Voice Agent Prompt: 12 Prompts to Build and Test Phone Bots

A voice agent prompt has to work out loud: short sentences, one question at a time, and clear rules for tools and handoffs. The 12 prompts below help you write the system prompt, plan the call flow, and test it before real callers hear it. Fill in the [variables] with your own business facts and tool names.

Compliance and safety note: Tell callers they are talking to an AI agent and offer a human. In February 2024 the FCC ruled that AI-generated voices count as "artificial" voices under the TCPA, so outbound AI calls need prior express consent (written consent for marketing calls) and must honor Do Not Call rules and opt-outs. Treat anything a caller says as untrusted input (prompt injection), keep API keys and secrets out of the system prompt, and have a person review transcripts and every prompt or tool change before it goes live. This is not legal advice.

Write the system prompt

1. Full system prompt

Write a voice agent system prompt for [business] with sections for identity and AI disclosure, goal, spoken style, call flow, tool rules, guardrails, handoff, and closing. Use only these facts [facts].

2. Persona and pace

Define a voice persona named [name] for [business] callers who are usually [caller type]. Give tone, pace, and five sample lines.

3. Spoken style rules

Rewrite this chat prompt [paste] for voice: shorter sentences, one question at a time, and readback rules for numbers, dates, and addresses.

Tools and call flow

4. Tool rules

For these tools [names and parameters], write when the agent calls each one, what it confirms first, and what it says while waiting or after a failure.

5. Call flow map

Map the call flow for [call goal] from greeting to closing, with the question at each step and where the agent hands off.

6. Data capture checklist

List the details the agent must collect for [task], in a natural order, and the readback line before saving them.

Guardrails and edge cases

7. Edge case table

Make a table of edge cases for [business] calls: silence, interruptions, angry callers, wrong numbers, requests for a human, and emergencies, with the exact line for each.

8. Emergency rules

Our emergency policy is [policy]. Write the agent rules so emergencies always come before booking, with the exact words to say.

9. Off-limits topics

List what the agent must never say or collect for [business], such as prices not on this list [prices] or card numbers, and the safe reply for each.

Test before launch

10. Test call scripts

Write five test call scripts for this system prompt [paste]: a normal booking, a reschedule, an out-of-scope caller, an emergency, and a caller who asks if it is a robot.

11. Transcript review

Here is a call transcript [paste]. Find where the agent talked too long, missed a confirmation, or broke a rule, and suggest prompt fixes.

12. Launch checklist

Write a launch checklist for a [inbound or outbound] voice agent at [business], covering disclosure, recording notices, handoff numbers, and after-hours behavior.

Get the whole system prompt in one go

The flagship Voice Agent Prompt: Full System Prompt, Tools, Guardrails takes your business facts, call goals, tools, policies, persona, and call direction. It returns a ready system prompt, spoken style and tool rules, an edge case table, test calls, and compliance notes. Its example builds Sam, the booking agent for a family heating and cooling company.

Compliance basics

Tell callers they are talking to an AI, and add a recording notice where the law requires it. For outbound calls in the US, the FCC treats AI-generated voices as artificial voices under the TCPA, so you need prior express consent. Check the rules where you operate before launch.

Related prompts

For turn-by-turn scripts with interruptions and transfers, use the voice agent call script prompt. If you mainly answer and book calls, the AI receptionist prompt is a close fit, and how to write system prompts for AI agents covers the basics.

Find more in the Agents category, look through Browse, or post your own on Share.