"Show HN is for something you've made that other people can play with. HN users can try it out, give you feedback, and ask questions in the thread." I would gu

"Show HN is for something you've made that other people can play with. HN users can try it out, give you feedback, and ask questions in the thread." I would guess prototypes are fine, but just "ideas" with no artifact are probably not the intended type of post.