What problem does it solve?
This Skill addresses the fragility of single-point validation by advocating for validation at every layer data passes through. This makes bugs caused by invalid data structurally impossible, preventing bypasses from different code paths, refactoring, or mocks, and significantly increasing system robustness and reliability.
Core Features & Use Cases
- Entry Point Validation: Reject obviously invalid input at the API or function boundary.
- Business Logic Validation: Ensure data makes sense for the specific operation being performed.
- Environment Guards: Prevent dangerous operations in specific contexts (e.g., refusing
git init outside temp directories in tests).
- Debug Instrumentation: Capture context (stack traces, environment variables) for forensic analysis when other layers fail.
- Use Case: After fixing a bug where an empty directory caused a system failure, apply this Skill to add validation at the API entry point, within the business logic, as an environment guard for tests, and with debug logging, ensuring that an empty directory can never again lead to a critical error.
Quick Start
Example: Entry Point Validation
function createProject(name: string, workingDirectory: string) {
if (!workingDirectory || workingDirectory.trim() === '') {
throw new Error('workingDirectory cannot be empty');
}
if (!existsSync(workingDirectory)) {
throw new Error(workingDirectory does not exist: ${workingDirectory});
}
if (!statSync(workingDirectory).isDirectory()) {
throw new Error(workingDirectory is not a directory: ${workingDirectory});
}
... proceed
}
