Test-driven development (for agents)

Prove intended product behavior with a failing test first, then make it pass with the smallest change. "Looks right" is not done.

Scope

In scope (full cycle): features and bug fixes in app code; domain rules, mapping, validation, non-trivial helpers; HTTP / persistence / CRUD contracts; regression guards for bugs with a meaningful automated hook.

Out of scope (no new test; never add one that only mirrors a literal you set):