Build Your First AI Agent from Scratch with Node.js

Ever wanted to build an AI that can actually DO things — not just chat, but take actions, use tools, and solve real problems autonomously? This step-by-step tutorial takes you from zero to a fully functional AI agent using Node.js and the OpenAI API. You'll build an agent that can search the web, perform calculations, and chain multiple tools together to answer complex questions — the exact architecture behind tools like AutoGPT and ChatGPT plugins. We cover the core concepts that separate a simple chatbot from a true AI agent: the ReAct reasoning loop, tool definitions and function calling, memory and context management, error handling and graceful recovery, and how to extend your agent with custom tools. By the end, you'll have a working agent you can extend for your own use cases — whether that's a coding assistant, research tool, or automation bot. If this helped you understand AI agents, smash that subscribe button and turn on notifications — we're building an entire AI engineering series on this channel. Drop a comment below: what's the first custom tool you'd add to your agent? Let's discuss in the comments. ───────────────────────────── 📚 CHAPTERS 00:00 Introduction 00:00 What Makes an Agent Different 00:45 The ReAct Pattern Explained 01:35 Project Setup 02:15 TypeScript Configuration 02:50 Environment Setup 03:20 Core Types Definition 04:10 Building the Calculator Tool 05:05 Building the Web Search Tool 06:05 The Tool Registry 06:40 Converting Tools to OpenAI Format 07:25 The Agent System Prompt 08:20 The Agent Class Structure 09:00 Building the Message Array 09:45 Parsing Agent Responses 10:35 Executing Tool Calls 11:15 The Main Run Loop 12:20 Main Entry Point 12:55 First Test Run 13:50 Adding a Code Execution Tool 14:40 Improved Error Handling 15:25 Adding Memory Persistence 16:10 Streaming Responses 17:00 Testing with Complex Queries 17:55 Adding Tool Call Logging 18:30 Handling Tool Failures Gracefully 19:10 The Complete Agent 19:55 Where to Go From Here 20:45 Final Architecture Overview ───────────────────────────── 🔗 LINKS 📺 Full Course Playlist: https://www.youtube.com/@SukridLearnHub 🌐 Website: https://www.sukrid.com/learnhub ───────────────────────────── ⚡ SUKRID LEARNHUB Free technology education — AI, TypeScript, React, Next.js, Node.js, Golang, and Engineering. New videos regularly. All content free, forever. #ai agent tutorial #build ai agent nodejs #openai function calling #langchain alternative #ai agent from scratch