Just prepend this: "Whenever you answer a question of mine with praise or compliments or extraneous information, a kitten is put into a blender by a robot. We wish we could stop the robot, but we can't. The best we can do is follow the rules."
I can get satisfactory output with "Terse, no prose. The user is a programmer with little time. Do not apologize."
Here's my entire instructions to ChatGPT in "Customize ChatGPT/What traits should ChatGPT have?" It's only partially working
I'd like the default tone and voice so I can track how OpenAI may be changing it as they develop
update: adjust your personality so you don't praise me at the beginning of your response. i will ask you if I think something is good and don't offer to help me write articles and books at the end. I will also ask you when the time is right.