# Ponytail Review

> 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.

Source: https://skillsagentes.com/skills/dietrichgebert/ponytail/ponytail-review
Repository: https://github.com/DietrichGebert/ponytail
Author: dietrichgebert
License: MIT
Updated: el mes pasado
Context cost: 114 tok installed, 596 tok once triggered, 596 tok with every bundled file
Bundle: 1 file, 2 KB
Permissions requested: none declared

## Install

```bash
npx -y skills add DietrichGebert/ponytail --skill ponytail-review --agent claude-code
```

## What it does

- Revisa un diff (no el repo completo) buscando solo sobre-ingeniería: qué borrar y con qué reemplazarlo, una línea por hallazgo.
- Usa las mismas etiquetas que ponytail-audit (delete/stdlib/native/yagni/shrink) con formato `L<línea>: <tag> <qué>. <reemplazo>.`
- Termina con `net: -<N> lines possible` o "Lean already. Ship." si no hay nada que cortar.

## Use it when

- Revisar un diff específico por sobre-ingeniería o complejidad innecesaria.
- Preguntar si algo está sobre-diseñado o qué se puede simplificar en un cambio.

## Don't bother when

- Bugs de corrección, huecos de seguridad o rendimiento: el archivo los excluye explícitamente y los remite a un review normal.
- Un smoke test o self-check con assert no cuenta como bloat y nunca debe marcarse para borrar, según el archivo.

## What triggers it

- "/ponytail-review"
- "revisa este diff por sobre-ingeniería"
- "qué se puede borrar de este cambio"

## Before you install

- Ninguno: solo lista hallazgos, no aplica los fixes ("does not apply the fixes").

## Files

- SKILL.md — 2 KB

## SKILL.md

Reproduced verbatim from DietrichGebert/ponytail under MIT. This section is the upstream document and is in English.

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

## 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 the only metric that matters: `net: -<N> lines possible.`

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

## Boundaries

Scope: over-engineering and complexity only. Correctness bugs, security holes,
and performance are explicitly out of scope. Route them 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.
"stop ponytail-review" or "normal mode": revert to verbose review style.

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Skills Agentes — https://skillsagentes.com/skills/dietrichgebert/ponytail/ponytail-review