ponytail: make Claude write the least code that works

AI assistants tend to over-build: a helper class where one line would do, a new dependency where the standard library already has it. ponytail makes Claude behave like the senior developer who replaces fifty lines with one, while never cutting validation, error handling, security or accessibility.

What’s inside: skills, slash commands, hooks. Published by: a third party, DietrichGebert/ponytail.

How it works

ponytail is essentially one prompt, skills/ponytail/SKILL.md. Before writing code, Claude reads the code the change touches, then climbs a "ladder" and stops at the first rung that holds:

  • Does this need to exist at all?
  • Is it already in this codebase?
  • Does the standard library do it?
  • Is there a native platform feature?
  • Does an installed dependency do it?
  • Can it be one line?
  • Only then: the minimum that works, plus one small test if it has logic.

Logic with a branch, a loop, a parser, money or security leaves a small test behind, and every reply ends with what was skipped or not checked. Hooks switch the mode on at session start (and for subagents) and track level changes, and a session-start map lists the project’s existing functions and exports so "reuse first" doesn’t cost a search.

Install

/plugin marketplace add DietrichGebert/ponytail
/plugin install ponytail@ponytail
claude plugin marketplace add DietrichGebert/ponytail
claude plugin install ponytail@ponytail

Skip the first line if you already added the ponytail marketplace. Reload the VS Code window or restart claude afterwards. New to plugins? See the install guide in this series.

How to use it

Once installed it is on by default at the full level. Switch levels with /ponytail lite, /ponytail full or /ponytail ultra, or turn it off with /ponytail off (or say "stop ponytail"). The default level can also be set with the PONYTAIL_DEFAULT_MODE environment variable.

  • /ponytail [lite|full|ultra|off]
  • /ponytail-review
  • /ponytail-audit
  • /ponytail-debt
  • /ponytail-gain
  • /ponytail-help
  • Add CSV export to the report page, ponytail
  • /ponytail-review
  • This feels over-engineered. Simplest solution that still works?

Good use cases

  • Keeping AI-written changes small and easy to review
  • Reviewing a diff for bugs, risky code without tests and code to cut (/ponytail-review), or the whole repo (/ponytail-audit)
  • Tracking deliberate shortcuts: it marks them with shortcut: comments, and /ponytail-debt collects them into a ledger

When not to use it

Prototypes where you want Claude to explore broadly, or when you have explicitly asked for a full abstraction. You can still insist on more code; ponytail will build it.