ponytail

ponytail is a skill for Claude Code from alonbaron/claude-skills. It costs 74 tokens per session (1,999 once invoked), scanned A, original, MIT.

A coding guideline that pushes solutions toward the smallest approach that actually works, using existing code and standard tools where possible.

In plain words
What is it for?
Use it while designing or reviewing implementation choices, especially when a change is growing beyond a simple solution. It encourages checking for reusable code and stopping at the first sufficient approach.
Why use it?
It helps avoid unnecessary abstractions, dependencies, scaffolding, and maintenance work for needs that may never arise.

Skill for Claude Code

Written for Claude Code: argument-hint in frontmatter. Also seen: mentions subagents.

Part of the alon-skills plugin — 6 skills shipped together

Good fit Use it while designing or reviewing implementation choices, especially when a change is growing beyond a simple solution. It encourages checking for reusable code and stopping at the first sufficient approach.

Compare 6 skills from other repositories ↓
Install with agentmods
npx agentmods add skills/alonbaron/claude-skills/ponytail
Install

Getting it into your agent

One page per mod, every tool's command on it. A separate URL per tool would split the same page into five that compete with each other.

Any agent
npx skills add alonbaron/claude-skills --skill ponytail
Clone the repo
git clone --depth 1 https://github.com/alonbaron/claude-skills

Made for: Claude Code.

Or install alon-skills, the plugin that ships this one along with the rest of its 6 skills.

Wrote this? Show the measurements

A badge with what this costs and how it scanned, read live from this page, so it follows the numbers instead of freezing them. Markdown for a README, HTML for a documentation site or a project page.

agentmods badge for ponytail

README.md
[![agentmods](https://agentmods.dev/badge/skills/alonbaron/claude-skills/ponytail/github.svg)](https://agentmods.dev/skills/alonbaron/claude-skills/ponytail)
Your own site
<a href="https://agentmods.dev/skills/alonbaron/claude-skills/ponytail"><img src="https://agentmods.dev/badge/skills/alonbaron/claude-skills/ponytail/github.svg" alt="Measured on agentmods" height="20"></a>

Or the 80×15 button, for a site that already has a row of RSS and ATOM ones. Only the verdict fits; the numbers stay here.

agentmods 80×15 button for ponytail

Your own site · 80×15
<a href="https://agentmods.dev/skills/alonbaron/claude-skills/ponytail"><img src="https://agentmods.dev/badge/skills/alonbaron/claude-skills/ponytail.svg" alt="Reviewed on agentmods" width="80" height="20"></a>
Per session 74 Skills are progressive disclosure: only the name and description are preloaded; the body loads when the skill is used.
When invoked 1,999 The whole file, excluding the scripts and references it only reads on demand.
Security scan A 0 findings. A grade says what 26 rules found in the file — not that it is safe.
Origin original No closer match found in the catalogue.
Token cost

What it costs to keep this loaded

Counted locally with the o200k_base tokenizer, which is exact for GPT models; Claude uses its own tokenizer and its counts differ. Treat this as one consistent yardstick across the catalogue rather than a bill. Prices are per million input tokens.

ModelPer sessionOnce invoked
Fable 5.1 $0.00074 $0.01999
Opus 5.5 $0.00030 $0.00800
Sonnet 5.5 $0.00015 $0.00400
Haiku 4.5 $0.00007 $0.00200

Measured 1mo ago against content hash 2765bd2c2f92, method: parsed. Prices are Anthropic first-party input rates as of 2026-10-07, from the pricing page.

Security

Grade A, and why

ponytail scanned grade A with 0 findings against 26 rules in 11 categories — prompt injection, anti-refusal, data exfiltration, privilege escalation, supply chain, agent snooping, system-prompt leakage, SSRF and excessive agency — measured 1mo ago.

A static scan of the body, not an audit. Every finding is printed with the line that produced it so you can judge whether it matters here. A mod is markdown that instructs an agent; that is exactly why what it instructs is worth reading.

Nothing flagged

None of the 26 patterns this scan looks for appear in this file: no shell pipes, no recursive deletes, no credential paths, no hidden text, no instruction-override or anti-refusal phrasing, no agent-config snooping. That is not a guarantee, it is the absence of the things that are checkable.

skills/ponytail/SKILL.md · 150 lines

How it starts

The opening of the file, as written. The whole thing — 150 lines — stays where its author put it; the contents beside it link to each section on GitHub.

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.

Proactive use

Invoke without being asked whenever a solution is outgrowing the minimum: announce in one line ("Ponytail: <what's over-built>") and proceed. Never ask permission to run it.

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 with a ponytail: comment (// ponytail: this exists), simple reads as intent, not ignorance. Shortcut with a known ceiling (global lock, O(n²) scan, naive heuristic)? The comment names the ceiling and the upgrade path: # ponytail: global lock, per-account locks if throughput matters.

Read the full file on GitHub · 150 lines

Changes

What this file has done since we first saw it

Hashed on every crawl. A supply-chain change to an agent config is a question of when, not whether, so the history is kept rather than the latest state alone.

  1. 1mo ago Changed · +12 lines · -82 tokens per session 2765bd2c2f92
  2. 1mo ago First seen · 138 lines · 156 tokens per session scan A 6992ddbba675

Subscribe to this mod's changes

ponytail is a skill published in the GitHub repository alonbaron/claude-skills (13 stars, last pushed 4d ago), licensed MIT. It adds 74 tokens to every session and 1,999 once invoked, about $0.0003 per session on Opus 5.5. A static security scan graded it A with 0 findings. No closer match exists in the catalogue, so it is treated as the original; first seen 2026-08-30.

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