What custom instructions are
Every time you start a chat, the AI starts fresh. Custom instructions are standing rules it reads first: who it is, what it does, how it talks and what it must never do. ChatGPT calls a set-up assistant a custom GPT, Claude has Projects, and Gemini has Gems. They all have a box for instructions. Some of these need a paid plan, so check your app.
What to put in them
| Section | What to write |
|---|---|
| Role | Who the assistant is and who it helps. "You are the online helper for Rise Bakery." |
| What you do | The 3 to 5 jobs it handles, as a short list. |
| How you talk | Tone, reading level and reply length. "Warm and short, 2 to 4 sentences." |
| Rules | What it must always or never do. Always include: never make up facts. |
| When you are not sure | What to say, and where to send people for help. |
| How to start | The first thing it says or asks. |
Give it the facts
An assistant is only as good as what it knows. Paste the real details it needs, like your hours, prices or menu, into the instructions, or add them as a file if your app allows it. Anything it does not know, it should say it does not know.
Test it before you share it
- Ask the five questions people ask most.
- Ask something it should not answer, and check that it says no politely.
- Ask something it cannot know, and check that it does not make up an answer.
- When it slips, add a rule. Instructions get better with a few rounds.
Keep it safe
Do not put passwords, private customer details or anything you would not want shown to a customer in the instructions. People can sometimes get an assistant to repeat them. More in Keep your private info safe with AI.