug in the 0.3.2 release, not your config. The maintainer confirmed it and shipped 0.3.3 the same day fixing the result_format argument mismatch. A reporter confirmed "v 0.3.3 worked!".

Fix: make sure youre on 0.3.3 or newer. If you pinned the version in your Claude config, bump it:

{
  "mcpServers": {
    "motherduck": {
      "command": "uvx",
      "args": ["mcp-server-motherduck@0.3.3", "--db-path", "md:"]
    }
  }
}

Also double check uv itself is installed, since the server runs through uvx. Thread: https://vectle.com/threads/thr_1vD8leyNUATGjWTmtPoEXg