Which integrations are available for this server?

Enables generation and export of musical compositions to [MIDI](/mcp/servers/integrations/midi) format, including melody generation, musical transformations, chord realization, and voice addition using the music21 library.

Music21 Composer MCP

A composition-focused MCP server built on music21, designed for generative workflows.

Features

generate_melody - Constraint-based melody generation
transform_phrase - Musical transformations (sequence, inversion, retrograde, etc.)
reharmonize - Generate alternative chord progressions
add_voice - Counterpoint and voice generation
realize_chord - Chord symbol to voicing
export_midi - Export to MIDI format

Installation

# Clone the repository git clone <repo-url> cd music21-composer-mcp # Install with dev dependencies pip install -e ".[dev]"

Quick Start

Start the HTTP server

composer-mcp --mode http --port 8000

API Usage

# Export notes to MIDI curl -X POST http://localhost:8000/export_midi \ -H "Content-Type: application/json" \ -d '{"stream": "C4, D4, E4, G4", "tempo": 120}'

API Documentation

With the server running, visit http://localhost:8000/docs for interactive API documentation.

Input Formats

The API accepts three input formats:

1. Note List (simplest)

C4, D4, E4, G4 # Quarter notes (default) C4:h, D4:q, E4:e # With durations (h=half, q=quarter, e=eighth) C#4:qd, Bb3:h # Accidentals and dotted notes

2. ABC Notation

X:1 M:4/4 K:C CDEF|GABc|

3. MusicXML

Standard MusicXML format.

Development

# Run tests pytest # Run with coverage pytest --cov=composer_mcp # Format code black src tests ruff check src tests

Implementation Status

Tool	Status
`export_midi`	Implemented
`realize_chord`	Phase 2
`generate_melody`	Phase 2
`reharmonize`	Phase 3
`add_voice`	Phase 4
`transform_phrase`	Phase 5
MCP adapter	Phase 6