extract-design-system

extract-design-system is a skill for Claude Code, Codex from espennilsen/pi. It costs 180 tokens per session (2,109 once invoked), scanned A, original, MIT.

A tool for studying a live website and turning its visual rules into a structured design system. It examines styles, visible components, and interactive states at mobile, tablet, and desktop sizes.

In plain words
What is it for?
Use it to inspect a public website or a local site, capture screenshots, and record how pages and components look and behave at different device sizes.
Why use it?
It helps when you need to recreate or extend a website but its design rules are undocumented. It gathers details such as colors, fonts, spacing, shadows, corner shapes, and screen-size changes in one place.

Skill for Claude CodeCodex

Install

Getting it into your agent

One page per mod, every tool's command on it. A separate URL per tool would split the same page into five that compete with each other.

agentmods
npx agentmods add skills/espennilsen/pi/extract-design-system
Any agent
npx skills add espennilsen/pi --skill extract-design-system
Clone the repo
git clone --depth 1 https://github.com/espennilsen/pi

Made for: Claude Code, Codex.

Wrote this? Show the measurements

A badge with what this costs and how it scanned, read live from this page, so it follows the numbers instead of freezing them. Markdown for a README, HTML for a documentation site or a project page.

agentmods badge for extract-design-system

README.md
[![agentmods](https://agentmods.dev/badge/skills/espennilsen/pi/extract-design-system.svg)](https://agentmods.dev/skills/espennilsen/pi/extract-design-system)
Your own site
<a href="https://agentmods.dev/skills/espennilsen/pi/extract-design-system"><img src="https://agentmods.dev/badge/skills/espennilsen/pi/extract-design-system.svg" alt="Measured on agentmods" height="20"></a>
Per session 180 Skills are progressive disclosure: only the name and description are preloaded; the body loads when the skill is used.
When invoked 2,109 The whole file, excluding the scripts and references it only reads on demand.
Security scan A 0 findings. Scan, not verified.
Origin original No closer match found in the catalogue.
Token cost

What it costs to keep this loaded

Counted locally with the o200k_base tokenizer, which is exact for GPT models; Claude uses its own tokenizer and its counts differ. Treat this as one consistent yardstick across the catalogue rather than a bill. Prices are per million input tokens.

ModelPer sessionOnce invoked
Fable 5.1 $0.00180 $0.02109
Opus 5 $0.00090 $0.01055
Sonnet 5 $0.00036 $0.00422
Haiku 4.5 $0.00018 $0.00211

Measured 6d ago against content hash b9723dfba919, method: parsed. Prices are Anthropic first-party input rates as of 2026-09-05, from the pricing page.

Security

Grade A, and why

extract-design-system scanned grade A with 0 findings against 26 rules in 11 categories — prompt injection, anti-refusal, data exfiltration, privilege escalation, supply chain, agent snooping, system-prompt leakage, SSRF and excessive agency — measured 6d ago.

The scan reads SKILL.md. This mod also ships 1 executable file (scripts/extract.mjs), listed below but not scanned — reading those needs a real analyzer, not pattern matching.

A static scan of the body, not an audit. Every finding is printed with the line that produced it so you can judge whether it matters here. A mod is markdown that instructs an agent; that is exactly why what it instructs is worth reading.

Nothing flagged

None of the 26 patterns this scan looks for appear in this file: no shell pipes, no recursive deletes, no credential paths, no hidden text, no instruction-override or anti-refusal phrasing, no agent-config snooping. That is not a guarantee, it is the absence of the things that are checkable.

skills/extract-design-system/SKILL.md · 224 lines

How it starts

The opening of the file, as written. The whole thing — 224 lines — stays where its author put it; the contents beside it link to each section on GitHub.

Extract Design System from Website

Reverse-engineer a complete design system from a live website using two passes:

  1. CSS source analysis — fetch and parse stylesheets for declared values
  2. Headed Playwright extraction — visually browse the site, interact with elements, extract computed styles, and capture screenshots at real device resolutions

Prerequisites

  • Playwright installed (npx playwright install chromium if not set up)
  • web_fetch tool for fetching raw HTML/CSS source

Quick Start

Run the extraction script against the target URL:

node scripts/extract.mjs <url> [outDir] [subpage1,subpage2,...]

Examples:

node scripts/extract.mjs https://example.com
node scripts/extract.mjs https://example.com ./my-tokens "/about,/pricing,/docs"
node scripts/extract.mjs http://localhost:3000 extracted "/dashboard,/settings"

The script opens a visible browser (headless: false) so you can watch the extraction. It uses real device profiles for accurate screenshots:

Breakpoint Device Viewport DPR Real image size
Mobile iPhone 15 393×659 3x 1179×1977
Tablet iPad Pro 11 834×1194 2x 1668×2388
Desktop 1440×900 2x 2880×1800
Wide 1920×1080 2x 3840×2160

Mobile and tablet use Playwright's built-in device descriptors (correct UA, isMobile, hasTouch) so sites serving different layouts render correctly.

Output Structure

{outDir}/
├── screenshots/
│   ├── pages/               — full-page at 4 breakpoints × each page
│   │   ├── home-mobile.png
│   │   ├── home-desktop.png
│   │   ├── home-dark-mode.png
│   │   └── ...
│   └── components/          — isolated component + hover/focus states
│       ├── nav.png
│       ├── button-primary.png
│       ├── button-primary-hover.png
│       ├── button-primary-focus.png
│       ├── nav-mobile-open.png
│       └── ...
└── raw/
    ├── colors.json          — CSS custom properties + computed colors
    ├── colors-dark.json     — dark mode variables (if detected)
    ├── typography.json      — font families, type styles, @font-face
    ├── spacing.json         — spacing, radii, shadows, borders, max-widths
    └── components.json      — component manifest + responsive layout data

Read the full file on GitHub · 224 lines

Files

What ships with it

1 file beside SKILL.md in the same directory: the scripts, references and assets a skill reads on demand. Not counted in the per-session cost; read them before you install if any of them is executable.

Changes

What this file has done since we first saw it

Hashed on every crawl. A supply-chain change to an agent config is a question of when, not whether, so the history is kept rather than the latest state alone.

  1. 6d ago First seen · 224 lines · 180 tokens per session scan A b9723dfba919

Subscribe to this mod's changes

extract-design-system is a skill published in the GitHub repository espennilsen/pi (117 stars, last pushed 13d ago), licensed MIT. It adds 180 tokens to every session and 2,109 once invoked, about $0.0009 per session on Opus 5. A static security scan graded it A with 0 findings. No closer match exists in the catalogue, so it is treated as the original; first seen 2026-08-30.

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