You can keep full Google Search visibility while opting out of Gemini AI training — Google separates the two controls, and its own documentation is explicit about it.
Google-Extended is training-only
Per Google, Google-Extended does not impact a site's inclusion in Google Search nor is it used as a ranking signal (see our directory entry with the source). It's a robots.txt control for whether your content trains future Gemini models and is used for AI grounding. Disallowing it costs you nothing in Search.
Don't confuse it with Googlebot
Blocking Googlebot removes you from Google Search over time — the opposite of what most people want. Keep Googlebot allowed; disallow Google-Extended only if you want to opt out of Gemini training.
What about the other AI trainers?
OpenAI's GPTBot and Anthropic's ClaudeBot are the equivalents for their models — separate tokens, each disallowed independently. Verify your live robots.txt with the robots.txt analyzer.