ponytail

Apply a simplicity ladder: first question whether the feature needs to exist, then check the standard library, native platform features, and already-installed dependencies before writing custom code. Stop at the first rung that solves the problem.

YAGNI means You Aren't Gonna Need It — skip building features based on speculative future needs. This Skill enforces it by questioning whether each task needs to exist and shipping only the minimum code that works.

Use the standard library whenever it covers the requirement, such as functools.lru_cache instead of a custom cache class. Never add a new dependency for something a few lines of existing code can accomplish.

Never simplify away input validation at trust boundaries, error handling that prevents data loss, security measures, accessibility basics, or anything explicitly requested. If the user insists on the full version, build it without re-arguing.

Use /ponytail lite, full, or ultra to change intensity. Lite names a lazier alternative while building what's asked, full enforces the simplicity ladder by default, and ultra aggressively deletes and challenges requirements.