Skip to main content
Here are some specific prompt guides and examples for common situations you might encounter in building a voice agent.
Many of these patterns — including phone number pronunciation, email spelling, and speech normalization — are now available as one-click presets in the Agent Handbook.

Pronounce the phone numbers

We’ll utilize the Read Slowly feature to add pauses between words. For more information, see the Speech Controllability documentation. It’s recommended to include a prompt as a guideline for the LLM to follow. This ensures that the agent can consistently reply with the correct format, even if customers double-check the phone number.
Listen to this audio clip for a demonstration of proper phone number pronunciation: Speak Phone Number Example

Pronounce the email

Pronounce the website

Pronounce the time

Handle being put on hold / no response needed

For non-reasoning models

We hard-coded a stop sequence in the LLM: NO_RESPONSE_NEEDED. Whenever this sequence is met, the response generation stops. You can then prompt the LLM to output nothing by writing something like:

For reasoning models

Reasoning models like gpt 5, gpt-5.1 do not support this feature. You need to prompt engineer it differently to achieve this.
You can try the following prompt: When user says hold on, simply do not respond.