llms.txt explained: what it is, whether it works, and how to write one
llms.txt is a small text file that summarises your website for AI tools. It takes ten minutes to write. Here's what it is, what we do and don't know about its effect, and a template.
By the Citeably team · · 4 min read
What llms.txt is
It's a proposed convention: a Markdown file at yourdomain.com/llms.txt that gives language models a short, clean overview of your site, plus links to the most important pages. Think of it as a table of contents written for machines, the way robots.txt is a set of instructions for crawlers.
Does it actually help?
Honestly: we don't know that it changes whether an assistant recommends you. As far as we are aware, the major AI engines have not publicly confirmed that they use llms.txt to decide what to recommend, and adoption by tools is uneven.
It's still worth doing. It costs almost nothing, it can't hurt, some developer tools and agents do read it, and writing it forces you to state, in plain words, what you do and who it's for. That clarity helps everywhere else too.
How to write one
Keep it short and factual: a title, a one-paragraph summary, then links to your key pages with a few words about each.
# Acme Mail > Acme Mail is email marketing software for independent creators. It helps you grow a newsletter, sell products, and automate sequences. ## Key pages - [Pricing](https://acme.example/pricing): plans from free to $49 per month - [Product overview](https://acme.example/product): how Acme Mail works - [Docs](https://acme.example/docs): setup guides and API - [Acme Mail vs Mailchimp](https://acme.example/vs/mailchimp): an honest comparison ## Facts - Category: email marketing software - Founded: 2022 - Contact: hello@acme.example
Common mistakes
- Marketing fluff: write like a reference page, not an ad.
- Broken or outdated links: check them when you update your site.
- Serving it as an HTML page instead of plain text or Markdown.
- Blocking AI crawlers in robots.txt at the same time, which defeats the purpose.
Frequently asked questions
Where does the file go?
At the root of your domain, for example https://yourdomain.com/llms.txt, served as plain text.
Is there a ready-made one for my site?
Yes. Citeably's free AI visibility check generates a personalised llms.txt for your website, along with structured data you can paste in.