The increasing integration of artificial intelligence (AI) agents in customer service is transforming how firms interact with customers and how service experiences are delivered. This entry examines how individuals respond behaviorally to AI agents, moving beyond a purely performance-based perspective to highlight the central role of psychological, emotional, and contextual factors. Drawing on marketing and related literature, the entry focuses on three key behavioral outcomes—trust, compliance with AI recommendations (advice taking), and delegation of decision-making—and synthesizes evidence on the mechanisms that shape these responses. A core contribution of the entry is the integration of existing literature into an AI–task–user fit framework, which helps explain why the same AI system may be accepted in some contexts and resisted in others. Specifically, customer responses are shown to depend on the interaction between (1) customer characteristics (e.g., personality traits and AI literacy), (2) agent design and communication (e.g., transparency and anthropomorphism), and (3) task and decision context (e.g., task structure and goal framing). By integrating insights across these dimensions, the entry provides a comprehensive understanding of when and why customers might trust, follow, or delegate decisions to AI agents. It also outlines managerial implications for designing AI-enabled service systems and identifies key avenues for future research on dynamic interactions and human–AI collaboration.