Ponytail Skill for Claude Code: GitHub Repo and Install

Ask a coding agent for a date picker and it may install a library, write a wrapper component and add a stylesheet. The ponytail skill steers Claude Code to <input type="date"> instead. It has 52,419 installs (skills.sh registry, GitHub).

Key takeaways

• The core ponytail skill has 52,419 installs and 128,041 catalog stars (skills.sh registry, GitHub). The repo is MIT licensed and was created on June 12, 2026 (GitHub).
• A 7-rung ladder makes the agent prefer existing code, the stdlib and native platform features over new code.
• One install brings 6 skills. ponytail-review (20,878 installs) and ponytail-audit (19,482 installs) list what to delete and change no files.
• The project's README reports 54% fewer lines of code and 20% lower cost than a no-skill baseline on Haiku 4.5 (n=4), against 20% fewer lines and 3% higher cost for caveman.
• The README recommends running it next to caveman, which shortens what the agent says. See the caveman skill guide.

What is the Ponytail skill for Claude Code?

Ponytail is a SKILL.md ruleset that tells Claude Code to write only the code a task needs. The GitHub repo description reads "Makes your AI agent think like the laziest senior dev in the room." The ponytail GitHub repo holds the SKILL.md files, examples and the benchmark harness.

The agent first reads the code a change touches, then climbs the ladder and stops at the first rung that holds: skip it if nobody needs it, reuse what the codebase has, use the stdlib, a native platform feature or an installed dependency, write one line, and only then write the minimum that works.

The laziness has hard limits in the SKILL.md. It never removes input validation at trust boundaries, error handling that prevents data loss, security measures or accessibility basics. For a bug fix, the agent greps every caller and puts one guard in the shared function. Non-trivial logic leaves one runnable check behind, such as an assert-based self-check. The reply is code first, then at most three short lines about what it skipped.

There are 3 levels. lite builds what you asked and names the lazier option, full (the default) enforces the ladder, and ultra challenges the requirement itself. Switch with /ponytail lite, /ponytail full or /ponytail ultra, and turn it off with stop ponytail.

What is the best Ponytail skill to install first?

Install the core ponytail skill first: 52,419 installs and 128,041 stars (skills.sh registry, GitHub), the highest count of the 6. The README gives two Claude Code commands and says to send them as two separate prompts:

/plugin marketplace add DietrichGebert/ponytail

/plugin install ponytail@ponytail

That install adds all 6 skills and two Node.js lifecycle hooks that switch on full mode every session, so node must be on your PATH. Without Node, the README says the skills still work and only the automatic activation stops. If you only want a reviewer, the ponytail-review skill has 20,878 installs. Compare it with other picks in Best skills for Testing & Review or browse the Testing & Review category.

Which Ponytail command should you use: review, audit, debt, gain or help?

Use review for a diff, audit for a whole repo and debt for the shortcuts you deferred. Each of the 5 extra skills is a one-shot command.

• /ponytail-review (20,878 installs) reviews the current diff for over-engineering. Each finding is one line with a tag (delete:, stdlib:, native:, yagni: or shrink:), and the report ends with net: -N lines possible.
• /ponytail-audit (19,482 installs) applies the same tags to the whole tree, ranks findings biggest cut first, and ends with the lines and dependencies you could remove.
• /ponytail-debt (18,130 installs) greps for ponytail: comments, the markers the core skill puts on deliberate shortcuts, and builds a ledger of each ceiling and upgrade trigger. A marker with no trigger gets a no-trigger tag.
• /ponytail-gain (16,775 installs) prints a fixed benchmark scoreboard. Its SKILL.md forbids printing a savings number for your repo.
• /ponytail-help (18,182 installs) shows the levels, the commands and the default-mode settings.

Review and audit skip correctness bugs, security holes and performance, so keep a regular reviewer from best code review skills for Claude Code. In Codex, the README says you call the same skills with @, as in @ponytail-review.

How does Ponytail compare to caveman?

The two skills cut different output, and the README tells you to run both. caveman, with 486,810 installs (skills.sh registry, GitHub), makes the agent talk less. Ponytail makes it build less.

The project's agentic benchmark writeup gave Claude Code on Haiku 4.5 twelve feature tickets against the full-stack-fastapi-template repo, four runs each. Against the same agent with no skill, the README reports ponytail at 54% fewer lines, 22% fewer tokens, 20% lower cost and 27% less time, with 100% on its safety checks. It reports caveman at 20% fewer lines but 7% more tokens, and a short YAGNI one-liner prompt at 33% fewer lines with 95% on safety. The largest cut in the README is a date picker that went from 404 lines to 23. These are the author's own measurements. For token savings from the prose side, read Claude skills to reduce token usage.

When can Ponytail make results worse?

The writeup lists its own limits. The agentic run used one model, Haiku 4.5, with 4 runs per task. The README also says a terse reasoning model can spend more thinking tokens on the ladder and cost more, and reports that result on GPT-5.5.

The safety tier was 6 surgical tasks with deterministic checks. The writeup says this shows whether an arm drops a known guard and does not prove the code is secure. On code that is already minimal, the README reports a cut near zero.

While ponytail is active, the ruleset also goes into every subagent Claude Code starts. To limit that, set PONYTAIL_SUBAGENT_MATCHER to a regex of the agent types that should get it.

A complete starter stack

1. ponytail skill in full mode, for fewer lines on tasks that tempt the agent to over-build.
2. /ponytail-review on each diff before merge, to read the net: line.
3. A correctness and security reviewer, since ponytail-review skips both.
4. /ponytail-debt before a release, so each ponytail: shortcut lands in a ledger with its upgrade trigger.
5. caveman skill, if you also want shorter replies.

Common pitfalls

• Quoting /ponytail-gain as your savings. The card shows the older single-shot figures of 80 to 94% less code, which the README now calls a per-task ceiling. The agentic mean it reports is 54%.
• Pasting both install commands into one prompt. The README says the install needs two prompts, and nvm or Nix users must put node on the non-interactive shell's PATH.
• Removing the plugin first. Run node scripts/uninstall.js before /plugin remove ponytail, or the mode flag, ~/.config/ponytail/config.json and any statusLine entry stay on disk.

Install the core skill, run /ponytail-review on your next diff, and check the net: line before you merge.

Common questions