ponytail

---
name: ponytail
description: Use when you want an AI coding agent to write less code — it runs a decision ladder before generating anything, reaching for existing code, stdlib, and native features first.
source: https://github.com/DietrichGebert/ponytail
generated: 2026-07-06T05:24:31.742Z
category: concept
audience: engineers
---

## When to use

- Stopping an agent from reflexively writing new code when the feature already exists or isn't needed
- Enforcing a minimalist bias across a codebase to cut diff size, cost, and review time
- Making an agent prefer stdlib, native platform features, and installed packages over hand-rolled code
- Standardizing a 'least code that works' policy across Claude Code, Codex, Copilot CLI, and other agents

## Key concepts

### Decision ladder

Before writing code, the agent walks a fixed sequence: Is this needed? Does it already exist? Can stdlib do it? Is there a native feature? Is an installed package available? Can it be one line? Only after exhausting these does it write new, minimal code.

### The best code is the code you never wrote

Ponytail's core principle: every line added is a line to maintain, review, and pay for. The cheapest, safest, fastest code is the code that was never generated in the first place.

### Safety is non-negotiable

Minimalism never trades away validation, error handling, security, or accessibility. In the authors' testing, safety was maintained at 100% while code volume dropped.

### Multi-platform plugin

Ships as an installable plugin/skill for Claude Code, Codex, GitHub Copilot CLI, OpenCode, Gemini, Devin and others, with manual file-copy for tools lacking a plugin system.

### Measured impact

On a real FastAPI + React codebase the authors report roughly 54% less code, ~20% cheaper, and ~27% faster runs versus an unguided agent.

## API reference

```
/plugin marketplace add DietrichGebert/ponytail
```

Install ponytail as a Claude Code plugin so the decision ladder is applied before code generation.

```
/plugin marketplace add DietrichGebert/ponytail
```

## Gotchas

- Minimalism is not an excuse to skip validation, error handling, security, or accessibility — those stay in
- Reaching for an installed package is preferred over hand-rolling, but don't add a new heavy dependency just to save a few lines
- The ladder only helps if the agent actually checks whether the code exists first — encourage it to search the repo before writing
- Tools without a plugin system need the files copied in manually; the behavior isn't automatic there

---
Generated by SkillMake from https://github.com/DietrichGebert/ponytail on 2026-07-06T05:24:31.742Z.
Verify against source before relying on details.

File: ~/.claude/skills/ponytail/SKILL.md