Iโm working on a voice-powered booking system that uses Retell AI to talk to callers and n8n as the backend. Retell collects all the booking details, confirms the exact UK date and time with the caller, and then sends one clean function call into n8n, for example: Book a table for four under Michael on 25/11/2025 at 2 PM. n8nโs Calendar Agent is then supposed to interpret this text and create, update, or cancel the event in Google Calendar. Whatโs going wrong Even though Retell now always sends explicit UK-format dates (dd/mm/yyyy) after confirming with the caller, the Calendar Agent inside n8n sometimes reinterprets that date โ usually by shifting the year backwards (e.g., 2025 โ 2024) or otherwise assuming a different date before creating the Google Calendar event. There are no node errors; the workflow technically โworksโ, but the booked date in Google Calendar is sometimes wrong unless the caller corrects it manually during the conversation. A typical example Retell sends: Book a table for four under Paul on 26/11/2025 at 11 AM. But the Calendar Agent replies with: โDo you mean Wednesday 27/11/2024?โ Which is obviously not what was said. This behaviour suggests the LLM inside the Calendar Agent is unnecessarily re-interpreting an already explicit date. What I've already tried I rewrote the Retell system message completely (the new 26 November version): Anchors todayโs date Forces future-only dates Requires explicit dd/mm/yyyy internal conversion Confirms the exact UK date verbally with the caller before sending anything to n8n Ensures Retell never sends vague phrases like โnext Tuesdayโ in the backend call I also updated the n8n Calendar Agent system message: If chatInput already contains a numeric UK date, it should trust that date 100% It should not convert โ26/11/2025โ into anything else It should only reject dates that are actually in the past Removed all automatic reinterpretation of relative dates when an explicit one is provided Removed availability checks unless the caller explicitly asks for it