9 short lessons, ~60 lines of Python. Each adds one concept — tool calling, memory, state, policy gates, self-scheduling — until you see the full agent stack.
The core loop is just a while loop. That's AgentExecutor. That's what the frameworks do.
Runs in the browser (Pyodide). No setup, no signup. Mock mode works instantly, or plug in a free Groq API key for live LLM responses.
Open source: https://github.com/ahumblenerd/tour-of-agents