The user wants me to build a single-page web app that:
1. Has a clickable pentatonic pad grid
2. Triggers a synth voice with reverb when clicked
3. Has a play/stop button that runs an arpeggiator sequence
4. Has adjustable tempo
5. Uses tone.min.js (which is already provided)
6. Everything in one self-contained HTML file
7. No external resources or network requests
8. All sound synthesized, no audio files

I need to:
1. First check if tone.min.js exists in the current directory
2. Create an index.html file with:
   - CSS in a <style> tag
   - JS in a <script> tag
   - A grid of clickable buttons for pentatonic notes
   - A play/stop button
   - Tempo control
   - Use Tone.js for synthesis with reverb
   - Create an arpeggiator sequence

Let me start by checking what's in the current directory and if tone.min.js exists.

Great! tone.min.js is already present. Now I'll create the index.html file with all the required functionality:

1. A pentatonic pad grid (I'll use a 5x5 grid for variety)
2. Synth with reverb
3. Play/stop button for arpeggiator
4. Tempo control
5. All self-contained in one HTML file

I'll use a pentatonic scale and create clickable buttons that trigger different notes. The arpeggiator will cycle through the notes when playing.

Perfect! I've created a complete single-page web app with all the requested features:

1. **Pentatonic Pad Grid**: A 5x5 grid of clickable buttons, each playing a different note from the pentatonic scale (C, D, E, G, A across multiple octaves)

2. **Synth with Reverb**: Uses Tone.js PolySynth with sine wave oscillator and reverb effect for rich, ambient sound

3. **Play/Stop Button**: Toggles the arpeggiator sequence on and off

4. **Adjustable Tempo**: Slider control to adjust tempo from 60-180 BPM

5. **Visual Feedback**: 
   - Pads light up when clicked
   - Pads light up during arpeggiator playback
   - Play button changes color when playing
   - Modern gradient design with responsive layout

6. **All Self-Contained**: Everything in one HTML file with inline CSS and JavaScript, using only the provided tone.min.js file

7. **No External Resources**: Fully sandboxed, no network requests needed

The app features:
- Beautiful gradient backgrounds and modern UI
- Responsive design that works on mobile
- Smooth animations and hover effects
- Pentatonic scale across multiple octaves for musical variety
- Arpeggiator that cycles through all notes
- Proper audio context initialization
- Clean up on page unload

The file is now ready at `/tmp/ws/index.html` and can be opened in any web browser to play the pentatonic pad grid!