What problem does it solve? Inconsistent error handling leads to swallowed exceptions, leaked stack traces, confusing user messages, and cascading failures in production services. This Skill provides proven patterns for structuring errors as first-class values across TypeScript, Python, and Go codebases. ## Core Features & Use Cases - Typed Error Hierarchies: Define base AppError classes with codes and HTTP status mappings in TypeScript, Python, and Go, including sentinel errors and error wrapping. - API Error Envelopes: Standardize error responses as { error: { code, message } } with global handlers for Next.js, Express, and FastAPI, plus Zod validation error mapping. - Resilience Patterns: Apply retry with exponential backoff and jitter, React ErrorBoundary components, and user-facing message mapping that hides internal details. - Use Case: When building a new API endpoint, use this Skill to wrap handler logic in a global error handler that returns typed error codes to clients while logging full context server-side. ## Quick Start Ask the agent to review your API route or service module and apply the error handling patterns, adding typed error classes, a global exception handler, and retry logic where external calls are made.
