Technology · September 2026
Is W3.CSS ready for AI agents?
W3.CSS has published figures this month, but not enough pages to publish a score.
Official websiteMeasured but not scored
These signals are kept apart from the dimensions because, next to them, a low figure would read as a bad grade for something the score never counts.
Sites with an AI crawler policy
- Sample
- n=100
- Coverage
- 100.0%
Not a Lighthouse audit: it is read from the robots.txt of the sampled sites, and counts the ones whose file names any of the AI crawlers we track. It measures having an explicit policy, whichever way it goes, and it does not count towards the score.
Sites serving an llms.txt
- Sample
- n=100
- Coverage
- 100.0%
The same llms-txt audit as the figure below, read differently: this one counts the pages that serve something at /llms.txt, valid or not. The distance between the two figures is large, and it is the interesting part: of the pages that serve something, 40.2% serve a file that parses. We believe a good share of the rest are soft 404s, that is, a server answering 200 with an HTML error page, although we cannot check it because we do not fetch those files. So the figure to cite is the valid one below, and this one is best read as an upper bound. Pages whose audit errored are excluded from both, and the coverage says how many that was.
Every other figure this month
Sites with an AI crawler policy
- Sample
- n=100
- Coverage
- 100.0%
Agents that can reach the site
- Sample
- n=100
- Coverage
- 100.0%
Sites serving an llms.txt
- Sample
- n=100
- Coverage
- 100.0%
Sites with a valid llms.txt
- Sample
- n=100
- Coverage
- 100.0%