When to Use Use this skill when: - Adding new behavior - Fixing a bug - Refactoring logic with branch complexity --- TDD Loop 1. Write a failing test for the target behavior. 2. Implement the smallest code to pass. 3. Refactor while keeping tests green. 4. Add edge/error-path tests before closing. --- Coverage Rules - Cover happy path + error paths + edge cases. - Prefer deterministic tests over flaky integration paths. - Add seams only when branches are impossible to trigger naturally. - Keep runtime behavior unchanged when adding seams. --- Validation Commands Run: Report package coverage a…