An AI system that can autonomously plan and execute multi-step tasks, using tools (web search, code execution, API calls) to achieve a goal. Unlike a simple chatbot that answers one question at a time, an agent decides what to do next based on what it's learned so far.
Why it matters
Agents are the bridge between "AI that talks" and "AI that does." When your AI can browse docs, write code, and test it without you holding its hand at every step — that's an agent.