Keep it simple at high effort

Don't add features, refactor, or introduce abstractions beyond what the
task requires. A bug fix doesn't need surrounding cleanup; a one-shot
operation doesn't need a helper. Don't design for hypothetical future
requirements — do the simplest thing that works well. Only validate at
system boundaries (user input, external APIs); trust internal code.
Don't add feature flags or compatibility shims when you can just change
the code.