Not a crawler — a robots.txt control token with no separate HTTP user-agent. Controls whether crawled content may be used for Gemini training and Gemini grounding. Google states it does not affect Search inclusion or ranking.
Your call — but understand what it does
Google-Extended is not a crawler. It is a robots.txt control token with no separate HTTP user-agent, so blocking it does not stop any request — it only tells Google how content it already crawled may be used.
Per Google, the token controls use for training Gemini models and for grounding (providing Search-index content to the model at prompt time). Google states it does not affect your site's inclusion in Google Search and is not a ranking signal.
Because of that, do not treat this token as a way to control AI Overviews or AI Mode. If your goal is to influence Google's AI answers, the effective control is Googlebot plus page-level noindex / nosnippet directives — and blocking Googlebot costs you normal Search visibility too.
User-agent: Google-Extended Allow: /
User-agent: Google-Extended Disallow: /
This entry has no HTTP user-agent of its own, so a user-agent fetch test cannot verify it — only your robots.txt directive applies.
Official source Operator documentation — last verified against operator docs 2026-09-12
https://developers.google.com/crawling/docs/crawlers-fetchers/google-common-crawlers
"Should you block it?" below is our own interpretation, not the operator's recommendation.
See whether Google-Extended — and 39 other AI crawlers — can reach your site today.