Matter Expert MCP Server

A local MCP server that gives Claude Code expert-level access to the full Matter specification suite, enabling accurate, spec-grounded answers during firmware development.

What It Does

When active in Claude Code, you can ask questions like:

• "What attributes are mandatory for the Door Lock cluster?"
• "What clusters does a Thermostat device type require?"
• "What's the SHALL requirement for commissioning window timeout?"
• "What semantic tags are available for home area locations?"

Claude Code calls the MCP tools to pull exact spec text and gives you accurate, normative answers instead of hallucinated ones.

Tools Available

Tool	Description
matter_search	Full-text search across all indexed specs
matter_cluster_lookup	Look up cluster attributes/commands/events
matter_device_type_lookup	Get required/optional clusters for a device type
matter_tag_lookup	Look up semantic tags and namespaces
matter_normative_check	Find SHALL/SHOULD/MAY requirements on a topic
matter_index_status	Check if index is built and ready

Setup

1. Install dependencies

cd matter-mcp
npm install

2. Download and place spec PDFs

Download the Matter specification PDFs from the CSA: https://csa-iot.org/developer-resource/specifications-download-request/

Create a pdfs/ subdirectory and copy in your Matter spec PDFs:

matter-mcp/
└── pdfs/
    ├── <matter-core-spec>.pdf
    ├── <matter-cluster-spec>.pdf
    ├── <matter-device-library>.pdf
    └── <matter-namespaces>.pdf

The indexer auto-detects PDFs by matching these keywords in filenames:

• core → Core Specification
• cluster → Application Cluster Specification
• device → Device Library Specification
• namespace → Standard Namespaces

Any PDF whose filename contains the matching keyword (case-insensitive) will be indexed under that doc key. Update PDF_KEY_PATTERNS in src/build-index.ts if your filenames use different conventions.

3. Build the index (one-time)

npm run build-index

This takes 2–5 minutes and creates matter_index.db. Only needs to be re-run when you update to a new spec version.

4. Register with Claude Code

Add the server to ~/.claude.json under mcpServers:

{
  "mcpServers": {
    "matter": {
      "type": "stdio",
      "command": "node",
      "args": ["/absolute/path/to/matter-mcp/dist/server.js"]
    }
  }
}

Replace /absolute/path/to/matter-mcp/ with the actual path on your machine.

5. Use in Claude Code

Restart Claude Code, then test:

> Check matter_index_status
> Look up mandatory attributes for the Door Lock cluster
> What does Matter require for OTA update requestors?

Updating to a New Spec Version

1. Replace the PDFs in pdfs/ with the new versions
2. Re-run npm run build-index
3. The old index is replaced automatically

File Structure

matter-mcp/
├── src/
│   ├── server.ts           # MCP server — all 6 tools
│   ├── build-index.ts      # One-time PDF indexer
│   └── search.ts           # FTS5/BM25 search engine
├── dist/                   # Compiled output (run `npm run build`)
├── matter_index.db         # Generated index (after running build-index)
├── package.json
├── tsconfig.json
├── README.md
└── pdfs/                   # Place your spec PDFs here