[harpersealtako]

I know this one from the Umineko visual novel series. Detectives in the Umineko universe are dimension-hopping reality auditors who wield the "rules of detective fiction" as rhetorical weapons (and sometimes literal weapons) when jumping into stories to fight against witches who are trying to create unsolvable mysteries to increase peoples' belief in magic. There's one detective who uses Knox's 10 rules, and another who uses Van Dine's 20 rules. It's a really fun, really meta story, one where the main characters are both participants in the story and genre-savvy readers debating who the murderer is using trope knowledge.