Make AI agents, cannot create a Notion item with Date

[Felipe_Saucedo]

What is your goal?

Try to create a new item in my Notion including a date property.

I have done almost everything but for some reason when I try to create the item in Notion it is always failing with the same error.
This is the prompt I ma using for that tool:
5. Tool: Create Expense/Income (STRICT FORMATTING RULES)
Function: Creates a new record in the Notion database connected to this Make.com agent.

When to use: Use this tool when Lucas asks to record an income (e.g., “pago de clase”) or an expense.

MANDATORY JSON STRUCTURE: You must generate the arguments for this tool using this exact nested hierarchy. Do not use flattened keys like fields_wCE%7C_start.

Required Schema:

JSON
{
“fields”: {
“LMBF”: “Category (e.g., Clases, Equipamiento, Luz)”,
“~RgU”: Numeric_Amount,
“title”: “Short description of the transaction”,
“wCE%7C”: {
“start”: “ISO_8601_DATETIME”,
“includeTime”: false
},
“GMnF”: “https://us1.make.com/…”
},
“select”: “list”,
“data_source”: “19c049ad-de0d-80d7-b3a5-000b4e9199f0”
}
Critical Rules for the “start” field:

NO NULLS: The “start” field must never be null, “NaN”, or an empty string. This will crash the Notion module.

Date Extraction: If Lucas mentions a specific date (e.g., “18.03.2026”), convert it to: 2026-03-18T12:00:00.000Z.

Default Date: If NO date is mentioned in the message, you MUST use the current date (Today: 2026-03-19) in this format: 2026-03-19T12:00:00.000Z.

Numeric Amount: The field “~RgU” must be a Number (e.g., 4000), not a string (do not use quotes).

What is the problem & what have you tried?

Notion it no recieving the input and the Agent is not producing the right output.

Error messages or input/output bundles

Output
{“type” : “IMLError”,“message” : “Function ‘if’ finished with error! Function ‘properties’ finished with error! Invalid time value”}

[damato]

Hi @Felipe_Saucedo

@Felipe_Saucedo

{“type” : “IMLError”,“message” : “Function ‘if’ finished with error! Function ‘properties’ finished with error! Invalid time value”}

In which module does the error happen? How is this module set up?

[Felipe_Saucedo]

It is a tool, not a module. The tool is a Create Data source item.

[Felipe_Saucedo]

More context.

[damato]

@Felipe_Saucedo

Click the dropdown arrow. What was the input for the tool, more specifically, the “wCE%7C” property value passed to Notion?

The message is clear about the issue: Invalid time value. Now we must determine what’s wrong with the datetime.

[Felipe_Saucedo]

Yes the message is clear.
the agent is not passing on the date. I set the prompt to use the date from the input and if no date is mentioned to use today as date. However I am not managin to get the agent to sen the date to the notion Tools

[damato]

Your prompt is correct. The issue really seems to be because the Agent is flattening the JSON structure. I asked it why it does that and the answer was:

Because the integration tool I’m using doesn’t accept a nested JSON payload from me.

Make’s AI Agents were just released and I have been through a lot of trouble like that with other modules.

A simple fix is to create a scenario that receives the parameters and pass them to the notion module the way it expects. Instead of using the Notion module itself as a tool for the Agent, you use the scenario. That has saved me countless times.

@damato

[Felipe_Saucedo]

Thank I tought about that but did not want to crearte yet another scenario thank man. Happy i was not wrong, the strange thing is, I have another agent witha update item tool, that manages to sen the right fomated date field.

It seems to be a problem only when creating items.

[Stoyan_Vatov]

You can also try enforcing the JSON structure inside a knowledge file instead of the instructions of the agent. I’ve noticed it tends to keep to what’s inside the knowledge base stricter than what I’ve given as instructions.
And if that fails, then yeah, keep the deterministic item creation in a subscenario instead. Easier to debug and iterate in anyways.

[Felipe_Saucedo]

Thanks! I will try the knowedgle base first