What is llms.txt — and does your business actually need one?

llms.txt is a small file you publish at the root of your site, in Markdown, that tells AI agents and assistants where your most useful content lives. It is one of the fastest-rising ideas in the agent-readiness space — and also one of the most over-hyped. Here is the honest version.

What it is

It sits at https://yoursite.com/llms.txt. It is plain Markdown: a short description of what you are, followed by curated links to the pages and resources an agent would actually want — key products, services, documentation, policies, contact routes. It is not a sitemap (that is for every URL) and it is not marketing copy. It is a concierge note for software.

What goes in a good one

A one-line description of what your business or site is.
Links to your most important pages, grouped sensibly (e.g. Products, Help, Policies).
The canonical URLs — the real, stable ones, not tracking links.
Optionally, pointers to machine-readable resources: an API catalog, an OpenAPI file, a Markdown version of key docs.

Keep it short. The value is in the curation, not the length.

Who actually needs one

Be honest with yourself here. You will benefit soonest if:

You sell or provide something an agent might research or buy on a user’s behalf.
You have documentation, policies or FAQs that agents are likely to be asked about.
You want to shape how assistants describe you, rather than leaving them to guess.

If you are a brochure site with three pages and no commercial intent for agent traffic, you can wait — though it costs almost nothing to add.

How to write one

You can write it by hand in ten minutes. Open a text file, describe your site, list your best links, and publish it at /llms.txt. Or generate a draft and edit it down.

AgentVisible generates a draft llms.txt for your site from a single scan — a starting point you review and refine, not a black box.

Common mistakes

The kitchen-sink dump. Linking every page defeats the point. Curate.
Stale URLs. Agents follow these links literally; broken ones erode trust.
Inventing capabilities. Do not point to APIs or tools that do not exist. Truthful resources are part of your credibility — overstating is worse than omitting.

The bottom line

llms.txt is genuinely useful and cheap to add, but it is one signal, not a magic switch. It works best as part of a readable, discoverable site.

See whether your site has one — and what else agents are looking for — with a free scan.