Every few years the web grows a new plain text file at the domain root. robots.txt told crawlers where not to go. sitemap.xml told them where everything was. The newest proposal, llms.txt, wants to tell AI systems what your site is about and where your most important content lives, in clean markdown they can digest without fighting your page templates.

The honest status in mid 2026: it is a proposal with growing but uneven adoption, and no confirmed guarantee that the major AI providers consistently consume it. So should you bother? My answer for most clients is yes, and the reasoning has less to do with the file than with what producing it forces you to do.

What llms.txt Actually Is

A markdown file at your domain root containing a short description of your site and a curated, annotated list of your most important pages, optionally with companion markdown versions of key content. Think of it as a manually curated sitemap written for language models: not everything, just what matters most, described clearly.

The Case For and Against, Honestly

If You Do It: The Right Way in Five Steps

Priority check before you start: if your content is client-side rendered or your schema is broken, fix those first. llms.txt is a refinement on top of machine-readable foundations, not a substitute for them.