pymat-mcp

MCP server exposing the py-materials curated material registry to AI agents — Claude Desktop, Cursor, MCP Inspector, any MCP-compatible client.

"Aluminum 6061-T6 yield strength?" — agent calls get_material instead of guessing. CAD prompts that need real density / mechanical properties stop hallucinating.

Install

Zero-install via uvx:

{
  "mcpServers": {
    "pymat": {
      "command": "uvx",
      "args": ["pymat-mcp"]
    }
  }
}

That's it. uvx fetches pymat-mcp (which transitively pulls py-materials) and runs it in an isolated venv per session.

For a pinned version: "args": ["pymat-mcp@0.1.0"].

For programmatic use, pip install pymat-mcp works too — the package is fully a normal Python module.

Tools

All tools are read-only. Errors come back as {"error": "...", "did_you_mean": [...]} rather than exceptions.

Example agent prompts

• "What's the yield strength of 17-4 PH H1025? Use the materials database."
• "I have a 50×50×10 mm 6061 plate; what's the mass?"
• "Give me a Three.js material dict for stainless steel with a polished finish."
• "Compare density and thermal conductivity for 6061, 7075, and copper."

Logging

Logs to stderr only (stdout is the MCP transport channel). Bump verbosity:

PYMAT_MCP_LOG=DEBUG uvx pymat-mcp

Development

git clone https://github.com/MorePET/mat
cd mat/clients/python/pymat-mcp
uv sync --all-extras
uv run pytest -v

To exercise the server interactively:

uvx mcp dev pymat-mcp     # MCP Inspector — point-and-click tool calls

Links

• Source: https://github.com/MorePET/mat/tree/main/clients/python/pymat-mcp
• Issues: https://github.com/MorePET/mat/issues
• py-materials (the wrapped library): https://github.com/MorePET/mat
• MCP spec: https://spec.modelcontextprotocol.io