AI agents powered by the Model Context Protocol (MCP) are transforming user interfaces from traditional screen-based interactions to conversational, context-aware systems. This shift requires developers to rethink frontend architecture, moving from designing static components to crafting intelligent workflows that agents can interpret. The article explores how multi-channel, multi-capability frameworks enable Jarvis-like assistants to seamlessly handle tasks across platforms, the design patterns needed for agent-first interfaces, and the challenges around reliability, privacy, and user trust that teams must address when building these systems.