llms.txt is a proposed plain-text file at a site's root that lists the URLs and short descriptions a site owner wants LLMs to prioritize when summarizing that site.
llms.txt is a proposed plain-text file at a site's root that lists the URLs and short descriptions a site owner wants LLMs to prioritize when summarizing that site.
The proposal lives at llmstxt.org. As of mid-2026 no major answer engine has publicly confirmed consuming it, but publication is cheap and machine-readable.
llms.txt is a proposed plain-text file at a site's root that lists the URLs and short descriptions a site owner wants LLMs to prioritize when summarizing that site — and as of mid-2026 no major answer engine has confirmed that it uses the file for retrieval or citation.
Markdown twins are plain-text or markdown copies of an HTML page served at a parallel URL (typically {url}.md) so retrieval systems can ingest the content without an HTML parser — a practical convention endorsed by the llms.txt proposal but not yet formally consumed by any major answer engine.