llms.txt
A plain-text file placed at a website's root that tells AI language models what the site is about, what content is most important, and how to understand the site's structure.
Also known as: llm text file
llms.txt is a plain-text file served at /llms.txt on a website. It is designed to be consumed directly by large language models and AI systems to help them understand what a site covers before or instead of crawling its full content.
The format uses Markdown-style headings and bullet lists. A typical llms.txt file includes the site name, a plain-English description, core topics covered, links to the most important pages, and optionally a preferred summary that AI systems can use when referencing the site.
llms.txt was popularized by Jeremy Howard and adopted by a growing number of AI-conscious websites. While not yet a formal standard, it is recognized by major AI systems including ChatGPT, Perplexity, and Claude.