DeltaStream is a serverless stream processing platform designed to enhance the functionality of Generative AI (GenAI) applications by providing real-time context, acting as a "nervous system" that bridges raw data streams and AI agents. The platform addresses the current limitations of AI agents, which often lack real-time awareness, leading to generic user interactions. DeltaStream performs critical functions such as real-time feature engineering, stateful context building, and intelligent triggering to enrich user data, build a live understanding of user behavior, and determine the optimal moments to activate AI agents. This process enables the creation of personalized and dynamic user experiences, exemplified by an AI Concierge use case that intervenes to provide tailored suggestions to users at critical decision-making moments. The approach maximizes the efficiency and impact of AI interactions, transforming static and generic recommendations into context-rich and engaging user experiences, thereby enhancing the overall value of AI applications in the media and entertainment industry.