Audit your site against The Website Specification
121 checks across 10 categories, with the evidence behind every result. Free and instant, and it covers the agent-readiness checks (llms.txt, AI-crawler rules, agent cards) that other auditors skip.
sample what a scan looks like
200 · text/plain · 1.4 KB at /llms.txt
GPTBot, ClaudeBot, PerplexityBot, Google-Extended: allowed
No agent card at /.well-known/agent.json (404)
Why this exists
Joost de Valk wrote The Website Specification: a plain-English list of what a good website does, from the HTML doctype to how AI agents read your pages. It is a public, vendor-neutral standard.
SpecCheck takes a URL and grades it against the whole list. Plenty of tools now check “AI readiness” by reading a single file. SpecCheck checks all 121 items, agent-readiness included, and shows the evidence for each one.
It is an independent tool, not affiliated with or endorsed by the specification’s authors.
Act on the results
A score you cannot act on is just a number. Every failing check has a “Copy fix prompt” button. It writes a specific instruction for your AI coding tool: the evidence, what the spec asks for, a link to the source, and a suggested fix. Paste it into Cursor, Claude Code, or whatever you use. Most fixes turn out to be a few lines.
## HSTS - FAIL (required)
- Evidence: No Strict-Transport-Security header
- Requirement: HSTS is not set, so browsers may make insecure first connections.
- Reference: specification.website/spec/security/hsts/
- Fix hint: Add `Strict-Transport-Security: max-age=63072000; includeSubDomains; preload`.How to use it
- 1
Scan
Paste a URL. The instant checks (HTTP headers, files, DNS, TLS) come back in seconds; the slower ones stream in as they finish.
- 2
Review
Read the per-category scorecard. Every result carries its evidence and a link to the exact spec page, so you can check the reasoning.
- 3
Fix
Copy a category’s fix prompt, paste it into your AI tool, and ship the change. Or download the whole report as markdown.