What is llms.txt?
llms.txt is a markdown file at the root of your site that describes what the site is and links to the pages worth reading. It is a proposed convention, not a standard, and no major model provider guarantees it is read. It costs an hour to write and it makes your positioning unambiguous in one fetchable place, which is why it is worth doing anyway.
What it is not
It is not robots.txt for AI. It does not grant or deny access — robots.txt still does that. It does not guarantee inclusion in any model's answers, and there is no evidence it changes ranking or citation probability on its own.
Anyone selling llms.txt as an AI visibility fix is overselling it. Treat it as documentation for machines, not as a growth lever.
Why write one anyway
Because the alternative is that a model infers your positioning from whatever page it happens to fetch. A single markdown file stating what you are, what you are not, and which pages matter removes that ambiguity cheaply — and the exercise of writing it usually exposes inconsistencies in how you describe yourself elsewhere.
It is also genuinely useful for the growing number of agents that fetch a site before acting on it.
The format
Keep it flat markdown. An H1 with your site name, a blockquote one-line summary, a few paragraphs of plain description, then H2 sections each containing a link list in the form of a link followed by a colon and a short description.
Include public marketing, documentation and content pages. Exclude login, account, admin, API and webhook routes — anything behind a session has no business in a file designed to be fetched by strangers.
Common mistakes
Listing every URL on the site, which buries the pages that matter. Writing marketing copy instead of description, which reads as noise. Letting it go stale after a redesign, so it points at pages that no longer exist. And listing authenticated routes, which is the one mistake with an actual security cost.
Frequently asked questions
Do ChatGPT or Claude read llms.txt?
There is no published confirmation that either uses it for retrieval or ranking. Some agents and crawlers do fetch it. Write one because it is cheap and clarifying, not because it is guaranteed to be read.
Where does the file go?
At the root, served at /llms.txt, alongside robots.txt.
Does it replace a sitemap?
No. A sitemap is for search engine crawling and is a real standard. llms.txt is a human-readable description with a curated link list.
Related guides
- AI crawlers and robots.txt — Every major AI crawler user-agent, what it feeds, and how to allow or block each one in robots.txt without losing visibility.
- Entity clarity and schema — How to make an AI model certain about what your brand is, using Organization and Person schema, sameAs links and consistent naming.
- AI search visibility — AI search visibility is how often answer engines mention and cite your brand. How to measure it properly, what moves it, and what to ignore.