Write a coding agent from first principles

Learn how to write a coding agent in Python in this tutorial that teaches how to interact with an LLM through an API, how to manage the context, and how to do tool calling. Introduction This tutorial will show you how to create your own coding agent from first principles. By doing so, you'll understand how coding agents work under the hood. Prerequisites To be able to follow this tutorial, you'll need prior Python experience: this tutorial is not suitable for people who don't have programming experience a valid Claude API key: you can get a Claude API key in the Claude Console dashboard[^1] uv: to manage the project you'll be working on The concepts explained in this tutorial are independent from your LLM provider but the code snippets will make use of the Claude API and its Python SDK. This means that you can follow along with a different model provider as long as you adapt the code snippets to match the format expected by the API of your provider. What's a coding agent? A coding…