MSR Synth is a research project exploring how to design AI agents with social intelligence—agents that can communicate, collaborate, and participate in human interaction in ways that are context‑aware, trustworthy, and aligned with human values. Drawing on human–computer interaction, AI‑mediated communication, and social computing, the project investigates how AI systems represent people, navigate relationships, and act with and on behalf of humans in everyday social and work settings. Through a combination of system building, real‑world deployments, and empirical study, MSR Synth seeks to surface the design principles, technical foundations, and ethical boundaries needed to support AI that augments human connection, understanding, and agency.