FastMCP Apps
FastMCP Apps is the framework's runtime for building interactive applications rendered directly inside MCP host conversations. Apps expose UI surfaces — approval flows, choice pickers, form input, and file uploads — alongside prefab and low-level HTML/generative UIs, with `FastMCPApp` as the primary entry point. Apps share the same transport and authentication stack as FastMCP servers, enabling rich agent experiences across Claude Desktop, Claude Code, Cursor, and other MCP-aware hosts.