Google-Extended

Google-Extended is a robots.txt control token, not a crawler. Google’s crawler documentation explains that it does not have its own user-agent string; it is a name you can use in robots.txt to say whether content Googlebot has already fetched may be used to train and ground Google’s Gemini models.

What it does and does not affect

• Affects: use of the content for Gemini training and grounding, as documented by Google.
• Does not affect: Googlebot’s crawling, indexing, ranking, or whether pages appear in Search, AI Overviews or AI Mode. Google states that AI Overviews eligibility follows the normal Search controls, not Google-Extended.

So a site that wants to stay in Search and AI Overviews while opting out of Gemini training can write:

User-agent: Google-Extended
Disallow: /

A common mistake

Blocking Google-Extended in the belief that it hides a site from AI Overviews. It does not; the controls for that are nosnippet, max-snippet and noindex, which also remove the page from ordinary snippets or results. Our AI crawler access tool shows how a robots.txt treats each documented token.

For the documented user-agent string, the robots.txt rules and how to verify a request, see the Google-Extended reference page.