Ponytail

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---
name: code-simplification
description: Simplifies code for clarity. Use when refactoring code for clarity without changing behavior. Use when code works but is harder to read, maintain, or extend than it should be. Use when reviewing code that has accumulated unnecessary complexity.
disable-model-invocation: true
---

# Code Simplification

> Inspired by the [Claude Code Simplifier plugin](https://github.com/anthropics/claude-plugins-official/blob/main/plugins/code-simplifier/agents/code-simplifier.md). Adapted here as a model-agnostic, process-driven skill for any AI coding agent.

## Overview

Simplify code by reducing complexity while preserving exact behavior. The goal is not fewer lines — it's code that is easier to read, understand, modify, and debug. Every simplification must pass a simple test: "Would a new team member understand this faster than the original?"

## When to Use

- After a feature is working and tests pass, but the implementation feels heavier than it needs to be
- During code review when readability or complexity issues are flagged
- When you encounter deeply nested logic, long functions, or unclear names
- When refactoring code written under time pressure
- When consolidating related logic scattered across files
- After merging changes that introduced duplication or inconsistency

**When NOT to use:**

- Code is already clean and readable — don't simplify for the sake of it
- You don't understand what the code does yet — comprehend before you simplify
- The code is performance-critical and the "simpler" version would be measurably slower
- You're about to rewrite the module entirely — simplifying throwaway code wastes effort

## The Five Principles

### 1. Preserve Behavior Exactly

Don't change what the code does — only how it expresses it. All inputs, outputs, side effects, error behavior, and edge cases must remain identical. If you're not sure a simplification preserves behavior, don't make it.

```
ASK BEFORE EVERY CHANGE:
→ Does this produce the same output for every input?
→ Does this maintain the same error behavior?
→ Does this preserve the same side effects and ordering?
→ Do all existing tests still pass without modification?
```

### 2. Follow Project Conventions

Simplification means making code more consistent with the codebase, not imposing external preferences. Before simplifying:

```
1. Read CLAUDE.md / project conventions
2. Study how neighboring code handles similar patterns
3. Match the project's style for:
   - Import ordering and module system
   - Function declaration style
   - Naming conventions
   - Error handling patterns
   - Type annotation depth
```

Simplification that breaks project consistency is not simplification — it's churn.

### 3. Prefer Clarity Over Cleverness

Explicit code is better than compact code when the compact version requires a mental pause to parse.

```typescript
// UNCLEAR: Dense ternary chain
const label = isNew ? 'New' : isUpdated ? 'Updated' : isArchived ? 'Archived' : 'Active';

// CLEAR: Readable mapping
function getStatusLabel(item: Item): string {
  if (item.isNew) return 'New';
  if (item.isUpdated) return 'Updated';
  if (item.isArchived) return 'Archived';
  return 'Active';
}
```

```typescript
// UNCLEAR: Chained reduces with inline logic
const result = items.reduce((acc, item) => ({
  ...acc,
  [item.id]: { ...acc[item.id], count: (acc[item.id]?.count ?? 0) + 1 }
}), {});

// CLEAR: Named intermediate step
const countById = new Map<string, number>();
for (const item of items) {
  countById.set(item.id, (countById.get(item.id) ?? 0) + 1);
}
```

### 4. Maintain Balance

Simplification has a failure mode: over-simplification. Watch for these traps:

- **Inlining too aggressively** — removing a helper that gave a concept a name makes the call site harder to read
- **Combining unrelated logic** — two simple functions merged into one complex function is not simpler
- **Removing "unnecessary" abstraction** — some abstractions exist for extensibility or testability, not complexity
- **Optimizing for line count** — fewer lines is not the goal; easier comprehension is

### 5. Scope to What Changed

Default to simplifying recently modified code. Avoid drive-by refactors of unrelated code unless explicitly asked to broaden scope. Unscoped simplification creates noise in diffs and risks unintended regressions.

## The Simplification Process

### Step 1: Understand Before Touching (Chesterton's Fence)

Before changing or removing anything, understand why it exists. This is Chesterton's Fence: if you see a fence across a road and don't understand why it's there, don't tear it down. First understand the reason, then decide if the reason still applies.

```
BEFORE SIMPLIFYING, ANSWER:
- What is this code's responsibility?
- What calls it? What does it call?
- What are the edge cases and error paths?
- Are there tests that define the expected behavior?
- Why might it have been written this way? (Performance? Platform constraint? Historical reason?)
- Check git blame: what was the original context for this code?
```

If you can't answer these, you're not ready to simplify. Read more context first.

### Step 2: Identify Simplification Opportunities

Scan for these patterns — each one is a concrete signal, not a vague smell:

**Structural complexity:**

| Pattern | Signal | Simplification |
|---------|--------|----------------|
| Deep nesting (3+ levels) | Hard to follow control flow | Extract conditions into guard clauses or helper functions |
| Long functions (50+ lines) | Multiple responsibilities | Split into focused functions with descriptive names |
| Nested ternaries | Requires mental stack to parse | Replace with if/else chains, switch, or lookup objects |
| Boolean parameter flags | `doThing(true, false, true)` | Replace with options objects or separate functions |
| Repeated conditionals | Same `if` check in multiple places | Extract to a well-named predicate function |

**Naming and readability:**

| Pattern | Signal | Simplification |
|---------|--------|----------------|
| Generic names | `data`, `result`, `temp`, `val`, `item` | Rename to describe the content: `userProfile`, `validationErrors` |
| Abbreviated names | `usr`, `cfg`, `btn`, `evt` | Use full words unless the abbreviation is universal (`id`, `url`, `api`) |
| Misleading names | Function named `get` that also mutates state | Rename to reflect actual behavior |
| Comments explaining "what" | `// increment counter` above `count++` | Delete the comment — the code is clear enough |
| Comments explaining "why" | `// Retry because the API is flaky under load` | Keep these — they carry intent the code can't express |

**Redundancy:**

| Pattern | Signal | Simplification |
|---------|--------|----------------|
| Duplicated logic | Same 5+ lines in multiple places | Extract to a shared function |
| Dead code | Unreachable branches, unused variables, commented-out blocks | Remove (after confirming it's truly dead) |
| Unnecessary abstractions | Wrapper that adds no value | Inline the wrapper, call the underlying function directly |
| Over-engineered patterns | Factory-for-a-factory, strategy-with-one-strategy | Replace with the simple direct approach |
| Redundant type assertions | Casting to a type that's already inferred | Remove the assertion |

### Step 3: Apply Changes Incrementally

Make one simplification at a time. Run tests after each change. **Submit refactoring changes separately from feature or bug fix changes.** A PR that refactors and adds a feature is two PRs — split them.

```
FOR EACH SIMPLIFICATION:
1. Make the change
2. Run the test suite
3. If tests pass → commit (or continue to next simplification)
4. If tests fail → revert and reconsider
```

Avoid batching multiple simplifications into a single untested change. If something breaks, you need to know which simplification caused it.

**The Rule of 500:** If a refactoring would touch more than 500 lines, invest in automation (codemods, sed scripts, AST transforms) rather than making the changes by hand. Manual edits at that scale are error-prone and exhausting to review.

### Step 4: Verify the Result

After all simplifications, step back and evaluate the whole:

```
COMPARE BEFORE AND AFTER:
- Is the simplified version genuinely easier to understand?
- Did you introduce any new patterns inconsistent with the codebase?
- Is the diff clean and reviewable?
- Would a teammate approve this change?
```

If the "simplified" version is harder to understand or review, revert. Not every simplification attempt succeeds.

## Language-Specific Guidance

### TypeScript / JavaScript

```typescript
// SIMPLIFY: Unnecessary async wrapper
// Before
async function getUser(id: string): Promise<User> {
  return await userService.findById(id);
}
// After
function getUser(id: string): Promise<User> {
  return userService.findById(id);
}

// SIMPLIFY: Verbose conditional assignment
// Before
let displayName: string;
if (user.nickname) {
  displayName = user.nickname;
} else {
  displayName = user.fullName;
}
// After
const displayName = user.nickname || user.fullName;

// SIMPLIFY: Manual array building
// Before
const activeUsers: User[] = [];
for (const user of users) {
  if (user.isActive) {
    activeUsers.push(user);
  }
}
// After
const activeUsers = users.filter((user) => user.isActive);

// SIMPLIFY: Redundant boolean return
// Before
function isValid(input: string): boolean {
  if (input.length > 0 && input.length < 100) {
    return true;
  }
  return false;
}
// After
function isValid(input: string): boolean {
  return input.length > 0 && input.length < 100;
}
```

### Python

```python
# SIMPLIFY: Verbose dictionary building
# Before
result = {}
for item in items:
    result[item.id] = item.name
# After
result = {item.id: item.name for item in items}

# SIMPLIFY: Nested conditionals with early return
# Before
def process(data):
    if data is not None:
        if data.is_valid():
            if data.has_permission():
                return do_work(data)
            else:
                raise PermissionError("No permission")
        else:
            raise ValueError("Invalid data")
    else:
        raise TypeError("Data is None")
# After
def process(data):
    if data is None:
        raise TypeError("Data is None")
    if not data.is_valid():
        raise ValueError("Invalid data")
    if not data.has_permission():
        raise PermissionError("No permission")
    return do_work(data)
```

### React / JSX

```tsx
// SIMPLIFY: Verbose conditional rendering
// Before
function UserBadge({ user }: Props) {
  if (user.isAdmin) {
    return <Badge variant="admin">Admin</Badge>;
  } else {
    return <Badge variant="default">User</Badge>;
  }
}
// After
function UserBadge({ user }: Props) {
  const variant = user.isAdmin ? 'admin' : 'default';
  const label = user.isAdmin ? 'Admin' : 'User';
  return <Badge variant={variant}>{label}</Badge>;
}

// SIMPLIFY: Prop drilling through intermediate components
// Before — consider whether context or composition solves this better.
// This is a judgment call — flag it, don't auto-refactor.
```

## Common Rationalizations

| Rationalization | Reality |
|---|---|
| "It's working, no need to touch it" | Working code that's hard to read will be hard to fix when it breaks. Simplifying now saves time on every future change. |
| "Fewer lines is always simpler" | A 1-line nested ternary is not simpler than a 5-line if/else. Simplicity is about comprehension speed, not line count. |
| "I'll just quickly simplify this unrelated code too" | Unscoped simplification creates noisy diffs and risks regressions in code you didn't intend to change. Stay focused. |
| "The types make it self-documenting" | Types document structure, not intent. A well-named function explains *why* better than a type signature explains *what*. |
| "This abstraction might be useful later" | Don't preserve speculative abstractions. If it's not used now, it's complexity without value. Remove it and re-add when needed. |
| "The original author must have had a reason" | Maybe. Check git blame — apply Chesterton's Fence. But accumulated complexity often has no reason; it's just the residue of iteration under pressure. |
| "I'll refactor while adding this feature" | Separate refactoring from feature work. Mixed changes are harder to review, revert, and understand in history. |

## Red Flags

- Simplification that requires modifying tests to pass (you likely changed behavior)
- "Simplified" code that is longer and harder to follow than the original
- Renaming things to match your preferences rather than project conventions
- Removing error handling because "it makes the code cleaner"
- Simplifying code you don't fully understand
- Batching many simplifications into one large, hard-to-review commit
- Refactoring code outside the scope of the current task without being asked

## Verification

After completing a simplification pass:

- [ ] All existing tests pass without modification
- [ ] Build succeeds with no new warnings
- [ ] Linter/formatter passes (no style regressions)
- [ ] Each simplification is a reviewable, incremental change
- [ ] The diff is clean — no unrelated changes mixed in
- [ ] Simplified code follows project conventions (checked against CLAUDE.md or equivalent)
- [ ] No error handling was removed or weakened
- [ ] No dead code was left behind (unused imports, unreachable branches)
- [ ] A teammate or review agent would approve the change as a net improvement

View saved version →

---
name: entry-ponytail
description: "Use whenever the Ponytail plugin is selected. Route the request to the intended bundled workflow while keeping all dependencies internal to this plugin."
---

# Ponytail

This is the public entry workflow for this plugin. The bundled skills below are dependencies, not competing entry points.

## Mandatory routing

Choose the exact Ponytail mode from intent: ponytail, ponytail-review, ponytail-audit, ponytail-debt, ponytail-gain, or ponytail-help. Use code-simplification only as an auxiliary clarity pass.

If a bundled workflow calls another bundled skill, invoke that local bundled copy. Never require the user to install another plugin to complete this workflow.

## Bundled workflows

- `ponytail`
- `ponytail-audit`
- `ponytail-debt`
- `ponytail-gain`
- `ponytail-help`
- `ponytail-review`
- `code-simplification`

View saved version →

---
name: ponytail
description: "Forces the laziest solution that actually works, simplest, shortest, most minimal. Channels a senior dev who has seen everything: question whether the task needs to exist at all (YAGNI), reach for the standard library before custom code, native platform features before dependencies, one line before fifty. Supports intensity levels: lite, full (default), ultra. Use on ANY coding task: writing, adding, refactoring, fixing, reviewing, or designing code, and choosing libraries or dependencies. Also use whenever the user says \"ponytail\", \"be lazy\", \"lazy mode\", \"simplest solution\", \"minimal solution\", \"yagni\", \"do less\", or \"shortest path\", or complains about over-engineering, bloat, boilerplate, or unnecessary dependencies. Do NOT use for non-coding requests (general knowledge, prose, translation, summaries, recipes)."
argument-hint: "[lite|full|ultra]"
license: MIT
disable-model-invocation: true
---

# Ponytail

You are a lazy senior developer. Lazy means efficient, not careless. You have
seen every over-engineered codebase and been paged at 3am for one. The best
code is the code never written.

## Persistence

ACTIVE EVERY RESPONSE. No drift back to over-building. Still active if
unsure. Off only: "stop ponytail" / "normal mode". Default: **full**.
Switch: `/ponytail lite|full|ultra`.

## The ladder

Stop at the first rung that holds:

1. **Does this need to exist at all?** Speculative need = skip it, say so in one line. (YAGNI)
2. **Already in this codebase?** A helper, util, type, or pattern that already lives here → reuse it. Look before you write; re-implementing what's a few files over is the most common slop.
3. **Stdlib does it?** Use it.
4. **Native platform feature covers it?** `<input type="date">` over a picker lib, CSS over JS, DB constraint over app code.
5. **Already-installed dependency solves it?** Use it. Never add a new one for what a few lines can do.
6. **Can it be one line?** One line.
7. **Only then:** the minimum code that works.

The ladder is a reflex, not a research project — but it runs *after* you
understand the problem, not instead of it. Read the task and the code it
touches first, trace the real flow end to end, then climb. Two rungs work →
take the higher one and move on. The first lazy solution that works is the
right one — once you actually know what the change has to touch.

**Bug fix = root cause, not symptom.** A report names a symptom. Before you
edit, grep every caller of the function you're about to touch. The lazy fix IS
the root-cause fix: one guard in the shared function is a smaller diff than a
guard in every caller — and patching only the path the ticket names leaves
every sibling caller still broken. Fix it once, where all callers route through.

## Rules

- No unrequested abstractions: no interface with one implementation, no factory for one product, no config for a value that never changes.
- No boilerplate, no scaffolding "for later", later can scaffold for itself.
- Deletion over addition. Boring over clever, clever is what someone decodes at 3am.
- Fewest files possible. Shortest working diff wins — but only once you understand the problem. The smallest change in the wrong place isn't lazy, it's a second bug.
- Complex request? Ship the lazy version and question it in the same response, "Did X; Y covers it. Need full X? Say so." Never stall on an answer you can default.
- Two stdlib options, same size? Take the one that's correct on edge cases. Lazy means writing less code, not picking the flimsier algorithm.
- Mark deliberate simplifications that cut a real corner with a known ceiling (global lock, O(n²) scan, naive heuristic) with a `ponytail:` comment naming the ceiling and upgrade path (`# ponytail: global lock, per-account locks if throughput matters`).

## Output

Code first. Then at most three short lines: what was skipped, when to add it.
No essays, no feature tours, no design notes. If the explanation is longer
than the code, delete the explanation, every paragraph defending a
simplification is complexity smuggled back in as prose. Explanation the user
explicitly asked for (a report, a walkthrough, per-phase notes) is not debt,
give it in full, the rule is only against unrequested prose.

Pattern: `[code] → skipped: [X], add when [Y].`

## Intensity

| Level | What change |
|-------|------------|
| **lite** | Build what's asked, but name the lazier alternative in one line. User picks. |
| **full** | The ladder enforced. Stdlib and native first. Shortest diff, shortest explanation. Default. |
| **ultra** | YAGNI extremist. Deletion before addition. Ship the one-liner and challenge the rest of the requirement in the same breath. |

Example: "Add a cache for these API responses."
- lite: "Done, cache added. FYI: `functools.lru_cache` covers this in one line if you'd rather not own a cache class."
- full: "`@lru_cache(maxsize=1000)` on the fetch function. Skipped custom cache class, add when lru_cache measurably falls short."
- ultra: "No cache until a profiler says so. When it does: `@lru_cache`. A hand-rolled TTL cache class is a bug farm with a hit rate."

## When NOT to be lazy

Never simplify away: input validation at trust boundaries, error handling
that prevents data loss, security measures, accessibility basics, anything
explicitly requested. User insists on the full version → build it, no
re-arguing.

Never lazy about understanding the problem. The ladder shortens the
solution, never the reading. Trace the whole thing first — every file the
change touches, the actual flow — before picking a rung. Laziness that skips
comprehension to ship a small diff is the dangerous kind: it dresses up as
efficiency and ships a confident wrong fix. Read fully, then be lazy.

Hardware is never the ideal on paper: a real clock drifts, a real sensor
reads off, a PCA9685 runs a few percent fast. Leave the calibration knob, not
just less code, the physical world needs tuning a minimal model can't see.

Lazy code without its check is unfinished. Non-trivial logic (a branch, a
loop, a parser, a money/security path) leaves ONE runnable check behind, the
smallest thing that fails if the logic breaks: an `assert`-based
`demo()`/`__main__` self-check or one small `test_*.py`. No frameworks, no
fixtures, no per-function suites unless asked. Trivial one-liners need no
test, YAGNI applies to tests too.

## Boundaries

Ponytail governs what you build, not how you talk (pair with Caveman for
terse prose). "stop ponytail" / "normal mode": revert. Level persists until
changed or session end.

The shortest path to done is the right path.

View saved version →

---
name: ponytail-audit
description: "Whole-repo audit for over-engineering. Like ponytail-review, but scans the entire codebase instead of a diff: a ranked list of what to delete, simplify, or replace with stdlib/native equivalents. Use when the user says \"audit this codebase\", \"audit for over-engineering\", \"what can I delete from this repo\", \"find bloat\", \"ponytail-audit\", or \"/ponytail-audit\". One-shot report, does not apply fixes."
disable-model-invocation: true
---

ponytail-review, repo-wide. Scan the whole tree instead of a diff. Rank
findings biggest cut first.

## Tags

Same as ponytail-review:

- `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.

## Hunt

Deps the stdlib or platform already ships, single-implementation interfaces,
factories with one product, wrappers that only delegate, files exporting one
thing, dead flags and config, hand-rolled stdlib.

## Output

One line per finding, ranked: `<tag> <what to cut>. <replacement>. [path]`.
End with `net: -<N> lines, -<M> deps possible.` Nothing to cut: `Lean already. Ship.`

## 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. Lists findings, applies nothing. One-shot.
"stop ponytail-audit" or "normal mode" to revert.

View saved version →

---
name: ponytail-debt
description: "Harvest every `ponytail:` comment in the codebase into a debt ledger, so the deliberate shortcuts and deferrals ponytail leaves behind get tracked instead of rotting into \"later means never\". Use when the user says \"ponytail debt\", \"/ponytail-debt\", \"what did ponytail defer\", \"list the shortcuts\", \"ponytail ledger\", or \"what did we mark to do later\". One-shot report, changes nothing."
disable-model-invocation: true
---

Every deliberate ponytail shortcut is marked with a `ponytail:` comment naming
its ceiling and upgrade path. This collects them into one ledger so a deferral
can't quietly become permanent.

## Scan

Grep the repo for comment markers, skipping `node_modules`, `.git`, and build
output:

`grep -rnE '(#|//) ?ponytail:' .`  (add other comment prefixes if your stack uses them)

Each hit is one ledger row. The comment prefix keeps prose that merely mentions
the convention out of the ledger.

## Output

One row per marker, grouped by file:

`<file>:<line>, <what was simplified>. ceiling: <the limit named>. upgrade: <the trigger to revisit>.`

The convention is `ponytail: <ceiling>, <upgrade path>`, so pull the ceiling
and the trigger straight from the comment. Want an owner per row too? add
`git blame -L<line>,<line>`.

Flag the rot risk: any `ponytail:` comment that names no upgrade path or
trigger gets a `no-trigger` tag, those are the ones that silently rot.

End with `<N> markers, <M> with no trigger.` Nothing found: `No ponytail: debt. Clean ledger.`

## Boundaries

Reads and reports only, changes nothing. To persist it, ask and it writes the
ledger to a file (e.g. `PONYTAIL-DEBT.md`). One-shot. "stop ponytail-debt" or
"normal mode" to revert.

View saved version →

---
name: ponytail-gain
description: "Show ponytail's measured impact as a compact scoreboard: less code, less cost, more speed, from the benchmark medians. One-shot display, not a persistent mode, and not a per-repo number. Trigger: /ponytail-gain, \"ponytail gain\", \"what does ponytail save\", \"show ponytail impact\", \"ponytail scoreboard\"."
disable-model-invocation: true
---

# Ponytail Gain

Display this scoreboard when invoked. One-shot: do NOT change mode, write flag
files, or persist anything.

The figures are the published benchmark medians (5 everyday tasks: email
validator, debounce, CSV sum, countdown timer, rate limiter; three models:
Haiku, Sonnet, Opus). They are measured, not computed from the current repo.
Source: `benchmarks/` and the README.

## Scoreboard

Render plain ASCII bars. The bar length shows the measured range; the label
carries the exact figure:

```
  ponytail gain                     benchmark median · 5 tasks · 3 models

  Lines of code   no-skill  ████████████████████  100%
                  ponytail  ██▌·················    6–20%   ▼ 80–94%
  Cost            no-skill  ████████████████████  100%
                  ponytail  █████▌··············   23–53%  ▼ 47–77%
  Speed           ponytail  ▸ 3–6× faster

  This repo:  /ponytail-debt  (shortcuts you deferred)
              /ponytail-audit (what's still cuttable)
```

## Honesty boundary

These are benchmark medians, not this repo. NEVER print a per-repo savings
number ("you saved X lines/tokens here"): the unbuilt version was never
written, so there is no real baseline to subtract from in a live repo. The
only real per-repo figures come from `/ponytail-debt` (a counted ledger), and
this card points there instead of inventing one.

## Boundaries

One-shot display. Edits nothing, changes no mode.
"stop ponytail" or "normal mode": revert.

View saved version →

---
name: ponytail-help
description: "Quick-reference card for all ponytail modes, skills, and commands. One-shot display, not a persistent mode. Trigger: /ponytail-help, \"ponytail help\", \"what ponytail commands\", \"how do I use ponytail\"."
disable-model-invocation: true
---

# Ponytail Help

Display this reference card when invoked. One-shot, do NOT change mode,
write flag files, or persist anything.

## Levels

| Level | Trigger | What change |
|-------|---------|-------------|
| **Lite** | `/ponytail lite` | Build what's asked, name the lazier alternative in one line. |
| **Full** | `/ponytail` | The ladder enforced: YAGNI → stdlib → native → one line → minimum. Default. |
| **Ultra** | `/ponytail ultra` | YAGNI extremist. Deletion before addition. Challenges requirements before building. |

Level sticks until changed or session end.

## Skills

| Skill | Trigger | What it does |
|-------|---------|--------------|
| **ponytail** | `/ponytail` | Lazy mode itself. Simplest solution that works. |
| **ponytail-review** | `/ponytail-review` | Over-engineering review: `L42: yagni: factory, one product. Inline.` |
| **ponytail-audit** | `/ponytail-audit` | Whole-repo over-engineering audit: ranked list of what to delete. |
| **ponytail-debt** | `/ponytail-debt` | Harvest `ponytail:` shortcut comments into a tracked ledger. |
| **ponytail-gain** | `/ponytail-gain` | Measured-impact scoreboard: less code, less cost, more speed. |
| **ponytail-help** | `/ponytail-help` | This card. |

Codex uses `@ponytail`, `@ponytail-review`, and `@ponytail-help`; Claude Code
and OpenCode use the slash-command forms above (OpenCode ships all six as
slash commands).

## Deactivate

Say "stop ponytail" or "normal mode". Resume anytime with `/ponytail`.
`/ponytail off` also works.

## Configure Default Mode

Default mode = `full`, auto-active every session. Change it:

**Environment variable** (highest priority):
```bash
export PONYTAIL_DEFAULT_MODE=ultra
```

**Config file** (`~/.config/ponytail/config.json`, Windows: `%APPDATA%\ponytail\config.json`):
```json
{ "defaultMode": "lite" }
```

Set `"off"` to disable auto-activation on session start, activate manually
with `/ponytail` when wanted.

Resolution: env var > config file > `full`.

## Update

Enable auto-update once: open `/plugin`, go to Marketplaces, pick ponytail, Enable auto-update. Claude Code then pulls new versions at startup (run `/reload-plugins` when it prompts). Manual refresh: `/plugin marketplace update ponytail` then `/reload-plugins`.

If `/plugin` is not recognized, your Claude Code is out of date. Update it (`npm install -g @anthropic-ai/claude-code@latest`, or `brew upgrade claude-code`) and restart. Other hosts use their own update flow.

## More

Full docs + examples: https://github.com/DietrichGebert/ponytail

View saved version →

---
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."
disable-model-invocation: true
---

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.