What is llms.txt?

llms.txt is an emerging convention — not yet a formal standard — for publishing a short markdown file at the root of a domain (/llms.txt) that gives AI systems a curated, machine-readable summary of a site: what it is, and links to its most important pages with a one-line description of each.

The idea mirrors what a sitemap does for traditional search crawlers, but tuned for how language models consume content: instead of exhaustively listing every URL, an llms.txt file is meant to be a short, hand-curated table of contents that fits comfortably in a model's context and points straight at the pages worth reading.

Adoption is still early, and no major AI provider has confirmed that it directly uses llms.txt files to inform answers today. It's best treated as a low-cost, forward-looking addition to a site's AI readiness — worth publishing because it's cheap and might help, not because its impact is proven yet.