Bradley Turner enhanced the contentful-migration library by introducing a BuiltinEditor union type, which explicitly enumerates all valid builtin editor identifiers. This addition enforces type safety and compile-time validation of widget IDs, preventing invalid identifiers from being used in migration scripts. Working in TypeScript, Bradley focused on type definitions and API development to reduce runtime errors and improve developer feedback. The changes, delivered to the contentful/contentful-migration repository, improved the maintainability and clarity of migration tooling by ensuring only valid editor IDs are referenced. This work demonstrates a thoughtful approach to type safety and long-term code quality in migration workflows.