Status
Open source
Period
June 2026
Stack
Claude Code skill · curl · grep
An effect that looks impressive usually has a simple implementation.
The skill reads the source the browser receives, not a summary of it, and every claim in the output is marked as confirmed from source or inferred.
1Problem
Working out how a site was built is slow by hand, and the obvious shortcut loses the answer: a fetch tool that routes the page through a summarising model returns prose about the page, not the code that makes it move.
2Task
Turn a single URL into a teardown document — stack, effects, design tokens, assets and a section-by-section build plan — without asking the person to open developer tools or paste anything.
3Approach
Fetch the raw page
curl with a browser user agent. Fall back to a fetch tool only when curl fails or returns an empty app shell; ask the person only if both fail.
Drop what is not the site
Tag managers, consent banners, captchas, CDN and CMS core scripts are filtered out; the app bundles stay.
Search the minified code
Grep the bundles for animation signatures — GSAP, ScrollTrigger, IntersectionObserver, Lenis and others — then read the code around each hit.
Pull the design system
Colours, type scale, spacing and easing are extracted from the CSS.
Write a fixed template
The result is saved as a dated markdown teardown with the same sections every time.
Say what is certain
Each finding is labelled as confirmed from source or inferred, and the document ends with a catalogue of twelve effects that look complex and are not.
4In use
The first real teardown was of a designer’s portfolio site with a text-scramble effect on hover. The skill identified nine technologies and broke down eight effects; the scramble turned out to be a per-character “lock-in” wipe driven by a frame counter — no library needed.
That became the scramble on the 23ag.one homepage: service names and footer links resolve left to right on hover. It was rewritten from scratch rather than copied, and it respects reduced-motion settings.
The most valuable part of a teardown is showing that an impressive-looking effect has a simple implementation.skills/site-teardown/SKILL.md
5Limitations
- Pages behind a login fail. Apps that render everything in JavaScript fall back to the summarising fetch and lose detail.
- There are no tests or evaluations — the evidence is use, not measurement.
- It reads other people’s code. The template asks for licensing concerns to be noted; rebuilding is expected to be a rewrite, not a copy.