Googlebot vs Google-Extended for AI Overviews

What each control actually governs

Because they are separate, the decision to opt out of one is not a decision about the other, and they should be reasoned about independently.

• Googlebot. Crawls for Google Search. Search indexing is the prerequisite for every Search feature, including AI Overviews. Blocking it removes you from Search.
• Google-Extended. A separate control for certain Gemini and Vertex AI uses. It does not affect Search indexing or ranking.

There is no AI Overview markup

Google's guidance is that its AI features build on the same fundamentals as Search: a page must be indexable, eligible for a normal snippet, and useful. Google does not document a special schema type, meta tag or text file for AI Overview eligibility.

This is why the useful work is ordinary: crawlable content, accurate structured data that describes what is really on the page, and pages worth citing.

Gemini and AI Overviews are different surfaces

An answer from the Gemini model and an AI Overview shown inside Google Search are separate products with separate retrieval. Keep the results separate so each reflects the system that produced it.

Limits of this measurement

• AI Overviews do not appear for every query, and whether one appears is Google's decision. Absence of an overview is not a site problem.
• Provider controls change. Confirm current behaviour in Google's own documentation before acting.

Sources

• Google Search Central: AI features and your website
• Google Search Central: overview of crawlers and user agents

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