Run an agent's calls on Vapi
Switched off until an operator turns it on
Switch an agent's calls from Grok to the Vapi engine, set up its Vapi assistant and test it.
Where to find it
Voice › Agent voice
Open this screenSteps
- Open Voice › Agent voice and pick the agent in AI agent at the top right.
- In Call engine, choose Vapi. It can be chosen only after the platform operator has added the Vapi API key.
- Press Choose a voice and pick a voice card; set Transcriber, Model, First message, Transfer number and Ending calls.
- Press Save and sync to Vapi. The pill on the card shows In sync with Vapi, Changed since the last sync or Sync failed.
- Press Web test call to talk to the agent in a new browser tab, or Phone call to call a number from one of the Vapi account's own numbers.
- Press Sync now if the pill says the agent changed since the last sync.
Settings on this screen
| Setting | What it does | Default |
|---|---|---|
| Call engine | Grok runs calls on Call's own call path; Vapi runs them on Vapi with this agent's prompt and knowledge. | Grok |
| Voice | The Vapi voice. Choosing one here also makes it the agent's call voice. | — |
| Transcriber | Provider, model and language of Vapi's transcriber. | — |
| Model | Provider and model that answer on Vapi. | — |
| First message | What the agent says first on a Vapi call. Up to 500 characters. | Empty |
| Transfer number | Optional: a number the agent can put the caller through to. | Empty |
| Ending calls | The agent may end the call when the conversation is over. | On |
Troubleshooting
"Vapi is not connected. The platform operator adds the Vapi API key on the System tab."
Ask the platform operator to connect Vapi. Until then the agent stays on Grok.
Phone call says to add or import a number in Vapi.
Call does not buy or import Vapi numbers. Add one in the Vapi dashboard, or use Web test call meanwhile.
"Vapi did not answer in time. Try again in a moment."
Press Sync now or the call button again after a moment.
Tips
- Web test call and Phone call are logged in the call log.
- On a Vapi call, the agent follows the same phone rules as Call’s own calls: short spoken answers in the line’s language, facts only from your knowledge base (searched quietly during the call), and a plain “I can’t confirm that” when it has no answer.
- Each Vapi call’s timing (AI, voice and transcription) is added to the call’s notes in call history.
Good to know
- Off until a platform operator adds the Vapi API key.
- Only workspace managers can change the engine or place test calls.
Related how-tos
- Agent voice Set up one AI agent's voice conversations: its prompt, call voice, engine, transcriber, messages, limits and quick replies.
- Choose a Vapi voice Switched off until an operator turns it on Pick a voice from Vapi's voice library as the workspace call voice.
- Conversation engine Choose the AI model that holds an agent's call conversations.