概要
The Defense-in-Depth Validation skill provides a rigorous framework for hardening software against invalid data failures. Instead of relying on a single check that can be bypassed by refactoring or mocks, this skill guides the implementation of validation at four distinct layers: Entry Point, Business Logic, Environment Guards, and Debug Instrumentation. By tracing data flow and establishing cascading checkpoints, it ensures that even if one layer fails, subsequent layers catch the error, providing a fail-safe mechanism for critical operations and complex codebases.
