AI Seen Score

What is llms.txt, and how to write one

Last updated: October 25, 2026

llms.txt is a Markdown file at the root of a website that gives AI tools a short, clean summary of the site and links to its most useful pages. It was proposed by Jeremy Howard in September 2024. Think of it as a table of contents written for language models instead of for search engines.

Be realistic: llms.txt is a proposal, not a standard that AI companies have committed to. There is no public evidence that adding one makes AI answers mention you more. It is cheap to add and harmless, so treat it as low-risk housekeeping, not a growth lever.

The format

The file lives at https://yourdomain.com/llms.txt. The proposal defines these parts, in this order:

  1. An H1 with the name of the site or project. This is the only required part.
  2. A blockquote with a one or two sentence summary.
  3. Optional paragraphs or lists with more detail, without headings.
  4. H2 sections that list links, one per line: - [Page name](URL): what it covers.
  5. An H2 section called "Optional" for links an AI tool can skip when it is short on space.

A copy-ready example

Here is a small example for a software company. Replace the names and links with your own.

# Acme Invoicing

> Acme is invoicing software for freelancers and small studios. It creates invoices, tracks payments and sends reminders.

Acme is used by about 5,000 freelancers. Plans start at $9 per month.

## Product

- [Features](https://acme.example/features): Invoices, recurring billing, payment reminders
- [Pricing](https://acme.example/pricing): Plans, limits and what each includes
- [Integrations](https://acme.example/integrations): Stripe, PayPal, QuickBooks

## Help

- [Getting started](https://acme.example/docs/start): Set up an account and send a first invoice
- [FAQ](https://acme.example/faq): Common questions about billing and data

## Optional

- [Changelog](https://acme.example/changelog): Release notes

Writing tips

  • Lead with what you are and who it is for. The summary is the part most likely to be quoted.
  • Link to pages with real answers: pricing, features, comparisons, documentation. Skip login pages and legal pages unless they matter to buyers.
  • Keep facts current. An llms.txt with old prices is worse than none.
  • Serve it as plain text. If your server returns your homepage for /llms.txt, the file effectively does not exist. Open the URL in a browser and check that you see the Markdown, not your site.
  • Do not use it to block anything. llms.txt is a guide, not an access rule. Use robots.txt to control crawlers.

What about llms-full.txt?

Some sites also publish llms-full.txt, a single file with the full text of their key pages. It is a common convention around the proposal rather than part of its core format. It can help documentation sites. For a typical marketing site, a good llms.txt is enough.

Check yours

The free AI Seen Score extension checks whether your site has an llms.txt, whether it is a real file rather than a page that returns your homepage, and whether it has a title and links.

Sources

Check your own site in one click. The free AI Seen Score extension runs these checks on the page you are viewing: AI crawler rules in robots.txt, llms.txt, structured data, titles and headings, and content that only appears after JavaScript runs. It runs in your browser and sends nothing to us.

Add to Chrome, free

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