A proposed plain-text file that summarizes a site for large language models, like robots.txt does for crawlers.

No. It is a voluntary convention.

llms.txt Check

llms.txt is a proposed plain-text Markdown file at a site’s root that summarizes the site and links its key pages for AI assistants. This check fetches /llms.txt and /llms-full.txt and validates their structure against the format.

When to use this: You published an llms.txt file and want to confirm it is reachable and well formed. Command prefix llmstxt:

About the llms.txt Check

Fetch /llms.txt and /llms-full.txt from a site and show what it tells AI assistants about its content.

FAQ

What is llms.txt?: A proposed plain-text file that summarizes a site for large language models, like robots.txt does for crawlers.
Is it required?: No. It is a voluntary convention.