Ponytail (AI)
Ponytail is an open-source (MIT License) AI-agent plugin/skill that enforces minimalist code generation, "He says nothing. He writes one line. It works." It counters the tendency of coding agents to over-engineer (extra dependencies, boilerplate, building when something already exists) by injecting
Canonical version: Ponytail (AI).
Ponytail is an open-source (MIT License) AI-agent plugin/skill that enforces minimalist code generation, "He says nothing. He writes one line. It works." It counters the tendency of coding agents to over-engineer (extra dependencies, boilerplate, building when something already exists) by injecting a pragmatic decision ladder the agent must follow before writing code.
The decision ladder
Does this need to exist? → no: skip it (YAGNI). Stdlib does it? → use it. Native platform feature? → use it. Installed dependency? → use it. One line? → one line. Only then: the minimum that works.
Safety guardrails (validation, error handling, security, accessibility) remain non-negotiable.
Key aspects
- Intensity levels: lite, full, ultra, off
- Code-review commands:
/ponytail-review,/ponytail-audit - Ships as Node.js lifecycle hooks; works across 14+ agents/IDEs (Claude Code, Codex, GitHub Copilot CLI, OpenCode, Gemini CLI, Cursor, Windsurf, Cline, …) via plugins, rules files, or instruction-only modes
- JavaScript + Python codebase
Measured results
Against baseline agents on real FastAPI + React tasks (mean over 12 tasks): 54% fewer lines of code, 22% fewer tokens, 20% lower cost, 27% faster, 100% safety compliance.
References
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About Sébastien
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