> ## Documentation Index > Fetch the complete documentation index at: https://notes.kodekloud.com/llms.txt > Use this file to discover all available pages before exploring further. # What is ChatGPT > Introductory course explaining ChatGPT, LLM fundamentals, and practical agent design with hands-on labs to build and run local AI agents safely and understand pretraining and chat interfaces AI can feel overwhelming. This course is designed to make AI approachable and practical, starting from the fundamentals and moving toward building AI agents you can run locally and understand deeply. We start with the absolute basics of AI and progress to agent design. Along the way, we dissect a popular open-source AI agent so you can see how components fit together in a real project. This lesson is hands-on. You will complete labs that let you build and test agents without exposing API keys or incurring unexpected charges. Everything you need is provided so you can focus on learning. By the end of this module you'll be able to: * Explain what ChatGPT is and how chat interfaces interact with large language models. * Describe core concepts behind generative models and why "pre-training" matters. * Build simple agents that use models to perform tasks and chain reasoning steps. Let's begin with something familiar: [ChatGPT](https://chat.openai.com). A retro-style graphic with two labeled panels: "CHAT — The Interface" on the left with chat bubbles and "GPT — The AI Brain" on the right accompanied by a pixelated brain icon. Bright cyan and yellow text sits on a dark background. "Chat" is the user-facing interface where you type messages and read replies. "GPT" — short for Generative Pre-trained Transformer — is the underlying model that produces those replies by predicting the next words, given a prompt. | Term | What it means | Why it matters | | - | - | - | | Chat | A conversational UI (web or app) where users enter prompts and receive responses | Makes the model accessible to people without programming knowledge | | GPT | A family of large language models trained to generate text from prompts | Provides the reasoning and language ability that powers chat, agents, and tools | Don't worry about the full meaning of "Generative Pre-trained Transformer" yet. We'll break down those terms shortly. For now, think of GPT as the AI brain and chat as the interface you use to talk to it. Links and references * [ChatGPT (web)](https://chat.openai.com) * [OpenAI — GPT models overview](https://platform.openai.com/docs/models) * [Introduction to large language models (LLMs)](https://en.wikipedia.org/wiki/Large_language_model) This documentation is built and hosted on [Mintlify](https://mintlify.com), a developer documentation platform.