As I refactored WDN, I realized I had no single source of truth for feature names, periods, or required input columns. Now: every feature is declared via a simple registry. Inputs, outputs, period compatibility, and compute function are all bundled. This change let me dry-run the entire DAG across 100+ feature/period combos in a few seconds... and catch the 12 that were silently doing nothing. [[ML]] [[Serendipity]]