Taeyeong Yoo developed a rewards-driven engagement enhancement for the sparcs-kaist/taxi-back repository, focusing on backend improvements using Node.js and JavaScript. He implemented a new rewards system that introduced phone verification incentives and badge-based bonuses, refactoring the quest reward structures and related event logic to increase user engagement. His work included cleaning up production logs by removing unnecessary debug statements from the completeQuest function, which improved runtime performance and maintainability. Throughout the project, Taeyeong applied skills in API development, backend development, and debugging, delivering a targeted feature and a bug fix that addressed both business value and code quality.