deepen — make modules deep Behavior is sacred: tests green before AND after. Every change shrinks an interface or hides a decision — deepen, don't churn. A deep module hides a lot behind a small interface; a shallow one's interface costs as much to use as writing the code yourself. Complexity = dependencies + obscurity, and it compounds. Deepen spends spare usage paying that down before it becomes a §B. Run it when the build is green & you have budget to drain — not under deadline. WHEN TO DEEPEN - Build is green, tests pass, & you have token budget spare. - A module's interface feels as comp…