The complete guide to llms.txt

llms.txt is a plain-text Markdown file served at the root of a website (https://example.com/llms.txt) that gives AI engines a curated, human-readable index of the most important pages and a short description of each. It is to AI engines what robots.txt is to search crawlers and what sitemap.xml is to indexers: a low-cost signal that helps machines understand the site without re-deriving it from raw HTML.