What agents really are

0:00 So, let me give you the honest one-sentence version here, which is that an AI agent is simply just a language model that can use tools, that's running in a loop until it finishes a job. That's it. That's literally all an AI agent is. Everything else is just a small detail. So, in this video, I'm going to break down what's actually happening under the hood, the real building blocks, and none of the fluff. And I'm going to show you how you can build the same agent in four completely different ways, from no code all the way down to writing it yourself in pure Python.

0:23 Now, by the end of the video, you're going to understand agents better than most people that are posting about them. So, let's dive in. So, first, let's clear up the most common confusion that I see, which is the difference between a chatbot and an agent. Now, regular chatbot or just a plain language model or LLM can only do one thing. It talks. Okay? You send it a message, it sends text back. Now, that's the entire interaction, right?

0:47 It can't check your email. It can't search the web. It can't book anything or update a database. It just generates words and predicts text. Now, an agent is what you get when you give this model two new abilities. Now, the first ability is to take actions in the real world, which we call tool calling. And the second ability is to keep going on its own, so step-by-step, instead of stopping after just a single reply. Now, that's the loop that we're talking about.

1:34 So, a chatbot answers a question, whereas an agent can be told a goal and then go and actually accomplish it by taking multiple steps and using the tools provided. Now, once you understand that, the whole thing really stops becoming magic and it starts becoming something you can actually build, because you know the foundation. So, with that said, let's look at these pieces specifically. Now, the first part here is the LLM or the brain. Now, at the center of every