I'm just trying a very basic setup with two assistants that I want to be able to transfer to each other (no telephony at the moment). When I add the assistants as destinations with the appropriate names, I get the error in the title. I've tried using the assitant ID instead of the name. My setup is like this Tools:

transfer_call_tool

with Destinations of

Agent1

and

Agent2

. Agent1: has tool

transfer_call_tool

Agent2: has tool

transfer_call_tool

It looks like the

transferCall

tool does not support direct assistant-to-assistant transfers by name or ID unless you are using the Squads feature, which is designed for multi-assistant workflows. Could you clarify if you are using the [Squads](https://docs.vapi.ai/squads) feature to manage your assistants, or are you trying to transfer between standalone assistants without a squad configuration? Sources: - [Squads documentation](https://docs.vapi.ai/squads) - [Squads example](https://docs.vapi.ai/squads-example)

Message marked as helpful by @Chan! 🎉

I was trying to transfer between standalone assistants.

The assistant should just have the name. Here is example code for reference: { "id": "XXXXXXXXXXXXXXXX", "createdAt": "2025-04-19T23:06:31.113Z", "updatedAt": "2025-05-21T03:08:25.247Z", "type": "transferCall", "function": { "name": "transfer_call_tool", "description": "transfer test", "parameters": { "type": "object", "properties": {}, "required": \[\] } }, "orgId": "XXXXXXXXXXXXXXXX", "destinations": \[ { "type": "assistant", "message": "Please hold on while I transfer you to Luna.", "transferMode": "rolling-history", "assistantName": "Luna" } \] }