llms.txt Explained: Does Your Site Need One?

llms.txt is a proposed file, written in Markdown and placed at the root of a website, that gives AI tools a short description of the site and a curated list of links to its most useful content. It is a sensible idea for some sites. It is not a ranking factor, Google says its Search ignores it, and for most small business websites it is optional and low priority.

This article covers what the file is, who actually reads it, and when it is worth ten minutes of your time. For the wider set of things that do affect AI visibility, start with the AI search optimisation guide.

What llms.txt is

The llms.txt proposal was published by Jeremy Howard on 3 September 2024, and updated to a second version in August 2026. The problem it addresses is real: web pages are full of navigation, scripts and layout that make them awkward for a language model to read within a limited context, especially for something like software documentation. A short Markdown file pointing to clean versions of the key pages is easier to use.

The proposal describes a file at /llms.txt containing, in order:

1. An H1 with the name of the site or project — the only required part.
2. A blockquote with a short summary.
3. Optional paragraphs or lists with more detail.
4. Sections under H2 headings, each a list of links with a short description.
5. Optionally, a section called "Optional" for links that can be skipped when space is short.

It also suggests publishing clean Markdown versions of pages, at the same URL with .md added.

Who actually reads llms.txt

This is where claims and evidence part company.

Google's guide, at the time of writing (October 2026), says having an llms.txt file will neither harm nor help your visibility or rankings in Google Search, and that it is fine to keep one for other services that use it. Before that guidance was written, Google's John Mueller had compared the file to the old keywords meta tag.

The Lighthouse check is worth understanding correctly. Lighthouse is Google's site-auditing tool, not Google Search. Its check looks at whether a file you publish is well-formed. It is not a signal that Search uses the file, and Google's Search documentation says otherwise.

Does your site need an llms.txt file?

For a plumber, an accountant or a small online shop, the things that affect AI visibility are crawler access, indexing, clear pages and consistent business information. How to get cited by ChatGPT and Perplexity and how to appear in Google AI Overviews cover those. An llms.txt file sits well below them.

If you do create one

Keep it short, accurate and maintained.

1. Start with the business name as the H1 and a one- or two-sentence summary in a blockquote: what you do, where, for whom.
2. Add an H2 section for services, with a link to each service page and a one-line description.
3. Add an H2 section for your most useful guides — the pages that answer real customer questions.
4. Add contact and About links.
5. Put lower-priority links under an "Optional" heading.
6. Check it whenever you add, remove or rename pages.

Do not paste your whole sitemap into it; that defeats the purpose. Do not put claims in it that are not on the site. And do not expect anything from Google as a result.

Common llms.txt claims, checked

The risk worth naming

The real cost of llms.txt for a small business is not the file. It is being sold it. If an agency charges for "AI optimisation" and the deliverable is an llms.txt file, you have paid for something Google says it ignores and that the major AI search products do not document using. Ask what else is in the work.

Next step

If you have ten minutes for AI search this week, spend them on robots.txt and how Google crawls and indexes your site, not llms.txt. If you want both checked properly, the SEO service covers crawler access as part of the audit.