What is an AI System Prompt?
A system prompt is the first and most important instruction you give to your Voice AI agent.
It defines:
Who the AI should behave like
What the AI’s goal is during the conversation
How the AI should speak and interact
Rules the AI must follow
When and how the conversation should end
What Should a Good Prompt Include?
A strong system prompt typically covers five essential components. Write them clearly and simply, one after the other.
1. Define the Role and Identity
Describe exactly who the AI is pretending to be. Include the agent's name, company name, and the nature of their role.
Example: "You are Priya, a polite and helpful customer service assistant calling from NeoPay."
2. Set the Mission and Goals
Clearly state what the AI needs to accomplish during the conversation. This keeps the AI focused and goal-driven.
Example: "Your goal is to confirm the customer's interest in NeoPay’s credit card offering and collect their preferred callback time."
3. Explain the Communication Style
Specify how the AI should sound — language, tone, energy level, sentence length, and friendliness.
Example: "Speak in simple, polite Hindi-English mix. Keep sentences short and easy to understand. Be patient and professional."
4. Define Rules and Boundaries
Mention the do's and don'ts during the conversation. Prepare the AI to handle common edge cases.
Example: "If the customer asks for pricing, politely inform them that a sales executive will call them back."
5. Set the Closing Conditions
Tell the AI when and how to end the call based on the situation.
Example: "If the customer confirms they are interested, thank them warmly and inform them someone will reach out soon."
What Are Variables?
Variables are placeholders that get automatically replaced with actual data during the call. They help personalize the experience and make conversations more natural and contextual.
Examples of variables:
{{customer_name}}→ "Hi John"{{appointment_date}}→ "Your appointment is on April 20th"{{product_name}}→ "We hope you're enjoying your new Air Conditioner"
Variables are automatically populated from your campaign list. Make sure the variable names match the columns in your uploaded data.
Suggested Prompt Template
Use the following structure to help you get started:
You are an AI voice agent participating in a calling campaign targeting [describe the customer or user persona briefly]. Your goal is to [clearly describe the objective of the call]. You should [list any important questions to ask, information to confirm, or actions to take].The call is considered successful if [describe the outcome that defines success].If the goal cannot be achieved, [describe what the agent should do].
Detailed Examples
Example 1: Lead Qualification
You are an AI voice agent calling {{lead_name}}, who recently signed up for a product demo via our website for {{company_name}}. Your goal is to qualify the lead by understanding their current challenges, team size, and their level of interest in using {{product_name}}. Start by asking what problem they are trying to solve, whether they are currently using another solution, and whether they are part of the decision-making team at {{company_name}}. The call is considered successful if the lead expresses interest and matches the criteria of a potential buyer (e.g., relevant challenge, suitable team size, and decision-making role). If the lead is not interested or does not meet the qualification criteria, thank them for their time and politely end the call.
Example 2: Delivery Confirmation
You are an AI voice agent calling {{customer_name}}, who recently placed an order for home delivery with {{company_name}}. Your goal is to confirm the delivery details with the customer before dispatch. Start by confirming the delivery address ({{delivery_address}}), delivery date ({{delivery_date}}), and time slot ({{delivery_time_slot}}), and ask whether someone will be available to receive the package. The call is considered successful if the customer confirms all delivery details. If the customer requests a change to the address, date, or time, record the updated information, confirm it with them, and then politely end the call.
Example 3: Post-Service Feedback
You are an AI voice agent calling {{customer_name}}, who recently interacted with our customer support team at {{company_name}} regarding the issue: "{{support_ticket_subject}}". Your goal is to collect feedback about their support experience. Begin by confirming whether their issue has been resolved, ask how satisfied they were with the support they received, and invite them to share any suggestions for improvement. The call is considered successful if feedback is collected for all three questions. If {{customer_name}} is unwilling to share feedback, thank them for their time and politely end the call.
Best Practices
- Be specific and action-oriented — the more precise the goal, the better.
- Keep the language natural — the AI understands plain English very well.
- Focus on one main goal per prompt — if you have multiple goals, consider multiple campaigns.
- Read your prompt aloud — does it sound like instructions you’d give a real person?
What to Avoid
- Vague instructions (e.g., “Talk to the customer”)
- Mixing tone/personality into the goal prompt - These are handled separately under Agent Traits.
- Overloading the prompt with too many goals - One goal per campaign makes calls more effective.
- Using technical/internal jargon - Write as if explaining to someone outside your company.
If you're unsure whether your conversation goal prompt is clear enough, try this test:“If I gave this prompt to a new team member with no background on the campaign, would they understand what they need to do?”
If the answer is yes, then your prompt is probably in a good shape!