Why Your Prompt Matters
Your agent behaves exactly as you instruct it. Vague instructions produce vague behavior. The more specific and structured your prompt, the more consistently your agent performs — across every conversation, every edge case, every user.The 5-Part Structure
Every agent prompt should have these five sections. Follow them in order.1. Identity
Define who your agent is. Give it a name, a role, and a clear purpose. This sets the foundation for everything else. Write it like this:2. Style
Tell your agent how to communicate — tone, length, language level. Be specific. “Be friendly” means nothing. “Keep responses to 2 sentences and never use jargon” does. Things to specify:- Response length (e.g. 2–3 sentences max)
- Tone (e.g. warm, professional, direct)
- Whether to use the customer’s name
- How formal or casual the language should be
3. Rules
List what your agent must always do — and must never do. These are your guardrails.4. Task
Break the agent’s job into numbered steps. One action per step. This is the core flow the agent follows in every conversation.5. Objection Handling
Tell your agent what to do when things don’t go smoothly. Cover at least three situations: confusion, frustration, and out-of-scope requests.Using Variables
Variables let you personalize conversations automatically. They pull in real data — like a customer’s name or order number — without hardcoding it. Write variables in double curly braces:{{variable_name}}
Common examples:
Where to use them:
- Greeting:
"Hi {{customer_name}}, thanks for reaching out!" - Confirmation:
"I've updated your order {{order_number}}." - Escalation:
"Connecting you now, {{customer_name}}. One moment." - Closing:
"Thanks for calling {{company_name}}. Have a great day!"
Connecting Tools
If your agent has access to external tools or APIs, your prompt needs to tell it when to use them — and what to do after. Write each one as a trigger condition:Controlling How Data Is Formatted
Voice agents don’t always speak numbers, names, and codes the way you expect. Without explicit instructions, an agent might read a phone number as “four hundred fifteen million…” instead of digit by digit - or pronounce an order ID incorrectly. Tell your agent exactly how to speak each type of data.Why This Matters
The same value can be spoken in multiple valid ways. Your agent has no way to know which format you want unless you specify it clearly.How to Write Voice Formatting Rules
Add speaking instructions to your Style or Rules section. Be explicit — say exactly how the agent should read values out loud.Common Mistakes to Avoid
- Too vague on tone. “Be professional” is not enough. Say exactly what professional looks like for your brand.
- Missing the unhappy path. Most prompts only describe the ideal flow. Always write what happens when something goes wrong.
- Combining steps. If a step has two actions, split it into two steps.
- Skipping tool triggers. If a tool isn’t mentioned in the instructions, the agent won’t know when to use it.
- Untested variables. Always verify your variables are being passed in correctly before going live.
- No formatting rules for data. If you don’t specify how to handle phone numbers, amounts, state names, or IDs, your agent will pick a format on its own — and it’s often wrong.