llms.txt
Also known as: LLMs.txt
In short
A proposed Markdown file format for providing concise website guidance and links that AI applications can use when accessing a site.
llms.txt is a proposal for publishing concise information that helps AI applications use a website. A file can provide background, guidance, and links to more detailed material in a readable Markdown format.
It is a publisher-supplied reference. It does not replace the underlying pages, a product feed, or the access rules used by crawlers.
A practical example
Imagine a software documentation site with separate guides for installation, authentication, and troubleshooting. Its llms.txt file explains the documentation structure and links to the current guides.
If an authentication method changes, the publisher updates the guide and checks that the summary remains accurate. This illustrative workflow avoids maintaining a second, conflicting account of how the product works.
Understand the limits
Publishing the file does not guarantee that an AI provider will read it, index its links, or cite the site. Google explicitly states that Google Search ignores llms.txt for visibility and rankings.
The file is also not a permission system for training or a mechanism to block access. Keep those decisions separate. Include factual, maintained information and use the file where it serves an identified reader or integration. Do not treat its existence as proof that a website is ready for every AI service.