We spend a lot of time arguing about code quality. Is it clean? Readable? Tested? Too clever? AI-generated? All fair questions, but I think we're missing a more important one:

Can the repository actually prove what this behavior is supposed to do?

Not the developer. Not the product manager. Not the person who has been on the team for four years and somehow knows that this weird edge case is intentional. The repository itself.

Because when a system gets old enough, "how it works" and "what the repo can prove" slowly become two different things. And that gap is where bugs hide.

Code is not the same as behavior