As artificial intelligence becomes increasingly embedded in students' academic lives, colleges face a critical question: How can AI support student success without replacing the thinking, judgment, and independence higher education seeks to develop? This interactive workshop presents a developmental approach to AI-supported student success grounded in a simple principle: scaffold, do not substitute. Drawing on an evaluated quantitative-reasoning intervention in a CUNY gateway STEM course and two purpose-built AI applications, an AI Tutor and an AI Research Coach, the session examines how the role of AI can evolve with students' needs, from explaining and practicing foundational concepts to guiding complex research processes and challenging higher-order reasoning. Participants will apply a practical framework to student affairs scenarios, identifying appropriate AI roles, boundaries, human intervention points, and strategies for building rather than diminishing student agency. Participants will leave with a transferable model for designing responsible AI-supported student services across CUNY.