MCP, A2A, and AG-UI: The Agentic Protocol Stack

Agentic systems are emerging as the next paradigm in AI application design - moving beyond static chatbots toward dynamic, context-aware, and modular ecosystems of intelligent agents. To operate effectively at scale, these systems must integrate three foundational capabilities: perceiving their environment, collaborating across specialized components, and interacting with users in real time. This talk introduces an architecture that leverages three interoperable protocols to achieve these goals. The Model Context Protocol (MCP) enables dynamic context hydration and semantic grounding, allowing agents to operate on structured and unstructured inputs tailored to specific tasks. The Agent-to-Agent Protocol (A2A) facilitates orchestrated collaboration between modular agents, enabling delegation, specialization, and distributed reasoning. The Agent-User Interaction Protocol (AG-UI) provides a real-time interface layer that closes the loop with users, supporting direct feedback, steerability, and reactive experiences. Together, these protocols form a cohesive foundation for building intelligent systems that are decoupled, composable, and resilient - minimizing integration debt while enabling rich, responsive behaviors. This session explores design patterns, practical challenges, and architectural strategies for applying MCP, A2A, and AG-UI in real-world agentic applications, offering a blueprint for anyone aiming to architect intelligent applications.