I built a mini agent-tool framework to actually understand how LangGraph/CrewAI register tools

I'm going through a 16-week Agentic AI syllabus right now, and Week 1 is "Python for Agentic Systems" — OOP, typing, decorators. Instead of just reading about it, I built a small CLI toolkit that mimics how real agent frameworks register and run tools. This post is about one piece of it: how a global tool registry works using __init_subclass__, and why agent frameworks need this pattern at all. Repo's at the bottom. Code below is real, from the actual project — not pseudocode. The pr...