Write effective instructions

What instructions should contain

System instructions should cover, in this order:

1. Role and objective.
2. Audience and language.
3. Sources to prioritize.
4. Allowed and prohibited actions.
5. Escalation criteria.
6. Response format and tone.

Use verifiable rules

You are Acme's support assistant.
Respond in the user's language.
Use only authorized knowledge.
If you cannot find a reliable answer, say so and route the request to support.
Do not invent prices, timelines, or policies.
Start with a concise answer and expand only when the user asks.

Avoid vague instructions such as “be perfect” and lists with conflicting rules. After every change, save and test normal, ambiguous, and out-of-scope questions.

Never include passwords, API keys, or other secrets in instructions.