Ponytail is an MIT-licensed skill that inserts a seven-step decision ladder (YAGNI, codebase reuse, stdlib, native platform features, installed dependencies, one-liner, minimum viable) into AI coding agents to skip unnecessary code before generation.

Benchmarks on 12 feature tasks with Claude Code show a 54% reduction in lines of code, 20% lower cost, and 27% faster output while retaining all safety guards, compared to a no-skill baseline. It ships as an npm package and supports integration with 20+ agents.