Worked on the web-infra-dev/midscene repository to deliver a centralized language preference handling feature for prompt processing. Developed a getPreferredLanguage function in TypeScript, integrating it across core modules to ensure that responses, error messages, and logs consistently reflect each user’s language settings. This approach reduced code duplication and streamlined future localization efforts, directly supporting internationalization goals. Updated unit tests and test snapshots to validate language-aware behavior throughout the system, covering prompt extraction, planning, and locating modules. The work enhanced the multilingual user experience and improved codebase maintainability, demonstrating a methodical approach to full stack development and robust testing practices.