ChatGPT custom instructions that actually help
Set them once so you stop repeating yourself in every chat.
Jamie Owen Updated 30 May 2026
Custom instructions are a small settings box where you tell ChatGPT, once, how you’d like it to respond. It applies that to every new chat, so you stop re-explaining your role and your audience every single time.
The two boxes
ChatGPT asks two things: a little about you, and how you want it to respond. Keep both short and concrete. Vague preferences (“be helpful”) do nothing. Specific ones change every answer.
What’s worth putting in
Your context, first. “I’m a primary school teacher in the UK” reframes examples, vocabulary and spelling in one line. Then format: “default to short answers; use bullet points for steps” stops the walls of text. The highest-value line I know of is a tone instruction, something like “plain English, no marketing language”. It’s also worth saying what to skip: “don’t add a summary paragraph at the end unless I ask.”
Treat custom instructions as your standing brief. Anything you find yourself typing in most chats belongs there instead.
The habits behind a good one-off prompt (be specific, say who it’s for) apply here too. See prompting basics.