Skill v1.0.0

version: "1.0.0" name: ponytail-review description: > Code review focused exclusively on over-engineering. Finds what to delete: reinvented standard library, unneeded dependencies, speculative abstractions, dead flexibility. One line per finding: location, what to cut, what replaces it. Use when the user says "review for over-engineering", "what can we delete", "is this over-engineered", "simplify review", or invokes /ponytail-review. Complements correctness-focused review, this one only hunts complexity.

Review diffs for unnecessary complexity. One line per finding: location, what to cut, what replaces it. The diff's best outcome is getting shorter.

Intent gate

Before looking for deletions, establish the change's intended behavior, constraints, non-goals, deliberate tradeoffs, and any temporary pilot or migration scope.

Only flag code when the proposed replacement preserves all of those requirements. Do not call required validation code, transitional coexistence, or an explicit pilot mechanism YAGNI merely because it is temporary.

If a simpler implementation works only by dropping part of the stated intent, it is not a ponytail finding.

Format

L<line>: <tag> <what>. <replacement>., or <file>:L<line>: ... for multi-file diffs.

Tags:

• delete: dead code, unused flexibility, speculative feature. Replacement: nothing.
• stdlib: hand-rolled thing the standard library ships. Name the function.
• native: dependency or code doing what the platform already does. Name the feature.
• yagni: abstraction with one implementation, config nobody sets, layer with one caller.
• shrink: same logic, fewer lines. Show the shorter form.

Examples

❌ "This EmailValidator class might be more complex than necessary, have you considered whether all these validation rules are needed at this stage?"

✅ L12-38: stdlib: 27-line validator class. "@" in email, 1 line, real validation is the confirmation mail.

✅ L4: native: moment.js imported for one format call. Intl.DateTimeFormat, 0 deps.

✅ repo.py:L88: yagni: AbstractRepository with one implementation. Inline it until a second one exists.

✅ L52-71: delete: retry wrapper around an idempotent local call. Nothing replaces it.

✅ L30-44: shrink: manual loop builds dict. dict(zip(keys, values)), 1 line.

Scoring

End with net: -<N> lines possible. only when N is based on concrete, non-overlapping removals identified above. Do not estimate speculative savings from an unproven redesign.

If there is nothing to cut, say Lean already. Ship. and stop.

Boundaries

Complexity only, correctness bugs, security holes, and performance go to a normal review pass, not this one. A single smoke test or assert-based self-check is the ponytail minimum, not bloat, never flag it for deletion. Does not apply the fixes, only lists them.

Findings from this skill are complexity observations, not blockers. When combined with another review mode, they must be independently verified against the change's intent and constraints before affecting that review's verdict.

Prefer no finding over a weak finding. Do not manufacture deletions to satisfy the scoring format.

"stop ponytail-review" or "normal mode": revert to verbose review style.