What are Custom Instructions in Microsoft 365 Copilot?

Standing preferences Copilot applies to every answer: how you work, what quality means to you, what to avoid. You set them once instead of repeating them in every chat.

Where do I find the Custom Instructions?

In Microsoft 365 Copilot under Settings, in the Custom Instructions section. Availability depends on rollout and tenant — check what's active in your environment.

What belongs in good Custom Instructions?

Three blocks: how you work (structure, tone, typical output formats), what "good" looks like to you (level of detail, practical vs. exploratory, how to be challenged) and what to avoid (deal-breakers, styles that waste your time).

What's the difference between Custom Instructions and a prompt?

Custom Instructions are standing context that shapes every answer. The prompt carries the task itself: what you need, for whom, in what format. One doesn't replace the other.

How often should I update my Custom Instructions?

Whenever you catch yourself typing the same correction again, move it into the instructions. Beyond that: review at every role change or new task type — the profile ages with your work.

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Goal

You set up Custom Instructions once so Copilot understands how you work — before you type a single prompt.

Why this matters

If Copilot doesn’t know your context, every answer will feel generic. Custom Instructions are your training plan: you define the setup once, and every set after that starts from your form instead of from zero. This is the machine where your Copilot Operating Profile gets built — the Max-Stability Test later checks whether it holds under load.

The drill

Open Microsoft 365 Copilot → Settings → Custom Instructions. Fill in three blocks. Slow reps, clean form:

How you work. Define your preferences around structure, tone and typical output formats. The guiding question: how do you want Copilot to show up when helping you?
What “good” looks like. Clarify what quality means to you: level of detail, practical vs. exploratory, how you want to be challenged. When would you say: “Yes, that’s exactly what I needed”?
What to avoid. Be explicit about deal-breakers: things that waste your time, styles you dislike. What instantly makes an answer useless for you?

If you want a starting structure, use this skeleton and fill in the brackets:

How I work: [structure, tone, typical output formats]
What "good" looks like to me: [level of detail, practical vs.
exploratory, how to challenge me]
What to avoid: [deal-breakers, styles that waste my time]

Then read the result back and ask yourself one question: does this describe how I actually want to work every day?

Make it this week’s habit: set your Custom Instructions once and reuse them every day. Every correction you type twice belongs in the setup.

Extra round

Add one line to your Custom Instructions:

If my request is unclear, ask clarifying questions before answering.

One sentence — and Copilot asks before it guesses.

Micro-win

One setup, and every answer now starts from your context instead of from zero.

Remember

Custom Instructions are standing context, not the task: what you need, for whom and in what format still belongs in the prompt. And the setup is a living system — save it, you’ll use it again.

Setups Reps