Online artificial intelligence (AI) algorithms are a critical component of digital health interventions and are designed to continuously learn and improve their performance. This paper focuses on balancing adaptability and reproducibility in online AI deployment. Online AI in digital health interventions is rapidly evolving, driven by advances in algorithms, sensors, software, and devices, and is characterized by iterative deployments. This iterative nature emphasizes the importance of reproducibility, requiring accurate data storage, auditability of algorithm behavior, and comparability of results over time. This paper proposes a reproducible scientific workflow for developing, deploying, and analyzing online AI decision-making algorithms in digital health interventions. Drawing on extensive real-world deployment experience, this workflow addresses key reproducibility challenges across all stages of the online AI algorithm development lifecycle.