Interactive Tutorial to how modern AI works – accessible to a middle schooler

I wrote an interactive tutorial for how modern AI works. Every chapter is explained with interactive playgrounds and every chapter has been proof read by my 11 year old son to confirm that it is accessible.

This was on hacker news a while back, but it now has 4 new chapters - taking the reader from next token prediction to a real AI agent with post-training, conversations, reasoning, and tool use.