midi-mcp 🎹

Give your AI agent ears and fingers. An MCP server that lets Claude (or any MCP client) listen to what you play on a MIDI keyboard and play back into your synth: harmonize your melody, loop a backing track while you solo, or just guess the tune you're playing (results may vary).

It works at the plain MIDI level, so there's no DAW and no plugin: any controller, any synth.

you:     *plays a folk tune on the keyboard*
claude:  "C major pentatonic, rising to a long A, settling home on C...
          my best guess is Auld Lang Syne?"
you:     "Down by the Salley Gardens."
claude:  "Close! Want me to harmonize it?"  *plays it back with chords*

Install

Requires uv. Tested on macOS; other platforms should work with a virtual MIDI port (e.g. loopMIDI on Windows) but are untested.

1. Create a virtual MIDI bus so the agent can reach your synth: Audio MIDI Setup → Window → Show MIDI Studio → IAC Driver → Device is online.

2. Let your synth listen to it: enable IAC Driver Bus 1 as a MIDI input (in Arturia Analog Lab: ☰ → Audio MIDI Settings → MIDI Devices).

3. Add the server to Claude Code:

   claude mcp add midi --scope user -- uvx --from git+https://github.com/thias42/midi-mcp midi-mcp

   For other MCP clients, run uvx --from git+https://github.com/thias42/midi-mcp midi-mcp as a stdio server.

Output goes to the first IAC bus and input comes from the first non-IAC port (your controller). Override with the MIDI_OUT / MIDI_IN environment variables (substring match) or the port argument on any tool.

Related MCP server: ableton-live-mcp

Things to try

• "Listen to what I play and tell me what key it's in."

• "Harmonize what I just played, then do it again in A minor with an arpeggio."

• "Loop Am, F, C, G as an arpeggio at 80 bpm while I improvise, then tell me what I played."

• "Play back my take a fifth higher and half as fast."

• "Save that as salley.mid."

Tools

play_notes, play_chords, replay and play_midi_file take wait=false to play in the background, and the note and chord tools take loops=0 to repeat until stop, so the agent can listen while a backing track loops.

Note names use C4 = MIDI 60.

Related projects

Other MIDI MCP servers do different jobs, and some do them better:

• Composing files: tubone24/midi-mcp-server creates MIDI from structured JSON, with a piano-roll preview in the chat. TripleAt/midi-mcp edits and transforms existing .mid files.

• Composing and playing out: mikeborozdin/vibe-composer-midi-mcp composes multi-track "whole band" arrangements and plays them on a synth. michelkro/midi-mcp adds music theory and genre tools.

• Raw MIDI in and out: ugufru/apple-midi-mcp is a native CoreMIDI bridge that can also read incoming messages and handles SysEx. pnilan/midi-mcp sends notes, CC and SysEx to hardware.

• Specific gear: feamster/digitakt-midi-mcp for the Elektron Digitakt.

midi-mcp focuses on playing along: it captures what you play as notes rather than raw messages, and it can loop a backing track while it listens.

How it started

With an Arturia Minilab3 and Analog Lab, I asked Claude Code "can you access my keyboard?" One session later it had guessed a tune (wrongly), harmonized it (nicely), researched whether any DAW already does this (none quite do), and written this server.

License

MIT