Checks the seven structural rules plus description quality. It cannot verify the file's live MIME type or 200 status, confirm those on your server.
Structural linter based on the llms.txt spec: single H1, third-person blockquote, broad H2 sections, and the mandatory - [Title](URL): Description syntax.
The rules it enforces
A valid llms.txt parses the same way every time: exactly one # H1 (your entity name, no tagline), a > blockquote summary right after it, resources under broad ## sections, and every link as - [Title](URL): Description with the mandatory colon. Descriptions should carry real facts, generic ones waste the format.
Build a compliant file with the generator, then confirm your server returns it as text/markdown with a 200.
How to use it
- Paste your existing llms.txt.
- See it linted against the spec.
- Fix the errors it flags before shipping.
Frequently asked questions
What does the validator check?
Spec compliance: exactly one H1, a blockquote summary, broad section headings, the mandatory colon on each link line, and fact-rich link descriptions. It flags the small syntax mistakes that make a file unreadable to the crawlers it is meant to guide.
What is the most common llms.txt mistake?
Missing or malformed link lines, no colon after the link, or vague descriptions. The validator catches these plus multiple H1s and missing summaries, so the file parses cleanly.
Is the llms.txt Validator free to use?
Yes. The llms.txt Validator is completely free, with no sign-up, no usage limits and no watermark on the output.
Is my data private?
Yes. The llms.txt Validator runs entirely in your browser. Nothing you paste or enter is uploaded, stored or sent to any server.
Related tools and reading
Keep going with the playbooks and tools behind this one.