GEO glossary

AEO is optimizing content to be selected as the direct answer to a question posed to an answer engine — a voice assistant, a chat interface, or a search engine's direct-answer box. It overlaps heavily with GEO and the two terms are often used interchangeably.

Agentic Browsing is a Lighthouse audit category that scores how well a page's accessibility tree, layout stability, llms.txt, and WebMCP integration support AI agents operating the page — separate from Lighthouse's Performance, Accessibility, Best Practices, and SEO categories.

An AI crawler is an automated bot operated by an AI company that fetches web pages — either to collect training data, to index content for an AI-powered search feature, or to retrieve a specific page a user asked about. GPTBot, ClaudeBot, and PerplexityBot are the most common.

ClaudeBot is Anthropic's web crawler for collecting training data for Claude. It's one of three separate Anthropic crawlers — ClaudeBot, Claude-User, and Claude-SearchBot — each with its own purpose and User-Agent, all of which respect robots.txt per Anthropic's own documentation.

GEO is the practice of making a website readable, parseable, and citable by generative AI answer engines — ChatGPT, Perplexity, Claude, Gemini, Google AI Overviews — rather than optimizing purely for ranking in a traditional search results list.

GPTBot is OpenAI's web crawler for collecting training data for its generative AI models. It identifies itself with a distinct User-Agent, respects robots.txt, and disallowing it signals that a site's content should be excluded from training datasets.

JSON-LD (JSON for Linking Data) is a format for embedding structured data in a webpage as a JSON object inside a <script> tag. It's how a page tells a search or AI engine explicitly what it is — an article, a product, an FAQ — instead of leaving the engine to infer it from prose.

llms.txt is a proposed plain-text file, published at a site's root, that gives an AI model a Markdown index of a site's content. Adoption by AI vendors is partial and unconfirmed — it's a low-cost, forward-looking addition, not a guarantee of anything.

PerplexityBot is Perplexity AI's web crawler that indexes content for its answer engine. Per Perplexity's help center, it respects robots.txt; a separate, user-triggered fetcher called Perplexity-User behaves differently, since it acts on a specific person's request rather than crawling in the background.

A zero-click search is a search query the user never clicks a result for, because the answer is shown directly in the search results page or an AI-generated summary. As AI Overviews and AI answer engines grow, a larger share of searches end this way — one widely-cited study put the figure at 68% of US Google searches in early 2026.