Should you block Google-Extended? Google's Gemini control
Google-Extended is operated by Google. It is a robots.txt control token for Gemini model training and for grounding Gemini responses with content from Google's search index. It is not an HTTP user agent.
Who should block Google-Extended, and who should not?
Block it if you do not want Google using your content to train Gemini or to ground Gemini app answers; Google says the block costs nothing in Search. It does not keep you out of AI Overviews or AI Mode, which are Search features governed by Googlebot and snippet controls. You will never see it in your logs, because it never visits: the rule in your robots.txt is the only evidence the block exists.
The verified facts
| User-agent token | Google-Extended |
|---|---|
| Operator | |
| Purpose | Model training and AI grounding controls |
| Honors robots.txt | Yes, per the operator's documentation. |
| Verification | Google-Extended is a robots.txt control token, not an HTTP user-agent string |
What does Google’s documentation add?
- Google-Extended has no user-agent string of its own. Google crawls with its existing crawlers and uses the token only to control how the fetched content may be used.
- It covers training future Gemini models (Gemini Apps and the Vertex AI API for Gemini) and grounding in Gemini Apps and Grounding with Google Search on Vertex AI.
- Google says it does not affect a site's inclusion in Google Search and is not used as a ranking signal.
How do you block Google-Extended?
Add this to your robots.txt:
User-agent: Google-Extended
Disallow: /Once you give a crawler its own group, it stops reading your User-agent: * rules, so run the whole file through the AI crawler robots.txt tester before you deploy it.
What does blocking Google-Extended cost you?
Content excluded from Gemini model training and grounding uses.
What else does Google document?
Google also documents Googlebot and GoogleOther, each with its own robots.txt token. How Google’s crawlers fit together.
Which crawlers in the same group should you decide on at the same time?
A robots.txt group for Google-Extended does nothing to crawlers with other tokens. In the same group, the directory also covers meta-externalagent (Meta), each with its own token and its own documented cost of blocking.