Beyond Data Mirrors” proposes a cybernetic framework for Urban Digital Twins (UDTs) grounded in participatory governance rather than technocratic optimization. Drawing on Stafford Beer’s principles and lessons from Project Cybersyn, the paper develops five principles for UDTs to operate as variety engineering tools: distributed data governance, recursive decentralized coordination, algedonic signals for system feedback, interoperability through federated structures, and scenario simulation for collective learning. The central argument is that urban complexity is not a problem to be solved through algorithmic control, but a condition to be democratically navigated by citizens with amplified capacity for meaningful engagement.