mcp-ui is a toolkit and framework for rendering interactive web components and managing communication between Model Context Protocol servers and host applications. It serves as a client interface library and a sandboxed web component renderer designed to move AI tool interactions beyond text-based outputs into visual interfaces.
The project is distinguished by its secure rendering system, which utilizes a double-iframe architecture and a proxy layer to isolate guest user interfaces from the host application. It employs a JSON-RPC bridge to synchronize state and route user intents, ensuring bidirectional messaging between the main application and embedded guest interfaces.
The framework covers server-driven UI workflows, including the generation of structured UI payloads and the delivery of interactive resources. It manages tool-to-UI linking via resource URI mapping and provides capabilities for web proxying to ensure external assets resolve correctly within sandboxed environments.
The SDK handles the full lifecycle of tool interfaces, from resource identifier generation and metadata analysis to the final rendering of sandboxed content within a compatible client interface.
