impeccable-deterministic-25-rule-design-scanner-zero-llm-cost

github.com/pbakaus/impeccable is a 3,590-line deterministic JS engine with 25 anti-pattern detection rules: 13 AI slop tells (Inter/default fonts, purple/blue gradients, glassmorphism, pill badges, gradient text, emoji in UI, etc.) and 12 general quality rules (contrast, spacing, hover states, z-index chaos, etc.). Runs via npx impeccable detect --json <file> with zero LLM cost, making it ideal as a PostToolUse hook on Write/Edit to HTML/CSS/JSX/TSX/Svelte/Astro files. Our existing frontend quality assessment is 100% LLM-based — this fills the deterministic verification gap.