In short. llms.txt is a proposed Markdown file that provides AI assistants with a website overview and links to detailed content.

Definition: llms.txt is a proposed Markdown file that gives AI assistants a website overview and links to detailed content. Markdown is a plain text format using symbols for headings and links, illustrated in the format specification.

Key facts

Jeremy Howard's llms.txt proposal is at version 2, modified on 10 August 2026, and allows files at the site root or a subpath.
As of 17 October 2026, Mintlify's documentation describes automatically generated llms.txt files listing documentation pages.
On the same date, Google's AI features documentation states that AI text files are unnecessary for appearing in AI Overviews or AI Mode.
The Robots Exclusion Protocol, published as RFC 9309 in September 2022, specifies crawler access rules in robots.txt.

What does the file contain?

The llms.txt specification requires a top-level heading naming the site or project. Optional elements include a blockquote summary and second-level headings grouping links with descriptions. This illustrative extract follows its example:

# Title

> Optional description goes here

## Section name

- [Link title](https://link_url): Optional link details

The proposal associates /docs/llms.txt with pages under /docs/. Where files overlap, it directs agents to use the most specific file. It also proposes Markdown page versions such as page.html.md or page.md.

How does llms.txt relate to AI search and robots.txt?

Google's AI features guidance says a page must be indexed and eligible for a search snippet to qualify as a supporting link in AI Overviews or AI Mode. Google also recommends making important content available as text and allowing crawling through robots.txt and hosting infrastructure.

For access management, RFC 9309 defines how crawlers interpret allow and disallow rules. It requires the rules file at the service's top-level /robots.txt path. These rules concern crawler access; the llms.txt proposal supplies an overview with content links.

How can a website check its implementation?

For Mintlify sites, the platform documentation gives a direct check: append /llms.txt to the documentation site's URL. Generated page links include .md, so following them opens Markdown versions of the pages. A custom file at the project root overrides the generated file of the same name.

Mintlify also serves llms-full.txt, which combines documentation into a single file containing each page's title, source URL, description and full Markdown content. The combined file follows the same visibility rules as Markdown page views. On fully authenticated Mintlify sites, both files require authentication; partially authenticated sites expose files containing public pages only.

FAQ

Is llms.txt required for Google's AI search features?

Google's documentation says you do not need new AI text files for these features. Page indexing and eligibility for a search snippet remain technical requirements.

Can you publish llms.txt below the site root?

Yes. The proposal explicitly permits subpaths, including /docs/llms.txt, covering URLs below that path.

Can you maintain a custom file on Mintlify?

Yes. Mintlify accepts a custom root-level llms.txt file in your project. Deleting it restores the automatically generated file.

Sources

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