Pixel, the UI agent
Pixel reviews every visual change in the UI, checking spacing, alignment, color, typography, and accessibility. It auto-escalates to Sonnet when changes touch design token boundaries or introduce changes across multiple components.
Model tiers
| Tier | Trigger | Model |
|---|---|---|
| T1 Per-change visual review | routine visual updates | GPT-5 Nano |
| T2 DESIGN.md enforcement | token boundary changes | Claude Sonnet 4.6 |
Escalation
Auto-escalates to Sonnet when changes touch token boundaries.
Sample
Visual review feedback
Settings panel: spacing changed from 16px to 14px in 3 places, blocks token contract
revert or update --space-md to 14px globally