Check if your website has a valid llms.txt file. See exactly how AI agents like ChatGPT, Claude, and Perplexity discover your content.
llms.txt is the robots.txt for AI agents. While robots.txt tells search engine crawlers what to index, llms.txt tells AI language models what your website is about, what content matters, and where to find it.
Placed at your site's root (yoursite.com/llms.txt), it uses simple Markdown formatting to describe your product, link to key pages, and provide context that helps AI assistants accurately recommend your site to users.
The standard was proposed by Jeremy Howard and is being adopted across the industry. Major companies including Sentry, Vercel, Supabase, Linear, and GitHub have already implemented it.
We scanned 61 major websites across 7 industries. Here's the current state of adoption:
| Industry | Adoption Rate |
|---|---|
| Developer tools | 83% |
| E-commerce / SaaS platforms | 50% |
| Education | 40% |
| Media / publishing | 38% |
| Fintech | 33% |
| Healthcare | 20% |
| Travel / consumer | 0% |
Adoption follows developer proximity — companies with engineering-heavy teams adopt first. If you're in a non-dev-tool industry, adding llms.txt puts you ahead of 60-100% of your competitors.
llms.txt to your website's root directory (next to robots.txt).# Your Product Name — a clear, one-line description of what your site does.## URLs sections to list your most important pages — pricing, docs, features, blog.
# Acme Analytics
> Real-time web analytics for developers.
> Privacy-first, no cookies, open source.
## Docs
- [Getting Started](https://acme.dev/docs/start): Installation and setup guide
- [API Reference](https://acme.dev/docs/api): Full REST API documentation
## Features
- [Real-time Dashboard](https://acme.dev/features/dashboard): Live visitor tracking
- [Funnels](https://acme.dev/features/funnels): Conversion funnel analysis
## Optional
- [Blog](https://acme.dev/blog): Product updates and tutorials
- [Changelog](https://acme.dev/changelog): Version history
Our scan of 36 Y Combinator S25 companies found that 53% already have llms.txt — higher than the industry average. But their average AEO score was still just 44/110.
That's because llms.txt is one signal out of seven that AI agents use to discover and understand your site. Without structured data (JSON-LD), proper robots.txt directives for AI bots, semantic HTML, and markdown-for-agents support, your llms.txt sits there unread.
Our full AEO Checker tests all seven dimensions — giving you a complete picture of your AI visibility, not just one file.