What is llms.txt, and does it work?
Published 4 min read
llms.txt is a text file that tells AI tools what your site is about. So far, one large study found little sign that AI tools use it.
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What is llms.txt?
llms.txt is a plain text file, usually at the root of a website, written in Markdown. It gives AI tools a short summary of the site and links to its key pages. Jeremy Howard proposed it in September 2024. It is a proposal, not an official web standard.
Does llms.txt work?
Not much, as far as we know today. In one study, most files got no requests in a whole month.
97%
Ahrefs study, June 2026: sites that use Ahrefs Web Analytics, requests from its bot logs. Ahrefs says its users skew technical.[ahrefs-llmstxt]
- Ahrefs found that AI bots made 19.5% of the requests that did reach llms.txt files.
- Google says you need no AI text files to appear in AI Overviews or AI Mode.
- Since May 2026, Google Lighthouse checks llms.txt among its agentic browsing audits. A missing file counts as not applicable.
What does Nenn's own llms.txt look like?
Short. The site code builds it from the same list of public pages as our sitemap.
# Nenn
> Nenn checks whether ChatGPT, Perplexity and Google AI name your company when customers ask, and drafts the fix.
## Pages
- [Home: what Nenn does](https://nenn.io/)
- [NennBot: our crawler and how to block it](https://nenn.io/bot)
- [Pricing: plans and prices](https://nenn.io/pricing)
- ...
## App
- [Nenn app](https://app.nenn.io)- It lists only public pages, and repeats one sentence from the site.
- We keep it because it costs nothing. We do not expect it to change AI answers.
How is llms.txt different from robots.txt and a sitemap?
Each file does a different job. Only robots.txt tells bots what they may crawl.
| File | What it does | Who reads it | Status |
|---|---|---|---|
| robots.txt | Tells bots which pages they may crawl | Search and AI crawlers, such as Googlebot and GPTBot | Standard: RFC 9309, 2022 |
| sitemap.xml | Lists the pages you want search engines to find | Search engines | Widely used protocol (sitemaps.org) |
| llms.txt | Sums up the site and its key pages for AI tools | Some AI tools. Few requests so far | Proposal from 2024 |
Questions about llms.txt
Is llms.txt worth it?
It takes little time to add. But do not expect more AI mentions from it today. Clear pages that bots can read matter more.
What is llms-full.txt?
Some sites add a second file with the full text of their pages in one place. The llmstxt.org proposal does not define it. The same limits apply.
Does Google use llms.txt for Search?
Google says you need no new AI text files to appear in AI Overviews or AI Mode. Its Lighthouse check looks at the file for AI agents, not for rankings.
Should I block AI bots instead?
That is a separate choice. robots.txt decides what bots may read. Should you block AI crawlers? walks through it.
Measure the effect yourself
Add the file, then compare weekly answers before and after. Nenn asks the same questions every week.
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Four checks that decide if AI bots can read your pages.