This paper presents a user-centered, empirically guided approach to multilingual metadata enrichment for children’s books. We combine LLMs with human-in-the-loop quality control in a scalable CI/CD pipeline to curate brand collections that enhance book discovery and engagement for young readers across multiple European markets. Our results demonstrate that this hybrid approach delivers high-quality, child-appropriate labels, improves user experience, and accelerates deployment in real-world production environments. This work offers practical insights for applying generative NLP in the media and publishing industry.