The IRT angle is interesting — most adaptive learning tools just do basic spaced repetition, but using Item Response Theory to estimate ability level in real-time is a much more honest approach to "personalized." The JSXGraph integration for gradable math graphs is a nice touch too, that's a hard problem. Quick question: how do you handle subjects where the "right answer" is more ambiguous? Does the LLM grading struggle with open-ended questions outside of math?