What is llms.txt?
Definition
llms.txt is a proposed plain-text Markdown file, placed at a website's root (for example, example.com/llms.txt), that gives AI tools a short, curated summary of the site and links to its most useful pages.
Last updated 2026-10-18 · Flowmatix
How llms.txt works
The format was proposed by Jeremy Howard and is published at llmstxt.org. A file starts with an H1 containing the site or project name, which is the only required section. A short blockquote summary usually follows, then H2 sections listing links in Markdown, each with an optional note. By convention, a section called "Optional" holds secondary links an AI tool can skip when it needs a shorter context.
A simplified file for a Toronto physiotherapy clinic might read:
# Example Physio Clinic> Physiotherapy and massage clinic in downtown Toronto. Direct billing to most insurers.## Servicesfollowed by links to the physiotherapy, massage and concussion pages## Optionalfollowed by links to the blog and careers page
The proposal says the file is intended mainly for use when an AI tool is answering a question (inference), rather than for training models. It is different from robots.txt, which states what automated access is allowed.
Why it matters for your business
AI assistants increasingly answer questions about services, prices and locations directly. A tidy llms.txt is a low-effort way to point those tools at accurate, current pages instead of an outdated blog post from five years ago.
Keep expectations realistic. llms.txt is a proposal, not a ratified standard, and publishing one does not guarantee that any assistant will read it or cite you. What earns citations is still clear, well-structured content, supported by schema markup and a crawlable site. Think of llms.txt as tidy signage, not a ranking factor.
Common mistakes
- Treating llms.txt as an access control. It blocks nothing; use robots.txt or authentication for that.
- Listing every URL on the site instead of the handful that actually answer customer questions.
- Linking to pages that are out of date, redirected or behind a login.
- Writing marketing slogans in the summary rather than a plain description of what you do and where.
- Expecting traffic gains from the file alone without improving the pages it points to.
Frequently asked questions
Is llms.txt worth adding?
For most businesses it takes under an hour and carries little risk, so it is a reasonable addition once the basics of generative engine optimisation are in place. Our article What is llms.txt, who reads it, and is it worth 20 minutes? covers the trade-offs in more depth.
Does llms.txt replace an XML sitemap?
No. An XML sitemap lists URLs for search engine crawlers. llms.txt is a short, human-readable guide for AI tools. Most sites that publish one should keep both.
How often should it be updated?
Whenever key pages change: a new service, a retired offer, a moved URL. A quick check during each quarterly content review is enough.
How Flowmatix can help
Our SEO for AI search work puts this into practice for businesses in Toronto and around the world. Get a personalised quote in about 3 minutes.
Related terms
Ready to see what your project costs?
Answer a few questions and get a personalised plan, a comparison with typical market prices, and a clear next step. No obligation, no sales pressure.