What
Claude Code keeps a short-lived cache of your conversation (the prompt cache) so follow-up messages cost less. Once it expires, picking the conversation back up costs more of your usage limit. Claude Code already warned about this when you resumed an old session. It can now also show the warning while a session has sat idle past the point where the cache is expected to have expired.
- The idle warning is off unless it is switched on remotely.
- It does not appear in embedded or thin-client sessions, or where the warning is disabled.
- The highlighted choice is to resume, or to start a new conversation when another remote setting chooses that.
Why
If you step away and come back, you may be told that carrying on will use more of your five-hour limit, and offered a fresh conversation instead.