AEO, GEO and AI Search Glossary

Short, citable definitions. Terms added from daily research link to the source that defines them. 39 terms.

Accountable crawler

Cloudflare's designation for bot operators that offer, or commit to offering, a training opt-out, an AI summaries opt-out, URL-level visibility and assurance that opting out will not affect search. Source

AEO (answer engine optimization)

The practice of making content easy for answer engines to find, understand and use when they respond to a question.

AgEO (agent engine optimization)

Our shorthand for making a site usable by AI agents that act on a person's behalf: reading pages reliably, following links, and, where relevant, completing tasks through APIs or tools.

AI agent

Software that uses a language model to pursue a goal by taking steps such as browsing, calling tools and making decisions, rather than only answering one prompt.

AI Catalog

A draft manifest published at /.well-known/ai-catalog.json that can link to or embed MCP Server Cards for domain-level discovery of AI artifacts. Source

AI Mode

Google's conversational search experience that answers multi-part questions with generated responses and links.

AI Overviews

Google's AI-generated summaries shown at the top of some search results, with links to supporting pages.

aipref (AI preferences)

An IETF working group whose draft vocabulary defines usage categories (AI Training, AI Use and Search) for expressing how automated systems may use content. The draft does not yet reflect working group consensus. Source

Answer engine

A system that responds to a question with a direct answer instead of only a list of links, such as an AI assistant, an AI search mode or a voice assistant.

Canonical URL

The preferred address for a page, declared with a link tag so duplicates point to one version.

Citation

A link or named reference to a source inside a generated answer.

ClaudeBot

Anthropic's crawler used to collect content that may be used for training its models.

Crawler (bot)

An automated program that fetches web pages. AI companies run separate crawlers for training, for search and for fetching a page when a user asks.

Disallow AI Training

A Cloudflare setting that publishes a no-training preference in robots.txt while accountable mixed-use crawlers stay allowed for search. Source

E-E-A-T

Experience, Expertise, Authoritativeness and Trust: the qualities Google's quality guidance asks raters to look for. It is a framework for assessing content, not a single ranking factor.

Entity

A distinct thing a search system can identify, such as a person, organization, product or concept, independent of the words used to describe it.

GEO (generative engine optimization)

The practice of improving how often and how accurately generative AI systems cite or mention your content in the answers they write. The term was introduced in a 2023 research paper.

Google-Extended

A robots.txt token that controls whether Google may use your content for some of its AI products. It does not affect Google Search, including AI Overviews and AI Mode.

GPTBot

OpenAI's crawler used to collect content that may be used for training its models.

Grounding

Supplying a language model with retrieved sources so its answer is based on them rather than only on its training.

Indexing

The process by which a search engine stores a page so it can be returned for queries. A page that is not indexed cannot appear in results or AI features that rely on that index.

JSON-LD

A format for embedding structured data in a page inside a script tag, without changing the visible HTML.

llms.txt

A community proposal for a markdown file at /llms.txt that lists a site's key pages for language models. No major AI provider has confirmed using it.

MCP (Model Context Protocol)

An open protocol for connecting AI applications to tools and data sources. Relevant to AgEO when a site or product exposes tools to agents.

MCP Server Card

A static JSON document that describes a remote MCP server (identity, transports, protocol versions) so clients can discover it before connecting. It is an optional extension and leaves out tools, resources and prompts. Source

Mixed-use crawler

A crawler that serves more than one purpose, such as search and AI training. Cloudflare cites Applebot, Bingbot and Googlebot as examples. Source

OAI-SearchBot

OpenAI's crawler used to surface sites in ChatGPT search results.

PerplexityBot

Perplexity's crawler used to index sites for its answer engine.

Personal Agent Protocol (PAP)

A proposed open standard from Sierra and Meta (announced 6 October 2026) for how personal AI agents authenticate with businesses and what the businesses let them do. Still a proposal. Source

Preferred Sources

A Google feature that lets users choose news outlets to favour; news carousels in AI Mode and AI Overviews highlight those sources. Google says use grew more than 7x in 2026. Source

Query fan-out

A technique where a system splits one question into several related searches across subtopics, then combines the results into one answer.

RAG (retrieval-augmented generation)

A design in which a system retrieves relevant documents first and then has a model write an answer using them.

robots.txt

A file at the root of a site that tells crawlers which paths they may fetch. It is a voluntary convention, not a security control.

schema.org

A shared vocabulary of types and properties, such as Organization, Article and BreadcrumbList, used to describe pages for machines.

Search generative AI control

A site-wide Search Console setting that manages a site's inclusion in Google's generative AI features on Search, including AI Overviews and AI Mode. Source

Snippet

The text excerpt a search engine shows for a result. Google says a page must be eligible to be shown with a snippet to be used in its AI features.

Structured data

Machine-readable markup, usually schema.org vocabulary in JSON-LD, that describes what a page is about. It must match the visible content.

Sub-query

A narrower search an answer engine writes from the user's question while retrieving sources. A 2026 arXiv study finds that which pages these sub-queries retrieve explains most of the variation in ChatGPT citations. Source

Zero-click search

A search where the user gets what they need from the results page and does not visit a site.