tonearmd-mcp

An MCP server that lets Claude read your Roon state, search your library, and put music on — by talking to tonearm's daemon.

Requires a running tonearmd

This server has no Roon credentials of its own and never talks to Roon directly. tonearmd owns the only Roon connection, which is what keeps Roon pairing to a single approval. Install and pair tonearm first; this server connects to its unix socket at $XDG_RUNTIME_DIR/tonearm/sock.

Related MCP server: lms-mcp-server

Install

git clone https://github.com/ssandys/tonearmd-mcp.git
cd tonearmd-mcp
npm install

Then point your MCP client at it:

{
  "mcpServers": {
    "tonearm": {
      "command": "node",
      "args": ["/absolute/path/to/tonearmd-mcp/src/server.js"]
    }
  }
}

Running it on the network

By default the MCP client spawns this over stdio, on the same machine as tonearmd. To let MCP clients elsewhere on your LAN drive the same daemon:

node src/server.js --http          # 0.0.0.0:9340
node src/server.js --http 9999     # another port
node src/server.js --http 127.0.0.1:9999

On first start it generates a key at ~/.config/tonearm-mcp/key (mode 0600) and prints it once. On every later start it prints where to find it instead — read it back with cat ~/.config/tonearm-mcp/key. Point remote clients at the URL with that key as a bearer token:

{
  "mcpServers": {
    "tonearm": {
      "type": "http",
      "url": "http://your-tonearm-box:9340/mcp",
      "headers": { "Authorization": "Bearer <the key>" }
    }
  }
}

To run it as a service, copy systemd/tonearmd-mcp.service to ~/.config/systemd/user/, adjust ExecStart to your checkout path, then systemctl --user enable --now tonearmd-mcp.

This is plain HTTP, for a LAN you trust. Anything already on the network can read the key and your listening history. That is a deliberate trade: TLS here would mean certificates every MCP client has to trust. If your network has guests or devices you don't trust, put a reverse proxy terminating TLS in front of it rather than exposing this directly.

All sessions share one zone. Two clients asking for music at once get one zone and last-writer-wins, not two streams — see docs/FOLLOWUPS.md item 2.

Requests carrying a non-localhost Origin header are refused with a bare 403, as DNS-rebinding protection — so a browser-based MCP client on the LAN needs a reverse proxy in front of this server; non-browser clients send no Origin and are unaffected.

Tools

Play and transport act on the zone the widget is following. To put music in a different room, play it and then tonearm_transfer it there.

How search works

A Roon search does not return albums — it returns category rows (Artists, Albums, Composers, Tracks, Works). This server descends into Albums and Tracks, capped at ten each, and returns a flat list of candidates so Claude can pick rather than guess.

Each candidate carries an opaque ref encoding the walk that found it. Playing one re-runs that walk rather than holding a browse cursor open, because a Claude turn can take minutes and a held cursor goes stale. The ref also records the title it was minted with, and playing refuses if the row at that position no longer matches — so a shifted result is an error you can see, never a different album playing quietly.

Running the tests

npm test

101 tests, no network and no daemon required — the fixtures are real daemon replies captured from a live Roon Core.

License

MIT. The only dependencies are @modelcontextprotocol/sdk and zod.