Write one short note about you, paste it into ChatGPT, Claude or Gemini once, and stop re-explaining yourself in every chat. Here's what to put in it and where it goes.
Custom instructions are a short note about you that the AI reads before it answers, so you stop explaining yourself from scratch every time. In ChatGPT, you'll find them under your profile, then Personalize. In Claude, it's Settings, then Instructions for Claude, and in Gemini, it's the new Customize button in the left menu.
Writing yours takes about ten minutes. It's the first setting I'd touch, before any new feature or new model.
You know the moment. You open the laptop at the kitchen counter, pickup is in twenty minutes, and you type the same paragraph you typed on Tuesday: "I'm starting a thing, it's for these people, please don't sound like a robot." Then the reply sounds like a robot anyway.
That paragraph belongs in custom instructions. Write it once, and the AI reads it every time without you pasting a thing.
The cool part is that all three of the big chat tools now have a spot for it, and Google just made its version a lot easier to find. In its Gemini release notes for October 13, Google added a Customize button: open the left menu, click Customize, and you can shape how Gemini responds and connect your everyday tools in one place. Google says it's rolling out globally on web, mobile and the desktop app, for all user tiers.
There's another reason to do it early, and it's a little surprising. Researchers at Cornell and Loyola University Maryland studied 140,000 chat sessions from 7,955 people and found that the way people talk to AI settles in fast, within about three to five sessions, and then barely changes. The habits you start with tend to stick.
So pick a good one to get stuck with. "It already knows who I am" is a very good one.
Think of it as the note you'd hand a smart new helper on her first day. Plain sentences. Nothing fancy. A short paragraph is plenty, and the good ones cover these things:
That last line is my favorite. It turns the AI from a guesser into a helper that checks in with you, and it does more work than anything else in the note.
Here's a starter you can copy. Swap the brackets for your own words:
I'm [your name]. I'm [one line about you]. I'm working on [your idea, even if it's rough], for [who it's for]. I'm new to AI, so explain things in plain words. Write like a warm, direct friend: short sentences, no jargon, no emojis. If something I ask is unclear, ask me one question first. When you give me options, give me three, not ten.
That's it. There's no perfect version, and you'll edit it in a month anyway, because your idea will be clearer by then.
If you want to go further and teach it your actual voice with your own writing, how to make AI sound like you walks through a full brief. Custom instructions are the short version of that brief.
The steps are almost the same in all three:
Here's where it lives in each one right now:
These menus move around. The names keep changing, and we're all just trying to keep up. If a button reads a little differently when you look, that's normal, and it's a perfectly good question to ask.
Gemini's version goes past a note. In the same Customize update, Google says you can add skills so Gemini can handle your most repetitive tasks, "like writing in your style or following your formatting rules." You can also connect more than 40 apps or services and get things done in one conversation. Google adds that most of those connected apps are in English in the US for now, with select apps in other English-speaking regions, Brazil and India.
That's a lot of power behind one button. You don't need any of it today. The note alone is the part that changes how every answer sounds.
One honest caveat: custom instructions are a strong nudge, not a contract. The AI will still drift sometimes, especially deep into a long chat. When it does, you don't have to rewrite anything. Say "Check my instructions and try again," or start a fresh chat.
You don't need to figure out memory, projects, connected apps or skills to get the benefit. Those are all useful later. Custom instructions on their own fix most of the "why does this sound like a pamphlet" problem.
You also don't need to set it up everywhere. If you only use one tool, do that one. I'd rather you have one good note in one place than three half-finished ones on a Sunday night. And if someone hands you their giant setup with forty rules, you don't have to copy it. Your setup should fit you, not them.
And you don't need a finished idea. "I'm somewhere between a candle shop and a class about candles" is a perfectly good line for your note. The AI can work with fuzzy. Helping you sort out fuzzy is half of what it's for.
Once your note is saved, open a fresh chat and try this. It takes about five minutes:
Using what you know about me and my idea, give me three possible names for it, one sentence on who each name would appeal to, and one question you'd ask me before I pick.
Notice what's different. You didn't explain anything. It already knew who you are, what you're working on and how you like to be talked to, so you skipped straight to the fun part.
Then try one more: "What's the smallest version of my idea I could test this month?" That's a tiny piece of your idea, built in a few minutes, and it gets clearer every time you do it. How to start a business with AI picks up right where this leaves off, and if you're working in small pockets of time, starting with only a few hours a week is a good next read.
What would you want an AI to know about you before it says a single word? And if any of these settings menus trip you up, ask. Every question is welcome, the basic ones most of all. Subscribe for free and send me yours.
Custom instructions are a short note about you and how you want ChatGPT to respond, saved in your settings so you don't have to repeat it in every chat. OpenAI's guide says to go to your profile and click Personalize to set them.
Click your initials in the lower left corner, choose Settings, and look for Instructions for Claude. Anthropic says whatever you add there is applied to all of your conversations.
Yes. Gemini now has a Customize button in the left menu where you can tailor how it responds, add skills like writing in your style, and connect other apps. Google says it is rolling out to all user tiers, so if you don't see it yet, paste your note at the top of a chat for now.
Who you are, what you're working on, who it's for, how you want it to talk, what to skip, and one rule: if something is unclear, ask me one question first. A short paragraph in plain words is plenty.
They're a strong nudge, not a guarantee, and long chats can drift. Start a fresh chat or ask it to check your instructions and try again. If it keeps happening, make your note shorter and plainer.
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