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llms.txt: What It Is, Whether AI Reads It, and How to Write One

What is llms.txt? Learn what the file does, what Google and server logs show, and how to write one, with a full llms txt example you can copy.

llms.txt is a plain Markdown file at your site root. It lists your key pages for AI tools. Jeremy Howard proposed it in September 2024. Google says its Search ignores the file. No AI company confirms that its answer engine reads it. A 2025 study of nearly 300,000 domains found no link to AI citations. It is cheap to publish, so treat it as optional.

Lourdes Paul Agilan, founder of Aquinel

Founder, Aquinel · Published · 10 min read

Note on verification: We read every source below on 12 October 2026. We could not fetch Gary Illyes's reported July 2025 remarks from a primary source, so we left them out. We did not use Reddit.

What is llms.txt?

llms.txt is a plain text file in Markdown. You place it at the root of your website. The address looks like yoursite.com/llms.txt.

The file gives an AI tool a short map of your site. It holds your name, a one-line summary, and links to your best pages. Jeremy Howard proposed the idea. The llmstxt.org page shows a publication date of 3 September 2024.

The proposal sets a few simple rules. The file needs one H1 with your site name. A short quote block follows with a summary. After that come H2 sections with link lists. An H2 named "Optional" marks links an AI tool can skip.

How is llms.txt different from robots.txt and sitemap.xml?

The three files do different jobs. Only one of them gives orders.

FileWho it talks toWhat it does
robots.txtCrawler botsSays which pages a bot may fetch. Well-behaved bots obey it.
sitemap.xmlSearch enginesLists every URL you want found, with last-changed dates.
llms.txtAI tools and agentsOffers a short, readable summary and a link list. It blocks nothing.

So llms.txt can't hide a page. Use robots.txt for that. Our AI crawler checklist covers the bots and the blocking rules, so we won't repeat them here.

Does any AI system actually read llms.txt?

Nobody has confirmed it for answer engines. The evidence comes from three places.

What does Google say about llms.txt?

Google has said no twice, in two forms. John Mueller of Google posted on Bluesky on 17 June 2025: "FWIW no AI system currently uses llms.txt." Search Engine Roundtable reported the post on 18 June 2025.

Google then wrote it into its docs. The Search Central guide to generative AI features says you don't need new machine readable files or AI text files. It adds that Google Search itself doesn't use them. Google logged a clarifying note on 15 June 2026.

The same guide calls it "completely fine" to keep one. It says the file will neither harm nor help your Google visibility. The guide was last updated on 10 July 2026.

Google's other teams point the other way. Chrome's Lighthouse has an agentic browsing audit. Its docs say agents "may spend more time crawling the site" without the file. A 404 does not fail that audit, because the file is optional (Lighthouse docs, last updated 5 May 2026). Search Engine Journal reported on 20 May 2026 that Google's guidance depends on the product you ask.

What do OpenAI, Anthropic and Perplexity say?

We found no statement from any of them that their answer engines read llms.txt on other sites. All three publish their own file for developers.

On 12 October 2026, we opened these three:

  • Anthropic's file at platform.claude.com/llms.txt starts with "Anthropic Developer Documentation."
  • OpenAI's file at developers.openai.com/llms.txt points to its guides and tools.
  • Perplexity's file at docs.perplexity.ai/llms.txt indexes its API docs.

Publishing a file for developers is not the same as reading files from your site. Their crawler pages tell a similar story. Anthropic's crawler help page does not mention llms.txt. OpenAI's and Perplexity's pages only link to their own docs index.

What do server logs show?

Two studies looked at who requests the file. They used different samples.

Ahrefs published its study on 15 June 2026. It took 137,210 domains with traffic in May 2026. About 28% had an llms.txt file. Ahrefs says that 28% is an upper bound, because its customers skew technical.

Of those files, 97% got zero requests in May 2026. Bots made 96% of the requests. SEO audit tools made the largest share, at 21.7%. AI retrieval bots made 1.1%. OAI-SearchBot led the retrieval bots at 0.74%. Ahrefs warns that a fetch does not prove a bot used the file.

Mintlify published the other study on 27 June 2025. Mintlify is vendor-funded: it sells a docs platform that creates these files. It used Profound's logs for 25 companies over 7 days. The median llms.txt got 14 visits. The median llms-full.txt got 79. Mintlify says ChatGPT drove most llms-full.txt visits, with no figure.

The two results differ in scope. They don't contradict each other. Mintlify looked at 25 sites that mostly serve developer docs. Ahrefs looked at 137,210 general sites. The pattern fits one idea: coding tools and docs readers fetch these files, while answer engines mostly don't.

Does llms.txt change AI citations?

No study we found shows that it does. SE Ranking, an SEO tool vendor, ran the best-known test in November 2025. It looked at nearly 300,000 domains. It measured how often each domain appeared as a source in sampled AI answers.

SE Ranking found llms.txt on 10.13% of those domains. It ran a correlation test and a machine learning model. It found no link between the file and citations. Removing the file from the model made the model more accurate. The company wrote that the file "doesn't seem to directly impact AI citation frequency. At least not yet."

That method has limits. A correlation can miss a small effect. SE Ranking did not publish an exact domain count. Nobody has run a controlled test, where one site adds the file and a matched site does not.

In short, no study shows a benefit, and none shows harm. Our guide to how ChatGPT searches now shows what ChatGPT does read before it names a source.

What does a good llms.txt example look like?

Here is an example for a made-up company. Northwind IT Services does not exist. The URLs below are placeholders.

# Northwind IT Services

> Northwind IT Services is a managed service provider (MSP) in Ohio. We run IT support, security and cloud backup for firms with 20 to 200 staff.

Northwind has served Ohio law, dental and accounting firms. Prices are published. Contracts run month to month.

## Services

- [Managed IT support](https://example.com/services/managed-it): Help desk, patching and monitoring for your team
- [Cybersecurity](https://example.com/services/security): Email filtering, endpoint protection and staff training
- [Cloud backup](https://example.com/services/backup): Daily backups with a tested restore plan

## Pricing and process

- [Pricing](https://example.com/pricing): Per-user monthly prices, what each plan includes
- [Onboarding](https://example.com/onboarding): The first 30 days, step by step

## Proof

- [Case study: dental group](https://example.com/case-studies/dental-group): Ticket times before and after

## Optional

- [Blog](https://example.com/blog): Guides for office managers
- [Careers](https://example.com/careers): Open roles

Every line follows the proposal. The H1 holds the name. The quote block holds the summary. Each list item has a link, then a colon and a short note.

How do you write an llms.txt file?

A small site can finish this in about 30 minutes. Follow these steps.

  1. Open a plain text editor. Save the file as llms.txt.
  2. Write the H1 with your company name.
  3. Write a one-sentence summary in a quote block. Say what you do and who you serve.
  4. Pick 5 to 12 pages a buyer would need. Start with services, pricing and proof.
  5. Write one short note after each link. Use plain facts, not slogans.
  6. Move low-value pages under "Optional."
  7. Upload the file to your site root. Open yoursite.com/llms.txt in a browser to check it.

Should you use an llms.txt generator?

You can. Many tools build the file from your sitemap. Docs platforms such as Mintlify create it for you.

Review the output before you publish it. A generator may list pages you don't want summarised. Ahrefs also found a crawler named prompt-injection-survey/1.0 among the research bots reading these files. Check that no page text could be misread as an instruction.

What is llms-full.txt?

llms-full.txt is a second file. It holds the full text of your docs in one long Markdown file. The shorter llms.txt only links to pages.

Mintlify, the docs vendor, says it built the format with Anthropic. The llmstxt.org page we fetched does not mention llms-full.txt. Treat Mintlify's claim as the vendor's own account.

The size gap is large. On Mintlify's own docs, llms-full.txt runs about 58,000 words. Its llms.txt runs about 1,600 words. A file that long suits developer docs that a coding tool can paste in as context.

An MSP site rarely needs one. Your pages are short sales pages, not 500-page docs. Skip llms-full.txt unless you publish real documentation.

Should you publish llms.txt? The cost and the benefit

The table sets the cost against the evidence.

What we found
CostAbout 30 minutes to write, plus a check each quarter.
RiskLow. Google says it neither harms nor helps Google Search.
Evidence of benefitNone in the studies we found. SE Ranking saw no link to citations. Ahrefs saw 97% of files with zero requests.
Possible upsideCoding tools and agents may fetch it. Lighthouse checks for it.

We suggest this: publish a short one if you have 30 minutes spare. Do it after the work that has proof behind it.

First, make sure the search bots can reach your pages. Second, write pages that answer buyer questions in the first lines. Third, track whether AI tools name you. Our guide on how to get cited by ChatGPT covers that order.

If a vendor sells llms.txt as a citation fix, ask for their test. Ask for the method, the sample size and the date. At the time of writing, we know of no public test that shows the effect.

Aquinel does this work for MSPs and IT services firms. See our services.

Questions

What is llms.txt?

llms.txt is a Markdown file placed at the root of your website, for example yoursite.com/llms.txt. It gives AI tools a short summary of your site and a list of links to your key pages. Jeremy Howard of Answer.AI proposed it. The llmstxt.org page shows a date of 3 September 2024.

Does Google use llms.txt?

No. Google's guide to generative AI features, last updated 10 July 2026, says Google Search itself doesn't use these files. The file will neither harm nor help your visibility or rankings in Google Search. Google also says it is fine to keep one for other systems.

Does llms.txt help you get cited by ChatGPT or Perplexity?

No study we found shows that it does. SE Ranking tested nearly 300,000 domains in 2025 and found no link between llms.txt and citation frequency. Ahrefs found 97% of the llms.txt files it studied got zero requests in May 2026.

What is llms-full.txt?

llms-full.txt is a second file that holds the full text of your docs in one Markdown file. Mintlify, a docs vendor, says it built the format with Anthropic. It is useful mainly for developer documentation. Most small business sites don't need it.

Is there a free llms.txt generator?

Yes, many tools generate one from your sitemap. A small site is faster to write by hand in about 30 minutes. If you use a generator, read the output before you publish. Remove any page you don't want a machine to summarise.

Sources

If you would like us to walk you through how this would work for your firm, the call is free.

Lourdes Paul Agilan, founder of Aquinel

About the author

Lourdes Paul Agilan

Founder of Aquinel. Works with MSPs and IT services firms from Chennai, India, on getting recommended by ChatGPT and found on Google.

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