timestamp issue · AI Automation Society

timestamp issue

I’m 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.

n8n’s Calendar Agent is then supposed to interpret this text and create, update, or cancel the event in Google Calendar.

What’s 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 — usually by shifting the year backwards (e.g., 2025 → 2024) or otherwise assuming a different date before creating the Google Calendar event.

There are no node errors; the workflow technically “works”, 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:

“Do you mean Wednesday 27/11/2024?”

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 today’s 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 “next Tuesday” 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 “26/11/2025” 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

Verified Google Calendar node settings (“Defined automatically by model”)

Deleted all old events to avoid contamination from earlier tests

Re-tested several flows today — the first booking works great, but edge cases can still trigger year drift

Workflow snippet

(Replace with your real snippet)

{

"nodes": [

{ "name": "Calendar Agent", "type": "n8n-nodes-base.openAi", ... },

{ "name": "Create Event", "type": "n8n-nodes-base.googleCalendar", ... }

]

}

Output from the last node

{

"output": "Your table for four under Paul is booked for Wednesday 26/11/2025 at 11 AM."

}

This is correct — but sometimes n8n initially reinterprets the date before accepting corrections, and I’d like it to never reinterpret dates in the first place.

Environment

n8n version: 1.117.3

Database: SQLite (default)

Execution process: main

Hosting: n8n Cloud

Client OS: Chrome OS

What I’m hoping for

I’m mainly looking for guidance on the best way to stop the Calendar Agent from second-guessing explicit dates that Retell already confirmed with the caller. I’d love to know whether:

There’s a recommended way to enforce strict date parsing in n8n AI agents

Other users have seen similar behaviour with LLM-driven date handling

I should restructure the agent prompt further or use another pattern

Or if this might be expected behaviour that needs an additional guardrail

Any help or suggestions would be massively appreciated — thanks in advance!

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