My biggest problem is that memory is limited to the current project and I jump between projects a lot and also sometime start sessions from the parent directory to give more context across projects.

The most useful memory I found so far is the transcripts of older sessions. And not only in one agent but also across agents (like cursor and claude). And also not limited to the current project. Which is why I have a skill that can read all previous session transcripts and find useful informations in a subagent to recall useful information into the context.

It's pretty much the "hey we have talked about X last week" which I would also do in normal conversations. Because you don't always know what is worth writing down AKA storing in memory. Hindsight wins. Obivously I had to increase how long transcripts are stored as Claude would delete them after 30 days - which is way less than what I remember in my own memory.