How Google Gemini and AI Mode Cite Sources

Two different products, one model family

Gemini and Google AI Overviews both run on Gemini models, and that's exactly why they get confused. They're separate products with separate retrieval paths. Google AI Overviews is a feature inside Google Search: it appears above the ranked results for certain queries, drawing on the same Search index that ranks everything else. The Gemini app (gemini.google.com and the mobile app) is a standalone conversational assistant with its own interface, separate from Search entirely. We already cover AI Overviews in depth elsewhere. This guide focuses on what's actually distinct about Gemini the assistant, and on a bot that gets misunderstood constantly.

Grounding with Google Search: how the Gemini app cites

The Gemini app doesn't search by default. When a query benefits from current or specific information, it can invoke Grounding with Google Search, an explicit tool call that runs a search and returns citations from what it finds, conceptually the same pattern as ChatGPT's search tool, Claude's web search, or Perplexity's default behavior. When grounding fires, it draws from the same Search index Googlebot builds. There is no separate 'Gemini index.'

Google-Extended: the most misunderstood bot in robots.txt

Getting this right matters: the confusion is common, and the cost is asymmetric. Get it wrong and you either give up training opt-out for nothing, or believe you've protected your visibility when you've actually done nothing of the sort. Google-Extended is not a crawler. It doesn't fetch pages. It's a robots.txt token layered on top of data Googlebot has already collected, and it controls exactly one thing: whether that data can be used to train or ground Gemini and Vertex AI models. It has no effect on classic Search ranking or on AI Overviews eligibility, because AI Overviews draws from Googlebot's index directly, not through the Google-Extended permission.

• Block Google-Extended alone: you opt out of Gemini/Vertex training. Search ranking and AI Overviews eligibility are unaffected.
• Block Googlebot instead: you lose Search ranking and AI Overviews both — Google-Extended's permission becomes irrelevant, because there's no Googlebot data left for it to govern.
• Google-CloudVertexBot is a third, separate bot again, used for enterprise Vertex AI, distinct from both of the above.

What actually controls citation eligibility

Since AI Overviews and Gemini's grounded answers both trace back to the same Search index, the fundamentals are identical to classical Google visibility, plus the AI Overviews-specific signals we cover separately: schema clarity, direct-answer structure, and the technical checks in our Google AI Overviews optimization guide. Nothing about targeting "Gemini" specifically changes those fundamentals. There is no separate Gemini-only ranking signal to chase.

What to check first

• Is Googlebot allowed? It's the one bot that actually governs both Search and AI Overviews eligibility.
• Decide on Google-Extended deliberately, based on training-data comfort, not a belief that it affects citation eligibility, since it doesn't.
• Don't conflate blocking one Google bot with blocking another. The three (Googlebot, Google-Extended, Google-CloudVertexBot) have zero overlap in what they control.

Further reading

• How to Optimize for Google AI Overviews in 2026 — the fundamentals this guide points to instead of repeating.
• How AI Overviews Cite Their Sources — the citation mechanism itself.
• AI crawlers and robots.txt: the 2026 guide — where Google-Extended fits among all tracked bots.
• How Claude Cites Sources: What We Know So Far — the parallel breakdown for Anthropic's bots.