This looks more like a logic and validation gap between your AI agent and Google Calendar, not just something a system prompt can fix.
From experience, issues like wrong dates, past bookings, and double bookings usually come from missing date normalization and timezone enforcement, plus no final validation before creating the event.
I’ve helped fix this by tightening how the AI interprets dates and adding a small validation layer before anything is pushed to the calendar. If you can share your logs or setup, I can quickly spot where it’s breaking and help you clean it up properly
@Ackerman