I open-sourced a Claude Code skill that audits SEO with separate Google/Bing scores

Why another SEO tool?

I run a small network of coupon/deals sites and got tired of SEO tools that

either cost money, require an API key + signup, or hand you one vague score

without saying which factors it's actually based on.

So I wrote SEO Rank Audit — an open source Claude Code

skill that audits any site and scores it 0-100 per criterion, separately for

Google and Bing, based on ranking factors both engines actually document

(not the real algorithm — nobody has that).

What it does

1. 
   Structure collector (no API key): titles, meta tags, headings, canonical,
   structured data, robots.txt, sitemap, HTTPS, alt text, internal links, and
   sponsored-link attributes — home page + 5-10 internal pages.


2. 
   Real Core Web Vitals via the public PageSpeed Insights API (no key,
   no signup) — LCP, CLS, INP from actual field data (CrUX) when available,
   lab data (Lighthouse) as fallback for smaller sites.


3. 
   Bing Webmaster Tools data (optional, requires your own API key) — only
   for sites you've verified in your own account. Traffic, crawl errors,
   backlinks straight from the source.

The core design principle: anything that can't be measured is marked

"unverified" and removed from the score base — never guessed, never zeroed

out. The final score is points earned / verifiable points × category max.

Why two scores instead of one

Google and Bing don't weigh the same signals. Bing is more literal about

keyword match in title/URL, weighs freshness more heavily, and recognizes

IndexNow. Google cares more about depth, authorship, and trust signals — and

Bing's index also feeds a chunk of AI assistant search, so the gap matters

more than its traffic share suggests.

Dogfooding it found real bugs

I ran the tool against my own site before publishing, found two real bugs

in the audit script itself (JSON-LD @graph wasn't being parsed, and a

false-positive on concatenated heading text caused by stripping whitespace

per text-node instead of once) — and one real bug on my own site (a FAQ

answering "yes, valid coupon" while stating 0 active coupons). All three

fixed before this post.

Try it

Requires the Claude Code CLI

running in a terminal (the /plugin command isn't available in IDE

integrations):

/plugin marketplace add ducrz/seo-audit-marketplace

/plugin install seo-rank-audit

Then just talk to it normally:

audit example.com

why isn't this page ranking on Bing?

compare my site's SEO to a competitor's

• Code: https://github.com/ducrz/seo-audit-marketplace (MIT)


• Docs: https://www.cupomdescontos.com/ferramentas/auditoria-seo
  

Feedback and PRs on scoring weights welcome.