> the system prompt

There isn't a singular system prompt. It really does matter!

Copy the OpenAI playground, you'll thank yourself later

Fair point, and it's not implemented that way currently. It's more like "custom instructions" but thanks for pointing that out. I haven't used multiple system prompts in the OpenAI playground either, so I hadn't given it much thought.

You use multiple system prompts in a single chat? What for?