How to write the prompt and call script for an AI voice agent
A practical guide to writing a voice agent prompt: identity, goals, data to collect, when to transfer, phone tone and how to test it.
The parts of a good prompt
- 1IdentityThe business name, who is answering and how it greets. A short greeting with the business name tells callers where they reached.
- 2GoalsWhat it resolves on the call: booking, rescheduling, quoting, reserving, informing or taking a message.
- 3Data to collectOnly what's needed. In Wenzy the agent asks for name, phone and the general reason, with no medical, legal or financial advice.
- 4When to transferComplaints, emergencies, negotiations or sensitive topics: to a phone or a teammate, with a briefing first.
- 5ClosingConfirm what was agreed and offer a WhatsApp summary, with the caller's permission.
Write for the ear, not the screen
- Short replies: on the phone people can't reread, so keep one idea per turn.
- No long lists: offer two or three time slots and ask which one works.
- Numbers said clearly: dates, times and prices the way people say them out loud.
- Confirm before acting: repeat the date and service before booking or reserving.
What doesn't belong in the prompt
Prices, hours, services and policies live better in the knowledge base than in the prompt, so a rate or schedule change doesn't mean rewriting instructions. In Wenzy the voice agent uses the same knowledge base as the chat.
Voice, tone and pronunciation
- Pick a voice per language and contact country from 25+ voices with accents from Latin America, Spain, Brazil, the US and the UK.
- Set the tone: warm when selling and calm with complaints.
- Use the pronunciation dictionary for names, brands or industry terms.
- Configure the business's ambient sound and hold music.
Example instructions
| Situation | Instruction for the agent |
|---|---|
| The caller wants an appointment | Ask for the service, offer two free slots and confirm before booking. |
| They want to talk to someone | Ask for the reason in one sentence and transfer with that summary. |
| They ask something off-topic | Say you don't have that information and offer to take a message. |
| They ask not to be called again | Confirm you won't call again; the agent records it automatically. |
Frequently asked questions
Do I need separate prompts for chat and voice?
No. In Wenzy the voice agent shares the prompt, tools and knowledge base with the chat; you adapt tone and reply length for the phone.
How do I know the prompt works?
Have the agent call you and review the live transcript and the tools it used. Then review recordings, summaries and transcripts from real calls.
Can my business have its own voice?
Yes. The Wenzy team prepares it in 1–2 business days from a sample; meanwhile you choose from 25+ voices.
Does the agent switch languages on its own?
Yes. It speaks Spanish, English and Portuguese and switches when the caller speaks another language.
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