llms.txt checker

Checks whether a site publishes an llms.txt file and whether it follows the format AI assistants expect.

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What the llms.txt checker does

llms.txt is a proposed convention for a Markdown file at the root of a site, like example.com/llms.txt, that gives AI tools a short summary of the site and links to its most useful pages. The checker fetches the file, confirms it exists and is served as text, and checks its structure against the proposal. It also looks for the optional llms-full.txt.

What a valid file looks like

The proposal, published by Jeremy Howard of Answer.AI in September 2024, describes this structure:

An H1 with the site or project name. This is the only required part.
A blockquote with a short summary.
Optional paragraphs with more detail.
H2 sections that list Markdown links, each with a short note. A section named Optional marks links a tool can skip when it's short on context.

What it does and doesn't do

llms.txt isn't an official standard, and none of the major AI search engines has said it ranks or cites pages based on it. It doesn't allow or block crawlers either. That's the job of robots.txt.

Treat it as a cheap, readable summary that some AI tools and agents may fetch when asked about your site. It takes an hour to write and does no harm.

Why it matters for cold email

Prospects who get a cold email look you up, and some now do it by asking an AI assistant. When a tool reads your site, a clear llms.txt helps it describe what you sell, who it's for and where the pricing lives, which is the same story your email told.

Questions

What is llms.txt?

A Markdown file at /llms.txt that summarizes a website for large language models, with links to its key pages. It's a community proposal from 2024, not an official standard.

Does llms.txt help SEO?

Not for Google rankings. It may help AI tools that choose to read it describe your site accurately. Treat it as low-cost groundwork, not a ranking factor.

What is the difference between llms.txt and robots.txt?

robots.txt tells crawlers what they may fetch. llms.txt tells AI tools what your site is about and where the important pages are. One controls access and the other offers a summary, and neither can force a bot to comply.

What is llms-full.txt?

An optional companion file with the full text of your key pages in one Markdown document, so a tool can read everything without following links. Keep it current or leave it out, because a stale copy misdescribes you.

Where do I put llms.txt?

At the root of your domain, served at /llms.txt as plain text or Markdown. The proposal also allows files under subpaths, like /docs/llms.txt, for sections of a large site.