System Prompt for Comet Assistant

I went to the system prompt section, but I don't understand where to enter it in Comet... It says the character limit has been exceeded.

<img width="2550" height="1230" alt="Image" src="https://github.com/user-attachments/assets/ea9147bf-6d79-478c-bddb-14e8cd3b1f0c" />