That's a good third layer: working memory inside the current session.

Keep the Why deliberately wouldn't pin the original prompt verbatim - that would turn project memory into a session log.

But if part of the request becomes durable project intent, a constraint, or a decision, that distilled part should survive in context/.

If compaction loses the current task goal before that point, I'd treat that as a session/runtime problem rather than project memory.

The live graph is a good illustration of what happens after something crosses that durability threshold: it becomes connected repository knowledge rather than another isolated session note.

https://keepthewhy.com/dashboard/live/#graph

Grunz's example is a really good illustration of the boundary.