The words get used interchangeably, but they are not the same thing, and the difference matters when you are deciding what to build.
A chatbot answers. You ask a question, it replies. It is reactive and it lives inside a conversation. Great for support, FAQs, and lead capture.
An agent acts. You give it a goal, and it takes a series of steps to reach it, using tools along the way. Think of the difference between asking what is on my calendar Friday and saying find a 30 minute slot next week, email the client three options, and book whichever they pick. The first is a chatbot. The second is an agent.
Agents are more powerful and more work. Because they take actions, they need guardrails, clear permissions, and a way to check their work before anything happens for real. A chatbot that gives a wrong answer is a bad reply. An agent that takes a wrong action can send the wrong email.
The practical takeaway: start with a chatbot for anything conversational, and reach for an agent only when you want software to actually do a multi step job for you. Most businesses need one good chatbot before they need an agent at all.