Should your business website have an llms.txt file?
llms.txt is a proposed text file that gives AI tools a short summary of your website, with links to the pages that matter. It's cheap to add. Google says its search ignores it, and no major AI company has said its answers use it. Treat it as a small extra and don't pay much for it.
You may have seen llms.txt on a list of things every website needs for AI. Some agencies sell it as a package on its own. Before you pay for one, here's what it is and what the companies behind the AI tools have said about it.
llms.txt is a short summary of your site for AI tools.
It's a plain text file that sits at yourdomain.com/llms.txt. Jeremy Howard of Answer.AI proposed it in September 2024. The idea is a tidy summary of your site written for AI tools: your name, a line or two on what you do, then links to your most useful pages with a sentence on each.
It's a proposal, and nobody enforces it. Anyone can publish one in any shape they like. It's aimed at the moment someone asks a question. The proposal expects AI tools to use it when they need information while helping a person, more than for training models.
The file is written in Markdown, a simple way of marking headings and links in plain text. For a roofing contractor it might contain:
- A title line with the business name
- A one-line summary, such as "Commercial roof replacement and repair across the Denver metro area"
- A heading for services, with a link to each service page and a line on what it covers
- A heading for the company, with links to the about, service areas and contact pages
It sits alongside two files most websites already have:
| File | What it's for | Who reads it |
|---|---|---|
| robots.txt | Tells crawlers where they may go | Search engines and the major AI crawlers, constantly |
| Sitemap | Lists the pages you want found | Search engines and other crawlers |
| llms.txt | Summarises your site for AI tools | Rarely requested by the major AI crawlers so far |
It doesn't replace anything on your pages. The summary is only as good as the pages it points to, so they still have to say what you do, where and how to reach you.
The AI companies haven't said they use it.
Google says its search ignores llms.txt, so the file won't help or harm how you appear there, AI features included. When it added that to its guidance in June 2026, it said site owners may still keep one for other services. Its page on AI Overviews and AI Mode also says you don't need new machine-readable files or AI text files to appear in them.
OpenAI, Anthropic and Perplexity each publish a page explaining their crawlers and how to control them. Those pages cover robots.txt rules for each crawler. None of them says their crawlers read llms.txt to answer questions. Each company does publish an llms.txt of its own, for its developer documentation.
Chrome's Lighthouse, the site-testing tool built into Google's browser, added an "agentic browsing" check in 2026 that looks at llms.txt. If you have one, it checks the file is well formed. If you don't, that check is marked not applicable, and Google's documentation calls the file optional for now.
Server logs show crawlers rarely ask for it.
What companies say is one thing. Whether their crawlers ask for the file is easy to measure. EZY Research put llms.txt on 83 websites and watched the server logs from 27 April to 19 July 2026. Crawlers that follow the rules fetch robots.txt before they crawl, so that column gives a rough idea of how often each one came by.
| Crawler | Requests for robots.txt | Requests for llms.txt |
|---|---|---|
| OpenAI | 3,990 | 7 |
| Anthropic | 3,120 | 9 |
| Perplexity | 775 | 0 |
| 5,125 | 67 | |
| Meta | 172 | 193 |
It's one study on a small set of sites, and this could change. Still, the crawlers behind ChatGPT, Claude and Perplexity checked robots.txt thousands of times and barely looked at llms.txt. Meta's crawler was the exception.
Add one if it's cheap.
Having one does no harm, and if your site is already clear it doesn't take long to write. If your web team offers to add one at little cost, go ahead.
Don't pay much for it, and be wary of anyone who sells it as the fix for AI visibility. Nobody has shown it gets a business named more often. Our free check notes whether you have one and doesn't mark you down if you don't.
If you do add one, keep it up to date along with the rest of the site. A summary that lists a service you've dropped or a phone number you've changed sends AI tools the wrong facts.
Start with what every AI tool reads today.
The things that decide whether AI tools can name you are on your pages, and every major tool depends on them now:
- AI crawlers can get into your site. See is your website blocking ChatGPT and Claude.
- Your pages show their text without JavaScript. See why AI tools can't read some websites.
- Your services, service areas and contact details are stated plainly on your pages.
- Your business facts are labelled with structured data that matches the page. See does structured data help you show up in AI answers.
If you only have time to look at one file, look at robots.txt. A wrong line there can keep AI tools out of your whole site. A missing llms.txt costs you nothing.
Our free AI Visibility Check looks at all of these in about 30 seconds. If it finds gaps, the AI Search Tune-Up fixes them in one to two weeks, from $1,500 for a site of up to 30 pages.