What is llms.txt?
llms.txt is a proposed plain-text file placed at the root of a domain that summarises the site and lists its most important pages for large language models. It is a voluntary convention, not a standard, and no engine is obliged to read it.
Also known as: LLMs.txt, llms text file
The file borrows its placement convention from robots.txt but serves the opposite purpose. Where robots.txt states what a crawler may not do, llms.txt offers a curated map of what is worth reading — a short description of the site, followed by annotated links to the pages that best represent it.
Its value is contested and worth stating plainly: there is no confirmed evidence that major engines use it as a ranking or retrieval input. Treat it as cheap insurance and a statement of intent rather than a lever.
Where it does help unambiguously is disambiguation. A concise, factual summary at a predictable location gives any system that does read it an authoritative description of the entity, which is useful precisely when the rest of the web is inconsistent.
Why llms.txt matters
The cost is a single static file. The upside is a clean, self-authored description of the entity at a predictable path — worth having even at low probability of use.
Location
Served at /llms.txt at the domain root, as plain text.
Keep it factual
Marketing language undermines the file's only purpose. A description that reads as promotional is the most likely thing to be discarded as unreliable.
Not a substitute for robots.txt
It grants nothing and blocks nothing. Crawler permissions are still governed entirely by robots.txt.
Adoption is unconfirmed
No major provider has documented using it in retrieval. Anyone claiming a measured ranking benefit is overstating the evidence.
Common questions
There is no public confirmation that any major engine reads it, and no credible measured ranking benefit. The honest position is that it costs almost nothing, cannot hurt, and gives a self-authored description of your site at a predictable path. Publish it for that reason, not because it is expected to move a metric.
Direct AEO AnswerThere is no confirmed evidence that major AI engines use llms.txt for ranking or retrieval. It is a low-cost convention, not a proven optimization.