Why it matters to a buyer
The file is often sold as a way to get cited by AI assistants, and that is where a buyer should be careful. Google has said its search systems do not use llms.txt, and the major assistants have not said they read it when choosing sources. It costs little to publish and can help coding tools and agents that are pointed at it, but it does not replace crawler access, clear pages or third-party presence, which are what actually drive citations.
How it is measured or applied
Applying it means writing a short Markdown file at /llms.txt with the site's name, a one-paragraph summary and grouped links to key pages, optionally with a fuller /llms-full.txt. It should say nothing a crawler cannot confirm on the pages themselves. Whether anything reads it can be checked in server logs by looking for requests to the file and the user agents making them. Because it controls nothing, blocking or allowing AI crawlers is still done in robots.txt and at the firewall.
Sources
- The /llms.txt file, llmstxt.org
