What is Google-Extended?
Google-Extended is a robots.txt token that controls whether content Google crawls may train future Gemini models and ground Gemini answers, without any effect on Google Search. Google-Extended is the most misread line in robots.txt. It controls Gemini training and grounding outside Search. It does not control AI Overviews or AI Mode, which are part of Google Search.
What does Google-Extended control?
It controls whether content Google crawls from your site may be used to train future Gemini models that power Gemini Apps and the Vertex AI API for Gemini, and for grounding in Gemini Apps and Grounding with Google Search on Vertex AI (Google's crawler docs, updated July 14, 2026).
Google describes grounding there as providing content from the Google Search index to the model at prompt time to improve factuality and relevancy.
Does blocking Google-Extended affect Google Search or AI Overviews?
No. Google states that Google-Extended does not impact a site's inclusion in Google Search nor is it used as a ranking signal in Google Search.
AI Overviews and AI Mode are Search features: a page must be indexed and eligible to show with a snippet to appear in them, and the controls that limit them are nosnippet, data-nosnippet, max-snippet and noindex (Google Search Central, read Oct 15, 2026). Those also limit how the page shows in normal results.
How do you use Google-Extended?
Add a group for it in robots.txt. Google-Extended has no separate HTTP user-agent string: Google crawls with its existing user agents, and the token is read only as a control, so you will not see it in your logs.
# Keep content out of Gemini training and grounding
User-agent: Google-Extended
Disallow: /
# Google Search, including AI Overviews and AI Mode, is unaffected
User-agent: Googlebot
Allow: /What does this mean in a real example?
In the public Tesla example (Oct 4, 2026), Google AI Overviews named Tesla in 16 of 25 answers to buyer questions and cited youtube.com 20 times, reddit.com 15 times and tesla.com once.
A Google-Extended rule on any of those sites would not have changed that answer set, because AI Overviews are built on Search. The levers there are indexing, snippet eligibility and being the page that answers the question.
How do you check your Google-Extended setting?
Read your live robots.txt for a Google-Extended group, on every host, and make sure no snippet control was added by mistake on pages you want in AI Overviews. The free AI crawler checker reads your live robots.txt for Google-Extended and the other AI agents, and Crawler access in Proofsource checks them over time.
Common questions about Google-Extended
Will blocking Google-Extended hurt my rankings?
No. Google says it is not used as a ranking signal and does not affect inclusion in Google Search.
How do I opt out of AI Overviews?
Only with snippet controls or noindex, which also limit normal results. There is no separate AI Overviews opt-out, and Google-Extended is not one.
Why don't I see Google-Extended in my server logs?
It has no user-agent string of its own. Google crawls with its existing user agents and reads Google-Extended only as a robots.txt control.
Does Google-Extended cover Gemini answers?
It covers training of future Gemini models and grounding in Gemini Apps and Vertex AI, by Google's description. Check Google's crawler documentation for the current scope.
Related terms
- Google AI Overviews
Google AI Overviews are the AI-written summaries Google shows above some search results, with links to the pages they draw on.
- Google AI Mode
AI Mode is Google's conversational AI search experience, where a question gets a written answer with links and can be followed with more questions.
- robots.txt
robots.txt is a plain-text file at the root of a website that tells crawlers which paths they may fetch, under the Robots Exclusion Protocol (RFC 9309).
- Grounding
Grounding is tying an AI model's answer to outside sources, such as live search results, so its claims rest on retrieved content rather than on memory alone.
Worked example: Tesla, public AI answers, Oct 4, 2026: Proofsource's first scan of Tesla, 25 buyer questions and 5 brand questions, one answer per question on each of four engines. A small sample from one brand, shown as an example, not a benchmark.
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Google AI OverviewsGoogle AI Mode
