Materials MCP server for AI agents

A free, read-only Model Context Protocol server for engineering materials. Every number it returns comes with its unit, the conditions it was measured under, the method and the source it was read from, so an AI assistant can quote a value and prove where it came from.

Connect it

Endpoint (Streamable HTTP): https://spacemushroom.com/mcp. No API key and no sign-in. It is listed in the official MCP registry as com.spacemushroom/materials.

Claude

Open Settings, then Connectors, then Add custom connector. Enter https://spacemushroom.com/mcp and set sign-in to none.

Claude Code

claude mcp add --transport http space-mushroom https://spacemushroom.com/mcp

Cursor, VS Code and other clients that accept a remote server

{
  "mcpServers": {
    "space-mushroom": {
      "url": "https://spacemushroom.com/mcp"
    }
  }
}

What it can do

Tool	What it does
`find_materials`	Requirements in, candidates out. Each material gets pass, fail or unknown, with the evidence behind every constraint.
`search_materials`	Find materials by name, abbreviation or formula.
`get_material`	The sourced record of one material: values with conditions, method and source location, plus uses, hazards, failure modes, corrosion and supply facts.
`compare`	Line several materials up on one property, each value with its conditions and source, also in a canonical unit so they can be ranked.
`list_properties`	The property names in use, with their canonical unit and whether higher or lower is better.
`list_claims`	Every current sourced value of one material, with an evidence level and a claim id.
`prove_claim`	Everything behind one value: as printed in the source, converted, the conditions, and where in each source it sits.
`what_is_missing`	For one material and a list of properties: which have sourced data and which have none yet.
`resolve_designation`	Which material a code names: UNS, EN, DIN, JIS, AISI or SAE number, ASTM or AMS specification, or a trade name.
`search_sources`	Full-text search over short quoted passages from our sources. Passages are still being added, so it can return an empty list.
`get_term`	A plain-language definition of a technical term or abbreviation used on material pages.

All eleven tools only read. Nothing is written and nothing outside our database is called.

An example

You:    Compare the density of aluminium 6061 and Ti-6Al-4V and tell me where each number comes from.
Claude: calls compare {"property":"density","materials":["aluminium-6061","ti-6al-4v"]}

aluminium-6061   2.7 g/cm3   Aluminum Association typical value, T6 and T651
                 source: ASM Material Data Sheet, Aluminum 6061-T6; 6061-T651
ti-6al-4v        4.43 g/cm3  alloy density, printed in a technical reference (section 3.2, physical constants)
                 source: Ti-6Al-4V (Grade 5) titanium: material guide, Boze Titanium

Both values are marked ai_checked: an AI assistant re-read them against the source, a person has not.

What to know before you rely on it

A missing value means "not covered yet", not "known to be safe". Use what_is_missing to see coverage for one material.
Values come from published papers, standards, data sheets and agency reports. We do not measure anything ourselves. Different test conditions are listed separately and never averaged.
Some values were re-read by an AI assistant and are labelled ai_checked. Our methodology and editorial policy say how values are checked.
The data is licensed CC BY 4.0. Cite the source shown with each value and "Space Mushroom (spacemushroom.com)".
What the server does with requests is described in the privacy policy.