Building an AI agent with tool use in Python (from scratch, no framework)
Ayi NEDJIMI
LangChain, AutoGen, CrewAI — the framework ecosystem for AI agents is crowded. Most tutorials jump straight into one of these, which is fine for getting something running fast. It is not fine for understanding what is actually happening. This tutorial builds a minimal ReAct-style agent from scratch: no framework dependencies, no magic, ~150 lines of Python. Once you have built it, you will understand exactly what any framework is abstracting — and when that abstraction is worth its cost. What is