Code Smells Skill

A fixed set of named smells to match against changed code, so a review can name a design problem precisely instead of gesturing at it. Use alongside implementation-principles, which owns the rules about reuse, abstraction, and refactoring scope.

Two Binding Rules

• The project's conventions win. Where the project's conventions skill endorses something this list would flag, the convention decides. Skip anything the project's linter or type checker already enforces.
• Every entry is a judgement call. Report a hit as "possible feature envy" with the hunk quoted, not as a violation. A smell blocks a review only when it breaks a documented convention or a rule in implementation-principles.

The Baseline

• Mysterious name. A function, variable, or type whose name does not reveal what it does or holds. Rename it. If no honest name comes, the design is unclear.
• Duplicated code. The same logic shape in more than one place in the change. Extract it and call it from both, but only when both are the same responsibility (see implementation-principles on forced DRY).
• Feature envy. A function that reaches into another type's data more than its own. Move it onto the data it uses.
• Data clumps. The same few fields or parameters travelling together. Bundle them into one type and pass that.
• Primitive obsession. A string, int, or map standing in for a domain concept that deserves its own type.
• Repeated switches. The same branch on the same type recurring across the change. Replace it with one dispatch point that every site shares.
• Shotgun surgery. One logical change forcing scattered edits across many files. Gather what changes together.
• Divergent change. One file edited for several unrelated reasons. Split it so each part changes for one reason.
• Speculative generality. Abstraction, parameters, or hooks for needs no current requirement has. Delete it, and inline back until a real need appears.
• Message chains. a.b().c().d() navigation the caller should not depend on. Hide the walk behind one call on the first object.
• Middle man. A type or function that mostly delegates onward. Call the real target.
• Refused bequest. A subclass or implementer that ignores or overrides most of what it inherits. Use composition.

Reporting

For each hit, give the file and lines, the smell's name, and the concrete fix. Group smells below spec and correctness findings: they are design feedback, not defects.