Impeccable

A design-language skill that makes your AI harness better at frontend design — “the vocabulary you didn’t know you needed.” Built by Paul Bakaus (@pbakaus), it extends Anthropic’s frontend-design skill with deeper reference material, a shared command vocabulary, and a deterministic anti-slop linter.

Links

Description

• Repo: github.com/pbakaus/impeccable
• Site / ready-to-use bundles: impeccable.style
• Package: impeccable on npm

Download or use

Download the ZIP for your tool at impeccable.style and extract into your project, or copy from the repo’s dist/ per harness. Standalone CLI needs no install: npx impeccable detect src/.

Reasoning for

The problem it solves: every model was trained on the same SaaS templates, so without guidance you get the same AI “tells” on every project — Inter for everything, purple-to-blue gradients, cards nested in cards, gray text on colored backgrounds, the rounded-square icon tile above every heading. Impeccable gives the agent a vocabulary and a set of guardrails to escape that generic aesthetic.

What it adds on top of a base design skill:

• 7 domain reference files, loaded on every command alongside a brand-vs-product register that shifts the defaults:

  Reference	Covers
  typography	Type systems, font pairing, modular scales, OpenType
  color-and-contrast	OKLCH, tinted neutrals, dark mode, accessibility
  spatial-design	Spacing systems, grids, visual hierarchy
  motion-design	Easing curves, staggering, reduced motion
  interaction-design	Forms, focus states, loading patterns
  responsive-design	Mobile-first, fluid design, container queries
  ux-writing	Button labels, error messages, empty states

• 27 deterministic anti-pattern rules + a 12-rule LLM critique pass. The deterministic rules run with no LLM and no API key (CLI or browser extension); each maps to specific guidance the skill teaches against.

🧩 Features

• 23 commands under /impeccable, a shared design vocabulary with the agent. Workflow: teach / document / extract (set up the design system) → shape → craft → critique / audit → polish. Tone/adjustment verbs: bolder, quieter, distill, animate, colorize, typeset, layout, delight, overdrive, harden, onboard, clarify, adapt, optimize, live. pin <command> creates standalone shortcuts (e.g. /audit).
• Standalone CLI — npx impeccable detect scans a directory, HTML file, or URL (Puppeteer); --fast --json for regex-only output. Catches 24 issues across AI slop (side-tab borders, purple gradients, bounce easing, dark glows) and general quality (line length, cramped padding, small touch targets, skipped headings).
• Explicit anti-patterns: no overused fonts (Arial, Inter, system defaults); no gray text on colored backgrounds; no pure black/gray (always tint); no everything-in-cards or nested cards; no bounce/elastic easing.
• Broad harness support: Cursor, Claude Code, OpenCode, Pi, Gemini CLI, Codex CLI, VS Code Copilot, Kiro, Trae, Rovo Dev, Qoder.

Alternatives considered

• Open Design, UX RULER — sibling open-source design/UX skills for agents
• DESIGN MD Spec / Awesome Design MD — the DESIGN.md persistent design-system approach
• UX Pilot — generative UI/wireframe platform (different layer: generation vs. design-language guardrails)
• Anthropic’s original frontend-design skill — Impeccable’s starting point

Resources

• License: Apache 2.0 — builds on Anthropic’s frontend-design skill (see NOTICE.md for attribution)
• Hub note: AI UX Design Tools
• Skill ecosystem: Agent Skills
• Follow @pbakaus on Twitter for release notes and lint-rule highlights

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