Code smell
A pattern in code that suggests a problem without proving one: a very long parameter list, one module reaching into another's data, the same switch in five places. It is a prompt to look, and it isn't a verdict.
Smell names are precise review vocabulary, so one word can replace a paragraph of instructions to an agent. Make it show what each one costs, though, because any model asked to find smells will find some.
Say it to your agent
“Review this diff for Long Parameter List, Feature Envy and Shotgun Surgery. For each hit, quote the lines and name the next change it makes expensive. If you can't name one, drop the finding.”