I created transfer_call_tool and attached it to Assistant tools and it`s called correctly during the call when I check the call log but no redirection occurs to the human number destination as attached in screenshots call ID : 93a6a83a-1995-4934-a9d7-f014fd384f27 https://cdn.discordapp.com/attachments/1392158033119023125/1392158033588650145/image.png?ex=686e83b4&is=686d3234&hm=0effaddf4d45493662c230cda8e2bff31197f3413bc2e22ec1dfc935054651e0& https://cdn.discordapp.com/attachments/1392158033119023125/1392158033882124480/image.png?ex=686e83b4&is=686d3234&hm=eb21ae8e489996fb8f701ce1220c50e2fdca02e37bd46a00feb6cace7e91336a& https://cdn.discordapp.com/attachments/1392158033119023125/1392158034205212733/image.png?ex=686e83b4&is=686d3234&hm=7957032fdf5425b65e20de53efc5059f41ae81918247dcd20f435f14294ae988&

Hey, I'll check in with our team and get back to you shortly. Lopping in @Shubham Bajaj

Hey @Ramy, you have to check with your telephony provider the call has been successfully transferred from our side.

{
  "callId": "93a6a83a-1995-4934-a9d7-f014fd384f27",
  "endedReason": "assistant-forwarded-call",
  "callType": "inboundPhoneCall",
  "phoneCallTransport": "sip",
  "destinationDetails": {
    "type": "number",
    "number": "+201120000819",
    "message": "I am forwarding your call to Operations team. Please stay on the line",
    "description": "Transfer to this destination when caller requests to talk to a human related to an operations topic",
    "transferPlan": {
      "mode": "blind-transfer",
      "sipVerb": "refer"
    },
    "numberE164CheckEnabled": true
  },
  "phoneCallProviderId": "1b62efae-1dca-4da8-919c-1a12f44ce581",
  "phoneCallControlEnabled": false,
  "phoneCallProviderBypass": false,
  "pcapFileUrl": "https://storage.vapi.ai/93a6a83a-1995-4934-a9d7-f014fd384f27-1751985006035-202c4677-faa5-459c-8d14-ac71a0200d98-sip.pcap",
  "userGuidance": "Check PCAP file for SIP REFER method. If REFER packet exists with 202 Accepted response, transfer was successful."
}

@Shubham Bajaj call forwarding is fixed to only one number although i added multiple destinations call ID : f01248b4-2ee0-4056-84fc-b8c572ab903b c0e01c49-3555-4e46-8125-2a60f0707396 dfec04e3-31de-41d1-9aad-382ace323639

The issue is the parameters of your transferCall tool are empty:

"parameters": {
  "type": "object",
  "properties": {},
  "required": []
}

1. Remove the custom function definition from your tool configuration 2. Improve your destination descriptions to be more specific 3. Let Vapi auto-generate the enum parameters Here's the updated configuration for your transfer call tool:

{
  "type": "transferCall",
  "destinations": [
    {
      "type": "number",
      "number": "+17375303589",
      "message": "I am forwarding your call to Sales team. Please stay on the line",
      "description": "Transfer to Sales team when caller wants to buy or lease a vehicle, discuss pricing, trade-ins, or financing options",
      "numberE164CheckEnabled": true,
      "callerId": "+17375303589",
      "transferPlan": {
        "mode": "blind-transfer",
        "sipVerb": "refer"
      }
    },
    {
      "type": "number",
      "number": "+12109475868",
      "message": "I am forwarding your call to Service team. Please stay on the line",
      "description": "Transfer to Service team when caller needs vehicle maintenance, repairs, or service appointments",
      "numberE164CheckEnabled": true,
      "callerId": "+12109475868",
      "transferPlan": {
        "mode": "blind-transfer",
        "sipVerb": "refer"
      }
    },
    {
      "type": "number",
      "number": "+12105963041",
      "message": "I am forwarding your call to Rental team. Please stay on the line",
      "description": "Transfer to Rental team when caller inquires about vehicle rentals or leasing options",
      "numberE164CheckEnabled": true,
      "callerId": "+12105963041",
      "transferPlan": {
        "mode": "blind-transfer",
        "sipVerb": "refer"
      }
    }
  ]
  // Remove the "function" property entirely - let Vapi auto-generate it
}