Checks
llms.txt presence
Checks whether the site publishes an llms.txt file at its root, an emerging standard that gives AI assistants a curated, direct guide to a site's most important pages.
What this check looks for
This check fetches /llms.txt (and separately checks for /llms-full.txt) from the site's origin. If the fetch failed entirely (network error), it reports "na". If the file doesn't exist, returns an error, is empty, or is actually an HTML page (a common SPA catch-all symptom, where every unknown path serves the same index page instead of a 404), it warns. If a real llms.txt is found, it passes, noting whether llms-full.txt is also present.
Why it matters
llms.txt (per the llmstxt.org specification) is a markdown file specifically designed to be read by language models rather than rendered in a browser — an emerging counterpart to robots.txt and sitemap.xml, purpose-built for the AI-assistant era of web crawling. It gives an assistant a curated summary of what the site is and direct links to its most important content, without the assistant having to crawl and interpret the entire site structure itself to figure that out. It's not yet a signal every AI system consumes, but as an early, cheap investment in AI discoverability, publishing one costs little and directly targets the audience this whole GEO check category is about.
How to fix it
Publish a markdown file at the site root following the llmstxt.org format:
# Acme Audio
> Acme Audio makes wireless headphones and speakers focused on
> noise cancellation and battery life.
## Products
- [Wireless Noise-Cancelling Headphones](https://www.acme.com/audio/headphones/wireless-nc)
- [Portable Speakers](https://www.acme.com/audio/speakers)
## Company
- [About Acme](https://www.acme.com/about)Serve it at exactly /llms.txt with a text/plain or text/markdown content type, not routed through your SPA's HTML catch-all.
See how your site scores on this check