What is AI Agent?
An AI that doesn't just answer — it takes actions, uses tools, and completes tasks on its own.
// Explanation
Unlike a chatbot that only answers questions, an agent acts. It works in a loop: observe the environment → decide what to do → execute an action using a tool (search the web, run code, send emails, read files) → observe the result → repeat until the goal is complete. The LLM is its 'brain' and the tools are its 'hands'. Claude Code, Manus, and Devin are examples of ready-to-use agents. There are also multi-agents (several specialized agents working as a team) and sub-agents (an orchestrator agent that delegates subtasks to other agents and consolidates results).
// Example
You tell an agent 'research the top 5 investment funds for 2026 and send me a summary by email'. The agent searches the web, analyzes data, writes the summary, and sends it — all on its own, without you guiding it step by step.