Strudel MCP Server

🎵 Open source MCP server for AI-powered music generation with Strudel.cc

Status: Actively developed | Experimental | Contributions welcome

An experimental Model Context Protocol (MCP) server that enables Claude to control Strudel.cc for AI-assisted music generation, live coding, and algorithmic composition.

Current State: Functional but under active development. Core features work reliably, but expect rough edges. Test coverage is at 78% with 1470 tests passing (1521 total, 51 skipped). See open issues for known limitations.

Table of Contents

• Features
• Installation
• Quick Reference
• Quick Start
• Available Tools
• Usage Examples
• Architecture
• Advanced Usage
• Configuration
• Security
• Troubleshooting
• Development
• Contributing

✨ Features

🎹 Complete Music Control

• 65 MCP Tools: Comprehensive suite for music creation and manipulation
• Real Browser Automation: Direct control of Strudel.cc through Playwright
• Live Audio Analysis: Real-time frequency analysis via Web Audio API
• Pattern Generation: AI-powered creation across 8+ music genres
• Music Theory Engine: Scales, chords, progressions, euclidean rhythms
• Session Management: Save, load, undo/redo with pattern storage

🔧 Testing & Development Status

• ✅ Test Suite: 1470 tests passing (1521 total, 51 skipped)
• ✅ Code Coverage: 78% statement coverage (goal: 80%)
• ✅ Browser Integration: Works with live Strudel.cc website
• ✅ Audio Analysis: Real-time FFT analysis functional
• ✅ Pattern Generation: Core music generation features working
• ✅ OIDC Publishing: Secure npm publishing with provenance attestation

Not Production-Ready: This is experimental software under active development. Use for exploration and experimentation. Expect breaking changes, bugs, and incomplete features. See CONTRIBUTING.md to help improve it.

🎼 Example Patterns

Explore 17 curated example patterns across 10 genres in patterns/examples/:

• Techno: Hard techno, minimal techno
• House: Deep house, tech house
• Drum & Bass: Liquid, neurofunk
• Ambient: Dark ambient, drone
• Trap: Modern trap, cloud trap
• Jungle: Classic jungle, ragga jungle
• Jazz: Bebop, modal jazz
• Intelligent DnB: Atmospheric, liquid, LTJ Bukem style
• Trip Hop: Portishead, Massive Attack, Flying Lotus style
• Boom Bap: DJ Premier, Alchemist, golden era hip hop

Each example includes pattern code, BPM, key, and description. See patterns/examples/README.md for details.

📦 Installation

Prerequisites

Requirement	Version	Notes
Node.js	18.x or 20.x	LTS versions recommended
npm	9+	Comes with Node.js
Chromium	Latest	Auto-installed by Playwright
Audio output	Any	Required for playback (speakers/headphones)

Optional: Docker for containerized deployment.

From npm

npm install -g @williamzujkowski/strudel-mcp-server

# Install browser (required once)
npx playwright install chromium

From Source

# Clone repository
git clone https://github.com/williamzujkowski/strudel-mcp-server.git
cd strudel-mcp-server

# Install dependencies
npm install

# Install Chromium for browser automation
npx playwright install chromium

# Build the project
npm run build

🚀 Quick Reference

Common commands for immediate use:

Action	Command
Initialize browser	init
Create techno beat	generate_pattern with style: "techno"
Play pattern	play
Stop playback	stop
Get current pattern	get_pattern
Analyze audio	analyze
Save pattern	save with name: "my-pattern"
Undo last change	undo

One-shot workflow:

compose with style: "dnb", key: "Am", bpm: 174, auto_play: true

🎯 Quick Start

1. Add to Claude

# If installed globally
claude mcp add strudel strudel-mcp

# If built from source
claude mcp add strudel node /path/to/strudel-mcp-server/dist/index.js

2. Start Using

claude chat

Then ask Claude:

• "Initialize Strudel and create a techno beat"
• "Generate a jazz chord progression in F major"
• "Create a drum & bass pattern at 174 BPM"

🛠️ Available Tools (65)

Core Control (10 tools)

Tool	Description	Example
init	Initialize Strudel in browser	"Initialize Strudel"
write	Write pattern to editor	"Write pattern: s('bd*4')"
play	Start playback	"Play the pattern"
stop	Stop playback	"Stop playing"
clear	Clear editor	"Clear the editor"
get_pattern	Get current pattern	"Show current pattern"
append	Add to pattern	"Add hi-hats"
insert	Insert at line	"Insert at line 2"
replace	Replace text	"Replace bd with sn"
pause	Pause playback	"Pause"

Pattern Generation & Manipulation (10 tools)

Tool	Description	Options
generate_pattern	Complete patterns	techno, house, dnb, ambient, trap, jungle, jazz, intelligent_dnb, trip_hop, boom_bap
generate_drums	Drum patterns	All styles + complexity (0-1)
generate_bassline	Bass patterns	techno, house, dnb, acid, dub, funk, jazz, intelligent_dnb, trip_hop, boom_bap
generate_melody	Melodic lines	Any scale, custom length
generate_variation	Pattern variations	subtle, moderate, extreme, glitch
transpose	Transpose notes	±12 semitones
reverse	Reverse pattern	-
stretch	Time stretch	Factor 0.1-10
quantize	Quantize to grid	1/4, 1/8, 1/16, etc.
humanize	Add timing variation	Amount 0-1

Music Theory (6 tools)

Tool	Description	Options
generate_scale	Generate scales	major, minor, modes, pentatonic, blues
generate_chord_progression	Chord progressions	pop, jazz, blues, rock, folk
generate_euclidean	Euclidean rhythms	hits/steps/sound
generate_polyrhythm	Polyrhythms	Multiple patterns
generate_fill	Generate drum fills	All styles, 1-4 bars
apply_scale	Apply scale to notes	Any scale

Effects (4 tools)

Tool	Description
add_effect	Add audio effect (reverb, delay, etc.)
remove_effect	Remove an effect from the chain
set_tempo	Set BPM (60-200)
add_swing	Add swing feel (0-1 amount)

Session Management (5 tools)

Tool	Description
save	Save pattern with tags
load	Load saved pattern
list	List all patterns
undo	Undo last action
redo	Redo action

Pattern History (3 tools)

Tool	Description
list_history	Browse pattern history with timestamps and previews
restore_history	Restore a previous pattern by ID
compare_patterns	Compare two patterns showing line-by-line differences

Audio Analysis (6 tools)

Tool	Description
analyze	Basic audio analysis (frequency, playing state)
analyze_spectrum	FFT spectral analysis
analyze_rhythm	Rhythm complexity analysis
detect_tempo	BPM detection
detect_key	Musical key detection
validate_pattern_runtime	Validate pattern with browser error checking

UX & Browser Control (6 tools)

Tool	Description
compose	One-shot pattern generation with auto-play
status	Get current browser/playback state
diagnostics	Detailed system diagnostics
show_browser	Bring browser window to foreground
screenshot	Capture browser screenshot
show_errors	Display captured console errors

Performance (2 tools)

Tool	Description
performance_report	Timing metrics and bottleneck analysis
memory_usage	Memory consumption statistics

AI Feedback (1 tool)

Tool	Description	Options
get_pattern_feedback	AI-powered creative feedback via Gemini	includeAudio: analyze audio (default: false), style: hint for context

Note: Requires GEMINI_API_KEY environment variable. Returns pattern complexity, estimated style, strengths, and suggestions.

🎵 Usage Examples

Basic Pattern Creation

Create a Simple Beat

You: Initialize Strudel and create a simple techno beat

Claude: [Initializes browser]
        [Generates and writes pattern]
        [Starts playback]

Pattern created:
setcpm(130)
stack(
  s("bd*4"),
  s("~ cp ~ cp"),
  s("hh*8").gain(0.4)
).gain(0.8)

Generate a Bassline

You: Add a techno bassline in C

Claude: [Generates bassline]
        [Appends to current pattern]

Added: note("c2 c2 c2 c2").s("sawtooth").cutoff(800)

Advanced Music Generation

Jazz Composition

You: Create a jazz progression in F major with a walking bass

Claude: Generated progression: "Gm7" "C7" "Fmaj7"

Pattern:
stack(
  note("Gm7" "C7" "Fmaj7").struct("1 ~ ~ ~").s("piano"),
  note("g2 c2 f2").s("sine").gain(0.7)
)

Drum & Bass Track

You: Generate a complete drum & bass track at 174 BPM

Claude: [Creates multi-layer pattern with drums, bass, and pads]

// dnb pattern in C at 174 BPM
setcpm(174)
stack(
  // Drums
  s("bd ~ ~ [bd bd] ~ ~ bd ~, ~ ~ cp ~ ~ cp ~ ~").fast(2),

  // Bass
  note("c1 ~ ~ c2 ~ c1 ~ ~").s("square").cutoff(400),

  // Pads (atmospheric)
  note("c3 eb3 g3 bb3").s("sawtooth")
    .attack(2).release(4).room(0.8).gain(0.6)
)

Real-Time Manipulation

Live Audio Analysis

You: Analyze what's playing and show me the frequency breakdown

Claude: Audio Analysis Results:
{
  "connected": true,
  "features": {
    "average": 78.5,
    "peak": 180,
    "peakFrequency": 120,
    "bass": 145,
    "mid": 82,
    "treble": 45,
    "isPlaying": true,
    "brightness": "balanced"
  }
}

Strong bass presence detected - typical for techno/house patterns.

Pattern Variations

You: Create a glitchy variation of the current pattern

Claude: [Applies glitch transformation]

Added: .sometimes(x => x.chop(8).rev).rarely(x => x.speed(-1))

Multi-Track Composition

Layered Ambient Track

You: Create an ambient soundscape with multiple layers

Claude: [Generates complex multi-layer pattern]

setcpm(90)
stack(
  // Deep bass drone
  note("c1").s("sine").attack(4).release(8).gain(0.5),

  // Texture pad
  note("c3 eb3 g3").s("sawtooth")
    .attack(2).release(6).room(0.9).gain(0.4),

  // Sparse percussion
  s("bd ~ ~ ~, ~ ~ ~ hh:8").room(0.9).gain(0.3),

  // Melodic sparkles
  note("c5 g5 eb5 bb5").struct("~ 1 ~ 1 ~ ~ 1 ~")
    .s("triangle").delay(0.5).room(0.8).gain(0.3)
)

Session Management

Save and Load Patterns

You: Save this pattern as "techno-groove-1" with tags "techno" and "experimental"

Claude: Pattern saved as "techno-groove-1"

---

You: List all my techno patterns

Claude: Saved patterns with tag "techno":
• techno-groove-1 [techno, experimental] - 2025-10-23T19:30:00.000Z
• acid-bassline [techno, acid] - 2025-10-23T18:15:00.000Z

---

You: Load "acid-bassline"

Claude: Loaded pattern "acid-bassline"
[Pattern written to editor]

Music Theory Applications

Generate Euclidean Rhythms

You: Create a 5/8 euclidean rhythm with kick drum

Claude: Generated Euclidean rhythm (5/8)

Pattern: s("bd").struct("1 ~ 1 ~ 1 1 ~ 1")

Complex Polyrhythms

You: Generate a polyrhythm with kick (4/16), snare (7/16), and hi-hat (3/16)

Claude: Generated polyrhythm

stack(
  s("bd").euclid(4, 16),
  s("cp").euclid(7, 16),
  s("hh").euclid(3, 16)
)

Integration with LLM Agents

AI-Assisted Composition

You: Analyze the mood of my current pattern and suggest complementary elements

Claude: [Analyzes pattern structure and audio features]

Your pattern has:
- Energetic rhythm (130 BPM)
- Strong bass presence
- Minimal melodic content

Suggestions:
1. Add arpeggiated synth for movement
2. Include occasional breaks/fills
3. Layer atmospheric pad for depth

Would you like me to add any of these?

You: Add an arpeggiated synth in C minor

Claude: [Generates and adds]

note("c4 eb4 g4 bb4 c5").struct("1 1 1 1 1 1 1 1")
  .s("triangle").delay(0.25).room(0.3).gain(0.5)

🧪 Testing

All tools have been tested with real Strudel.cc interaction:

# Run integration tests
npm run test:integration

# Run browser tests
node tests/strudel-integration.js

# Test results: 1470/1521 tests passing (96.6%), 51 skipped (browser tests in CI)

⚙️ Configuration

config.json

{
  "headless": false,        // Set true for background operation
  "strudel_url": "https://strudel.cc/",
  "patterns_dir": "./patterns",
  "audio_analysis": {
    "fft_size": 2048,
    "smoothing": 0.8
  }
}

🏗️ Architecture

System Overview

The Strudel MCP Server is built with a modular architecture that separates concerns and enables robust music generation:

┌─────────────────────────────────────────────────────────────┐
│                       Claude AI                              │
│                  (MCP Client)                                │
└───────────────────────┬─────────────────────────────────────┘
                        │ MCP Protocol (stdio)
                        │
┌───────────────────────▼─────────────────────────────────────┐
│              EnhancedMCPServerFixed                          │
│  ┌────────────────────────────────────────────────────────┐ │
│  │  Tool Request Handler                                  │ │
│  │  - Validates inputs                                    │ │
│  │  - Routes to appropriate service                       │ │
│  │  - Handles errors gracefully                           │ │
│  └────────────────────────────────────────────────────────┘ │
└───────┬────────────┬────────────┬───────────┬──────────────┘
        │            │            │           │
   ┌────▼────┐  ┌───▼────┐  ┌───▼────┐  ┌──▼──────┐
   │ Strudel │  │ Music  │  │Pattern │  │ Pattern │
   │Controller│  │ Theory │  │Generator│  │  Store  │
   └────┬────┘  └────────┘  └────────┘  └─────────┘
        │
   ┌────▼────────────────────────────┐
   │   Playwright Browser            │
   │  ┌──────────────────────────┐   │
   │  │   Strudel.cc Website     │   │
   │  │  ┌────────────────────┐  │   │
   │  │  │  CodeMirror Editor │  │   │
   │  │  └────────────────────┘  │   │
   │  │  ┌────────────────────┐  │   │
   │  │  │  Audio Context     │  │   │
   │  │  │  + Web Audio API   │  │   │
   │  │  └────────┬───────────┘  │   │
   │  └───────────┼──────────────┘   │
   └──────────────┼──────────────────┘
                  │
          ┌───────▼────────┐
          │ Audio Analyzer │
          │  - FFT Analysis│
          │  - Frequency   │
          │  - Spectral    │
          └────────────────┘

Core Components

1. EnhancedMCPServerFixed (src/server/EnhancedMCPServerFixed.ts)

Main MCP server implementation handling:

• 65 Tool Definitions: Complete API surface for music control
• Request Routing: Directs tool calls to appropriate handlers
• State Management: Tracks initialization, undo/redo stacks, pattern cache
• Error Handling: Graceful degradation and informative error messages
• Lazy Initialization: Browser starts only when needed

Key Features:

- Pattern caching before browser init
- Undo/redo stack management
- Session history tracking
- Generated pattern storage
- Safe fallback mechanisms

2. StrudelController (src/StrudelController.ts)

Browser automation layer using Playwright:

• Browser Management: Chromium instance lifecycle
• Editor Control: CodeMirror manipulation via DOM
• Playback Control: Keyboard shortcuts for play/stop
• Performance Optimizations:
  • Editor content caching (100ms TTL)
  • Direct CodeMirror API access
  • Resource blocking (images, fonts)
  • Fast DOM content loading

// Example: Optimized pattern writing
async writePattern(pattern: string) {
  await this.page.evaluate((newPattern) => {
    const editor = document.querySelector('.cm-content');
    const view = editor.__view;
    view.dispatch({
      changes: { from: 0, to: view.state.doc.length, insert: newPattern }
    });
  }, pattern);
}

3. AudioAnalyzer (src/AudioAnalyzer.ts)

Real-time audio analysis via Web Audio API injection:

• FFT Analysis: 1024-point FFT for spectral data
• Frequency Bands: Bass, low-mid, mid, high-mid, treble
• Analysis Caching: 50ms TTL for performance
• Features Extracted:
  • Average amplitude
  • Peak frequency
  • Spectral centroid
  • Playing state detection
  • Frequency distribution

Features provided:
- average: Overall amplitude (0-255)
- peak: Maximum amplitude
- peakFrequency: Dominant frequency in Hz
- bass/mid/treble: Band-specific amplitudes
- brightness: Timbral classification
- isPlaying: Boolean playback state

4. MusicTheory (src/services/MusicTheory.ts)

Music theory engine providing:

• 15+ Scales: Major, minor, modes, pentatonic, blues, whole-tone
• Chord Progressions: Pop, jazz, blues, rock, folk, EDM
• Euclidean Rhythms: Mathematical rhythm generation
• Arpeggio Generation: Multiple patterns (up, down, random)
• Note Transposition: Semitone-based pitch shifting

Supported scales:

major, minor, dorian, phrygian, lydian, mixolydian,
aeolian, locrian, pentatonic, blues, chromatic,
wholetone, harmonic_minor, melodic_minor

5. PatternGenerator (src/services/PatternGenerator.ts)

AI-powered pattern creation:

• Genre Templates: Techno, house, DnB, trap, ambient, jazz, intelligent_dnb, trip_hop, boom_bap
• Drum Patterns: 4 complexity levels per genre
• Basslines: 8 different styles
• Melody Generation: Scale-based with musical intervals
• Variations: Subtle, moderate, extreme, glitch, evolving
• Fills: 1-4 bar drum fills

Example generation:

generateCompletePattern('techno', 'C', 130)
→ Multi-layer pattern with drums, bass, chords, melody

6. PatternStore (src/PatternStore.ts)

Persistent pattern storage:

• JSON-based: Simple file storage
• Metadata: Name, tags, timestamp, audio features
• Tag Filtering: Organize by genre, mood, project
• Sorted Retrieval: Most recent first

Directory Structure

strudel-mcp-server/
├── src/
│   ├── server/
│   │   ├── EnhancedMCPServer.ts          # Original implementation
│   │   └── EnhancedMCPServerFixed.ts     # Production version
│   ├── services/
│   │   ├── MusicTheory.ts                # Theory engine
│   │   └── PatternGenerator.ts           # Pattern creation
│   ├── utils/
│   │   └── Logger.ts                     # Logging utility
│   ├── types/
│   │   └── index.ts                      # TypeScript types
│   ├── StrudelController.ts              # Browser automation
│   ├── AudioAnalyzer.ts                  # Audio analysis
│   ├── PatternStore.ts                   # Pattern persistence
│   └── index.ts                          # Entry point
├── tests/
│   ├── browser-test.js                   # Browser integration
│   ├── integration.test.js               # Integration tests
│   ├── manual-test.js                    # Manual testing
│   ├── mcp-tools.test.ts                 # MCP tool tests
│   └── strudel-integration.js            # Full integration
├── patterns/                             # Saved patterns
├── config.json                           # Server configuration
├── package.json                          # Dependencies
└── tsconfig.json                         # TypeScript config

Data Flow

1. Tool Invocation

   Claude → MCP Protocol → EnhancedMCPServerFixed
   

2. Pattern Generation (without browser)

   Server → PatternGenerator → MusicTheory → Pattern String
   

3. Pattern Execution (with browser)

   Server → StrudelController → Playwright → Strudel.cc
   

4. Audio Analysis

   Strudel.cc → Web Audio API → AudioAnalyzer → Feature Data
   

Performance Characteristics

Operation	Latency	Notes
Pattern Generation	{
// Implementation
return Result: ${param1};
}

4. **Test the tool**:
```bash
# Build
npm run build

# Test via MCP
echo '{"jsonrpc":"2.0","method":"tools/call","params":{"name":"my_new_tool","arguments":{"param1":"test"}},"id":2}' | node dist/index.js

Testing Strategy

1. Unit Tests

# Run with Jest
npm test

# Watch mode
npm run test:watch

2. Integration Tests

# Full integration with real browser
npm run test:integration

# This tests:
# - Browser initialization
# - Pattern generation
# - Audio analysis
# - Pattern storage
# - All 65 tools

3. Manual Testing

# Development mode
npm run dev

# In another terminal
claude mcp add strudel-dev node $(pwd)/dist/index.js
claude chat

# Then interact with Claude

Code Quality

TypeScript Configuration

// tsconfig.json
{
  "compilerOptions": {
    "strict": true,           // Strict type checking
    "esModuleInterop": true,  // Better module compatibility
    "target": "ES2020",       // Modern JavaScript
    "module": "ES2020",       // ES modules
    "moduleResolution": "node"
  }
}

Linting & Formatting

# ESLint
npm run lint

# Prettier
npm run format

# Pre-commit hooks recommended

Debugging

Enable Debug Logging

# Set DEBUG environment variable
DEBUG=strudel:* npm start

# Or specific modules
DEBUG=strudel:controller npm start
DEBUG=strudel:audio npm start

VS Code Launch Configuration

{
  "type": "node",
  "request": "launch",
  "name": "Debug MCP Server",
  "program": "${workspaceFolder}/dist/index.js",
  "preLaunchTask": "npm: build",
  "console": "integratedTerminal",
  "env": {
    "DEBUG": "strudel:*"
  }
}

Playwright Debugging

// In StrudelController.ts
this.browser = await chromium.launch({
  headless: false,  // See the browser
  devtools: true,   // Open DevTools
  slowMo: 100       // Slow down actions
});

Performance Monitoring

The server includes built-in performance monitoring:

// Access performance metrics
You: Show me performance metrics

Claude: Performance Report:
{
  "averageLatency": {
    "init": "3.2s",
    "write": "52ms",
    "play": "105ms",
    "analyze": "18ms"
  },
  "cacheHitRate": "85%",
  "totalOperations": 1247,
  "bottlenecks": [
    {"tool": "init", "avgTime": 3200, "calls": 1},
    {"tool": "write", "avgTime": 52, "calls": 156}
  ]
}

Contributing Guidelines

1. Fork the repository

   git clone https://github.com/YOUR_USERNAME/strudel-mcp-server.git
   

2. Create a feature branch

   git checkout -b feature/my-new-feature
   

3. Make your changes

   • Follow existing code style
   • Add tests for new features
   • Update documentation
   • Ensure all tests pass

4. Commit with meaningful messages

   git commit -m "feat: Add support for custom scale generation"
   

   Follow Conventional Commits:

   • feat: New feature
   • fix: Bug fix
   • docs: Documentation changes
   • refactor: Code refactoring
   • test: Adding tests
   • chore: Maintenance tasks

5. Push and create PR

   git push origin feature/my-new-feature
   

   Then create a Pull Request on GitHub with:

   • Clear description of changes
   • Link to related issues
   • Screenshots/examples if relevant

Release Process

# 1. Update version in package.json
npm version patch  # or minor/major

# 2. Update CHANGELOG.md
# Add entry for new version

# 3. Build and test
npm run build
npm test
npm run test:integration

# 4. Commit version bump
git add .
git commit -m "chore: Bump version to X.Y.Z"

# 5. Create git tag
git tag vX.Y.Z

# 6. Push to GitHub
git push origin main --tags

# 7. Publish to npm (if you have access)
npm publish --access public

# 8. Create GitHub release
gh release create vX.Y.Z --generate-notes

Docker Development

# Build development image
docker build -t strudel-mcp:dev .

# Run with volume mount for hot reload
docker run -it --rm \
  -v $(pwd)/src:/app/src \
  -v $(pwd)/patterns:/app/patterns \
  strudel-mcp:dev

# Run tests in container
docker run -it --rm strudel-mcp:dev npm test

Environment Variables

# Logging level
LOG_LEVEL=debug        # debug, info, warn, error

# Performance monitoring
ENABLE_PERF_MONITORING=true

# Pattern storage
PATTERNS_DIR=./patterns

# Browser configuration
HEADLESS=false
BROWSER_TIMEOUT=15000

# Audio analysis
FFT_SIZE=1024
SMOOTHING=0.8

📊 Performance

• Pattern Generation: x.fast(2))

Version 2 (moderate): original.every(4, x => x.rev).sometimes(x => x.fast(2))

Version 3 (glitchy): original.sometimes(x => x.chop(8).rev).rarely(x => x.speed(-1))

### Performance Optimization Tips

**Pattern Caching**

// The server caches patterns intelligently: // - Generated patterns stored before browser init // - Editor content cached for 100ms // - Audio analysis cached for 50ms

// For fastest performance:

1. Generate patterns before initializing browser
2. Initialize once and reuse the session
3. Batch multiple changes together

**Headless Mode**
```json
// In config.json:
{
  "headless": true,  // Faster, no GUI
  "strudel_url": "https://strudel.cc/",
  "patterns_dir": "./patterns"
}

Integration Patterns

Workflow Automation

You: Create a complete track:
     1. Start with techno drums at 130 BPM
     2. Add acid bassline in E
     3. Layer ambient pads
     4. Save as "track-001" with tags "techno", "acid", "experimental"

Claude: [Executes full workflow]
        [Initializes browser]
        [Generates drum pattern]
        [Adds bassline]
        [Layers pads]
        [Saves with metadata]

Complete! Pattern saved as "track-001"

Audio-Reactive Composition

You: Monitor the audio and suggest adjustments based on frequency balance

Claude: [Analyzes current playback]

Analysis shows:
- Bass: 180 (strong)
- Mid: 45 (weak)
- Treble: 30 (weak)

Recommendations:
1. Reduce bass gain by 20%
2. Add mid-range melodic content
3. Include hi-hat pattern for treble

Apply changes? [Yes/No]

Advanced Pattern Manipulation

Dynamic Transformations

You: Apply these transformations in sequence:
     1. Transpose up 3 semitones
     2. Add 10% humanization
     3. Apply reverb with 0.6 room size
     4. Every 4th cycle, reverse the pattern

Claude: [Applies transformations]

Final pattern:
[original]
  .transpose(3)
  .nudge(rand.range(-0.1, 0.1))
  .room(0.6)
  .every(4, x => x.rev)

Conditional Logic

You: Create a pattern that evolves:
     - Bars 1-4: Simple kick pattern
     - Bars 5-8: Add snare
     - Bars 9-16: Add full drum kit
     - Then loop with variations

Claude: [Generates evolving pattern]

s("bd*4")
  .struct("1 ~ ~ ~")
  .mask("/4")  // First 4 bars
  .stack(
    s("~ cp ~ cp")
      .mask("/8")  // Bars 5-8
  )
  // Full complexity from bar 9
  .every(8, x => x.sometimes(y => y.fast(2)))

🔒 Security

Pattern Validation

All patterns are validated before execution:

• Dangerous gain levels (>2.0) are flagged
• Eval blocks are rejected
• Path traversal attacks are blocked in PatternStore

Browser Sandboxing

• Playwright runs Chromium in sandbox mode
• No access to local filesystem from browser context
• Resource blocking prevents loading external content

Known Limitations

• No authentication: The MCP server trusts all incoming requests
• Local only: Designed for local development, not network deployment
• Pattern execution: Patterns execute in browser context with audio access

Reporting Security Issues

Found a vulnerability? Please open a security issue or email the maintainer directly. Do not disclose publicly until patched.

🐛 Troubleshooting

Common Issues

Browser doesn't open

Symptom: Error: Browser not initialized or Chromium launch fails

Solutions:

# Install Chromium for Playwright
npx playwright install chromium

# If that fails, try installing all browsers
npx playwright install

# Check Playwright installation
npx playwright --version

# For Linux, install dependencies
sudo npx playwright install-deps chromium

Audio analysis returns "not connected"

Symptom: Audio analysis shows connected: false

Solutions:

1. Ensure pattern is playing first:

   You: Play the pattern, wait 2 seconds, then analyze
   

2. Reinitialize the browser:

   You: Stop, close the browser, reinitialize, and try again
   

3. Check audio context activation:

   • Audio contexts require user interaction on some systems
   • The browser window must be visible (not headless) for first run

Pattern syntax errors

Symptom: Pattern doesn't play or shows errors in console

Solutions:

Common issues:
1. Missing quotes: s(bd*4) → s("bd*4")
2. Unmatched parentheses: stack(s("bd")) → stack(s("bd")))
3. Invalid note names: note("h2") → note("c2")

Test with minimal pattern first:
s("bd*4")

Then build complexity gradually.

MCP connection issues

Symptom: Claude can't find the server or tools

Solutions:

# Verify server is built
npm run build

# Check if server responds
echo '{"jsonrpc":"2.0","method":"tools/list","id":1}' | node dist/index.js

# Should return JSON with 65 tools

# Reinstall MCP server in Claude
claude mcp remove strudel
claude mcp add strudel node $(pwd)/dist/index.js

# Restart Claude
claude chat

Performance issues / Slow response

Symptom: Operations take longer than expected

Solutions:

1. Enable caching (default, but verify):

   • Editor caching: 100ms TTL
   • Audio analysis: 50ms TTL

2. Use headless mode for faster operation:

   // config.json
   { "headless": true }
   

3. Batch operations:

   Instead of:
   - Add drums
   - Add bass
   - Add melody
   
   Do:
   - Generate complete pattern with drums, bass, and melody
   

4. Reduce browser overhead:

   • Close other browser instances
   • Disable browser DevTools
   • Use resource blocking (enabled by default)

Patterns not saving

Symptom: save command fails or patterns don't persist

Solutions:

# Check patterns directory exists
ls -la ./patterns

# Create manually if needed
mkdir -p ./patterns

# Verify write permissions
touch ./patterns/test.json
rm ./patterns/test.json

# Check for invalid pattern names
# Valid: "techno-beat-1", "my_pattern", "track001"
# Invalid: "pattern/with/slashes", "name:with:colons"

Platform-Specific Issues

macOS

# Keyboard shortcut uses Meta (Cmd) key
# Already handled by ControlOrMeta

# If Chromium crashes on M1/M2:
npx playwright install chromium --with-deps

Linux

# Install system dependencies
sudo npx playwright install-deps chromium

# If running in Docker/headless environment:
# Ensure config.json has headless: true

Windows

# Use PowerShell or Git Bash
# Paths should use forward slashes in config.json

# If Chromium doesn't launch:
npx playwright install chromium

Debugging Tips

Enable Verbose Logging

# Set environment variable
DEBUG=* node dist/index.js

# Or in Claude:
You: Enable detailed logging for the next operation

Check Browser State

You: Show me the current browser initialization state
     and any cached patterns

Claude: Browser state:
- Initialized: true
- Cached patterns: 2
- Undo stack depth: 5
- Last operation: write_pattern (2.5s ago)

Validate Pattern Syntax

You: Before playing, validate this pattern syntax:
     s("bd*4, ~ cp ~ cp")

Claude: [Checks syntax]
Valid Strudel pattern.
Ready to play.

Getting Help

If you encounter issues not covered here:

1. Check existing issues: GitHub Issues
2. Run integration tests: npm run test:integration
3. Enable debug mode: DEBUG=* npm start
4. Consult Strudel docs: Strudel.cc documentation
5. Create new issue: Include error messages, OS, Node version, and steps to reproduce

🤝 Contributing

We need your help! This project is actively developed and welcomes contributions of all kinds:

Ways to Contribute

• Report Bugs: Found an issue? Open a bug report
• Suggest Features: Have ideas? Create a feature request
• Improve Docs: Fix typos, add examples, clarify confusing sections
• Write Tests: Help us reach 80% coverage (currently 78%)
• Fix Issues: Check open issues for bugs to fix
• Add Features: Implement new tools or improve existing ones

Quick Start for Contributors

1. Fork the repository
2. Create a feature branch (git checkout -b feature/amazing-feature)
3. Make your changes and add tests
4. Ensure tests pass (npm test)
5. Commit with clear messages (git commit -m 'fix: resolve audio analysis bug')
6. Push to your fork (git push origin feature/amazing-feature)
7. Open a Pull Request

First time contributor? Look for issues labeled good-first-issue or help-wanted.

Feedback Welcome

• Questions? Open a Discussion
• Found something confusing? Tell us!
• Have a use case we haven't considered? Share it!

We review PRs promptly and welcome contributors of all skill levels. See DEVELOPMENT.md for detailed setup instructions.

📄 License

MIT License - see LICENSE file

🙏 Acknowledgments

• Strudel.cc - Amazing live coding environment
• TidalCycles - Pattern language inspiration
• Anthropic - Claude AI and MCP protocol
• Playwright - Reliable browser automation

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v2.4.0 - Open Source | Experimental | Report Issues | Contribute

This project is under active development. Core features work, but expect bugs and breaking changes. Not recommended for production use.