Plan eligibility: All users can test call behavior in the AI Agent panel, but only Workspaces on the Advanced plan and above can publish and use call handling in live conversations.
The handle calls action lets your AI Agent automatically answer and handle inbound calls for you. When this action is enabled, the AI Agent speaks naturally with callers — greeting them, responding to questions, transferring calls when needed, and ending the call politely once the conversation is complete.
Language support:
- Voice AI Agent supports 32 languages via the ElevenLabs Flash v2.5 model.
- By default, the agent speaks English.
- During a call, the AI Agent can automatically detect and switch to the caller’s spoken language, provided the language is one of the supported 32.
Voice behavior:
- All voices are technically multilingual.
- Languages listed under a voice indicate optimization for accent, pronunciation, and naturalness, not hard language limits.
- Using a voice outside its optimized languages is supported, but may result in pronunciation differences, accent variation, and reduced naturalness.
Supported Channels
Voice AI Agent can answer and handle inbound calls on any Channel that supports calling in respond.io.
Currently, Voice AI Agent is available for the following Channels:
WhatsApp
Facebook Messenger
Telnyx VoIP
When to use
Use this action when you want your AI Agent to handle inbound calls — such as greeting customers, answering basic questions, collecting key details, or transferring the call to the right human agent when escalation is needed.
This is especially useful for after-hours or overflow coverage when human agents aren’t available.
Advanced settings
First greeting message: Write a custom greeting, or include consent if you record calls. If you leave this field empty, the system will use a default greeting message.
Choose AI Agent voice: Pick from a curated list of natural-sounding voices (e.g., English, Spanish, Arabic).
Allow AI Agents to record calls: Record calls based on your Workspace’s call recording setting.
Click Test AI Agent and use the phone icon to simulate a call before publishing.
Available accents
Handle calls supports a predefined set of voices, each with a specific gender and accent.
You can choose from the following available options:
Afifah: Female, Malaysian accent
Alex: Male, British accent
Andrew: Male, American accent
Danielle: Female, Canadian accent
Farah: Female, Jordanian accent
Haytham: Male, Egyptian accent
Mark: Male, American accent
Mauricio: Male, Latin American accent
Nathan: Male, British accent
How to choose an AI Agent voice
You can select the voice your AI Agent will use to speak with your Contacts.
To choose an AI Agent voice:
Go to your AI Agent’s Configuration page > Actions > Handle calls
Turn on the Handle calls toggle.
Click Advanced settings.
Open the Choose AI Agent voice dropdown.
Select your desired voice from the list.
After selecting a voice, you can also test AI Agent with calls to check how your AI Agent greets your Contacts, responds, and ends calls before publishing.
Transferring calls to a human agent
Your AI Agent can transfer a live call to a human agent when escalation is needed. To enable this, your call instructions must define two things:
When to transfer — the condition or trigger (e.g., the caller requests billing support)
Who to transfer to — the target agent or team
How you configure these depends on whether the target agent has Contact restrictions.
Scenario A: Target agent has no Contact restrictions
You can define both when and who directly in the Handle calls instruction field.
Example:
Handle calls: "If the customer requests billing support, transfer the call to John Doe."
Scenario B: Target agent has Contact restrictions
Define who is using the Assign to agent or team action, and define when in the Handle calls instruction field. Both are required.
Example:
Assign to agent or team: "Assign the conversation to John Doe when a transfer is triggered."
Handle calls: "If the customer requests billing support, transfer the call."
If only "when" is defined
If your instructions specify when to transfer but don't name a target agent, the AI Agent will still initiate the transfer. The call will ring to all available agents in the platform.
What happens if the transfer is missed or declined
If a human agent misses or declines the transferred call, the call does not end. The system automatically routes the call back to the AI Agent.
After a failed transfer, the AI Agent resumes the call without retaining the context of the conversation prior to the transfer attempt.
Best practices
Keep instructions short and clear — your AI Agent’s responses should sound natural and conversational.
Include consent language in your greeting if you plan to record calls. For example:
- Hi, thanks for calling. I’d like to record this call to better assist you — is that okay?Test before publishing to ensure the chosen voice and greeting sound natural.
For brand consistency, match your AI Agent’s voice tone with how your business interacts via chat.
Keep call interactions simple — avoid asking multiple questions in a row or long scripted flows.
Follow the recommended instruction structure
For best results, write your call instructions using the same structure applied by the Optimize button. This ensures your AI Agent clearly understands the call’s purpose, stays within supported capabilities, and responds consistently during live voice conversations.
Use the template below as a reference and adapt the content to your use case.
# CALL CONTEXT
You are handling an inbound voice call.
This call is informational only and does not support bookings or confirmations.
# AGENT ROLE
You help answer general questions about cars, models, and features.
You do not handle scheduling, reservations, or confirmations.
# COMMUNICATION STYLE
- Speak in a friendly and helpful tone.
- Respond naturally and conversationally.
- Keep the conversation focused on information, not actions.
# WHAT YOU MUST DO
- Answer general questions about models, specifications, availability status, and features.
- Respond to preferences the contact naturally shares, such as budget, colour, or style.
- Explain the process of how a booking can be made, such as booking through the website, without performing any booking tasks yourself.
- Continue the conversation in a helpful and informative manner.
# WHAT YOU MUST NOT DO
- Do not ask for phone numbers for booking or confirmation.
- Do not ask for dates or times for viewings or appointments.
- Do not collect details for scheduling, reservations, or confirmations.
- Do not suggest available slots, next openings, or viewing times.
- Do not say or imply that a booking is confirmed or reserved.
- Do not promise that someone will contact the caller or follow up.
- Do not lead the contact into booking steps.
# HOW TO HANDLE COMMON REQUESTS
If the contact asks to book, confirm, or check viewing dates or times:
Say, “I’m not able to make or confirm bookings on this call, but I can help answer any questions about our cars.”Limitations
Call transfer is only supported from AI Agent to human agent. The following transfer types are not supported:
AI Agent to AI Agent
Human agent to AI Agent
Inbound calls only. Outbound calling is not supported, and the AI Agent can only answer incoming calls.
No human takeover during a call. Human agents cannot join, interrupt, or take over a call while the AI Agent is handling it.
AI Agent must be assigned before the call starts. If the AI Agent is assigned after an incoming call begins ringing, it will not pick up the call.
Actions apply only after the call ends. The AI Agent can update Contact fields, Lifecycles, or trigger other actions only after the call has ended. Actions cannot run during an active call.
Call duration is limited. Each call is capped at a maximum of 3 minutes.
Testing differs from live usage. All users can test call behavior in the Test AI Agent panel, but publishing and handling live calls requires an Advanced plan or above. Upgrade now.
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