AI visibility, AEO and GEO, defined in plain words.
AI visibility is how often AI assistants such as ChatGPT, Perplexity, Claude and Google AI Overviews name your brand when people ask about your category. AEO and GEO are two names for the work of raising it. Every term below opens with a one-sentence definition, then the detail and a source.
2 free scans, today and tomorrow: 25 questions on 4 engines. No card.
What is AI visibility, and what are AEO and GEO?
- AI visibilityAlso: AI search visibility
AI visibility is how often AI assistants such as ChatGPT, Perplexity, Claude and Google AI Overviews name your brand when people ask about your category.
It is measured per question and per engine, usually as a mention rate. Unlike a search ranking there is no fixed position: the same question can name you in one answer and leave you out of the next, which is why it has to be sampled, not checked once.
- AEOAnswer engine optimization
AEO is the work of getting your brand named, and your pages cited, in the answers AI assistants give.
In practice it means publishing pages that answer buyer questions directly, earning places on the third-party pages engines cite, and making sure AI crawlers can read your site. An AEO tool measures whether that work is moving the answers.
- GEOGenerative engine optimization
GEO is another name for the same work as AEO: improving how generative AI engines describe and recommend you.
The term comes from a 2023 research paper, GEO: Generative Engine Optimization (Aggarwal et al.). AEO and GEO are used interchangeably; neither is a separate discipline from the other. See what a GEO tool does.
How is AI visibility measured?
- Mention rate
Mention rate is the share of AI answers to a question that name your brand.
Named in 6 of 20 answers is a 30% mention rate. On its own that figure hides how uncertain it is, which is what a Wilson interval is for.
- Wilson intervalWilson score interval
A Wilson interval is the range a measured percentage could plausibly sit in, given how many answers it is based on.
Named in 6 of 20 answers is 30%, with a 95% Wilson interval of about 14.5% to 51.9%. Named in 60 of 200 is also 30%, but the interval narrows to about 24.1% to 36.7%. Same number, very different certainty.
It was introduced by E. B. Wilson in 1927 and is the standard interval for a proportion from a small sample (reference). Proofsource puts one on every percentage; see the methodology.
- PromptAlso: tracked question
In AI visibility, a prompt is a question tracked across AI engines, written the way a buyer would ask it.
"What's the best AI visibility tool for a small team?" is a prompt. Tools price by how many prompts you track, because each one is asked on every engine, every time the tool samples.
What do AI engines read and cite?
- Citation
A citation is a web page an AI engine links to or lists as a source for its answer.
Being named and being cited are different things. An engine can name your brand while citing a competitor's comparison page, or cite your page without naming you. In our own scan of 80 category answers on 4 Oct 2026, 43.5% of citations were comparison pages: listicles, "alternatives" pages and "X vs Y" pages.
- Query fan-out
Query fan-out is when an AI engine splits one question into several related searches and builds its answer from all the results.
Google says both AI Overviews and AI Mode may issue multiple related searches across subtopics and data sources to build a response (Google Search Central). It is why a page can be cited for a question it never mentions: it answered one of the sub-searches.
- Google AI Overviews
Google AI Overviews are the AI-written summaries Google shows above some search results, with links to the pages they draw on.
Google says a page must be indexed and eligible to show with a snippet to appear in them (Google Search Central). They are one of the four engines Proofsource tracks.
Can AI crawlers reach and read your site?
- Crawler access
Crawler access is whether the bots AI companies send can fetch and read your pages.
OpenAI, for example, runs separate bots for search (OAI-SearchBot), for training (GPTBot) and for fetching a page a user asked about (ChatGPT-User) (OpenAI docs). A bot can be blocked in robots.txt or, less visibly, at your CDN's edge by a bot-blocking setting. And a bot that gets through can still see an empty page if your text only appears after JavaScript runs.
- llms.txt
llms.txt is a proposed plain-text file at the root of a website that lists its most useful pages for language models.
It was proposed at llmstxt.org. It is cheap to add and harmless, but it is not a ranking lever: none of the four engines we track has said it uses llms.txt to decide what to name or cite, and Google states that you do not need new machine-readable files, AI text files or markup to appear in AI Overviews or AI Mode (Google Search Central).
Treat it as documentation for agents, not as optimisation.
What people ask about AI visibility terms
Is AEO the same as GEO?
Yes, in practice. AEO (answer engine optimization) and GEO (generative engine optimization) both mean getting your brand named and your pages cited in AI answers. GEO comes from a 2023 research paper; AEO is more common in marketing.
What is a good AI mention rate?
There is no universal benchmark, because it depends on how crowded your category is. Compare your rate with the brands named most often for the same questions on the same engines, and read the interval: a rate from 20 answers can sit a long way from the true figure.
What is the difference between a mention and a citation?
A mention is your brand's name in the answer text. A citation is a web page the engine links to as a source. You can be mentioned without being cited, or cited without being mentioned, so track both.
Does llms.txt improve AI visibility?
There is no evidence that it does. Google says no special AI text files are needed to appear in AI Overviews or AI Mode, and none of the four engines Proofsource tracks has said it uses llms.txt for ranking. Readable pages and open crawler access matter far more.
See your own mention rate, with its interval.
See which buyer questions name your brand, who gets named instead, and what to fix. 2 free scans, today and tomorrow: 25 questions on 4 engines. No card.
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