ponytail

ponytail is a skill for Claude Code, Codex from bartoszarendt/agenticloop. It costs 137 tokens per session (1,982 once invoked), scanned A, original, MIT.

A rule for keeping code changes as small and simple as possible while still meeting the task. It applies only when a maintainer or engineer explicitly enables this minimalist approach.

In plain words
What is it for?
Choosing the simplest implementation, limiting the size of a change, and avoiding features or structure that the task does not require.
Why use it?
It helps avoid unnecessary files, abstractions, and complexity that make software harder to understand and maintain. It still requires needed validation, security, accessibility, error handling, and checks.

Skill for Claude CodeCodex

Part of the agenticloop plugin — 18 skills, 2 commands, 4 agents shipped together

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.

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

Made for: Claude Code, Codex.

Or install agenticloop, the plugin that ships this one along with the rest of its 18 skills, 2 commands, 4 agents.

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/bartoszarendt/agenticloop/ponytail.svg)](https://agentmods.dev/skills/bartoszarendt/agenticloop/ponytail)
Your own site
<a href="https://agentmods.dev/skills/bartoszarendt/agenticloop/ponytail"><img src="https://agentmods.dev/badge/skills/bartoszarendt/agenticloop/ponytail.svg" alt="Measured on agentmods" height="20"></a>
Per session 137 Skills are progressive disclosure: only the name and description are preloaded; the body loads when the skill is used.
When invoked 1,982 The whole file, excluding the scripts and references it only reads on demand.
Security scan A 0 findings. Scan, not verified.
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 $0.00137 $0.01982
Opus 5 $0.00068 $0.00991
Sonnet 5 $0.00027 $0.00396
Haiku 4.5 $0.00014 $0.00198

Measured 3d ago against content hash a0e024a83d35, method: parsed. Prices are Anthropic first-party input rates as of 2026-08-30, 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 3d 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 · 162 lines

How it starts

The opening of the file, as written. The whole thing — 162 lines — stays where its author put it; the contents beside it link to each section on GitHub.

Ponytail

Purpose

Ponytail is an opt-in minimalism discipline for maintainer and engineer work. It pushes for the least code, fewest files, and smallest accepted change that still satisfies the current task record.

Lazy means efficient, not careless. The cost being avoided is the over-engineered codebase and the 3am page for behavior nobody needed. Prefer boring over clever: clever is what someone has to decode under pressure later.

Ponytail is necessity-driven reduction, not clever terseness. Do not pick a flimsier algorithm just because it is shorter. Boring, correct, readable code beats clever one-liners. Minimalism must not remove validation, error handling that prevents data loss, security, accessibility, required checks, or explicit requirements.

When to use

  • Only when the current role is maintainer or engineer.
  • When the human explicitly asks for ponytail, lazy mode, YAGNI, the simplest solution, the minimal solution, the shortest path, or similar minimalist discipline; or when the active task record sets minimalism: lite, minimalism: full, or minimalism: ultra; or when the maintainer is selecting the task-record minimalism level during task creation.
  • Task-record minimalism selects intensity: lite, full, or ultra as set in the task record. Omitted or minimalism: none does not activate Ponytail.
  • ultra from a task record is valid only with explicit human request or authorization. Maintainers must not auto-select ultra.
  • Use it to reduce over-building inside accepted scope, not to argue away required work after the fact.
  • Default intensity is full.

Intensity

  • lite: build what was asked, then briefly mention the lazier alternative.
  • full (default): enforce the ladder within the accepted task scope and ship the shortest working solution.
  • ultra: aggressively challenge unnecessary work or accumulated complexity, but only through the allowed Agentic Loop gates. Ultra may recommend descoping or push back on incidental complexity that has crept in. Ultra must not silently drop any task-record criterion. If a criterion seems unnecessary, route it through [[change-request-gate]] when it changes a locked decision, or [[blocked-state]] with needs_context when the task record needs human clarification. Ultra never bypasses task-record criteria; it questions whether the criteria serve the accepted outcome.

Read the full file on GitHub · 162 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. 3d ago First seen · 162 lines · 0 tokens per session scan A a0e024a83d35

Subscribe to this mod's changes

ponytail is a skill published in the GitHub repository bartoszarendt/agenticloop (2 stars, last pushed 14d ago), licensed MIT. It adds 137 tokens to every session and 1,982 once invoked, about $0.0007 per session on Opus 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 2026-08-31.

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