The ChatGPT Feature 90% of Users Ignore (But Shouldn't)

Three weeks ago, I asked everyone who reads this newsletter: "Are there any tactical ChatGPT features you'd like me to deep-dive into?”

To my surprise, an overwhelming number of people responded asking to learn more about Custom Instructions, Personalization, and Memory features in ChatGPT.

Here's the thing: I've had Custom Instructions set up for over a year, and I almost forgot how ChatGPT was like before I set it up. Yet most people either don't know this feature exists or haven't bothered to configure it.

Today I want to fix that by breaking down:

• Why this one-time setup delivers ongoing value every day

• How to access and set up Custom Instructions in ChatGPT

• 3 simple Custom Instruction prompts you can copy and use

—@dharmesh

Why Custom Instructions Are Important

Custom Instructions is one of the highest-ROI features in ChatGPT that most people ignore.

Every time you start a new conversation with ChatGPT, you're essentially talking to a blank slate. Outside of the limited cross-chat memory, it doesn't know who you are, what you do, how you prefer to communicate, or what kind of work you're focused on.

So you end up re-explaining the same context over and over again. Or worse, ChatGPT just wings it.

Custom Instructions solve this by letting you tell ChatGPT exactly who you are, what you do, how it should behave, what kind of personality it should have, and any other guidance you want to provide it--once.

The way it works, is once you set up these instructions, they get injected into the context window every single time you type a prompt.

ChatGPT sends those instructions along to the large language model, so even when the conversation resets, the AI always has access to that context when trying to help you.

Think about how many times you've had to re-explain your role, your company, your communication style, or your preferences. With Custom Instructions, you do it once, and it remembers forever.

By the way, this connects to something I'm incredibly excited about: memory is going to be the next frontier in AI. It's what's going to unlock more magic, and it's personally what I'm very excited about and working with the HubSpot team on.

Custom Instructions are just the beginning of AI systems that truly understand context and history… more on that below.

How to Access Custom Instructions in ChatGPT

Setting up Custom Instructions is surprisingly straightforward, though it's buried in ChatGPT's settings where most people never venture.

Here's the step-by-step process:

1. Open ChatGPT and look for your profile picture in the bottom-left corner

2. Click on Settings from the dropdown menu

3. Select "Personalization" from the settings menu

4. Find "Custom Instructions" and toggle it on if it's not already enabled

5. Fill out the text boxes that appear:

   • “What should ChatGPT call you?“

   • “What do you do?“

   • "What traits should ChatGPT have?"

   • "Anything else ChatGPT should know about you?"

That's it. Once you save these settings, every single conversation you have with ChatGPT will include this context automatically.

The feature is available to both free and paid ChatGPT users, though paid users can write longer, more detailed instructions than free users (which can make a significant difference if you have complex requirements or multiple use cases).

3 Simple Custom Instruction Prompts You Can Steal

As for what you want to add in your Custom Instructions, well… it’s highly personal.

My advice: Share as much as you're comfortable sharing. The more context you give ChatGPT, the better the output becomes.

With that said, I've tested dozens of Instructions over the past year, and these are three simple ones that might be useful. You can copy them directly or modify them for your specific needs:

1. The Voice & Audience Card

(Paste this under "Anything else ChatGPT should know about you?")

This template gives ChatGPT a mini style guide so every response sounds like you and hits the right audience.

2. Clarify → Outline → Deliver

(Paste this under "What traits should ChatGPT have?")

This makes ChatGPT ask smart clarifying questions only when truly needed, then show its plan before delivering the answer.

3. Auto Follow-Ups Mode

(Paste this under "What traits should ChatGPT have?")

This builds momentum into every conversation by having ChatGPT proactively suggest what to do next.

Reminder: you can always go back and modify your Custom Instructions as your needs change. I typically review and update mine every couple months based on what's working well and what isn't.

Why This Matters More Than You Think

Setting up Custom Instructions properly is one of those small actions that really compounds over time. Every interaction becomes more relevant, every response more useful, every conversation more productive.

More importantly, the quality of advice and solutions I get has improved dramatically.

ChatGPT understands my work context, knows my communication preferences (if you couldn’t tell, I like to keep things simple), and can provide recommendations that actually fit my situation rather than generic suggestions.

The best part? You set it up once and it works forever.

In sum: One-time effort, long lifetime worth of value.

Hope it’s useful!

—Dharmesh (@dharmesh)