CharacterFlywheel: Scaling Iterative Improvement of Engaging and Steerable LLMs in Production

Meta presents CharacterFlywheel, an iterative process for improving large language models in production social chat applications across Instagram, WhatsApp, and Messenger. Starting from LLaMA 3.1, the system achieved significant improvements through 15 generations of refinement, with the best models showing up to 8.8% improvement in engagement breadth and 19.4% in engagement depth while substantially improving instruction following capabilities.