---
title: "Initiate Attended Transfer"
method: POST
path: "/vapi/initiate-attended-transfer"
tags: ["Vapi"]
---

# Initiate Attended Transfer

`POST /vapi/initiate-attended-transfer`

Park the inbound caller in a Twilio conference room with hold music, then
kick off the screener-ask outbound call. Replaces the built-in Vapi
transferCall used in Phase 0; eliminates the dial-tone gap because the
caller's leg is moved into the conference directly via the live Twilio
CallSid (no second outbound call to a parking number).

The screener-accept bridge step joins the same ``conference_name`` we pin
here, so accept flow auto-bridges. Decline reconnect (Phase 3) reads the
same row and reroutes the caller's leg.

Vapi custom tool. Expects arguments:
  - caller_name: str (required)
  - call_reason: str (required for unknown callers; optional for known contacts)
  - special_caller: bool (optional, default False)

Known-contact status is determined server-side via a strict E.164
phone-number lookup (see ScreeningService.lookup_known_contact); it is NOT a
tool argument. Any ``is_known_contact`` arg the agent sends is ignored.

## Request body

- VapiCustomToolRequest — Wrapper for Vapi custom tool requests.
  - `message` VapiMessage, required
    - `type` string, required
    - `toolCallList` VapiToolCall[], required
      - `id` string, required
      - `type` string
      - `function` VapiToolCallFunction, required
        - `name` string, required
        - `arguments` object, required
    - `call` VapiCallObject
      - `id` string, required

## Response `200`

Successful Response

- VapiCustomToolResponse — Standard Vapi custom tool response format.
  - `results` VapiToolResult[], required
    - `toolCallId` string, required
    - `result` string, required

## Other responses

- `422` — Validation Error

---

[API](https://skmtc.dev/openintake/apis/fastapi.md) · [All operations](https://skmtc.dev/openintake/apis/fastapi/llms.txt) · [OpenAPI document](https://skmtc-service-production.skmtc.workers.dev/v1/apis/openintake/fastapi/revisions/b642b91e0a5c/schema)