Lesson 16 min

What is an Agent?

An LLM that can take actions in a loop, not just chat.

What you will learn

✓How an agent differs from a chatbot
✓The think-act-observe loop
✓When agents are (and aren't) the right tool

Explanation

A chatbot only talks. An agent is an LLM wired to tools and run in a loop: it decides an action, takes it, observes the result, and decides again — until the goal is met.

This loop (think → act → observe) lets it do real work: search the web, query a database, send an email, run code.

Agents shine for multi-step tasks with tools, but they add cost and unpredictability — for a single answer, a plain prompt is better.

Real-world use

A 'book me a flight' assistant that searches, compares, and fills a form is an agent; one that just lists tips is a chatbot.

Common mistakes

• Building an agent for a task a single prompt could solve — it adds cost and failure modes.

Practice

Describe a task you'd give an agent and list the tools it would need.

Knowledge check

0/1 answered

1. What makes an AI system an 'agent'?

Answer all questions to check.