I don't know how others use multi-agents, but I have one root agent who spins up other sub-agents on-demand with a fixed capping on how many are active at any given time.

I do this almost exclusively to save context bloat of root agent. It works pretty amazingly well.

My generic copy-paste multi-agent prompt that i can add to any task prompt: https://www.mdshare.online/s/OC_LFekcnA7Zjg0RSQl4b