概要
The Defense-in-Depth skill provides a rigorous framework for hardening software by enforcing data validation at every layer of execution, including entry points, business logic, environment guards, and debug instrumentation. By moving beyond single-point checks, this skill helps developers create systems where bugs are caught regardless of code paths, mocks, or refactoring, ensuring that invalid data cannot cause failures deep within the system. It is particularly effective for backend development where data integrity and environment-specific safety are critical to system stability.
