Hi Team I’m using a custom tool 'check_calendar' in my assistant to check calendar availability via a Make webhook. The webhook executes correctly and returns a result, but the assistant still says “No result returned.” Important notes: The webhook responds with plain text (e.g., "03:00 PM is available.") During tool testing, the correct response is returned. However, during a real conversation with the assistant, after the tool is triggered, no result is returned to the agent, even though the webhook response from Make is sent successfully. Can you confirm whether Vapi now requires tool responses to be wrapped in a results[] array with a toolCallId and result field, in order for the assistant to process them correctly? Or has something changed recently that would cause plain text tool responses to no longer be recognized?

Yes, Vapi requires tool responses to be wrapped in a specific JSON format with a

results[]

array containing

toolCallId

and

result

fields. Your plain text response needs to be formatted like this:

json
{
    "results": [
        {
            "toolCallId": "X", // Use the actual toolCallId from the request
            "result": "03:00 PM is available."
        }
    ]
}

According to [Vapi's documentation](https://docs.vapi.ai/tools-calling), returning a response in the wrong format will be treated as an error. Sources: - [Vapi Tools Calling Documentation](https://docs.vapi.ai/tools-calling) - [Discord Discussion on Tool Response Format](https://discord.com/channels/1211482211119796234/1342188078437236916)

Hey! To help track down this issue, could you share: - The call ID - When exactly this happened (the timestamp) - What response you expected to get - What response you actually got instead This would really help us figure out what went wrong!

1. call id: call_eoWjpAou9RyCd4ocjNdikISq 2. Last time happened May 1, 2025 8:50 AM (GMT +4) 3. I expect to get "[time] is available", in example below "2:00 PM isa vailable" (screenshot is from make.com) 4. Vapi assistant does not receive any answer, during the call he says that something went wrong and he can not check the avaiable time, despite the fact that the script in make.com is being processed and the make sends a response. https://cdn.discordapp.com/attachments/1367370020845518958/1367575356927770704/image.png?ex=6815154d&is=6813c3cd&hm=81d5973a10f377f4b5bad93d88457831babe50b2cc7ad9961bb11ccee014a8ea&

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