Claude Code “Prompt Cache Has Likely Expired” (What It Means)
Summary: Claude Code’s “prompt cache has likely expired” notice means your session sat idle longer than the prompt cache lasts. As of Sep 2026, by default, that’s 1 hour on Pro or Max while you’re within your included usage, and 5 minutes if you’re using an API key, a cloud provider, or usage credits. Your conversation is still there, but your next message will likely re-process all of it once. That turn can be slower and cost you a LOT






