Google-Extended

What does Google-Extended actually control?

Two things, both outside Search. Google documents Google-Extended as governing whether your content is used for “training future generations of Gemini models that power Gemini Apps and Vertex AI API for Gemini”, and for grounding in those same products. Disallowing it is a training and grounding opt-out for Google’s assistant surfaces.

What it does not touch is stated equally plainly: Google-Extended “does not impact a site’s inclusion in Google Search nor is it used as a ranking signal in Google Search”. Your organic positions cannot move because of this token, in either direction. So it is one of the few AI controls with no search cost attached to either choice, which makes it worth setting deliberately rather than leaving at the default.

Does Google-Extended turn off AI Overviews?

No, and this is the most repeated error in AI crawler advice after the GPTBot one. AI Overviews are part of Google Search, built from ordinary Googlebot crawling, and Google’s position is that “AI is built into Search and integral to how Search functions”, so the control is the robots.txt directive for Googlebot rather than a separate token.

The controls that do limit what an AI Overview may show are the snippet controls you already have: nosnippet, data-nosnippet, max-snippet and noindex. Every one of them costs you something in ordinary search at the same time, which is the trade nobody selling an AI Overviews opt-out mentions. There is no setting that removes you from AI Overviews and leaves your blue links untouched.

The nearest thing to a partial control is max-snippet with a small number, which caps how much of your page can be quoted anywhere rather than turning anything off. Whether a shorter snippet makes you less useful to quote or simply less quoted is not something anybody has measured, and it will cost you snippet length on the ordinary results page either way. Treat it as a lever with a known price and an unknown benefit.

Why will Google-Extended never appear in your logs?

Because nothing sends it. Google is explicit that “Google-Extended doesn’t have a separate HTTP request user agent string” and that the token is used “in a control capacity”. So an access log will never carry a Google-Extended line, no verification is possible or needed, and a tool that reports Google-Extended as blocked or allowed is reporting your own robots.txt back to you rather than any observed behaviour.

That is a useful thing to report, as long as it is labelled as policy. Be suspicious of any AI crawler audit that shows Google-Extended in a column of live response codes, because there is nothing there to respond. The same caution applies to Applebot-Extended, which works the same way and is misread the same way.

Where does this show as policy rather than evidence?

Related terms

• AI OverviewAn AI Overview is the written summary Google places above its ordinary search results, assembled from web pages and shown with links to a few of them.
• Google AI ModeGoogle AI Mode is a conversational search surface where a written answer replaces the ranked results page rather than sitting above it.
• GPTBotGPTBot is OpenAI’s training crawler.
• AI CitationAn AI citation is a link an AI assistant attaches to its answer, naming a page as a source.