llms.txt Checker

SEOptimer’s llms.txt Checker tells you whether your site publishes an llms.txt file at its root, the emerging standard for giving AI assistants a curated map of your content.

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About the llms.txt File

What is an llms.txt file?

An llms.txt file is a short markdown document at the root of a site, at /llms.txt, that points AI assistants at the pages worth reading and gives a line on each saying what it covers. It was proposed by Jeremy Howard of Answer.AI in late 2024.

It exists because a model reading a page directly has to work through navigation, banners and markup to reach the content, with limited room to do it in. A curated index of clean pages is a better starting point than a crawl of everything.

This checker fetches /llms.txt for the domain you enter and reports whether one is published.

A convention still being adopted

llms.txt is new, and publishers have moved first. Documentation sites took it up early, support has appeared across a growing list of frameworks, and the number of sites publishing one climbs steadily.

The AI providers have not made public commitments about reading it, which is normal at this stage - the same was true of XML sitemaps and of structured data before either became routine.

That makes publishing one a sensible early move rather than a ranking tactic: an afternoon to write, nothing to maintain beyond keeping the links current, and in place before support settles.

What a good file contains

An H1 with the site or project name, which is the only required line.
A blockquote summarising the site in a sentence.
H2 sections, each a list of links written as name, URL and short description.
Descriptions that say what is on the page rather than repeating its title.
A section headed Optional for links that can be skipped when space is short.

Selectivity is the point. Twenty well-described pages are more useful than every URL you have, and a file listing hundreds is a sitemap with extra steps.

What this tool checks

It requests /llms.txt at the root of the domain and reports whether a file is served there.

It confirms presence rather than judging the contents, so a file that exists but lists nothing useful still passes. Read the result as "is this in place", then judge the file itself on the points above.

Where to go next

If you do not have one yet, our llms.txt generator will build a correctly formatted file from your site details in a few minutes. Then check that the pages it points at are actually crawlable with the AI crawler checker and the robots.txt checker.

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