AI search optimization: what it is, what it is called and how each AI engine picks sources

What is AI search optimization?

AI search optimization, also called AI search engine optimization, covers two jobs. First, AI search tools must be able to reach your pages, read them and use them as sources. Second, the answers they write should name your brand, describe it correctly and link to you. Together, that is your AI visibility: how often and how well AI represents you.

The word “search” matters. This page is about engines that look things up on the web when someone asks. ChatGPT, for example, may search the web on its own when a question would benefit from current information, OpenAI says. What a model remembers from its training data is the other half of the picture; generative engine optimization covers both and explains where that term comes from.

The result looks different from a page of search results. Instead of ten ranked links, the reader gets a paragraph that names a few brands and cites a few pages, and the next answer to the same question may name different ones. So the goal is not one position. It is a share of the answers, on each engine.

What is AI search optimization called?

The same work goes by at least six names, and the choice usually says more about the writer than about the method. Google's own guide to generative AI features mentions AEO and GEO as terms that “are common online” and warns that many suggested “hacks” don't work for Google Search. Its own name for the topic is simply generative AI features on Google Search.

• Generative engine optimization (GEO): the research term, from the November 2023 paper GEO: Generative Engine Optimization by Pranjal Aggarwal and five co-authors, accepted to KDD 2024. It is also the most searched of the specific names. It covers any system that writes an answer, including answers from a model's memory. See generative engine optimization.
• Answer engine optimization (AEO): older, rooted in featured snippets and voice assistants, so it stresses one clear answer that is easy to lift. See answer engine optimization.
• LLM SEO: the name SEO teams give the hands-on checklist for large language models. See LLM SEO.
• AIO: “AI optimization” or “artificial intelligence optimization” in some guides. The same three letters are also used as shorthand for Google's AI Overviews, so check which one a guide means.
• AI SEO: ambiguous, because it also means doing SEO with AI writing tools.
• AI search optimization and AI search engine optimization: the plain descriptions, and the names this page uses.

Where GEO and AEO really differ is covered in AEO vs GEO. In US Google searches, “AI search optimization” averaged 1,300 searches a month from September 2025 to August 2026, starting and ending at 1,600 after a low of 720 in December 2025, while “what is ai search optimization” went from 30 searches in September 2025 to 1,000 in August 2026. “Generative engine optimization” is still searched more, 4,400 times a month on average, but fell from 6,600 to 3,600 over the same twelve months.

The table below the article lists the main names. The full monthly series is in our generative engine optimization statistics.

How AI search engines pick sources

The vendors describe the same basic loop. The engine decides whether a search would help, sends one or more searches to an index, reads the pages that come back and writes an answer with links to some of them. Google calls this retrieval-augmented generation, or grounding: its AI features rely “on our core Search ranking systems to retrieve relevant, up-to-date web pages from our Search index”.

What differs is whose index is searched and which crawler fills it. This is what each vendor says, read on 3 October 2026:

• ChatGPT search: OpenAI's crawler OAI-SearchBot is “used to surface websites in search results in ChatGPT's search features”. Sites that block it “will not be shown in ChatGPT search answers, though can still appear as navigational links” (OpenAI's crawler overview). ChatGPT search also “sometimes partners with other search providers”; OpenAI's help page points to Microsoft's and Shopify's privacy policies for them.
• Gemini: the Gemini app is grounded in Google's Search index. Google's crawler documentation describes grounding as “providing content from the Google Search index to the model at prompt time”. The Google-Extended token decides whether your content may be used for that grounding and for training future Gemini models. It does not affect Google Search.
• Google AI Overviews and AI Mode: they are part of Search, and Google's guide says they are “rooted in our core Search ranking and quality systems”. A page must be indexed and eligible to show with a snippet, and Googlebot rules in robots.txt are the crawl control (AI features and your website).
• Perplexity: PerplexityBot is “designed to surface and link websites in search results on Perplexity” and is not used to crawl content for AI foundation models (Perplexity's crawler page).
• Claude: Anthropic runs Claude-SearchBot to index pages for search, and says blocking it “may reduce your site's visibility and accuracy in user search results” (Anthropic's crawler page).
• Microsoft Copilot: Microsoft describes “Copilot experiences powered by Bing” (Bing Webmaster blog), so being indexed in Bing comes first.

The same companies run crawlers for other jobs too. GPTBot and ClaudeBot collect training data, and ChatGPT-User, Claude-User and Perplexity-User fetch a page when a user's question calls for it. On the vendors' own account, blocking a training crawler does not remove you from their search answers. The table below the article lists the crawler and the opt-out for each engine.

One question, many searches

An AI engine rarely searches for your question word for word. Google says AI Overviews and AI Mode may use a “query fan-out” technique, “issuing multiple related searches across subtopics and data sources”. Its example: a question about fixing a lawn full of weeds may fan out to “best herbicides for lawns”, “remove weeds without chemicals” and “how to prevent weeds in lawn”.

The other engines describe the same habit in their own words. OpenAI says ChatGPT search “typically rewrites your query into one or more targeted queries” for its search partners, and may send more specific ones after reading the first results. Google's documentation for developers grounding Gemini says the model “automatically generates one or multiple search queries and executes them”; that page covers the Gemini API, not the Gemini app. And Bing Webmaster Tools now shows site owners a sample of grounding queries: the “key phrases the AI used when retrieving content” that Copilot and Bing's AI summaries cited.

Two things follow. A page can be used for a question nobody typed in the form you target, if it answers one of the sub-questions clearly. And there is no point in writing a page for every variation: Google warns that creating separate content for fan-out queries “primarily to manipulate rankings or generative AI responses” violates its scaled content abuse policy. Answer the questions a buyer asks next on the page that owns the topic instead.

How to optimize for AI search

Most of the work is ordinary SEO and marketing, checked against one question: could an engine that reads this page name you, describe you and say who you are for? Roughly in order:

• Let the search crawlers in. Allow Googlebot, OAI-SearchBot, PerplexityBot, Claude-SearchBot and Bing's crawler in robots.txt, and check your CDN and firewall too. Google asks for crawling to be “allowed in robots.txt, and by any CDN or hosting infrastructure”, and OpenAI and Perplexity ask sites to allow their published IP addresses. Decide on training crawlers such as GPTBot, ClaudeBot and Google-Extended as a separate question.
• Get indexed where each engine searches. Google's AI features only use pages that are indexed and eligible for a snippet, and Microsoft says Copilot is powered by Bing. Check your key pages in Search Console and Bing Webmaster Tools.
• Write pages worth quoting. Put the facts buyers ask about in plain text near the top: what you offer, for whom, what it costs and how it compares. Google's 2026 guide puts unique, non-commodity content first and says it “will likely influence your website's presence in generative AI search in the long run more than any of the other suggestions”.
• Be described on other people's pages. Answers often cite review sites, comparison articles and forums, not only brand websites: in our measurement below, Gemini cited zapier.com in 19 of 33 answers and reddit.com in 14. Earn that coverage honestly. Google says “seeking inauthentic ‘mentions’ across the web isn't as helpful as it might seem”.
• Keep facts fresh and consistent. Change a fact everywhere it appears, not only on one page. Bing recommends IndexNow to tell it about changed pages, and Google says recrawling “can take anywhere from several days to several months”.
• Skip the hacks. For Google Search, Google says you don't need AI text files, special markup or schema, content “chunked” into small pieces or text rewritten just for AI.

Many large sites already split search from training. In our study of which websites block AI crawlers, with robots.txt files fetched on 3 October 2026, 11.7% of the 6,528 top sites whose robots.txt rules we could read (out of 10,000 we tried) fully blocked GPTBot, OpenAI's training crawler, but only 5.1% blocked OAI-SearchBot. Of the 766 sites that block GPTBot, 443 leave OAI-SearchBot open, while 3.8% of all the sites shut out all three AI search crawlers we checked, from OpenAI, Anthropic and Perplexity. Googlebot was fully blocked by 1.7%. The per-site data is in the study's CSV.

The step-by-step version, with the user agents to check and a log template for measuring, is in our guide to LLM SEO.

How to measure AI search optimization

“AI search” is not one engine, and the engines disagree. On 3 October 2026 we asked ChatGPT and Gemini 11 real search phrases about our own category, AI visibility tools, such as “best ai visibility tools” and “best chatgpt visibility tracker”. Each phrase went three times to each engine, every time in a new logged-out session: 66 answers, all successful.

Four differences stood out:

• Different shortlists. For each phrase we compared the five tools each engine named most often. On average, 2.6 of the 5 were on both lists (a Jaccard overlap of 0.38). For “best chatgpt visibility tracker” only one tool was on both; for “best ai visibility tools”, four were.
• Different tools overall. The answers named 59 tools: 29 on ChatGPT, 44 on Gemini and only 14 on both. Scrunch appeared in 18 of 33 ChatGPT answers and 2 of 33 Gemini answers. SE Ranking and its SE Visible appeared in 7 on ChatGPT and 16 on Gemini.
• Different sources. ChatGPT cited 62 different domains and Gemini 59, and only 8 domains were cited by both. ChatGPT's most cited was dataforaisearch.com, in 14 of 33 answers; Gemini's was zapier.com, in 19 of 33.
• Different answers on the same engine. Asked the same phrase three times, ChatGPT named a given tool in all three runs 64% of the time and in only one run 21% of the time. For Gemini it was 46% and 34%.

So measure each engine separately, ask each question more than once and compare shares of answers, not screenshots. Our AI visibility audit guide shows how to do that by hand. Keep the same questions between rounds, so that changes mean something: on the four phrases we had also asked ChatGPT on 1 October, the top five tools were the same two days later, but Promptwatch fell from 6 of 12 answers to 2.

First-party reports cover only part of this. Google points to the Generative AI performance report in Search Console for AI Overviews, AI Mode and Discover, and Bing Webmaster Tools' AI Performance counts how often your pages are cited in Copilot and Bing's AI summaries. Neither shows what ChatGPT or the Gemini app say about your brand.

Download the data (CSV): the tools named and the domains cited in all 66 answers. The full tables are on our dataset page Which AI visibility tools do ChatGPT and Gemini recommend?, and how we collect and count answers is described in our methodology.

Llamat makes a free AI visibility checker that runs this kind of measurement for your brand, with no sign-up. You enter your website and e-mail; after you confirm the e-mail, we research real search phrases about what the site offers and turn them into up to 20 prompts. Each prompt goes three times to ChatGPT and three times to Gemini, each in a new logged-out session, and is checked once in Google AI Overviews. The report usually arrives within 30 minutes of your confirmation. It shows your mention, recommendation and citation rates, average position, AI Visibility score and the competitors named instead. Google AI Mode, Perplexity, Claude and Microsoft Copilot are available as paid add-ons on request. For software that repeats the check on a schedule, compare AEO tools.