Personalize ChatGPT with Custom Instructions

Customize ChatGPT's output in order to get better responses from it

A while back ChatGPT unveiled Custom Instructions, a largely unheralded and seemingly infrequently used tool. Custom Instructions allow you to customize ChatGPT’s output. OpenAI explains them thus:

ChatGPT will consider your custom instructions for every conversation going forward. The model will consider the instructions every time it responds, so you won’t have to repeat your preferences or information in every conversation. 

For example, a teacher crafting a lesson plan no longer has to repeat that they're teaching 3rd grade science. A developer preferring efficient code in a language that’s not Python – they can say it once, and it's understood. Grocery shopping for a big family becomes easier, with the model accounting for 6 servings in the grocery list.

This isn’t very insightful. Here’s Dan Shipper, explaining in more detail why Custom Instructions are so powerful:

Using Custom Instructions properly can completely transform your experience with ChatGPT. Custom Instructions will help you turn ChatGPT into a personalized, always-on, super-smart coach and tutor that knows who you are, your strengths and weaknesses, and the people in your life, so it can help you make better decisions and achieve your goals. You won’t have to explain anything twice because it will already know enough context about you to help—and it will do so in ways that surprise and delight you.

For reasons known only to the algorithmic gods, at some point in the past few months Twitter/X surfaced these custom instructions to me. I don’t know the person who shared these custom instructions, but I copied them verbatim, and use them to this day.

So, let’s consider a practical example. Consider the following prompt: What muscles do cable rows engage? Provide the information in tabular format.

Here’s the entire discussion. Note that if you click on this link you will see the discussion, and you will be able to continue the discussion, however, you will not be able to use my custom instructions.

Here’s the table that ChatGPT provided to me (screenshotted):

I asked it to modify the table a bit: Ok add a column to the table to inducate where on the body the particular muscle being referenced is located.

It did this without a problem:

The point here is that Custom Instructions enhance the quality of ChatGPT’s output. Your custom instructions should be written to reflect your interests and your preferred style of thinking and information presentation. I’d take a look at the cusom instructions I use (again, linked above) and then take a look at the chat dialogue that I link to above. This will help you understand how I am able to get such great output from ChatGPT.

Hopefully this will help you understand why Custom Instructions are important, and how to use the feature for your benefit.