> Prompts are not copyrightable

Surely that varies on a case by case basis? With agentic coding the instructions fed in are often incredibly detailed.

In practice the output of the LLM does not tell what the prompt was, and the output varies randomly, so it is unlikely you would be sued for copying the prompt. And in fact you would not know what the prompt, if any, was for the original unless you copied the prompt from somewhere.