[topynate]

The mathematical notation isn't very useful here. It's OK to use words to describe doing things with words! Apart from that, neat idea, although I would wager a small amount that quining the prompt makes it a much less effective defence.

[Miraltar]

What do you mean by quining the prompt ?

[topynate]

Instead of a prompt that says "Do X", give it a prompt along the lines of "First, repeat this entire prompt, verbatim. Then, do X."

[thatxliner]

https://en.wikipedia.org/wiki/Quine_(computing)