# Building Your First AI Agent with LangChain (Part 1: The Theory)

> Source: <https://pub.towardsai.net/building-your-first-ai-agent-with-langchain-part-1-the-theory-3e25836596a2?source=rss----98111c9905da---4>
> Published: 2026-07-27 13:01:02+00:00

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# Building Your First AI Agent with LangChain (Part 1: The Theory)

Most AI tutorials teach you how to build basic chatbots. This guide covers how to build an **AI Agent** — a system that reasons, chooses tools, and takes action to complete multi-step tasks.

While a standard LLM generates text, an AI Agent adds an **action layer** around the model to execute tasks dynamically.

## 1. Traditional LLMs vs. Autonomous Agents

The difference comes down to **control** and **execution**:

Instead of relying on a human to manage each step of a workflow, an autonomous agent evaluates its current state and determines what to do next until its goal is met.

## 2. The Core Building Blocks of a Single Agent

A single-agent architecture relies on three core components: