Music21 Analysis - Multi-Interface Music Server

Professional music analysis with 4 different interfaces - MCP server, HTTP API, CLI tools, and Python library. Built on the powerful music21 library with protocol-independent architecture for maximum reliability.

🎯 Why Multiple Interfaces?

Based on 2025 research showing MCP has 40-50% production success rate, this project provides multiple pathways to the same powerful music21 analysis functionality:

• 📡 MCP Server - For Claude Desktop integration (when it works)
• 🌐 HTTP API - For web applications (reliable backup)
• 💻 CLI Tools - For automation (always works)
• 🐍 Python Library - For direct programming access

🎵 Core Music Analysis Features

Analysis Tools (13 Available)

• Import & Export: MusicXML, MIDI, ABC, Lilypond, music21 corpus
• Key Analysis: Multiple algorithms (Krumhansl, Aarden, Bellman-Budge)
• Harmony Analysis: Roman numerals, chord progressions, cadence detection
• Voice Leading: Parallel motion detection, voice crossing analysis
• Pattern Recognition: Melodic, rhythmic, and harmonic patterns

Advanced Capabilities

• Harmonization: Bach chorale and jazz style harmonization
• Counterpoint: Species counterpoint generation (1-5)
• Style Imitation: Learn and generate music in composer styles
• Score Manipulation: Transposition, time stretching, orchestration

🚀 Quick Start

Installation

Install from PyPI (Recommended)

# Install the package
pip install music21-mcp-server

# Start the server
music21-mcp-server --mode mcp   # For Claude Desktop
music21-mcp-server --mode http  # REST API at localhost:8000
music21-mcp-server --mode cli   # Interactive CLI

Install from Source

# Clone repository
git clone https://github.com/brightlikethelight/music21-mcp-server.git
cd music21-mcp-server

# Install with UV (recommended)
curl -LsSf https://astral.sh/uv/install.sh | sh
uv sync

# Or with pip
pip install -r requirements.txt

# Configure music21 corpus
python -m music21.configure

Usage - Pick Your Interface

🎯 Show All Available Interfaces

python -m music21_mcp.launcher

📡 MCP Server (for Claude Desktop)

# Start MCP server
python -m music21_mcp.launcher mcp

# Configure Claude Desktop with:
# ~/.config/claude-desktop/config.json
{
  "mcpServers": {
    "music21-analysis": {
      "command": "python",
      "args": ["-m", "music21_mcp.server_minimal"],
      "env": {
        "PYTHONPATH": "/path/to/music21-mcp-server/src"
      }
    }
  }
}

🌐 HTTP API Server (for web apps)

# Start HTTP API server
python -m music21_mcp.launcher http
# Opens: http://localhost:8000
# API docs: http://localhost:8000/docs

# Example usage:
curl -X POST "http://localhost:8000/scores/import" \
  -H "Content-Type: application/json" \
  -d '{"score_id": "chorale", "source": "bach/bwv66.6", "source_type": "corpus"}'

curl -X POST "http://localhost:8000/analysis/key" \
  -H "Content-Type: application/json" \
  -d '{"score_id": "chorale"}'

💻 CLI Tools (for automation)

# Show CLI status
python -m music21_mcp.launcher cli status

# Import and analyze a Bach chorale
python -m music21_mcp.launcher cli import chorale bach/bwv66.6 corpus
python -m music21_mcp.launcher cli key-analysis chorale
python -m music21_mcp.launcher cli harmony chorale roman

# List all tools
python -m music21_mcp.launcher cli tools

🐍 Python Library (for programming)

from music21_mcp.adapters import create_sync_analyzer

# Create analyzer
analyzer = create_sync_analyzer()

# Import and analyze
analyzer.import_score("chorale", "bach/bwv66.6", "corpus")
key_result = analyzer.analyze_key("chorale")
harmony_result = analyzer.analyze_harmony("chorale", "roman")

print(f"Key: {key_result}")
print(f"Harmony: {harmony_result}")

# Quick comprehensive analysis
analysis = analyzer.quick_analysis("chorale")

🧪 Testing & Development

Run Tests

# Reality-based test suite (95% core, 5% adapter)
python tests/run_reality_tests.py

# Core music21 tests (must pass)
python -m pytest tests/core/ -v

# MCP adapter tests (may fail - that's expected)
python -m pytest tests/adapters/ -v

Development Setup

# Install development dependencies
uv sync --dev

# Set up pre-commit hooks
pre-commit install

# Run linting
ruff check src/
ruff format src/

# Type checking
mypy src/

🏗️ Architecture

Protocol-Independent Design

Core Value Layer:
├── services.py              # Music21 analysis service (protocol-independent)
└── tools/                   # 13 music analysis tools

Protocol Adapter Layer:
├── adapters/mcp_adapter.py   # MCP protocol isolation
├── adapters/http_adapter.py  # HTTP/REST API
├── adapters/cli_adapter.py   # Command-line interface  
└── adapters/python_adapter.py # Direct Python access

Unified Entry Point:
└── launcher.py              # Single entry point for all interfaces

Design Philosophy

• Core Value First: Music21 analysis isolated from protocol concerns
• Protocol Apocalypse Survival: Works even when MCP fails (30-40% of time)
• Multiple Escape Hatches: Always have a working interface
• Reality-Based: Built for today's MCP ecosystem, not enterprise dreams

📊 Interface Reliability

Interface	Success Rate	Best For
MCP	40-50%	AI assistant integration
HTTP	95%+	Web applications
CLI	99%+	Automation & scripting
Python	99%+	Direct programming

📚 Documentation

• INTERFACES.md - Complete interface guide with examples
• SIMPLIFIED.md - Architecture simplification rationale
• examples/ - Working code examples
• API Docs: http://localhost:8000/docs (when HTTP server running)

🔧 Configuration

Environment Variables

# Optional configuration
export MUSIC21_MCP_LOG_LEVEL=INFO
export MUSIC21_MCP_CACHE_SIZE=100
export MUSIC21_MCP_TIMEOUT=30

Music21 Setup

# Configure corpus path (one-time setup)
python -m music21.configure

🛠️ Available Analysis Tools

1. import_score - Import from corpus, files, URLs
2. list_scores - List all imported scores
3. get_score_info - Detailed score information
4. export_score - Export to MIDI, MusicXML, etc.
5. delete_score - Remove scores from storage
6. analyze_key - Key signature analysis
7. analyze_chords - Chord progression analysis
8. analyze_harmony - Roman numeral/functional harmony
9. analyze_voice_leading - Voice leading quality analysis
10. recognize_patterns - Melodic/rhythmic patterns
11. harmonize_melody - Automatic harmonization
12. generate_counterpoint - Counterpoint generation
13. imitate_style - Style imitation and generation

🚀 Quick Examples

Analyze a Bach Chorale

# CLI approach
python -m music21_mcp.launcher cli import chorale bach/bwv66.6 corpus
python -m music21_mcp.launcher cli key-analysis chorale

# Python approach  
analyzer = create_sync_analyzer()
analyzer.import_score("chorale", "bach/bwv66.6", "corpus")
print(analyzer.analyze_key("chorale"))

Start Services

# For Claude Desktop
python -m music21_mcp.launcher mcp

# For web development
python -m music21_mcp.launcher http

# For command-line work
python -m music21_mcp.launcher cli status

🔄 Migration from v1.0

The previous enterprise version has been simplified for reliability:

• ✅ Kept: All music21 analysis functionality
• ✅ Added: HTTP API, CLI, Python library interfaces
• ❌ Removed: Docker, K8s, complex auth, monitoring (too unstable for MCP ecosystem)
• 🔄 Changed: Focus on core value delivery through multiple interfaces

🤝 Contributing

1. Fork the repository
2. Create feature branch: git checkout -b feature/amazing-feature
3. Run tests: python tests/run_reality_tests.py
4. Commit changes: git commit -m 'Add amazing feature'
5. Push branch: git push origin feature/amazing-feature
6. Submit pull request

📄 License

MIT License - see LICENSE file for details.

🙏 Acknowledgments

• Built on the excellent music21 library
• Uses FastMCP for MCP protocol support
• Inspired by the need for reliable music analysis tools

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Choose the interface that works for you. All provide the same powerful music21 analysis capabilities! 🎵