Missing llms.txt: make your site AI-agent ready

What it means

The llms.txt file is a discovery file that AI agents look for when crawling a site. It tells them which pages to read, but it's not required for Search to work.

Why it matters

AI agents that fetch content for AI Overviews and AI Mode may not find your pages without it, since they look for the file at the root. Google itself does not use llms.txt for ranking, and the file gets very few requests from actual AI retrieval bots, so missing it is mostly a visibility issue rather than a ranking problem.

How to fix it

1. Create an llms.txt file at the root of your domain (e.g., /llms.txt).
2. Format it as Markdown with a top-level heading and short sections linking to your key pages — that is the llms.txt convention (there is no special <link> tag; agents fetch /llms.txt directly).
3. Include a list of your main content URLs with brief descriptions so agents know what to read.
4. Verify the file is not blocked by robots.txt — it must be reachable for agents to fetch it.

When it's not a problem

If you're not actively building for AI Overviews or AI Mode, or if your pages already rank on page one and get cited through organic Search, you can safely ignore this notice. The file is more useful for developer-product documentation consumed by coding assistants than for general SEO.

How common is it?

72 audited sites in our corpus currently show this issue. The breakdowns below show which platforms, gatekeepers, verticals and countries are most exposed.