MIDI MCP Server is a Model Context Protocol (MCP) server that enables AI models to generate MIDI files from text-based music data. This tool allows for programmatic creation of musical compositions through a standardized interface.

npm install
npm run build

After building the project, simply add the server to your MCP client configuration:

"mcpServers": {
    "musicComposer": {
        "command": "node",
        "args": ["/path/to/midi-mcp-server/build/index.js"]
    }
}

Replace /path/to/ with the actual path to your project directory.

• Generate MIDI files from structured JSON music data
• Support for multiple tracks and instruments
• Customizable tempo, time signature, and note properties
• Save MIDI files to specified locations

The server provides a tool called create_midi that generates MIDI files from structured music data.

• title: String - The title of the composition
• composition: String - A JSON string representing the music data
• output_path: String - Path where the MIDI file will be saved

The composition should follow this structure:

{
  "bpm": number,
  "timeSignature": { "numerator": number, "denominator": number },
  "tracks": [
    {
      "name": string,
      "instrument": number,
      "notes": [
        { "pitch": number, "startTime": number, "duration": number, "velocity": number }
      ]
    }
  ]
}

• bpm: Tempo in beats per minute
• timeSignature: Time signature (e.g., {numerator: 4, denominator: 4} for 4/4 time)
• tracks: Array of instrument tracks
  • name: Track name
  • instrument: MIDI program number (0-127)
  • notes: Array of note objects
    • pitch: MIDI note number (0-127)
    • startTime: Start time in beats
    • duration: Note duration in beats
    • velocity: Note velocity/volume (0-127)

const composition = {
  "bpm": 120,
  "timeSignature": { "numerator": 4, "denominator": 4 },
  "tracks": [
    {
      "name": "Piano",
      "instrument": 0,
      "notes": [
        { "pitch": 60, "startTime": 0, "duration": 1, "velocity": 100 },
        { "pitch": 64, "startTime": 1, "duration": 1, "velocity": 100 },
        { "pitch": 67, "startTime": 2, "duration": 1, "velocity": 100 }
      ]
    }
  ]
};

• @modelcontextprotocol/sdk: MCP server implementation
• midi-writer-js: Library for creating MIDI files

For example, the prompt below, which is a request to create a minor scale 8-bar choral piece, can be processed by the server:

8小節の合唱曲を作って。
若干マイナー調で、メロディックな音階を作ってほしい

melodic_minor_chorus.mid

This MCP server runs locally and communicates via standard input/output (stdio). No network configuration is required as the MCP client will automatically start the server process and establish communication.