defense-in-depth

Layered validation enforces data integrity checks across API boundaries, business logic, environment guards, and debug instrumentation. This defense-in-depth approach prevents invalid input from propagating deep into the execution path.

Apply defense-in-depth validation at entry points, business logic, environment guards, and debug instrumentation. This layered approach catches invalid data across API boundaries before it propagates deep into the execution path.

Implement the four-layer validation model by adding entry point checks for incoming API data, enforcing business logic rules, setting environment guards, and adding debug instrumentation to catch defects during software development and QA.

Apply defense-in-depth validation during software development and QA, specifically during bug fixes. Layered checks ensure a defect cannot bypass early validation and propagate through the stack, reducing late-stage failures.

No dependencies are required. You need a properly formatted SKILL.md frontmatter with name and description, and may include optional scripts, references, or assets directories to support activation of the layered validation model.

Relying solely on entry point validation risks deep execution failures if invalid data bypasses early checks. Without business logic validation, environment guards, and debug instrumentation, late-stage failures remain a significant risk.