ponytail

Activate ponytail mode, which applies a decision ladder before writing code: check if the task is needed, reuse existing code, prefer stdlib and native features, then write the minimum that works. It blocks unrequested abstractions like single-implementation interfaces and speculative configuration.

The ladder requires exhausting stdlib and already-installed dependencies before adding anything new. A new dependency is only justified when a few lines of existing tools genuinely cannot solve the problem, and the simplification tradeoff is marked with a comment.

Lite builds what is asked but names a lazier alternative in one line. Full, the default, enforces the ladder with shortest diff and explanation. Ultra is YAGNI-extremist, preferring deletion and challenging the requirement itself while shipping a one-liner.

Never simplify away input validation at trust boundaries, error handling preventing data loss, security measures, accessibility basics, or anything explicitly requested. Hardware-facing code also needs calibration knobs that a minimal model cannot anticipate.

No. Non-trivial logic such as branches, loops, parsers, or money and security paths must leave one runnable check, like an assert-based self-check or a single small test file. Trivial one-liners need no test since YAGNI applies to tests too.