Over the weekend, I wrote this small Python library to teach myself the core idea behind modern agentic systems. This kind of software sits at the core of Claude Code, Codex, etc. I wanted to see if I could build it from scratch, so this is mostly educational for me.

The result is a surprisingly simple piece of software. At its core are immutable DAGs, which keep the design simple and easy to reason about.

I also added a set of built-in tools that are inspired by Claude Code's built-in tools.

A bonus point: it can also capture Claude Code auth tokens, so you can use it with your Claude Code subscription. However, there is a chance that Anthropic will ban you if they detect this, so use it at your own risk.

P.S.: One additional point I also want to mention is that Claude Code (SDK) is closed-source, so I cannot modify it for my use case or fix its buggy UI on my own. This is one of the factors for why I'm creating this library.