Coaley Peak GEO Research Centre Engine guide
Google AI Overviews and AI Mode How Google's AI answers choose their links, and how to be one of them.
AI Overviews put an AI answer above Google's results, and AI Mode turns Search into a conversation. Google says the first has more than 2.5 billion monthly users and the second more than a billion. Both are built on Google's search index. This guide covers their timeline, the four layers behind them, Google's crawlers and every control Google now offers.
Independent guide: Coaley Peak is not associated with Google LLC. Trademarks
- Owner
- Google LLC
- Launched
- AI Overviews May 2024 (US), August 2024 (UK); AI Mode May 2025 (US), July 2025 (UK)
- Home market
- 248 countries and territories
- Languages
- 98 languages
- Open weights
- No: custom Gemini models (Gemma is Google's separate open family)
- Crawlers
- Googlebot; Google-Extended governs training, not display
Overview
What Google AI Overviews and AI Mode is, and who uses it
Google began testing generative answers in Search in May 2023 as the Search Generative Experience, a Search Labs experiment in the US. It launched them to everyone in the US as AI Overviews on 14 May 2024, and to the UK, India, Japan, Indonesia, Mexico and Brazil that August. AI Mode, a conversational search experience, opened as an experiment in March 2025, reached all US users that May and the UK in July 2025.
Scale is what sets them apart. Google says AI Overviews have more than 2.5 billion monthly users and AI Mode more than a billion, across 248 countries and territories and 98 languages. Gemini 3 has powered AI Overviews globally since January 2026, and in May 2026 Google made Gemini 3.5 Flash AI Mode's default model worldwide.
Regulators have followed. The European Commission opened an antitrust investigation in December 2025 into Google's use of publishers' content for AI Overviews and AI Mode. In the UK, the Competition and Markets Authority designated Google with strategic market status in search in October 2025 and, in June 2026, required it to give publishers an opt-out from its AI features. Google rolled out a Search Console control worldwide on 31 August 2026.
For SEO teams, the rules are the most familiar of any AI engine: a page must be indexed by Googlebot and eligible for a snippet to be a supporting link, and Google says no special markup or AI text files are needed. What has changed is how queries are answered, through 'query fan-out' across many related searches, and how success is measured.
Timeline
Google AI Overviews and AI Mode, from launch to today
Google is formally established after its first outside investment.
Google opens the Search Generative Experience as a Search Labs experiment in the US.
Google announces the Google-Extended robots.txt token for opting out of use in Bard and Vertex AI models.
AI Overviews roll out to everyone in the US, powered by a custom Gemini model.
AI Overviews launch in the UK, India, Japan, Indonesia, Mexico and Brazil.
AI Overviews expand to more than 200 countries and territories and over 40 languages, and AI Mode rolls out to everyone in the US.
AI Mode launches in the UK.
AI Mode expands to more than 180 more countries and territories, in English.
The European Commission opens an antitrust investigation into Google's use of publishers' content for AI Overviews and AI Mode.
Gemini 3 becomes the default model for AI Overviews globally, with follow-up questions flowing into AI Mode.
Google says AI Mode has passed a billion monthly users and makes Gemini 3.5 Flash its default model worldwide.
The UK CMA imposes a conduct requirement giving publishers an opt-out from Google's AI features, and Google begins testing a Search Console opt-out with UK sites.
Google rolls out the Search generative AI control and a generative AI performance report to all websites worldwide.
Things to know
Things to know about Google AI Overviews and AI Mode
To appear as a supporting link, a page must be indexed and eligible for a snippet. Google says no special schema.org markup, machine-readable files or AI text files are needed.
Since 31 August 2026, any verified Search Console property can exclude itself from AI Overviews, AI Mode and Discover's generative AI features with one setting, without affecting its classic rankings.
Excluding a site means no traffic or impressions from those features, and it does not stop training: Google points to Google-Extended for that.
nosnippet and max-snippet explicitly govern how much of a page can be used as direct input to AI Overviews and AI Mode; data-nosnippet hides marked sections.
In Search Console, every link in an AI Overview shares the Overview's single position, clicks to external pages count as clicks, and an AI Mode follow-up counts as a new query.
A separate generative AI performance report shows impressions from AI Overviews and AI Mode by page, country and device.
Because of query fan-out, AI features can show a wider and more varied set of links than a classic search for the same query, and AI Overviews and AI Mode can show different links.
Google-Extended does not affect whether a site appears in Google Search, AI features included, or how it ranks.
Changes to preview controls apply only after a recrawl, which Google says can take days to months. URL Inspection shows what Googlebot received.
Users cannot switch AI Overviews off, but the 'Web' filter shows text links only.
The four layers
How Google AI Overviews and AI Mode builds an answer
Every AI answer is made in four layers: what the model learned in pre-training, how it was tuned, what it retrieves live, and how it puts the answer together. Here is each one for Google AI Overviews and AI Mode, and what it means for a brand that wants to be cited.
Layer 1
Pre-training: the base (foundation) model
Both features use custom versions of Google's closed Gemini models: Gemini 3 for AI Overviews since January 2026, and Gemini 3.5 Flash for AI Mode since May 2026, with Gemini 3 Pro selectable by subscribers. Google publishes no cut-off for the Search versions; the underlying model cards give January 2025 for Gemini 3 Pro and March 2026 for recent Flash models. Gemini 3's training data, per its model card, includes public web documents, crawled data gathered in line with robots.txt, licensed data, user data under Google's controls and synthetic data.
What it means for you: The model's own knowledge matters less here than in any other engine, because AI Overviews and AI Mode are grounded in the live index. What it learned shapes how it reads your category; what it retrieves decides whether you are cited.
Layer 2
Post-training: tuning and alignment
Gemini 3 was post-trained with instruction tuning, reinforcement learning and human preference data. After errors at launch in May 2024, Google said it had improved detection of nonsensical queries, limited satire and misleading user-generated content, restricted when AI Overviews trigger, aimed not to show them on hard-news topics and refined their use for health. Trained reviewers rate quality.
What it means for you: Google's tuning favours reliable, non-satirical sources and holds back on news and health. In those areas AI answers may not appear at all, and where they do, sources with demonstrable expertise win.
Layer 3
Retrieval: live search
Both features are built on Google's search index, crawled by Googlebot. Both may use 'query fan-out', running many related searches across subtopics and data sources, and they may use different models and techniques, so their links differ. AI Overviews appear only when Google judges them useful, so many queries never trigger one. AI Mode also draws on real-time data and the Shopping Graph, and Personal Intelligence can use a user's connected Google apps.
What it means for you: Classic SEO fundamentals decide eligibility, and fan-out rewards pages that cover a topic's sub-questions well, not just its head term. Content that answers the follow-up questions in your category is how you are picked up by searches you never see.
Layer 4
The answer: what people read
AI Overviews show an AI snapshot above or within the results, with supporting links; Google has added more inline links and site previews, and Preferred Sources and subscription labels now apply. Users can ask a follow-up and continue in AI Mode. AI Mode gives conversational answers with links and follow-ups, takes voice, image and file input, shows interactive visuals and, in some markets, books things for the user.
What it means for you: One position, many links: an AI Overview is a single result shared among its sources. Measure it with Search Console's generative AI report, and aim for the passages Google quotes, not just the ranking beneath them.
Crawlers
Google AI Overviews and AI Mode's crawlers and user agents
The user-agent tokens to look for in your server logs and to name in robots.txt.
| User-agent token | What it does | robots.txt |
|---|---|---|
| Googlebot Documentation | Crawls for Google Search and every Search feature, which covers AI Overviews and AI Mode. Google calls robots.txt for Googlebot the access control for Search's AI features. | Follows robots.txt for automatic crawls. |
| Googlebot-Image Documentation | Crawls images for Google Images, Discover and the Search features that show images, logos and favicons. | Follows robots.txt, and also matches rules for Googlebot. |
| Google-Extended Documentation | Not a crawler: a robots.txt token controlling whether pages Google crawls may train future Gemini models and ground answers in Gemini Apps. It does not affect inclusion or ranking in Google Search, including AI Overviews and AI Mode. | A robots.txt control token, read by Google's existing crawlers. |
| Google-InspectionTool Documentation | Used by Search testing tools such as the Rich Results Test and URL Inspection, which Google suggests for checking what Googlebot sees. No effect on Search. | Follows robots.txt, and also matches rules for Googlebot. |
| Google-Agent Documentation | Used by agents running on Google's infrastructure to navigate sites and act on a user's request; Google does not say which products use it. Some requests are signed with Web Bot Auth. | Generally ignores robots.txt, as a user-triggered fetcher. |
Googlebot's smartphone user agent ends 'compatible; Googlebot/2.1; +http://www.google.com/bot.html', with a Chrome version that changes over time, so match on the Googlebot token. Google generally caches robots.txt for up to 24 hours.
Crawl sources
Where Google AI Overviews and AI Mode crawls from, and how to verify it
Google publishes its crawler IP ranges as JSON files under developers.google.com/static/crawling/ipranges/: common-crawlers.json for Googlebot and similar crawlers, special-crawlers.json, user-triggered-fetchers.json and user-triggered-fetchers-google.json, and user-triggered-agents.json for Google-Agent. The old googlebot.json path now redirects to common-crawlers.json.
To verify a request, run a reverse DNS lookup and then a forward lookup that returns the original IP. Googlebot resolves to crawl-***-***-***-***.googlebot.com or geo-crawl-***-***-***-***.geo.googlebot.com, special crawlers to rate-limited-proxy hostnames on google.com, and Google's user-triggered fetchers to google-proxy hostnames on google.com, or to gae.googleusercontent.com when a user's own cloud project makes the fetch.
Google crawls mainly from US addresses and may crawl from other countries if US requests are blocked, which matters for sites that serve different content by country.
Opting out
How to opt out of Google AI Overviews and AI Mode, or limit what it uses
Exclude your site in Search Console
Under Settings, then Search generative AI, choose Exclude to keep your links and content out of AI Overviews, AI Mode and Discover's generative AI features, including as grounding input. It takes about one to two days, is not used as a ranking signal elsewhere, and does not affect training or remove pages from Search.
Official pageLimit what can be quoted
nosnippet stops a page being used as direct input to AI Overviews and AI Mode, max-snippet caps how much text can be used, and data-nosnippet hides marked sections. All three also limit your classic snippets.
Official pageRefuse Gemini training
User-agent: Google-Extended with Disallow: / limits use of your content for training Gemini models and for grounding in Gemini Apps and Vertex AI. It does not remove content from Search or its AI features.
Official pageRemove pages from Search entirely
noindex, or blocking Googlebot, removes pages from Google Search and therefore from AI Overviews and AI Mode.
Official pageHide or refresh results
Search Console's Removals tool hides URLs for about six months; for permanent removal, delete, password-protect or noindex the page. Anyone can ask Google to refresh results for pages that have changed or gone.
Official pageLegal and personal removals
Report content for legal reasons such as defamation or copyright, use the right-to-be-forgotten form in the EU and UK, or ask for results showing your home address, phone number or email to be removed.
Official pageGive feedback on an answer
Every AI Overview has a thumbs-down and 'Report a problem', which send the query and response to Google for review.
Official page
Excluding your site does not stop similar content from other sites appearing in AI answers, and it gives up AI traffic and impressions entirely. Google-Extended and the Search Console control do different jobs: one governs training and Gemini grounding, the other display in Search's AI features. For most brands that want visibility, the right setting is to stay included.
How we help
How we get brands cited in Google AI Overviews and AI Mode
The Coaley Peak GEO Research Centre researches and implements GEO for SEO agencies and in-house teams, with foreign markets as our speciality.
AI Overviews and AI Mode audit
We find the queries in your markets that trigger AI answers, record which sources Google links, and measure your share against competitors, market by market and language by language.
Content built for query fan-out
We map the sub-questions Google's fan-out explores in your category and build pages that answer them, so you are found by the searches behind the answer, not just the head term.
Technical eligibility
Indexing, snippet eligibility, structured data and preview controls, checked with URL Inspection, so nothing stops Google using your best passages.
International Google
AI Overviews run in 98 languages. We localise content for each market with native writers, rather than translating it, so you are cited in Japanese, German or Portuguese as well as English.
Measurement in Search Console
We set up the generative AI performance report alongside your classic data, so you see AI impressions and clicks by page, country and device.
More on our research, services and team at the Coaley Peak GEO Research Centre.
FAQ
Google AI Overviews and AI Mode GEO: questions
How does Google choose sources for AI Overviews?
A page must be indexed and eligible to appear with a snippet. Google then uses query fan-out, running related searches across subtopics, and links the pages that support the answer. Google says no special markup is needed and standard SEO fundamentals apply.
Can I opt out of AI Overviews and AI Mode?
Yes. Since 31 August 2026 any verified Search Console property can choose Exclude under Search generative AI. Your pages stay in classic results but get no traffic or impressions from AI Overviews, AI Mode or Discover's generative AI features.
Does Google-Extended keep me out of AI Overviews?
No. Google-Extended controls Gemini training and grounding in Gemini Apps and Vertex AI. It does not affect Google Search, including AI Overviews and AI Mode; use the Search Console control or snippet directives for those.
How do I measure traffic from AI Overviews?
Clicks and impressions are included in Search Console's Performance report under the Web search type, where every link in an AI Overview shares its position. A separate generative AI performance report breaks impressions down by page, country and device.
Do I need special markup or an llms.txt file?
Google says no special schema.org markup, machine-readable files or AI text files are needed to appear in AI Overviews or AI Mode. Structured data still helps Google understand pages, as it does for classic results.
Where are AI Overviews available?
Google lists 248 countries and territories and 98 languages for both AI Overviews and AI Mode, including the UK and the EU. Mainland China is not on the list.
Want a free chat about Google AI Overviews and AI Mode?
Tell us which market and brand you are working on. If we can help, we will set up a free, no-obligation chat with Stephen or Ethan.
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Independence and trademarks. Google, Google Search and Gemini are trademarks of Google LLC. Coaley Peak is independent: we are not associated with, endorsed by or a partner of Google LLC. This guide is our own research from public documentation and reputable reporting, checked in October 2026.
Reviewed by Stephen Grindley, research centre lead. Last checked .
Document reference: ISO_webpage_geo_engine_google_ai_overviews_v1
Last modified: 7 October 2026
GEO Research Centre·Engine guides·Google AI Overviews and AI Mode