What Is an AI Agent?

An AI agent is an AI system that autonomously plans and executes multi-step tasks toward a goal — searching, browsing pages, calling tools and APIs, and making intermediate decisions without step-by-step human direction. Where a chatbot responds, an agent acts: given "find me the best CRM under $50 per seat and start a trial," it researches, compares, navigates, and executes.

What makes something an agent

Practitioners converge on three ingredients: a reasoning loop (the model plans, acts, observes results, and re-plans), tool access (web search, browsers, code execution, APIs — increasingly standardized through the Model Context Protocol, introduced by Anthropic in November 2024), and autonomy across steps. Deep Research modes in ChatGPT and Gemini are research agents; operator-style products that click through real websites extend the same loop to transactions.

Agentic browsing changes who reads your site

For years the audiences of a webpage were humans and search crawlers. Agents are a third audience with distinct behavior: they fetch on demand at the moment of user intent, follow links purposefully, extract specific facts, and abandon slow or convoluted pages quickly. They do not watch hero animations or interpret clever navigation. A pricing page that requires three clicks and a modal to reveal numbers is, to an agent, a pricing page without numbers.

The commercial stakes

Agentic purchasing raises the stakes from visibility to transactability. When an agent shortlists vendors, its criteria are whatever it can verify machine-readably: transparent pricing, explicit feature lists, structured product data, working checkout flows. Being the recommendation is step one; being executable — the option the agent can actually complete — is the emerging step two, covered under agentic commerce in the glossary.

Preparing for agents overlaps heavily with core GEO fundamentals: server-side rendering, clean semantic markup, structured data, and single sources of truth for critical facts. The difference is urgency — an agent mid-task will not come back later, and the sale it was carrying goes to whichever site it could read.