Simon Willison’s Weblog


Prompt injected OpenAI's new Custom Instructions to see how it is implemented. ChatGPT added a new “custom instructions” feature today, which you can use to customize the system prompt used to control how it responds to you. swyx prompt-inject extracted the way it works:

“The user provided the following information about themselves. This user profile is shown to you in all conversations they have—this means it is not relevant to 99% of requests. Before answering, quietly think about whether the user’s request is ’directly related, related, tangentially related,’ or ’not related’ to the user profile provided.”

I’m surprised to see OpenAI using “quietly think about...” in a prompt like this—I wouldn’t have expected that language to be necessary.