llms.txt V2: what changed
In August 2026 the llms.txt proposal was revised. The file format is the same. What is new is how pages point to their llms.txt and their Markdown versions, how files in subdirectories work, and what the Optional section means.
Last updated
llms.txt V2 is the August 2026 revision of the proposal published at llmstxt.org. An existing V1 file is still a valid V2 file. The revision adds standard discovery links, allows two forms of Markdown page URL, defines what a file in a subdirectory covers, and removes the special meaning of ## Optional. The source is the V2 change notes.
Why was the proposal revised?
The original was written in September 2024, when the idea of language models routinely reading websites was still a prediction. By 2026 thousands of sites published a file, documentation platforms generated them automatically and, in the proposal’s own words, coding agents used them reliably. The commonest request was discoverability: given a page, how does an agent find its Markdown version, or the llms.txt that covers it, without guessing?
What changed, point by point
| Area | V1 (2024) | V2 (August 2026) |
|---|---|---|
| Finding the llms.txt for a page | Guess /llms.txt at the root | A rel="describedby" link on the page, or the same in an HTTP Link header |
| Markdown version of a page | .md appended to the full URL (page.html.md) | Either form: appended or replacing the extension (page.md), linked with rel="alternate" type="text/markdown" |
| Files in subdirectories | Allowed, meaning undefined | A file covers the pages under its path, and the most specific file applies |
| How files are used | Described a tool that expanded the file into one big context | Agents read or search the file, then follow links to Markdown-friendly pages |
## Optional | Told that tool which links it could leave out | Still allowed as a convention for secondary links, with no special behaviour |
What do the new links look like?
Both are ordinary HTML <link> elements in the page head:
HTML head
<link rel="describedby" type="text/plain" href="https://example.com/llms.txt"> <link rel="alternate" type="text/markdown" href="https://example.com/pricing.md">
If you cannot edit the HTML, the same relation can travel as an HTTP response header:
HTTP header
Link: <https://example.com/llms.txt>; rel="describedby"
What should you change on your site?
Nothing is broken. A V1 file keeps working, so treat these as improvements in order of value:
- Keep your root
/llms.txt. It is still where most readers look first. - Add
rel="describedby"to your pages, through a template or a server header. It costs one line. - Publish Markdown versions of key pages if your platform can produce them, and link them with
rel="alternate". Point the links in your llms.txt at those versions where they exist. - Give large sections their own file if a separate team runs them, for example
/docs/llms.txt. It covers everything under/docs/. - Keep
## Optionalif you like it, as a label for background material. Nothing reads it specially any more.
How does this site follow V2?
Every page here carries both links in its head and a Link header. Each page has a Markdown version at the same address ending in .md, for example /what-is-llms-txt.md, and the site’s own llms.txt links to those versions. The validator follows V2: a file in a subdirectory gets a note rather than an error, and ## Optional placement is only noted.
Does V2 make llms.txt a standard?
No. It is still a proposal maintained in public, with no standards body behind it and no obligation on anyone to read the file. Google, for one, says you do not need AI text files to appear in its AI features (Google’s guidance on AI features). V2 makes the file easier to find and use for the tools that already choose to read it, which is the right ambition for it.
Frequently asked questions
Do I have to update my llms.txt for V2?
No. A V1 file is valid under V2. The changes add optional ways to link pages to the file and to Markdown versions of themselves.
Is ## Optional deprecated?
No. It is still allowed and still a useful label for secondary links. It simply no longer triggers special behaviour in any tool described by the proposal.
Which Markdown URL form should I use?
Either is allowed: page.html.md or page.md. Pick the one your platform produces easily and link it with rel="alternate" type="text/markdown" so nobody has to guess.
Where is the official text?
At llmstxt.org, with the revision summarised on its changes page and the history in the proposal’s GitHub repository.