Worked on the gchq/CyberChef repository to deliver enhanced input validation and user feedback for the hexdump feature. Focused on hardening the input handling by implementing maximum width validation, which prevents users from entering excessive values that could lead to crashes or misprocessing. Improved error handling and messaging to provide clearer guidance when invalid inputs are detected, thereby reducing potential support issues. Utilized JavaScript and applied skills in error handling, input validation, and unit testing to ensure robust and testable changes. The update aligned with security and quality objectives while maintaining a seamless user experience and repository hygiene throughout development.