What Is llms.txt? What It Does and Whether You Need One

llms.txt is a proposed Markdown file that sits at the root of a website and gives AI systems a short summary of the site plus a list of its most useful pages. It was suggested in 2024 by Jeremy Howard of Answer.AI, and since then thousands of sites have added one, often because an SEO plugin offered it with a single click.

The harder question is whether anything reads it. This guide covers the format, the evidence on who uses it as of 2026, and a simple way to decide whether your site should have one. If you want one, our free generator builds it from your sitemap in a few minutes.

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What an llms.txt file looks like

An llms.txt file uses a fixed order of Markdown elements:

1. An H1 with the site or project name. This is the only required part.
2. A blockquote with a one- or two-sentence summary.
3. Optional paragraphs with anything a reader should know first.
4. H2 sections, each containing a list of links written as - [Title](URL): short note.
5. An optional section called Optional for pages that can be skipped when space is short.

A small example:

# Acme Widgets

> Acme sells modular shelving for small homes, shipping across the US and Canada.

## Products

- [Shelving systems](https://acme.example/shelving/): sizes and prices
- [Assembly guides](https://acme.example/help/assembly/): step-by-step instructions

## Optional

- [Company history](https://acme.example/about/)

The proposal also describes llms-full.txt, a companion file with the full text of key pages in one document. That one mainly suits software documentation.

Why it was proposed

Web pages are built for people: menus, adverts, scripts and layout wrap the text an AI actually needs. An AI model working with a limited context window wastes a lot of it on that clutter. The idea behind llms.txt is to hand AI tools a clean map, in plain Markdown, so they can jump straight to the right page instead of crawling the site to work out its structure.

Does anything actually read it?

Very little, so far. The clearest data comes from an Ahrefs study of 137,000 sites: of roughly 38,000 domains with a valid llms.txt file, 97% received no requests for it at all during May 2026. Most of the rare visits came from tools and bots cataloguing the web, not from AI assistants answering questions.

Google’s position is consistent. Its May 2026 guidance on generative AI features in Search says site owners don’t need llms.txt or any special AI files to appear in them. John Mueller has compared the file to the old keywords meta tag and described it as a temporary crutch for coding tools rather than something for search. No major AI company has publicly confirmed that it uses llms.txt for answers or citations.

There is one genuine use. AI coding assistants and browsing agents do sometimes fetch llms.txt from documentation sites, because a tidy index saves them time and tokens. Chrome’s Lighthouse also added an llms.txt check to its experimental agentic browsing audits in 2026, on the basis that agents navigating a site on a user’s behalf may benefit from it.

Does llms.txt help SEO or AI visibility?

Not in any way anyone has measured. It isn’t a Google ranking factor, and there’s no public evidence that it makes ChatGPT, Claude or Perplexity cite a site more often. What does influence AI visibility is the same work that helps search: clear, accurate pages, a crawlable site, and not blocking the AI crawlers you want to reach you. Our guide on controlling AI crawlers with robots.txt covers that side, and the AI Crawler Access Checker shows which bots your site currently allows.

The file is harmless, though. It takes minutes to make, costs nothing to host, and doesn’t create duplicate-content problems as long as you don’t publish Markdown copies of every page as separate indexable URLs.

Should your site have one?

Your site	Recommendation
Software docs, APIs, developer tools	Yes. Coding assistants are the one group that uses it.
SaaS or product site with a help centre	Worth adding. Point it at your docs and key product pages.
Blog, news or content site	Optional. It won’t bring traffic; add one only if it takes minutes.
Local business or small brochure site	Low priority. Spend the time on your pages and Google Business Profile first.

Mueller’s own rule of thumb is practical: if an AI platform that sends you customers asks for the file, make one.

How to create an llms.txt file

1. List the 10 to 30 pages that best explain what you offer: key products or tools, pricing, help and documentation.
2. Write a one- or two-sentence summary of the site for someone who has never heard of you.
3. Group the pages into a few H2 sections and add a short note to each important link.
4. Move secondary pages into an Optional section.
5. Save the file as llms.txt and upload it to your site’s root, then open yoursite.com/llms.txt to check it loads.

The free generator does steps 1 to 4 from your sitemap. On WordPress, Yoast SEO can also generate and update the file automatically.

Common mistakes to avoid

• Listing every URL. An llms.txt file with hundreds of links is just a worse sitemap. Curate it.
• Relative links. Use full URLs starting with https://.
• Marketing copy as the summary. “The world’s best platform” tells an AI nothing. Say what you do and for whom.
• Treating it as a blocking tool. llms.txt can’t stop AI crawlers. That’s what robots.txt is for.
• Forgetting it. A file pointing to deleted pages is worse than none. Update it when your site structure changes.

The short answer

llms.txt is a Markdown index of a site’s most useful pages for AI tools. As of 2026 almost nothing reads it, Google says it isn’t needed for Search, and it doesn’t affect rankings. It’s worth adding for documentation and developer sites, and harmless elsewhere if it only takes a few minutes. Build one with our free tool, keep it short, and put your real effort into the pages it points to.