Materials

What Materials MCP server does

The Materials MCP server exposes computed materials data to MCP-compatible agents. It provides two domain-specific tools: materials_search for finding computed crystal structures and materials_stability for examining formation energies and thermodynamic stability from OQMD.

Structure searches can cover the OPTIMADE materials-database federation, including OQMD, Materials Project, NOMAD, and Alexandria. Results include a structure identifier, reduced formula, elements, site count, and a link. Searches can be narrowed by an element set such as Fe and O, an exact reduced formula such as Fe2O3, or the number of elements.

Stability queries focus on a chemical system and return phase-level results. Available values include composition, formation energy in eV per atom, hull stability in eV per atom, band gap, space group, and prototype. Hull stability values at or below zero indicate stable phases.

How it works

The service is available through a hosted Pipeworx endpoint or as a local package. The hosted materials endpoint uses streamable HTTP at https://gateway.pipeworx.io/materials/mcp. A full gateway endpoint is also available at https://gateway.pipeworx.io/mcp.

The hosted pack endpoint lists the Materials tools along with shared Pipeworx meta-tools. Those shared tools can route questions to other sources through ask_pipeworx, discover tools, search within the gateway, and handle related gateway functions. The exact tool scope is reported by the connection's initialize response.

For direct non-MCP HTTP use, the tools can be called through the gateway's REST interface. For example, POST https://gateway.pipeworx.io/v1/tools/materials_search accepts JSON arguments such as elements, formula, and limit.

Setup and configuration

Add the hosted endpoint to an MCP client as a server with the URL https://gateway.pipeworx.io/materials/mcp. The README names Claude Desktop, Cursor, and Windsurf as supported setup targets.

For a local stdio connection, run the package with:

{
  "mcpServers": {
    "materials": {
      "command": "npx",
      "args": ["-y", "@pipeworx/mcp-materials"]
    }
  }
}

Running npx -y @pipeworx/mcp-materials directly can confirm that the local server starts. The local mode handles MCP over standard input and output and exposes only the Materials tools, without the gateway's shared meta-tools or gateway routing.

Tools and capabilities

• materials_search: Find computed DFT crystal structures across the supported materials-database federation.
• materials_stability: Query OQMD for formation energy and phase stability in a specified element system.
• Filter structure searches by elements, reduced formula, and element count.
• Restrict stability results to phases on or below the convex hull when stable phases are the target.
• Use ask_pipeworx on the hosted gateway to ask materials questions in natural language instead of calling a domain tool directly.

Limitations and notes

The structure search covers computed entries, described as a collection of millions of records, rather than experimental structures. The README directs users seeking experimental crystallography to the COD pack. Stability and formation-energy results come from OQMD and use DFT calculations; they should not be treated as experimental measurements.

A pack-specific hosted connection still exposes shared gateway schemas, so its listed tool count can be larger than the two Materials tools. The standalone package avoids those additional schemas but also does not provide ask_pipeworx routing. The hosted and local modes use the same source tools, while the hosted mode adds gateway access around them.