> I think the best option would be tell a user who is about to resurrect a conversation that has been evicted from cache that the session is not cached anymore and the user will have to face a full cost of replaying a session

This feature has been live for a few days/weeks now, and with that knowledge I try remember to a least get a process report written when I'm for example close to the quota limit and the context is reasonably large. Or continue with a /compact, but that tends to lead to be having to repeat some things that didn't get included in the summary. Context management is just hard.