When should I use the Defense-in-Depth skill?

Use it when fixing bugs caused by invalid data that originated far from where the failure actually occurred, or when hardening systems against edge cases.

What is the Defense-in-Depth validation pattern?

It is a strategy of validating data at every layer of a system—Entry, Business, Environment, and Debug—to ensure bugs are structurally impossible rather than just fixed in one location.

Does this replace unit testing?

No, it complements testing by ensuring that the application itself is resilient enough to catch errors that tests might miss due to mocking or narrow scope.

How does this skill improve code reliability?

It ensures that even if one validation layer is bypassed by a mock or refactor, other layers catch invalid data before it causes a critical failure deep in execution.

What are Environment Guards in this context?

Environment Guards are Layer 3 checks that prevent dangerous operations (like git init or file deletion) from occurring in specific contexts, such as during automated testing.

Defense-in-Depth Validation

Name: Defense-in-Depth Validation
Author: cipherstash

bycipherstash

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セキュリティとテスト

Implements multi-layered data validation patterns to make bugs structurally impossible across every architectural level.

概要

This skill guides Claude in applying a robust 'Defense-in-Depth' strategy to software development, moving beyond single-point checks to comprehensive multi-layered validation. By implementing specific checks at the entry point, business logic layer, environment level, and through debug instrumentation, it ensures that invalid data is caught regardless of the code path, refactoring, or mocking. It is an essential pattern for developers looking to harden their applications against edge cases and ensure system integrity in complex data flows.

主な機能

Four-layer validation implementation (Entry, Business, Environment, Debug)
Structural bug prevention via data flow tracing
Environment-specific guards to prevent dangerous operations in tests
Forensic debug instrumentation for better error context
Checkpoint mapping for end-to-end data integrity
4 GitHub stars

ユースケース

Hardening complex API boundaries against malformed input
Preventing accidental file system operations in test environments
Securing business logic transitions against bypasses via mocks

概要

主な機能

Four-layer validation implementation (Entry, Business, Environment, Debug)
Structural bug prevention via data flow tracing
Environment-specific guards to prevent dangerous operations in tests
Forensic debug instrumentation for better error context
Checkpoint mapping for end-to-end data integrity
4 GitHub stars

ユースケース

Hardening complex API boundaries against malformed input
Preventing accidental file system operations in test environments
Securing business logic transitions against bypasses via mocks