What is Google-Extended?
Google calls Google-Extended "a standalone product token". Publishers use it to manage whether content Google crawls from their sites may be used for training future Gemini models and for grounding in Gemini Apps and Grounding with Google Search on Vertex AI (Google Search Central: Google's common crawlers, last updated 30 October 2026, read 1 November 2026).
There is no Google-Extended bot in your logs. Google writes that it "doesn't have a separate HTTP request user agent string". Google crawls with its usual user agents; the token only carries your choice.
Does Google-Extended affect Google Search or AI Overviews?
On Search, Google's page is direct: "Google-Extended does not impact a site's inclusion in Google Search nor is it used as a ranking signal in Google Search."
On AI Overviews, the Google-Extended section says nothing. Another Google page does. It says AI is built into Search, "which is why robots.txt directives for Googlebot is the control" for how sites are crawled for Search. To limit what is shown, it points to nosnippet, data-nosnippet, max-snippet and noindex. Google-Extended is for "AI training and grounding in some of Google's other systems" (Google Search Central: AI features and your website, last updated 10 December 2025, read 1 November 2026).
Our reading of the two pages together: blocking Google-Extended does not keep you out of AI Overviews or AI Mode. Those follow Googlebot and the snippet controls.
Why does Google-Extended matter for B2B SaaS?
It separates two choices that are easy to mix up. You can stay fully in Google Search, AI features included, and still opt out of Gemini training and Gemini Apps grounding. Or you can allow both.
The trade-off: grounding is how Gemini Apps pull content from the Google Search index at prompt time. Blocking Google-Extended means Gemini Apps may not use your pages that way. If you want Gemini to quote your product pages, think twice before blocking it.
How do you use Google-Extended?
Add a group to your robots.txt. Google's own example allows one folder and blocks the rest of a section:
- user-agent: Google-Extended
- allow: /archive/1Q84
- disallow: /archive/
To opt the whole site out, use "disallow: /" under the Google-Extended user-agent line. Leave your Googlebot rules as they are.
What is changing in 2027?
Google's page adds a note: Google "intends to support the AIPREF shared machine-readable training preference signal" in early 2027, written as "user-agent: __usage_ai-training". AIPREF is the IETF AI Preferences working group. Its charter is to standardize ways to state how content may be collected and used for AI models. Watch Google's page for details before you change anything.
A hypothetical example
A hypothetical CRM vendor blocks Google-Extended on its help center to keep it out of Gemini training, and allows it on its product and pricing pages. Googlebot can crawl everything. The help center can still show in Search and in AI Overviews, under Google's normal rules.
How does it relate to other AI crawler controls?
Google-Extended plays the training role that GPTBot plays for OpenAI and ClaudeBot plays for Anthropic. The difference: it is a token, not a crawler. The LLM SEO guide covers how pages get cited in AI answers.