Amazing! This is something I wanted to look into too.
The Apple Foundation models SDKs are surprisingly cool. I recently started working on a personal productivity app that tries to keep track of all the projects I work on, and the ideas and initiatives within these. It does so by creating a graph of events, fed by Claude transcripts and the git and browser history, then letting FM summarize and describe all events; that in turn feeds a semantic search index in an SQLite database.
What I have now is an app that shows me where all my projects stand, what I last worked on, where I left forks behind (like deciding for one idea and doing something else "later"), and how to get back into something I wasn’t working on for a while. It also has a built-in MCP server, so I can ask Claude code about any past event or decision or roughly-similar keyword, and it’ll get sensible answers back!
Called the thing Pensieve :-)
However, one thing still missing is actually being able to ask it directly, or talk to it, so Yap looks like a great opportunity to learn!