Google-Extended shows up in a lot of “block the AI bots” templates, usually with a note that it might affect AI search features. Google’s own crawler documentation says the opposite, in one of the least ambiguous sentences in any vendor doc:
“Google-Extended does not impact a site’s inclusion in Google Search nor is it used as a ranking signal in Google Search.”
What it actually controls is whether crawled content “may be used for training future generations of Gemini models” and for grounding in Gemini apps and Vertex AI. It isn’t even a crawler in its own right — “Google-Extended doesn’t have a separate HTTP request user agent string. Crawling is done with existing Google user agent strings; the robots.txt user-agent token is used in a control capacity.”
The control that does govern AI features in Search is the one merchants already know. From Google’s AI-features documentation:
“AI is built into Search and integral to how Search functions, which is why robots.txt directives for Googlebot is the control for site owners to manage access to how their sites are crawled for Search.”
And for shopping specifically, Gemini’s product answers ride on the Shopping Graph, which Google describes as fed “either through information retailers share directly via Google Merchant Center or from what retailers and brands post across the web.” Merchant Center feed quality and Googlebot access are the levers; Google-Extended is a training preference.
The takeaway: block Google-Extended or don’t — it is a philosophical choice about model training. Just don’t block Googlebot thinking the two are separable in effect: that one takes your store out of Search, AI Overviews, and the crawl side of the Shopping Graph at once.