Definition
llms.txt is a proposed convention: a Markdown file at the root of a website that summarizes what the site is and links to its most important pages, written for AI systems rather than people.
It is not a standard that AI search services have committed to, and Google has said it is not needed for AI Overviews or AI Mode. Publishing one costs little and may help some tools; relying on it instead of fixing the pages themselves helps nothing.
Why it matters
It is worth knowing precisely because it is often oversold. The file is optional; crawlable, accurate, well-structured pages are not.
How it works
If you publish one, keep it short, factual and current: what the company does, the key product pages, the verified facts page. Treat it as a convenience for AI tools, not as a substitute for on-page work.
