Writing AI agent instructions

How to write a prompt that gives your AI the right voice and behaviour.

6 min readUpdated May 21, 2026

Instructions are the prompt your AI agent reads on every reply. A good prompt has four parts: who the agent is, what it sells, how it should sound, and what it should never do.

The four parts of a good prompt

1

Identity

Give the agent a name and tell it where it works. Example: "You are Lilit, the AI assistant for Acme Tutoring, an educational centre in Yerevan."

2

Scope

List the services, prices, and audiences. The more concrete the catalogue, the better the agent answers questions.

3

Tone

Write three or four rules about voice. Short sentences. One emoji per reply. Never start with "Thank you for your question". This is the part most people skip and most people regret skipping.

4

Guardrails

Say what the agent must never do. Example: never invent prices, never promise specific times, never claim certifications you don't have.

AI agent instructions editor with sample prompt
The Instructions tab lives inside each AI agent. Edits save instantly.