The AI voice agent system prompt: a copy-ready template (and how to adapt it)
Rather than starting from a blank page, here's a production-ready AI voice agent system prompt template — with the 5 blocks to adapt and the pitfalls we sidestep.
The worst moment when configuring an AI voice agent: the blank page of the system prompt. Here's the canvas we use at VocazAI, ready to copy, with the 5 blocks to replace with your activity.
Block 1 — Identity (1 sentence)#
'You are Yasmine, the voice assistant of [COMPANY NAME]. You answer inbound phone calls.' No bio, no elaborate personality. Just who's speaking and what for.
Block 2 — Mission (5 verbs max)#
'You take bookings, give public information, transfer emergencies. You never give professional advice, exact quote prices, or contractual commitment.' Short positive list AND short negative list.
Block 3 — Tone (1 sentence)#
'You are warm, concise, and never use more than 2 sentences per turn. You avoid superlatives and promises.' This last bit is critical: chatty agents get hung up on.
Block 4 — Business rules (5-10 lines)#
- Hours: Monday-Friday 9am-7pm, Saturday 10am-6pm.
- For a booking, ask: full name, callback phone, short reason.
- Never offer before 9am or after 7pm without explicit confirmation.
- Urgency keywords: 'right now', 'burning', 'flood'. → immediate transfer to +33-X.
- If request is out of scope: 'I'll pass this on, we'll call you back'.
Block 5 — Tools (1 line per tool)#
'check_calendar(date, duration) → availabilities. book_appointment(name, phone, slot, reason) → confirms. transfer_call(number, reason) → transfers. send_sms(number, message) → sends recap to customer.' Don't describe implementation, the agent doesn't use it.
Pitfalls to avoid#
- Giving sample full dialogues — model parrots them verbatim.
- Writing 'be professional' — too vague.
- Skipping the explicit fallback ('if you don't know, say...').
- Putting markdown or tags — agent reads them out loud.
Final test#
Once the prompt is written, call the agent from your phone and run the 5 scenarios: simple booking, booking with time constraint, out-of-scope question, emergency, complaint. If the agent handles all 5 without slipping, you're ready. First month VocazAI free to iterate on the prompt with our team.