Widget Framework For Mcp Tool Ui Composition

via “ui resource declaration and server-side tool-ui linkage”

Official repo for spec & SDK of MCP Apps protocol - standard for UIs embedded AI chatbots, served by MCP servers

Unique: Uses a declarative ui:// URI scheme with tool metadata linking rather than imperative iframe creation. Servers declare resources once; hosts handle fetching, sandboxing, and lifecycle management. This separates concerns: servers focus on tool logic and UI content, hosts handle rendering and security.

vs others: Cleaner than embedding UI URLs in tool responses because the UI is declared upfront with versioning support, allowing hosts to pre-fetch and cache resources, and enabling capability negotiation before tool execution.