Ponytail Claude: Install the Lazy-Senior Coding Skill (MIT)

What Ponytail is

Ponytail is one prompt (skills/ponytail/SKILL.md) plus adapters that load it into coding agents. The author's pitch: channel a "lazy senior" who solves the task with the least new code, prefers the standard library, and still keeps validation, error handling, security and accessibility. It is not a Claude model and not an Anthropic product — it is a third-party skill you attach to your agent.

License: MIT. Repo: DietrichGebert/ponytail.

Install in Claude Code (official)

Send these as two separate prompts (one install needs both):

/plugin marketplace add DietrichGebert/ponytail

/plugin install ponytail@ponytail

Then start a new session so the plugin loads. In the Claude Code Desktop app's Code tab you can type the same two /plugin commands, or use + → Plugins → Add plugin.

Node on PATH: the Claude Code / Codex plugins run small Node lifecycle hooks. If node is missing you still get the skills, but you may see a harmless node: command not found on each hook call — install Node (or put it on the non-interactive shell PATH) to silence it.

Levels

Level	Behavior (from the project's skill docs)
lite	Build what was asked; name a smaller option in one line and let you pick.
full	Default "lazy senior" ruleset.
ultra	Also push back on parts of the request that the need does not justify.
off	Turn Ponytail off for the session.

Set the default for new sessions with env PONYTAIL_DEFAULT_MODE=lite|full|ultra|off, or defaultMode in ~/.config/ponytail/config.json (Windows: %APPDATA%\ponytail\config.json). Default is full.

Commands (skill-capable hosts)

Command	What it does
/ponytail [lite|full|ultra|off]	Set intensity, or report the current level when called with no argument (if off, turns it on at the default).
/ponytail-review	Review the current diff for bugs, security, load, missing tests, slow paths, and what to cut.
/ponytail-audit	Same checks for the whole repo, ranked.
/ponytail-debt	Collect deferred shortcut: comments into a ledger.
/ponytail-gain	Show the project's measured impact scoreboard from its benchmark.
/ponytail-help	Quick reference.

These need a skill-capable host (Claude Code, Codex, and others listed in the repo). Instruction-only adapters (some Cursor/Windsurf/Cline setups) load the always-on rules without the slash commands.

Other agents (short)

Official install paths also exist for Codex, GitHub Copilot CLI, OpenCode, Gemini CLI, Cursor hooks, and more — see the project's INSTALL.md. Skills-only install: npx skills add DietrichGebert/ponytail.

Benchmark claim (author's, not ours)

The README for Ponytail 5 reports an internal Claude Code benchmark (39 tasks, Opus 5.5, 5 runs each) with less code/time/cost/tokens and higher test coverage on risky logic versus the same agent without the skill. Treat those numbers as the maintainer's published results, not an independent Toolsiftly lab test. Method link in the repo: benchmarks/results/2026-10-07-agentic.md.

Safety

• Install only from DietrichGebert/ponytail on GitHub or @dietrichgebert/ponytail on npm. The author warns that copies shipping .exe / .dll are not theirs.
• Related Toolsiftly page: Claude Code Mods (general mod concepts). This page is the Ponytail-specific install guide.