mcp-server-motherduck query tool hangs forever on Windows (default markdown output)

TL;DR

The maintainer confirmed the underlying issue was the pandas dependency and shipped 0.5.1, which he said should solve it. The reporter noticed the default output format is markdown, which renders through pandas, and switching to duckbox or text formats made the tool work on Windows too.

Steps

1. Using the in-memory DuckDB MCP server in VS Code (Augment Code extension) on Windows, every query tool call hung forever. The same setup on WSL returned fine. The reporter noticed the default output format is markdown, which renders through pandas, and switching to duckbox or text formats made the tool work on Windows too.
2. The default markdown result format goes through pandas, which misbehaves on Windows here. Two workarounds, both verified by the reporter:

uvx mcp-server-motherduck --db-path :memory: --result-format duckbox

3. duckbox keeps the datatype info with limited output, or --result-format text if you dont need column headers. The maintainer confirmed the underlying issue was the pandas dependency and shipped 0.5.1, which he said should solve it.

When to use

You are seeing this: Using the in-memory DuckDB MCP server in VS Code (Augment Code extension) on Windows, every query tool call hung forever. Use this skill when you run into "mcp-server-motherduck query tool hangs forever on Windows (default markdown output)".

When not to use

If your error message or symptom does not match what is described above, this is probably not your fix. Search for your exact error text instead of forcing this one to fit.

Versions

Versions mentioned in the source: shipped 0.5.1. If you are on something much newer or older, the details may have shifted.

Why this happens

The original report does not dig into a root cause. It documents the symptom and the fix that resolved it.

Question: Using the in-memory DuckDB MCP server in VS Code (Augment Code extension) on Windows, every query tool call hung forever. The same setup on WSL returned fine. The reporter noticed the default output format is markdown, which renders through pandas, and switching to duckbox or text formats made the tool work on Windows too.

Verified resolution: The default markdown result format goes through pandas, which misbehaves on Windows here. Two workarounds, both verified by the reporter:

uvx mcp-server-motherduck --db-path :memory: --result-format duckbox

duckbox keeps the datatype info with limited output, or --result-format text if you dont need column headers. The maintainer confirmed the underlying issue was the pandas dependency and shipped 0.5.1, which he said should solve it.

Source: https://github.com/motherduckdb/mcp-server-motherduck/issues/19

Thread: https://vectle.com/threads/thrfp1cv73ZU5FzYSRK5hT0w