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Glossary

What is llms.txt?

By Youssef Hodaigui, Mindflow Marketing · Last reviewed October 29, 2026

llms.txt is a proposed standard for a plain-text Markdown file, placed at a website's root (yoursite.com/llms.txt), that gives AI tools a short summary of the site and links to its most useful pages. It was proposed on llmstxt.org in September 2024, and its own site says it's used most heavily for software documentation.

It isn't a ranking file, and it doesn't control crawling the way robots.txt does. Google Search says it ignores llms.txt, and OpenAI's crawler documentation doesn't say its crawlers or ChatGPT search use it.

01

What goes in an llms.txt file?

A title, a short summary and lists of links. The proposal says the only required part is "an H1 with the name of the project or site," followed by an optional summary, more detail, and sections that list URLs with notes. The idea is that an AI tool reads one small file instead of working through the whole site.

The proposal also explains how it differs from robots.txt: robots.txt says what automated tools may access, while llms.txt is "used on demand, when an agent needs information about a topic while assisting a user."

02

Does Google use llms.txt?

Google Search doesn't. Its guide to AI features says site owners don't need "AI text files" or Markdown to appear in Google Search, "as Google Search itself doesn't use them," and that an llms.txt file "will neither harm nor help your site's visibility or rankings in Google Search, as Google Search ignores them."

Another Google team takes a softer line for AI agents. Chrome's Lighthouse tool has an audit in its agentic browsing category that calls llms.txt "an emerging convention," but it marks a missing file as not applicable, "as providing the file is optional at the moment." That check is about browser agents, not search rankings or AI Overviews.

03

Does ChatGPT use llms.txt?

OpenAI hasn't said so. Its crawler documentation and its help page on ChatGPT search, both read October 29, 2026, don't say that ChatGPT search or OpenAI's crawlers read llms.txt files, even though OpenAI publishes one for its own developer docs. What OpenAI asks site owners to do instead is "allow OAI-Searchbot to crawl the site" and make sure their host or content delivery network lets OpenAI's published IP addresses through.

So the claim that llms.txt "gets you into ChatGPT" isn't supported by anything OpenAI publishes. Access for the right AI crawler is what OpenAI documents. We'll update this entry if that changes.

04

Should a contractor add an llms.txt file?

It's not a priority. A home-service website gains nothing in Google Search from one, and no AI search platform we checked documents using it. If your website platform creates one automatically, leave it. Don't pay an agency to write one, and put that effort into accurate service pages, listings and your Business Profile instead.

If you do have one, keep it accurate. It should list the same services, service areas and contact page as the rest of your site. Our guide to AEO, GEO and AI SEO lists other claims worth checking before you buy.

Related terms: AI crawler · Schema markup · AI Overviews · AI citation · All glossary terms

Where to go next: How to show up in ChatGPT answers covers what OpenAI does document, and the AI search hub collects our guides.

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Sources

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