Worked on the nestjs/nest repository to enhance error reporting for invalid module usage within the NestJS core framework. Focused on backend development using TypeScript, the developer improved error handling by including decorator types in invalid-class-module errors and specifying the type of received values in invalid-module errors. These targeted changes standardized error messages to align with existing diagnostics patterns, streamlining debugging and reducing triage time for module misconfigurations. The work also emphasized maintainability by clarifying error handling paths, which simplifies future enhancements and onboarding for contributors. Unit testing was used to ensure reliability and consistency across module validation workflows.