Ponytail
DietrichGebert/ponytail
Makes a coding agent write only the code a task needs, reaching for built-in and existing options first.
Ponytail is a free, MIT-licensed pack of 6 agent skills by Dietrich Gebert that pushes a coding agent toward the smallest solution that works. Before writing code the agent walks a seven-step ladder: skip it, reuse it, use the standard library, use a native platform feature, use an installed dependency, write one line, and only then write the minimum. It installs as a plugin in Claude Code, Codex, GitHub Copilot CLI, Gemini CLI and other agents, with hooks that keep it active in every session.
Facts checked on against the sources listed at the end of this page.
- GitHub stars
- 151,446
- Skills in the pack
- 6
- Agents supported
- 15plus rule files for Windsurf, Cline, Kiro and others
- Instruction size
- 2.5k wordsacross all SKILL.md files
How to install Ponytail
| Agent | Command | Copy |
|---|---|---|
| Claude Code | Send the two commands as separate prompts. | |
| Codex | Then open /hooks in Codex, review and trust its two lifecycle hooks, and start a new thread. | |
| Cursor | Adds two hooks to ~/.cursor/hooks.json. Keep the checkout where it is, because the hooks run from it. | |
| Gemini CLI | | |
| GitHub Copilot CLI | |
Commands for 8 more agents
| Pi | | |
|---|---|---|
| Antigravity CLI | | |
| Hermes Agent | Restart Hermes after installing. | |
| Devin CLI | | |
| Grok Build | The plugin is off by default. Enable it under /plugins. | |
| OpenClaw | | |
| OpenCode | Add "@dietrichgebert/ponytail" to the plugins list in opencode.json. | |
| Windsurf, Cline, Kiro and other rule-based tools | Copy the matching rules file from the repo. This loads the always-on ruleset without the commands. |
Commands as given in the README on 2 October 2026.
What is inside Ponytail
| Skill | What it makes the agent do |
|---|---|
| ponytail | The always-on ruleset. Sets the level to lite, full, ultra or off, and reports the current level when called with no argument. |
| ponytail-review | Reviews the current diff for over-engineering and returns a list of things to delete. |
| ponytail-audit | Audits the whole repo for over-engineering, not only the diff. |
| ponytail-debt | Collects the shortcuts marked with ponytail comments into a ledger so deferred work is not forgotten. |
| ponytail-gain | Shows the measured results from the maker's benchmark. |
| ponytail-help | A quick reference for the commands. |
What Ponytail runs on your machine
| Hooks | Yes. The Claude Code and Codex plugins and the Cursor install run two Node.js lifecycle hooks that load the ruleset into each session and into subagents. Node must be on your PATH. |
|---|---|
| Bundled scripts | Yes. The hooks are JavaScript files, and the repo ships install and uninstall scripts for Cursor. |
| Network calls | None named in the README. |
| API keys needed | None. An optional config file or the PONYTAIL_DEFAULT_MODE variable sets the default level. |
These are facts read from the repo, not a security rating. Read the files before you install any skill.
How much context Ponytail uses
| All 6 skills | 2,538 words across every SKILL.md file |
|---|---|
| Largest skill | ponytail, 1,079 words |
| Loaded at start | Only each skill's name and description. The full text loads when a task needs that skill. |
Word counts are measured from the repo every day. Reference files a skill loads on demand are not counted.
How Ponytail works
Ponytail is aimed at one habit of coding agents: building more than the task needs. Its example is a date picker. Asked for one, an agent installs a library and writes a wrapper component, where Ponytail's rules lead it to the browser's native date input. The agent reads the code the change touches first, then stops at the first rung of the ladder that holds.
The README says the rule is not the fewest tokens: validation at trust boundaries, error handling, security and accessibility are never cut. The maker's own benchmark, run on Claude Code with a real FastAPI and React repo across 12 feature tasks, reports about 54% fewer lines of code than the same agent without the skill. The README notes the cut is near zero where code is already minimal.
A good fit for
- Codebases where agents add dependencies, wrappers and abstractions nobody asked for
- Reviews: ponytail-review and ponytail-audit return a concrete list of code to remove
- People who want the rule active in every session without calling a skill
- Using next to a prose-compression skill, since Ponytail changes the code and leaves the wording alone
Skip it if
- Setups without Node on the PATH: the skills still work but the always-on hooks stay quiet
- People who want nothing written outside the plugin folder: it keeps a mode flag and config file in your home directory
- Cursor subagents and cloud agents, which the README says do not receive the ruleset
- Expecting lower cost on every model: the README says a reasoning model can spend more tokens deciding, and names GPT-5.5 as one that does
Is Ponytail still maintained?
| Last commit | , 3 hours ago |
|---|---|
| Latest release | v4.10.1, 2 October 2026 |
| Stars gained in 7 days | Shown after 7 days of tracking |
| Stars gained in 30 days | Shown after 30 days of tracking |
| Open issues and pull requests | 309 |
| Forks | 8,120 |
Tools Ponytail works with
Questions about Ponytail
What does Ponytail do?
It makes a coding agent check whether code needs to exist at all, then prefer existing code, the standard library, native platform features and installed dependencies before writing anything new.
How much less code does Ponytail write?
The maker's benchmark reports about 54% fewer lines on average across 12 feature tasks, up to 94% where an agent would over-build, and near zero where code is already minimal. These are the maker's own numbers, with the method published in the repo.
How do I uninstall Ponytail?
In Claude Code run /plugin remove ponytail, and in Codex run codex plugin remove ponytail. Run node scripts/uninstall.js first if you also want to remove the mode flag, config file and status line entry it leaves outside the plugin folder.
Does Ponytail work with Cursor?
Yes, in two ways. The hooks install gives you level switching in every chat, and the rule file in .cursor/rules loads the ruleset without commands. The README says to use one or the other.
Is Ponytail free?
Yes. It is open source under the MIT license.