What Is a Claude Skill?
A Claude Skill is a folder — a SKILL.md file plus scripts and reference docs — that teaches Claude how to do a specific job well, the same way a new hire's onboarding doc would. Claude Code, Cowork, and claude.ai can all load one and follow it. Since Anthropic introduced the format, it's become a genuine cross-tool standard: the same SKILL.md shape now works across Cursor, Gemini CLI, Codex, and Windsurf too.
In plain terms: instead of re-explaining your methodology to Claude every single time, you write it once as a Skill. Claude reads it, follows it, and produces consistent output — an SEO audit that scores the same way every time, not however Claude happens to feel like scoring it that day.
How Crowded Is This, Really?
Before listing my own three, it's worth being honest about the landscape, because most "top Claude Skills" posts aren't. This space is genuinely mature:
- SEO/GEO/AEO skills — at least four separate, well-engineered projects already do serious work here, one backed by a 24,800-star, 364-skill collection with automated content rewriting and a cross-LLM citation ledger.
- UI/UX and motion skills — even more saturated, with individual repositories past 80,000 stars.
- Google Sheets automation skills — exist, but none of the ones I found cover the specific pattern of using a spreadsheet as a website's CMS, which is why that's the one I'd point to first if you only try one.
None of that is a reason to skip building — it's a reason to be specific about what each one actually does differently, which is the point of this post.
1. AI-Ready Audit — SEO, GEO & AEO Auditor
A zero-dependency site auditor that scores four separate dimensions: traditional SEO, GEO (can AI systems actually cite you), AEO (is your content structured to be quoted), and a fourth axis most competing skills skip — Future-Readiness, whether the site is built for where AI crawling is heading, not just where it is today.
The single highest-value check it runs is rendering-risk detection: whether a page's real content lives in the initial HTML or only appears after JavaScript executes. A crawler that can't run JavaScript sees an empty shell either way — and that's usually the actual reason a technically weaker competitor outranks a better site, not anything to do with content quality.
| Detail | AI-Ready Audit |
|---|---|
| Setup required | None — one Python script, standard library only |
| API key needed | Never, at any tier |
| What makes it different | Four scores never blended into one number, each traced to a cited source |
| License | MIT |
2. Sheet-as-CMS Toolkit — Google Sheets Validation
This is the one built around a genuinely uncontested niche. A lot of small teams and solo developers use a Google Sheet as their entire CMS because it's free and their content editor already knows how to use it — but the pattern fails in three quiet, predictable ways: a renamed column silently breaks the site, a client-side fetch hits Google's rate limits the day real traffic shows up, or a content editor pastes rich text that turns out to carry a hidden onclick= handler.
This toolkit catches all three before they ship: schema-drift detection, row-level validation, and content-safety scanning for exactly the injection risks a spreadsheet has no built-in defense against.
Why this one first, if you only try one: I checked it against five separate 300+-skill GitHub collections while building it, and found nothing else covering this specific pattern — the closest matches were general Google Workspace automation tools, not CMS-pipeline validators.
View Sheet-as-CMS Toolkit on GitHub
3. Motion Audit Toolkit — Shipped Animation Performance
Most animation tooling is about generating new motion — picking a personality, writing the component. This one does the opposite: it audits animations already sitting in a codebase for three specific things — whether they're running on the compositor thread or forcing a layout recalculation every frame, whether prefers-reduced-motion actually covers every animation or just some of them, and whether the same interaction (a hover state, a modal entrance) uses wildly different timing in different components.
It deliberately stays out of easing-curve quality and "what's missing" gap analysis — both are well covered by other tools already, and trying to do everything is how a narrow, useful skill turns into a mediocre broad one.
View Motion Audit Toolkit on GitHub
Which One Do You Need?
| If you're asking... | Use this one |
|---|---|
| "Why don't we show up in ChatGPT or Perplexity when we rank fine on Google?" | AI-Ready Audit |
| "My Google-Sheets-backed blog is showing blank posts / hitting rate limits" | Sheet-as-CMS Toolkit |
| "Why does this page feel janky, and is our reduced-motion coverage real?" | Motion Audit Toolkit |
How to Install Any of These
Clone the repo
Each one is a self-contained GitHub repository — clone it or download the ZIP from the releases page.
Point Claude at the folder
In Claude Code or Cowork, point your skills directory at the cloned folder. In claude.ai, upload the folder directly to a conversation with code execution enabled.
Ask in plain language
No slash commands to memorize — just ask Claude to audit a URL, validate a sheet, or check your animations, and the relevant skill activates.
Conclusion
All three are free, MIT-licensed, and built around a real problem I actually ran into — not written as a portfolio piece first and a tool second. The honest version of this post is the useful one: two of these compete in genuinely crowded categories and say so upfront, and the third exists specifically because nothing else did.
All three live under AI Skills on this site, alongside the technical details, tested code, and full methodology for each.
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