Sam Blackburn enhanced command-line argument handling in the dotnet/command-line-api repository, focusing on clearer error messaging and improved user guidance. Using C# and unit testing, Sam refined the way missing arguments are reported by ensuring error messages now specify the exact argument name, and updated the HelpName logic to provide better fallback behavior. The work included expanding test coverage to validate scenarios with multiple missing arguments, ensuring the new error handling was robust and consistent. Over the course of the month, Sam’s contributions improved code clarity and maintainability, delivering a more reliable and user-friendly command-line interface for downstream tools.