Worked on the facebook/buck2-prelude repository to enhance the reliability of build error reporting by addressing a bug in the Duplicate Class Checker. Focused on Python-based build systems, the work involved refactoring error handling logic to resolve message truncation issues, ensuring that full diagnostic information is displayed during build failures. This improvement streamlined error message formatting, making output more readable and actionable for developers. By prioritizing code refactoring and robust error handling, the changes reduced ambiguity in build diagnostics and contributed to smoother CI workflows. The effort emphasized stability and developer experience over new feature development during the project period.