EchoTwin AI is a Physical AI–powered Cognitive City platform transforming how cities operate. By turning existing municipal fleets into mobile sensing platforms, we give agencies real-time visibility into road conditions, critical assets, and curbside/parking environments. Powered by AI cameras, digital twins, and proprietary vision-language models, the system continuously observes the city—detecting infrastructure hazards, defects, and compliance issues—predicting failures before they escalate, and understanding context to route actions through compliant workflows. It creates work orders, evidence trails, and prioritized operator queues, then closes the loop with verification by re-checking locations to confirm fixes and quantify outcomes. The result is measurable: safer streets, faster repairs, lower operational costs, and a unified intelligence layer that moves cities from reactive, manual inspections to self-healing, auditable, and scalable municipal service delivery—systems that can truly see, think, and act.