Free Tool · llms.txt Validator
Validate your llms.txt against the spec.
Paste your domain and we fetch your existing /llms.txt and check it line by line against llmstxt.org — H1, summary, sections, links and every malformed line. No signup to try it.
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No signupUnlimited & freellmstxt.org spec
What the validator reads
01 / Present
File exists.
Whether /llms.txt is actually served as plain text — not an HTML catch-all masquerading as one.
02 / H1
Site name.
The spec requires a single leading `# Site Name` heading — the first thing an agent reads.
03 / Summary
Blockquote summary.
A `> ` one-liner that lets agents judge relevance before parsing every link.
04 / Sections
Section headers.
`## ` groups that turn a flat list into a navigable map.
05 / Links
Markdown links.
Valid `- [name](url)` list items — the actual content an agent follows.
06 / Malformed
Syntax errors.
Exact line numbers of anything that breaks the spec, so you can fix it fast.