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Best custom instructions for Claude

The best custom instructions for Claude are not a long list of rules. They are a short, plain-English description of how you like to communicate, what your AI should know about you, and what it should never do.

What Claude custom instructions actually do

Claude custom instructions live in your settings and shape every conversation. Instead of typing “please be concise” over and over, you tell Claude once:

  • How formal or casual you want it to be
  • Whether you want short answers or detailed explanations
  • What you are working on and what matters to you
  • What it should never do (for example, save passwords or use jargon)

A prompt is not the same as a profile

A prompt is a one-off question. Custom instructions are a lasting setup. If you find yourself adding the same preamble to every chat — “keep it short,” “I’m a beginner,” “don’t be too enthusiastic” — those are exactly the things that belong in your custom instructions.

Without custom instructions

“Can you help me write an email to a client?”

Result: Claude writes a long, generic email and you have to edit it.

With custom instructions

“Can you help me write a short, direct email to a client? I prefer to get to the point quickly and use examples rather than long explanations.”

Result: a shorter, more useful first draft that matches your style.

What the best custom instructions look like

Here is a realistic example of a Known by AI Profile — the kind of custom instructions we build from your answers. It covers how your AI should work with you, what it should know, and what it should remember.

Example profile

How to work with me: Get to the point in the first two sentences. If I’m wrong, say so plainly and tell me why. When I ask for help deciding, give me one clear recommendation first, then the alternatives.

What to remember about me: I run a small consulting business. I prefer short emails, morning meetings, and examples over theory. Never save account numbers or passwords.

This is a sample. Your own profile is built from your answers.

How to paste custom instructions into Claude

  1. 1Open Claude.ai and click your profile icon in the lower-left corner.
  2. 2Go to Settings → Profile.
  3. 3Paste your “How to work with me” text into “What personal preferences should Claude consider in responses?” Claude calls this Instructions for Claude.
  4. 4Save, then start a new chat to test it.

Claude also has Projects, where you can add the same text as project-level custom instructions. Your “What to remember about me” details can use the separate Memory toggle under Settings → Memory. If Memory is off, the personal-preferences field still works. If your menu looks different, look for Profile, Instructions, Personalization, Projects, or Memory — Anthropic moves labels around, but the idea is the same.

Build your own in about 10 minutes

Known by AI turns six easy questions about yourself into a ready-to-paste profile for ChatGPT or Claude. No prompt engineering. No AI jargon. You answer in plain English, and we turn your words into a setup that makes your AI stop sounding generic.

“The interface design was clear and easy on the eyes — no flashing or pop-ups. The dictate feature is fantastic.”
— Amber

Want Claude that actually sounds like you?

Answer a few simple questions and get your own Known by AI Profile — ready to paste into ChatGPT or Claude.

Get my AI profile — $19

Using ChatGPT instead? Read the ChatGPT guide.