What Is llms.txt? What It Does, Who Reads It, and Do You Need One

llms.txt is a proposed text file, placed at the root of a website, that gives AI tools a short Markdown summary of the site and links to its most useful pages. It was proposed in September 2024 by Jeremy Howard of Answer.AI as a way to help large language models find the important content on a site without parsing navigation, ads and scripts. Since then it has become one of the most heavily marketed “AI SEO” tactics. The honest picture is more modest: Google says it doesn’t use llms.txt, the major AI companies haven’t committed to reading it, and server logs show AI crawlers rarely request it. This guide explains what the file is, who reads it, and when it is worth five minutes of your time.

What is llms.txt?

The llms.txt proposal describes a plain Markdown file served at /llms.txt. It starts with the site or project name as a heading, a short summary in a blockquote, then sections of links to the pages an AI model would find most useful, each with a one-line description. Some sites also publish llms-full.txt, a single file containing the full text of their documentation.

A minimal example for a services business:

# Foundier
> Foundier is an AI SEO agency that helps law firms, clinics and B2B service firms get found on Google and named in AI answers.

## Services
- [AI Visibility Audit](https://foundier.com/services/audit/): 5-day audit, $750
- [AI SEO services](https://foundier.com/services/ai-seo/): fixed-price tiers from $3,000

## About
- [About Foundier](https://foundier.com/about/): founder, team and guarantees

It is often compared to robots.txt and sitemap.xml, but it does a different job. robots.txt tells crawlers what they may access. A sitemap lists the URLs you want indexed. llms.txt is a curated reading list written for a language model.

Does Google use llms.txt?

No. Google’s guide to optimizing for generative AI features is explicit: “You don’t need to create new machine readable files, AI text files, markup, or Markdown to appear in Google Search.” Google Search doesn’t use them, and creating them neither helps nor harms your visibility in Google. Google adds that other services may use such files, which is a fair caveat.

So llms.txt has no effect on Google rankings, Google AI Overviews or Google AI Mode. Google’s AI features retrieve pages from its normal index; what helps there is ordinary SEO.

Do ChatGPT, Claude or Perplexity read llms.txt?

Not in any way they have committed to. No major AI provider has said its crawlers rely on llms.txt when deciding what to cite. Analyses of server logs reported by Ahrefs and others found AI crawlers rarely request the file (PPC Land). Several AI and developer-tool companies publish their own llms.txt for their documentation, which is not the same as reading everyone else’s.

Where the file does get used is in AI coding assistants and agent tools. A developer can point a tool at a library’s llms.txt, or a tool can fetch it when asked about a product, and get a clean map of the documentation. That is why adoption is highest among software and documentation sites. A September 2026 check of 100 cybersecurity vendors found about a third served a working llms.txt, and many others returned errors or block pages to AI-style requests (hrbrmstr, Cyber 100 census).

Should you add an llms.txt file?

If you do publish one, treat it like any public page: accurate prices, live URLs only, no marketing claims you couldn’t defend, and an update whenever your services change. A stale llms.txt that contradicts your site is worse than none.

What matters more than llms.txt

• Crawler access. Make sure robots.txt, your firewall and your CDN aren’t blocking Googlebot or the AI search crawlers you want, such as OAI-SearchBot and PerplexityBot. Many security tools block them by default.
• Content in plain HTML. Key facts shouldn’t be locked inside images, PDFs or scripts.
• Pages worth citing. Original, first-hand answers to the questions your buyers ask.
• Consistent business facts across your site, Google Business Profile and the directories in your industry.
• A genuine reputation: reviews, coverage and expert mentions you earned.

These help every engine at once. llms.txt, at best, helps a few tools find pages they could already crawl. For the bigger picture, see our guide to answer engine optimization (AEO) and our technical SEO audit checklist.

How to create an llms.txt file in five minutes

1. Create a plain text file named llms.txt.
2. Add an H1 with your business name and a one-sentence summary in a blockquote.
3. Add H2 sections (Services, About, Guides) with links to your 5 to 15 most important pages and a one-line description each.
4. Upload it to your site root so it loads at https://yourdomain.com/llms.txt. On WordPress, some SEO plugins can generate it.
5. Check it loads publicly, then set a reminder to update it whenever prices or services change.

The bottom line

llms.txt is a reasonable idea with limited real-world uptake. Add one if it is quick and you’ll keep it accurate. Don’t pay for it as a visibility strategy, and be wary of any AI SEO offer that leads with it. If you want to know what actually stands between your business and AI recommendations, Foundier’s AI Visibility Audit tests 25 buyer questions across Google AI Overviews, ChatGPT, Perplexity and Claude and gives you a ranked fix plan. Or start with a free AI visibility snapshot.

FAQ

What is llms.txt used for?

llms.txt is a Markdown file at a site’s root that gives AI tools a short summary of the site and links to its most useful pages. It is mainly used by documentation sites so AI coding assistants and agents can find the right pages quickly.

Does llms.txt help SEO?

Not for Google. Google says it doesn’t use llms.txt or other AI text files, and that creating them neither helps nor harms visibility in Google Search. Other AI tools may read it, but no major provider has said it uses the file to decide what to cite.

Is llms.txt an official standard?

No. It is a proposal published by Jeremy Howard of Answer.AI in September 2024. It has no formal standards body and no commitment from the major search or AI companies to support it.

What is the difference between llms.txt and robots.txt?

robots.txt tells crawlers which URLs they may or may not access. llms.txt is a curated, human-readable list of your most useful pages for AI tools. robots.txt is honored by major crawlers; llms.txt is optional and rarely requested.

Can llms.txt hurt my website?

Only if it is wrong. A file that lists staging URLs, private pages, outdated prices or claims that contradict your site can confuse the tools that read it. If you publish one, keep it accurate and current.