# Claude Code Requirements for Arpeggiator

## CRITICAL FUNCTIONALITY - DO NOT FORGET

### Armed State System (ESSENTIAL)
- **MUST have orange "armed" state** when arpeggiator is playing
- When user clicks button during playback:
  1. Button turns ORANGE (armed)
  2. Change does NOT apply immediately 
  3. Change waits until pattern end/loop completion
  4. At pattern end: orange button turns GREEN (active), previous green turns gray
- When arpeggiator is stopped: changes apply immediately (no armed state needed)
- **This is critical for live performance** - prevents jarring mid-pattern changes

### Button Layout Requirements
- NO horizontal spacing between buttons (buttons touch side-by-side)
- Button height should be minimal but readable (16px for 12px font)
- 12px bold font for readability
- Green for active selection, orange for armed selection, gray for inactive

### GUI Structure
- Quadrant layout: Basic Settings (top-left), Channel Distribution (top-right), Pattern Settings (bottom-left), Timing Settings (bottom-right)
- All buttons must be visible without scrollbars
- Equal-sized quadrants

## Implementation Notes
- Check `self.arpeggiator.is_playing` before applying changes
- Use `self.arpeggiator.arm_*()` methods when playing
- Connect to `self.arpeggiator.armed_state_changed` signal
- Implement `update_armed_states()` to handle orange→green transitions