As AI assistants become a primary way people find businesses, a simple new file is emerging to help them understand your website: llms.txt. If you have heard of robots.txt, the concept will feel familiar — but the purpose is different and increasingly relevant to AI visibility.
llms.txt is a plain-text, markdown-formatted file placed at the root of your website that gives large language models a clean, curated map of your most important pages and a short description of what your business does. It helps AI systems understand and represent you accurately when they answer questions about your category.
Where llms.txt came from
The standard was proposed in September 2024 by Jeremy Howard of Answer.AI, the well-known AI researcher, and is documented at the official specification site, llmstxt.org. The motivation is simple: AI models have limited context windows and struggle with the navigation, ads, and markup of full HTML pages. A concise, structured markdown file gives them a clean summary of what matters — without the noise.
llms.txt vs robots.txt
The two are often confused, so it is worth being precise:
- robots.txt tells crawlers what they are allowed to access. It is about permissions.
- llms.txt tells AI models what is important and how to describe it. It is about understanding.
robots.txt restricts; llms.txt guides. They serve different jobs, and most sites should have both.
Which reputable websites use llms.txt?
Adoption has been led by major, developer-focused companies whose audiences rely on AI assistants. Reputable organizations that publish an llms.txt file include:
- Anthropic — the maker of Claude, on its documentation.
- Stripe — on its API documentation.
- Cloudflare — on its developer documentation.
- Vercel — including the Next.js documentation.
- Zapier — on its integration documentation.
- Hugging Face — on its model documentation.
According to BuiltWith, more than 844,000 websites had implemented llms.txt by late 2025, though overall adoption is still early — estimated at roughly 5–15% of sites in early 2026. In other words, publishing one today still puts you ahead of most of your competitors.
An honest caveat
It is worth being straight with you: as of 2026, no major AI platform has officially confirmed that it automatically reads llms.txt. The file is a proposed standard with strong momentum and broad adoption, not a guaranteed ranking factor. So why bother? Because it is low-effort and low-risk, it is aligned with where AI search is clearly heading, and the exercise of writing it — stating exactly what you do and which pages matter — sharpens your whole GEO strategy. It is an inexpensive bet with real upside.
What goes in an llms.txt file
The format is deliberately simple — readable markdown. A good llms.txt typically includes an H1 with your business name, a short blockquote summary, and H2 sections grouping markdown links (with one-line descriptions) to your most important pages.
The rule that trips people up: entries must be real markdown links, not bare URLs, and the file needs at least one H1. A file of plain URLs will fail validation.
A concrete example
Here is a simple, valid example for a fictional local business, "Acme Plumbing":
# Acme Plumbing
> Acme Plumbing is a licensed plumbing company serving Austin, TX, offering emergency repairs, water heater installation, and drain cleaning for homes and small businesses.
## Main Pages
- [Home](https://acmeplumbing.com/): Licensed Austin plumber for repairs, installs, and emergencies.
- [Services](https://acmeplumbing.com/services): Full list of residential and commercial plumbing services.
- [Contact](https://acmeplumbing.com/contact): Book a plumber or request an emergency callout.
## Services
- [Emergency Plumbing](https://acmeplumbing.com/emergency): 24/7 emergency plumbing across Austin.
- [Water Heater Installation](https://acmeplumbing.com/water-heaters): Repair and installation of tank and tankless heaters.
- [Drain Cleaning](https://acmeplumbing.com/drains): Fast, clean drain and sewer clearing.
## Service Areas
- [Austin, TX](https://acmeplumbing.com/austin): Plumbing services across Austin and Central Texas.
## Contact
Phone: (512) 555-0100 · Email: [email protected]
Notice the pattern: a clear H1, a one-line blockquote summary, then sections of linked pages each with a short description. That is all a valid llms.txt requires — the value is in the clarity, not complexity. Some sites also publish a longer companion file, llms-full.txt, containing fuller content for models that want more depth.
How to create your llms.txt
- List your most important pages — home, services, key service pages, locations, products, contact, blog.
- Write a one-line description for each, in plain language.
- Format as markdown with an H1, a blockquote summary, and H2 sections of linked items.
- Save it as llms.txt and upload it to your site root so it is reachable at yourdomain.com/llms.txt.
- Keep it current — update it whenever you add important pages, so AI never works from a stale map.
Where it fits in the bigger picture
An llms.txt file is one signal among several. To genuinely become the business AI recommends, pair it with schema markup, answer-ready content, and the tactics in our guides on ranking in ChatGPT and appearing in Google AI Overviews, and measure your progress with an AI Visibility Audit. If you would rather have the whole program — llms.txt, schema, content, and citations — built and maintained for you, that is exactly what our Generative Engine Optimization service delivers.
