What you’ll build
You will set up an AI voice agent that answers inbound calls on your phone number, asks the caller a few qualifying questions, then books a meeting in Google Calendar or transfers the call to a person on your team. When a call ends, its transcript and a playable recording land in the client’s chat on the Chats screen, so your team can follow up from one place.
If your phone line details and agent instructions are ready, the setup takes about 10 minutes.
Before you start
- An agent with instructions. The voice agent is built from your agent’s instructions and knowledge base at the moment you connect the channel.
- A phone line you already have. Either a SIP Trunk from your telephony provider or a number you own in your Twilio Account.
- Google Calendar, if the agent should book meetings. Calendar access is granted per agent.
- A message balance. Calls are billed by duration, prorated by the second: 3 AI messages per minute for standard voices, 5 for high-quality voices. See pricing.
Setup, step by step
- Write the call brief. In the agent’s instructions, describe the goal of the call: greet the caller, ask the qualifying questions, then offer a meeting or a transfer. On the phone, short and specific beats long and vague.
- Connect Google Calendar. Open Integrations, select the agent, find Google Calendar under Productivity & Scheduling and click Connect. Pick the Google account, tick the calendars and click Save calendar selection. Do this before you create the Calls channel.
- Go to Channels, select your agent and open Calls.
- Under Provider, choose SIP Trunk or Twilio Account.
- Under Voice (Optional), use Play preview to pick a voice. The voice also sets the agent’s primary language.
- Fill in the provider fields. SIP Trunk: Phone Number in international format, Address, Transport (TCP by default, or TLS), plus SIP Trunk Username and SIP Trunk Password for digest authentication. Twilio: Phone Number, Twilio Account SID and Twilio Auth Token. Click Connect phone number.
- Turn on Transfer to human operator. Set the Operator number, an optional Phone line extension and a Transfer Condition, for example, when the caller explicitly asks for a manager.
- Click Make a test call to talk to the agent in your browser and check the voice, first message and behavior.
- Turn on Connect agent to this channel. New Calls channels start switched off.
Options that matter
- First Message: the agent’s opening line. By default it is your agent’s welcome message.
- Speech Speed: 0.7 is slower, 1.2 is faster; the default is 1.2.
- Max Call Duration (minutes): a hard cap on call length, 10 minutes by default.
- LLM and TTS Model: the reply model and the text-to-speech model, picked automatically per language.
- Additional languages: languages the agent can switch to mid-call, plus Automatic language switching to detect the caller’s language. Adding languages moves the agent to the v3 Conversational voice, billed at 5 AI messages per minute.
- End conversation: how and when the agent wraps up and ends the call.
Common problems and fixes
- Calls are not answered. Check that Connect agent to this channel is on. Connecting the provider alone does not activate calls.
- The error ‘A channel with this phone number is already connected’. A number can be connected only once, and this one is already used on another Calls channel.
- The SIP connection fails. Enter only the host or IP in Address, without a sip: prefix. If your trunk uses IP allowlisting, leave the username and password empty.
- Edited instructions are not used. When the Sync prompt appears, click Sync Agent to push them to the voice agent.
- The agent cannot book. Changing which integrations feed the agent requires recreating the Calls channel. If you connected Google Calendar after creating it, recreate the channel.