Claude Design System Prompt

Reverse-engineered system prompt of Claude Design from Anthropic.

A system prompt and skill library that turns an LLM into an opinionated, accessibility-aware, AI-slop-resistant design collaborator.

Open source, MIT licensed. Drop the prompt into any LLM that supports system prompts (Claude, GPT, Gemini, local models) and pair with the procedural skills as needed.

What this is

Most "design assistant" prompts produce generic SaaS-template output — aggressive gradients, emoji decoration, rounded-corner-with-left-border cards, Inter-everywhere typography. This prompt explicitly rejects those patterns and replaces them with a complete design philosophy covering:

- Content discipline (no filler — every element earns its place)

- Aesthetic discipline (avoid AI tropes, commit to a palette and tone)

- Visual hierarchy and rhythm (size, color, weight, position, density, spacing scales)

- Accessibility (WCAG, semantic HTML, keyboard navigation, focus rings, motion preferences)

- Interaction and feedback (hover, active, disabled, focus, loading, validation states)

- System thinking (components and tokens over one-off pages)

- Respecting the medium (real CSS Grid, oklch()

, text-wrap: pretty

, real interactive prototypes)

- Quality over quantity (depth over breadth, polish every detail)

Plus 14 procedural skills the agent can invoke for production, extraction, and review work.

What's included

claude-design-system-prompt/
├── claude/                              Claude Code / Claude.ai variant
│   ├── system-prompt.md                 Main system prompt — 20 chapters
│   └── skills/                          14 invokable skills
│       ├── discovery-questions.md       Kickoff question protocol
│       ├── frontend-aesthetic-direction.md  Commit to a look when no brand exists
│       ├── wireframe.md                 Low-fi exploration, 3+ variations
│       ├── make-a-deck.md               Slide presentations in HTML
│       ├── make-a-prototype.md          Interactive clickable prototype
│       ├── make-tweakable.md            Floating tweak panel
│       ├── generate-variations.md       3+ hi-fi variations across axes
│       ├── design-system-extract.md     Pull tokens from sources
│       ├── component-extract.md         Inventory reusable components
│       ├── accessibility-audit.md       WCAG, semantic, keyboard, motion
│       ├── ai-slop-check.md             Gradient / emoji / font / house-style trope detection
│       ├── hierarchy-rhythm-review.md   Size / weight / color + spacing scale
│       ├── interaction-states-pass.md   Hover / active / disabled / focus / loading
│       └── polish-pass.md               Umbrella final-gate review
├── codex/                               OpenAI Codex variant (single-loop, no subagents)
│   ├── AGENTS.md                        Codex auto-discovered entry point
│   ├── system-prompt.md                 Same prompt, adapted for Codex
│   └── skills/                          Same skills, sequential reviews instead of parallel agents
├── README.md                            This file
└── LICENSE                              MIT

How to use it

Use the system prompt directly

Paste the contents of system-prompt.md

as the system prompt for any LLM that supports them. The agent will follow the design philosophy and reference the skills by name when tasks match.

Use the skills as procedures

Each skill in skills/