Gamification is being used in developer tools such as CodiumAI to make writing tests more engaging and interactive by incorporating elements like point systems, badges, and leaderboards. Badges can be earned for completing tasks or achieving certain goals, giving users a sense of accomplishment and progress. Leaderboards rank users based on their achievements, motivating them to continue using the tool. By making testing more enjoyable and rewarding, gamification can increase adoption and effectiveness of this critical software development practice.