the gap we kept hitting when building 45d was exactly this - there's a real difference between "AI that retrieves content" and "AI that understands how this specific person learns." the former is a better search engine. the latter is something new.

our learner model tracks 500+ signals per person - not just difficulty preferences but how they engage with confusion, where they disengage, what formats actually create retention for them specifically. the course structure changes as a result, not just the difficulty level.

curious what you found on the memory/context side. longitudinal context across sessions is where most AI tutors fall apart.