Transfer Call Static Params

When creating a tool with type: "transfer_call" via the Create Tool endpoint, the static_params object configures how calls are transferred — including routing, transfer type, and warm transfer behavior.

Recommended Tool-Level Defaults

When creating a transfer_call tool, the following tool-level fields should be set alongside your static_params:

Field	Recommended Value	Notes
`speak_during_execution`	`false`	AI should not speak during the transfer. The dashboard sets this to `false`. If omitted, the database default is `true`.
`speak_after_execution`	`false`	AI should not speak after the transfer. The dashboard sets this to `false`. If omitted, the database default is `true`.
`async`	`false`	The dashboard sets this to `false`. Defaults to `false` if omitted.

If you omit speak_during_execution and speak_after_execution, they will default to true (the database default), which is not the intended behavior for transfer calls. Always set them explicitly to false.

Basic Fields

These fields are at the top level of static_params:

Field	Type	Required	Description
`routing_rules`	string	Conditional	Dynamic routing logic that tells the AI where to transfer based on conversation context. Must include phone numbers with country codes. Required if `default_transfer_number` is not set.
`default_transfer_number`	string	Conditional	A fixed phone number in E.164 format (e.g., `+15551234567`) to transfer all calls to. Required if `routing_rules` is not set.
`transfer_type`	`"cold"` \| `"warm"`	Yes	`"cold"`: the call is transferred immediately without a debrief. `"warm"`: the AI provides context to the receiving agent before connecting the caller.

You must provide either routing_rules or default_transfer_number (or both). When both are set, routing_rules takes precedence and default_transfer_number serves as a fallback.

Warm Transfer Behavior Settings (`transfer_settings`)

When transfer_type is "warm", include a transfer_settings object inside static_params to configure the handoff behavior. All fields within use snake_case.

Hold & Ring

Field	Type	Default	Description
`extension`	string	—	Extension number to dial after connecting. Only applicable when using a static number.
`on_hold_music`	`"ringtone"` \| `"silence"` \| `"music"`	`"ringtone"`	Audio played to the original caller while they wait during the transfer.
`ring_duration`	number	`30`	How long (in seconds) to ring the transfer destination before giving up. Min: 10, Max: 120.

Field	Type	Default	Description
`navigate_ivr`	boolean	`false`	Enable this if the transfer destination has an IVR (automated phone menu) that needs to be navigated.
`navigate_ivr_prompt`	string	—	Instructions for the AI on how to navigate the IVR. Only used when `navigate_ivr` is `true`. Example: `"Navigate to the sales department by pressing 2"`.

Human Detection

Field	Type	Default	Description
`human_detection`	boolean	`false`	When enabled, the AI will only proceed with the debrief if it detects a real human (not a voicemail or automated system).
`detection_timeout`	number	`30`	Maximum seconds the AI waits to determine if the transfer target is a human. Min: 0, Max: 300. Only used when `human_detection` is `true`.
`ai_auto_greet`	boolean	`true`	When enabled, the AI says “Hello” after connecting to encourage a response from the transfer target. Only used when `human_detection` is `true`.

Whisper Message

A private message spoken only to the transfer target (receiving agent) before connecting them to the original caller.

Field	Type	Default	Description
`whisper_message`	boolean	`true`	Whether to speak a whisper message to the transfer target.
`whisper_message_type`	`"prompt"` \| `"static"`	—	How the whisper message is generated. Only used when `whisper_message` is `true`.
`whisper_message_prompt`	string	`"Give the User a brief summary like name of the caller, purpose etc"`	AI prompt to generate the whisper message dynamically. Used when `whisper_message_type` is `"prompt"`.
`whisper_message_static`	string	—	A fixed whisper message. Used when `whisper_message_type` is `"static"`.

Human Agent Confirmation

Field	Type	Default	Description
`human_confirmation`	boolean	`true`	When enabled, the AI asks the receiving agent for confirmation before connecting the original caller. If the agent declines, the transfer is cancelled.

Check Availability Message

A message spoken to the original caller while the AI checks if the transfer target is available.

Field	Type	Default	Description
`check_availability_message`	boolean	`true`	Whether to speak a message while checking availability.
`check_availability_message_type`	`"prompt"` \| `"static"`	—	How the message is generated. Only used when `check_availability_message` is `true`.
`check_availability_message_prompt`	string	`"Say please hold on, I will check if they are available"`	AI prompt for generating the message. Used when type is `"prompt"`.
`check_availability_message_static`	string	—	A fixed message. Used when type is `"static"`.

Transfer Success Message

A message spoken to the original caller when they are about to be connected to the transfer target.

Field	Type	Default	Description
`transfer_success_message`	boolean	`true`	Whether to speak a message when connecting.
`transfer_success_message_type`	`"prompt"` \| `"static"`	—	How the message is generated. Only used when `transfer_success_message` is `true`.
`transfer_success_message_prompt`	string	`"Say like I am transferring you now"`	AI prompt for generating the message. Used when type is `"prompt"`.
`transfer_success_message_static`	string	—	A fixed message. Used when type is `"static"`.

Three-Way Message

A message spoken after the transfer is successful, audible to both the original caller and the transfer target.

Field	Type	Default	Description
`three_way_message`	boolean	`false`	Whether to speak a three-way message after connecting both parties.
`three_way_message_type`	`"prompt"` \| `"static"`	—	How the message is generated. Only used when `three_way_message` is `true`.
`three_way_message_prompt`	string	—	AI prompt for generating the message. Example: `"Say you both are now connected. I'll be disconnecting now."`
`three_way_message_static`	string	—	A fixed message. Used when type is `"static"`.

Fallback Message

A message spoken to the original caller when the transfer target hangs up or doesn’t answer.

Field	Type	Default	Description
`fallback_message`	boolean	`true`	Whether to speak a fallback message.
`fallback_message_type`	`"prompt"` \| `"static"`	—	How the message is generated. Only used when `fallback_message` is `true`.
`fallback_message_prompt`	string	`"Say they are not available, I will take a message if you like"`	AI prompt for generating the message. Used when type is `"prompt"`.
`fallback_message_static`	string	—	A fixed message. Used when type is `"static"`.

Session Limits

Field	Type	Default	Description
`disable_extended_prompt`	boolean	`false`	Prevents the AI from using extended prompting during the warm transfer process.
`max_session_duration_after_transfer`	number	`15`	Maximum duration (in minutes) for the call after the transfer completes. Min: 1, Max: 60.

Webhook Fields

These fields are at the top level of static_params and configure webhook-based dynamic routing as an alternative to static routing.

Field	Type	Default	Description
`transfer_number`	string	—	Phone number in E.164 format used for webhook mode transfers.
`pre_tool_webhook`	boolean	`false`	When enabled, a webhook is called before executing the transfer. The webhook can return dynamic variables including `transfer_number` to override the destination.
`pre_tool_webhook_use_pre_call_url`	boolean	`false`	When `true`, reuses the bot’s pre-call webhook URL instead of a custom URL.
`pre_tool_webhook_url`	string	—	Custom webhook URL (must be HTTPS). Used when `pre_tool_webhook` is `true` and `pre_tool_webhook_use_pre_call_url` is `false`.

Examples

Cold Transfer to a Static Number

Immediately transfer the call without any debrief.

{
  "type": "transfer_call",
  "name": "transfer_to_support",
  "description": "Transfer the call to the support team when the customer has a technical issue",
  "static_params": {
    "default_transfer_number": "+15551234567",
    "transfer_type": "cold"
  },
  "speak_during_execution": false,
  "speak_after_execution": false,
  "async": false
}

Cold Transfer with Dynamic Routing

Route calls to different numbers based on conversation context.

{
  "type": "transfer_call",
  "name": "transfer_to_department",
  "description": "Transfer the call to the appropriate department based on the customer's needs",
  "static_params": {
    "routing_rules": "If the customer wants support, transfer to +15551234567. If the customer wants sales, transfer to +15559876543. Otherwise, transfer to +15550001111.",
    "default_transfer_number": "+15550001111",
    "transfer_type": "cold"
  },
  "speak_during_execution": false,
  "speak_after_execution": false,
  "async": false
}

Warm Transfer with Debrief

Transfer the call with full warm transfer behavior — whisper message, human detection, and fallback.

{
  "type": "transfer_call",
  "name": "warm_transfer_to_sales",
  "description": "Transfer the call to the sales team with a debrief when the customer wants to make a purchase",
  "static_params": {
    "default_transfer_number": "+15551234567",
    "transfer_type": "warm",
    "transfer_settings": {
      "on_hold_music": "music",
      "ring_duration": 45,
      "human_detection": true,
      "detection_timeout": 30,
      "ai_auto_greet": true,
      "whisper_message": true,
      "whisper_message_type": "prompt",
      "whisper_message_prompt": "Give the agent a brief summary including the caller's name, what they're interested in purchasing, and any relevant details from the conversation.",
      "human_confirmation": true,
      "check_availability_message": true,
      "check_availability_message_type": "prompt",
      "check_availability_message_prompt": "Say please hold on, I will check if a sales representative is available.",
      "transfer_success_message": true,
      "transfer_success_message_type": "static",
      "transfer_success_message_static": "I'm connecting you with our sales team now.",
      "three_way_message": true,
      "three_way_message_type": "static",
      "three_way_message_static": "You are both now connected. I'll disconnect now. Thank you!",
      "fallback_message": true,
      "fallback_message_type": "prompt",
      "fallback_message_prompt": "Say that the sales team is not available right now and offer to take a message or schedule a callback.",
      "max_session_duration_after_transfer": 30
    }
  },
  "speak_during_execution": false,
  "speak_after_execution": false,
  "async": false
}

Transfer to a destination that has an automated phone menu.

{
  "type": "transfer_call",
  "name": "transfer_to_partner",
  "description": "Transfer the call to a partner company's support line",
  "static_params": {
    "default_transfer_number": "+15559876543",
    "transfer_type": "warm",
    "transfer_settings": {
      "navigate_ivr": true,
      "navigate_ivr_prompt": "Navigate to the sales department by pressing 2, then press 1 for English.",
      "human_detection": true,
      "detection_timeout": 60,
      "whisper_message": true,
      "whisper_message_type": "static",
      "whisper_message_static": "Incoming transfer from OpenMic AI. Customer needs help with their account."
    }
  },
  "speak_during_execution": false,
  "speak_after_execution": false,
  "async": false
}

Webhook-Based Dynamic Routing

Use a webhook to determine the transfer destination at runtime.

{
  "type": "transfer_call",
  "name": "dynamic_transfer",
  "description": "Transfer the call using dynamic routing based on agent availability",
  "static_params": {
    "transfer_number": "+15550001111",
    "pre_tool_webhook": true,
    "pre_tool_webhook_url": "https://your-domain.com/webhook/route-call"
  },
  "speak_during_execution": false,
  "speak_after_execution": false,
  "async": false
}

When pre_tool_webhook is enabled, your webhook receives call details and can return a transfer_number in the dynamic_variables response object to override the destination. If the webhook fails or times out (3 seconds), the transfer_number configured in static_params is used as a fallback. See the Pre-Tool Webhook documentation for the request/response format.

For the UI-based setup guide, see the Transfer Call Custom Function documentation.

V2

Legacy

Transfer Call Static Params

Recommended Tool-Level Defaults

Basic Fields

Warm Transfer Behavior Settings (`transfer_settings`)

Hold & Ring

IVR Navigation

Human Detection

Whisper Message

Human Agent Confirmation

Check Availability Message

Transfer Success Message

Three-Way Message

Fallback Message

Session Limits

Webhook Fields

Examples

Cold Transfer to a Static Number

Cold Transfer with Dynamic Routing

Warm Transfer with Debrief

Warm Transfer with IVR Navigation

Webhook-Based Dynamic Routing

​Recommended Tool-Level Defaults

​Basic Fields

​Warm Transfer Behavior Settings (transfer_settings)

​Hold & Ring

​IVR Navigation

​Human Detection

​Whisper Message

​Human Agent Confirmation

​Check Availability Message

​Transfer Success Message

​Three-Way Message

​Fallback Message

​Session Limits

​Webhook Fields

​Examples

​Cold Transfer to a Static Number

​Cold Transfer with Dynamic Routing

​Warm Transfer with Debrief

​Warm Transfer with IVR Navigation

​Webhook-Based Dynamic Routing

Recommended Tool-Level Defaults

Basic Fields

Warm Transfer Behavior Settings (`transfer_settings`)

Hold & Ring

IVR Navigation

Human Detection

Whisper Message

Human Agent Confirmation

Check Availability Message

Transfer Success Message

Three-Way Message

Fallback Message

Session Limits

Webhook Fields

Examples

Cold Transfer to a Static Number

Cold Transfer with Dynamic Routing

Warm Transfer with Debrief

Warm Transfer with IVR Navigation

Webhook-Based Dynamic Routing