During August 2025, Marumaru Tsuku developed an API Stamp UUID Array Validation feature for the traPtitech/traQ repository, focusing on enhancing data integrity and API reliability. They implemented strict validation logic using YAML to enforce uniqueness and a maximum of 200 items within stamp UUID arrays, directly addressing potential data inconsistencies and abuse scenarios. This work required careful alignment of API documentation with the updated validation rules, ensuring that usage constraints were clearly communicated to other developers. Marumaru’s contribution demonstrated a focused approach to API documentation and validation, delivering a targeted solution that improved system robustness without introducing unnecessary complexity.