What problem does it solve? TypeScript codebases often accumulate unsafe escape hatches like any types and unchecked as casts that silently defeat the type system. This Skill defines type-safety objectives and the deterministic compiler and lint checks that mechanically verify them, so unsafe patterns are caught as defects instead of slipping through review. ## Core Features & Use Cases - Deterministic Verification: Uses tsc --noEmit with strict mode and type-checked @typescript-eslint rules (no-explicit-any, no-unsafe-*, consistent-type-assertions, switch-exhaustiveness-check) as the ground-truth gate. - Type Modeling Objectives: States requirements for discriminated unions, as const/satisfies derivations, branded nominal types, and enforced exhaustiveness so invalid states are unrepresentable. - Use Case: When writing or reviewing type definitions for a new API response with multiple variants, model the data as a discriminated union, then run the strict compiler and no-unsafe lint to confirm no any or unsafe cast was introduced. ## Quick Start Review my TypeScript type definitions for the order status variants and verify they pass tsc strict mode and the no-unsafe ESLint rules.
