I have seen the value of recording past sessions but I am more skeptical of the value in recording facts, which may soon become stale, about a constantly changing code base. Got benchmarks?
In short, this is for my agents to have a shared skill library, a shared fact library and durable information such as which projects run where.
The rest should be in your repo.
Same principle. It's a good idea to have a schedule to clean them up periodically - an idea you can also put into a note.