llms.txt is a proposed standard (from llmstxt.org) for a markdown file served at the root of your domain that tells large language models which pages matter and what they contain. Think of it as robots.txt's helpful cousin: where robots.txt says what crawlers may not touch, llms.txt curates what they should read first.
The file is short by design — a title, a one-line description, and a linked, annotated list of your most important pages grouped by section. A companion file, llms-full.txt, holds the fuller canonical text. Together they give answer engines a clean, ambiguity-free source instead of forcing them to reconstruct your site from rendered HTML.
Shipping llms.txt is one of the cheapest AIO moves available: a single static file, no backlinks, no rebuild. For young domains it is disproportionately valuable because it hands the engines exactly the claims you want cited.
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Frequently asked
Where do I put llms.txt?
At the root of your domain, served as plain markdown at https://yoursite.com/llms.txt. Keep it concise and link to a fuller llms-full.txt for the complete canonical text.
Is llms.txt an official standard?
It's a community proposal (llmstxt.org) that has gained fast adoption rather than a formal W3C or IETF standard. Several major AI engines look for it, and the cost of shipping it is trivial, so the expected value is high even while the spec settles.
Does llms.txt replace a sitemap?
No. A sitemap tells search crawlers every URL; llms.txt curates the handful of pages and claims you most want AI engines to understand. Keep both — they serve different audiences.
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