A2UI + MCP Apps: Combining the best of declarative and custom agentic UIs- Google Developers Blog

This post introduces two architectural patterns for integrating Model Context Protocol (MCP) Apps with Agent-to-User Interface (A2UI) components: 'A2UI over MCP servers' and 'Running MCP Apps in A2UI Components'. The former leverages MCP Resources or Tool calls to deliver A2UI payloads, enabling native rendering and bypassing iframe limitations for improved performance, security, and portability. The latter encapsulates MCP Apps within A2UI components to delegate complex, state-intensive modules while maintaining host design consistency and secure state synchronization. It also discusses the differences between A2UI over MCP and A2UI over A2A architectures.