GapCite
GapCite Blog ยท AI visibility basics

Give AI agents a map of your site

llms.txt is a real, spec-defined markdown file that tells an AI agent what your site is and which pages matter, build a spec-compliant one below.

By Joe WangUpdated September 20262-minute tool
The short version
  1. llms.txt is a real markdown file at /llms.txt that gives an AI agent a structured summary of your site, proposed by Jeremy Howard in September 2024, now on version two.
  2. It's not a ranking signal and not a permissions file like robots.txt. It's a map: what your site is, and which pages actually matter.
  3. Fill in your details below, copy the generated file to /llms.txt on your own domain.

What llms.txt actually is, and isn't

The spec is deliberately small. It requires exactly one thing: an H1 with your site or project's name. Everything else is optional but expected, a one-line blockquote summary underneath the H1, then any number of plain paragraphs, then any number of H2-delimited sections listing links in the form [name](url): note. That's the whole format.

It's easy to lump this in with robots.txt since both are plain-text files at a predictable path, but they do opposite jobs. robots.txt says what a crawler is allowed to access, pure permissions, no description of what any of it means. llms.txt assumes an agent is already reading your site and hands it a summary and a short list of the pages that actually matter, the same way a table of contents helps a person, not a bouncer at the door.

Worth being honest about where adoption actually stands: there's no confirmed evidence that a specific major AI assistant fetches and prioritizes llms.txt today. What's real is that it's a voluntary convention with genuine, growing adoption, thousands of sites publish one, documentation platforms like Mintlify generate it automatically, and Chrome's own Lighthouse now audits for it as part of its agentic-browsing checks. It costs little to have and does nothing to hurt you, which is a reasonable bar even before broader model adoption is confirmed.

See it in action: this exact site publishes a real one at gapcite.com/llms.txt, open it in a new tab while you build your own below.

Build your llms.txt

Toolllms.txt generator
Pre-filled with an example, replace it with your own real site.

Your llms.txt


      

Doing it right

Where it goes

Save the output as plain text at yourdomain.com/llms.txt, no server configuration beyond hosting a static file, the same mechanism as robots.txt. A file scoped to one section of a large site can also live at a subpath, like /docs/llms.txt, covering everything beneath it.

FAQ

Who created llms.txt, and is it an official standard?

Jeremy Howard (of Answer.ai and fast.ai) proposed it in September 2024; the spec is now on its second version. It isn't an official standard ratified by a body like W3C, but it has real adoption, thousands of sites publish one, documentation tools like Mintlify generate it automatically, and Chrome's own Lighthouse audits for it as part of its agentic-browsing checks.

Does having an llms.txt file guarantee ChatGPT or Perplexity will read it?

No. There's no confirmed evidence that any specific major AI assistant currently fetches and prioritizes llms.txt when answering questions. It's a low-cost, forward-looking convention rather than a guaranteed input to any one model today.

How is llms.txt different from robots.txt?

robots.txt is permissions. It tells crawlers what they may access. llms.txt is a map. It describes what your site is and points an agent that's already reading it toward the pages that matter most. They do different jobs and having one says nothing about the other.

Where does the file need to live?

At your domain's root as /llms.txt (or a subpath like /docs/llms.txt, covering everything beneath it), served as plain text, the same mechanism as robots.txt. No server configuration beyond hosting a static file.

Sources