Hey guys, It was working before and now is not working anymore, whenever I use a tool to check available slots on a calendar the response goes thru but the assistant keep saying that could not get any availability. Any one now whats going on ? Thank you! https://cdn.discordapp.com/attachments/1369849915173376000/1369849915357921311/Screenshot_2025-05-07_at_6.33.12_PM.png?ex=681d5ba6&is=681c0a26&hm=4de418ecbc14e5a0ea06aa809141f9ce2d9a81e664bf3ba08d01d27894c9dec0&

Check your webhook response format. Vapi requires a specific JSON structure with the exact

toolCallId

that matches what was sent in the request:

json
{
  "results": [
    {
      "toolCallId": "call_PddCTkgbV9UPsmf3dPrRmfMz",
      "result": "Available slots: 10:00 AM, 10:30 AM, 11:00 AM, 11:30 AM, 12:00 PM, 12:30 PM, 3:30 PM, 4:00 PM, 4:30 PM"
    }
  ]
}

Make sure line breaks in your result are properly escaped with

\\n

. Sources: - [Vapi Tools Calling Documentation](https://docs.vapi.ai/tools-calling) - [Discord Channel Tool Call ID Discussion](https://discord.com/channels/1211482211119796234/1325000684231196775)

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!

@Shubham Bajaj - Call ID: call_0EVEcI6mj57aQ85kMZeJ8tOX - Timestamp: 1746668375380 - Expected to get the time sots available like on my screen shot - The Agent said that was not possible to access the available slots.

Hey, what you have shared is not a Call ID, instead it's a tool Call ID. You can get the Call ID from the dashboard under the Observe section and then the Call Logs page. Let me know if you require any help finding out the Call ID.

@Shubham Bajaj Here is some Call IDs hopefully helps, Thank you! 381f26f0-1726-4131-b276-e3b646002a15 6e43f91e-922d-4842-8407-72083e1ea905 23c5bb2d-9844-4325-9124-a4e816b70f56 ef90bf8a-992c-4a9e-a1a2-c7d25860733e

The VAPI webhook handling expects: 1\. The

result

field must be a string type (not a direct JSON object) 2\. The string should be a single line without line breaks 3\. If you're returning JSON data, it needs to be properly stringified Your example showed multi-line text with line breaks, which would cause issues in VAPI's processing. When VAPI attempts to parse or process this multi-line result, it likely encounters errors that prevent it from properly handling the response. For your n8n workflow, update the "Respond to Webhook" node to: 1\. Format your data as a proper JSON object 2\. Use JSON.stringify() to convert it to a single-line string 3\. Ensure no manual line breaks are inserted 4\. Return this string in the

result

field This is a common issue with webhook integrations that's often overlooked but can completely break the data flow.

@Shubham Bajaj Thank you so much! I really appreciate your help.