Agentic Web CensusCheck your site
EN

Trends · Sites with a valid llms.txt

Sites with a valid llms.txt across the web

A valid llms.txt tells agents what matters. It has gone up since May 2026, and again last month. Both steps clear their margin.

Poor14.8%

Sites with a valid llms.txt in September 2026

What the Sites with a valid llms.txt in September 2026 is, and how it is measured

Measured on 158,165 pages, 95.3% of which carried the agentic category, with a confidence margin of ±0.13 pp.

▲ +0.9 pp
Sites with a valid llms.txt in September 2026 over 5 months

3.5%14.8%

15.9%2.4%Sites with a valid llms.txt · May: 3.5%Sites with a valid llms.txt · June: 8.8%Sites with a valid llms.txt · July: 13.6%Sites with a valid llms.txt · August: 13.9%Sites with a valid llms.txt · September: 14.8%Sites with a valid llms.txtMayJuneJulyAugustSeptember
Sites with a valid llms.txt, May 2026 to September 2026, one measurement a month. The last step was a real rise.

What this measures

Who moved

How to read these figures

Every figure here comes from a sample, not from counting every site — so it carries a margin: how much it could move if we had happened to sample different pages. A figure measured on a thousand pages has a wide margin; one measured on a hundred thousand has a narrow one. It matters for one thing: two figures that differ by less than the wider of their margins are not one above the other, they are tied. That is why nothing here has a position number.
SegmentAugust 2026September 2026Movement
Bootstrap 15.7%78.4%▲ +72.7 pp
.click0.0%40.1%▲ +40.1 pp
Intercom46.7%11.0%▼ −35.7 pp
Vuetify1.6%32.3%▲ +30.6 pp
Linkedin Ads7.9%33.1%▲ +25.2 pp
Fathom6.6%31.3%▲ +24.7 pp
Imgix28.6%7.3%▼ −21.3 pp
Tealium19.6%36.9%▲ +17.3 pp
Bootstrap 230.7%16.9%▼ −13.8 pp
Glider.js73.9%60.6%▼ −13.3 pp
Amazon Webstore8.0%19.6%▲ +11.6 pp
Popup Maker 17.4%18.4%▲ +11.0 pp
Ahrefs24.4%34.8%▲ +10.3 pp
Leadfeeder12.5%22.8%▲ +10.3 pp
Amazon Pay70.1%80.1%▲ +10.0 pp

How to move it on your own site

2 · Guide

27% of the score

You serve an llms.txt at your root, and it parses.

It is where you tell an agent what matters on your site instead of letting it guess. And there is a trap in the scoring worth knowing: Lighthouse gives no points for not having one, and no points for having a broken one — so a file that does not parse costs you exactly what publishing nothing would, plus the work.

What to do

  1. Create /llms.txt at your root, served as text/plain.
  2. Follow the format: a single H1 with your site name, an optional blockquote summary, then H2 sections of markdown links with short descriptions.
  3. Point it at what you want an agent to read — documentation, product pages, prices — not at your whole sitemap. It is an editorial file, not an index.
  4. Validate it before you publish. Two out of three of the sites that publish one publish one that does not parse.
  5. Keep it short enough that someone updates it. A file that goes stale describes a site that no longer exists.
# Acme Tools

> Hand tools for timber framing, made in Bilbao since 1974.

## Products
- [Chisels](https://acme.example/chisels): sizes, steel and prices
- [Mallets](https://acme.example/mallets): weights and handles

## Help
- [Sharpening guide](https://acme.example/guides/sharpening): angles and stones
- [Shipping and returns](https://acme.example/shipping): times, costs, conditions
llms.txtOne H1, one summary, then sections of links. Replace the words and it parses.

A morning, mostly spent deciding what to point at.