Gemini is Google’s AI assistant, and it is also the model family behind the AI answers inside Search. Google documents a grounding mode where, instead of answering from memory, Gemini decides to search and pulls Google Search results into its response. Understanding how that grounding works tells you exactly what makes a page eligible to be quoted.
Gemini grounds in Google Search
Google documents the mechanism for the Gemini API plainly. When grounding is on, “the model analyzes the prompt and determines if a Google Search can improve the answer.” If it can, Gemini “automatically generates one or multiple search queries and executes them,” then “processes the search results, synthesizes the information, and formulates a response.” The answer comes back with inline citations pointing at the source pages.
The practical consequence: to be a source Gemini can pull, be a page Google Search can find and use. That is the same foundation as AI Overviews. Crawlable, indexed, snippet-eligible, and helpful. If you have that, you are in the pool Gemini draws from.
Because Gemini returns inline citations, well-attributed, quotable writing earns a link back. The same two habits pay off here as everywhere: authority and proof so you look like a source worth trusting, and writing for extraction so an engine can lift a clean answer.
The Google-Extended line most sites got wrong
This is the Gemini-specific lever, and it is the one worth checking today. Google-Extended is a robots.txt product token. Google describes it as a control “web publishers can use to manage whether content Google crawls from their sites may be used for training future generations of Gemini models,” and for grounding.
Here is the trap. In 2023 and 2024, a lot of sites added this to robots.txt to opt out of AI training:
User-agent: Google-Extended
Disallow: /If that line is on your site, you may have also opted out of being used to ground Gemini’s answers. And the decision is cleaner than it felt at the time, because Google states that Google-Extended “does not impact a site’s inclusion in Google Search nor is it used as a ranking signal.” Allowing it does not cost you anything in Search. Blocking it is what keeps you out of Gemini grounding. So check your robots.txt; a stray line from two years ago may be quietly holding you back.
An honest limit
Google documents the grounding mechanism for its developer API and states that Gemini grounds its answers in Google Search. The exact retrieval path inside the consumer Gemini app is not published in full. Treat the reliable takeaway as the Search-eligibility foundation and the Google-Extended control; both are documented, and both are things you can act on now.
Where to start
Two moves cover most of it. Make sure Google can crawl and index the pages you want quoted (your Free Scan report checks this), and open your robots.txt to confirm you are not blocking Google-Extended. For how this fits the bigger picture of retrieval and citations, read how AI engines work.