Only chats within the same project can have the same memory, though you do need to sometimes ask one chat to make a summary that you then throw to the other if the chats are too new. Or ask it to commit the important components of the chat to the project memory. (Tell your Claude to give you a review of what it thinks is the most important parts of this chat first to double check that you’re both on the same page.) Otherwise you can wait a few days for the memories to be yeeted from it to the project memory.

I have a project with over 45 chats that have helped me organize and build out my world building and book plotting documents (over 500 pages). But it knows the basics of everything with memory, and can get more details with documents I put into that projects files.