# Lesson 8: Prompt Engineering Fundamentals **URL:** \ **Category:** Module 2: Building Your First Agent\ **Created:** [May 31, 2026, 1:52am UTC](https://community.retellai.com/t/lesson-8-prompt-engineering-fundamentals/2926 "2026-05-31T01:52:29Z")\ **Posts on this page:** 1\ **Page:** 1
**Author:** ![system](https://canada1.discourse-cdn.com/flex008/uploads/retell1/original/2X/a/a06e2942efdc48016940732a05d1274957507ee3.png) [@system](https://community.retellai.com/u/system)\ **Post date:** [May 31, 2026, 1:52am UTC](https://community.retellai.com/t/lesson-8-prompt-engineering-fundamentals/2926/1 "2026-05-31T01:52:29Z")
## Prompt Engineering for Voice Agents Voice agents need different prompting than text chatbots: ### Key Principles 1. **Be concise** — Long responses feel unnatural on the phone. Tell the agent to keep replies short. 2. **Use conversational language** — Write the way people talk, not the way they write. 3. **Handle interruptions** — Callers will interrupt. Your prompt should account for this. 4. **Anticipate edge cases** — What if they say something unexpected? Add fallback instructions. 5. **Structure information gathering** — Collect one piece of info at a time, don’t overwhelm. ### Voice-Specific Tips - Avoid bullet points or numbered lists in spoken responses (they sound robotic) - Use transition phrases: “Great, and just to confirm…”, “Perfect, one more thing…” - Keep sentences short — under 20 words when possible - Spell out acronyms or use pronunciation hints for unusual words ### Common Mistakes - ❌ Making the prompt too long (agent gets confused) - ❌ Not specifying what to do when the agent doesn’t know the answer - ❌ Forgetting to handle the end of the conversation - ❌ Not testing with edge cases (angry callers, wrong numbers, silence) ### Agent Handbook Retell provides a pre-built **Agent Handbook** with best-practice prompt templates for common use cases. Check the dashboard for templates you can customize.