Module @modelcontextprotocol/ext-apps/react

React utilities for building MCP Apps.

This module provides React hooks and utilities for easily building interactive MCP Apps using React. This is optional - the core SDK (App, PostMessageTransport) is framework-agnostic and can be used with any UI framework or vanilla JavaScript.

Main Exports

useApp - React hook to create and connect an MCP App
useHostStyleVariables - React hook to apply host style variables and theme
useHostFonts - React hook to apply host fonts
useDocumentTheme - React hook for reactive document theme
useAutoResize - React hook for manual auto-resize control (rarely needed)

Example: Basic React App

function MyApp() {
  const { app, isConnected, error } = useApp({
    appInfo: { name: "MyApp", version: "1.0.0" },
    capabilities: {},
  });

  if (error) return <div>Error: {error.message}</div>;
  if (!isConnected) return <div>Connecting...</div>;

  return <div>Connected!</div>;
}

Interfaces

AppState
UseAppOptions

Functions

useApp
useAutoResize
useDocumentTheme
useHostFonts
useHostStyles
useHostStyleVariables

References

App → App
applyDocumentTheme → applyDocumentTheme
applyHostFonts → applyHostFonts
applyHostStyleVariables → applyHostStyleVariables
AppNotification → AppNotification
AppRequest → AppRequest
AppResult → AppResult
getDocumentTheme → getDocumentTheme
HOST_CONTEXT_CHANGED_METHOD → HOST_CONTEXT_CHANGED_METHOD
INITIALIZE_METHOD → INITIALIZE_METHOD
INITIALIZED_METHOD → INITIALIZED_METHOD
LATEST_PROTOCOL_VERSION → LATEST_PROTOCOL_VERSION
McpUiAppCapabilities → McpUiAppCapabilities
McpUiAppCapabilitiesSchema → McpUiAppCapabilitiesSchema
McpUiClientCapabilities → McpUiClientCapabilities
McpUiDisplayMode → McpUiDisplayMode
McpUiDisplayModeSchema → McpUiDisplayModeSchema
McpUiHostCapabilities → McpUiHostCapabilities
McpUiHostCapabilitiesSchema → McpUiHostCapabilitiesSchema
McpUiHostContext → McpUiHostContext
McpUiHostContextChangedNotification → McpUiHostContextChangedNotification
McpUiHostContextChangedNotificationSchema → McpUiHostContextChangedNotificationSchema
McpUiHostContextSchema → McpUiHostContextSchema
McpUiHostCss → McpUiHostCss
McpUiHostCssSchema → McpUiHostCssSchema
McpUiHostStyles → McpUiHostStyles
McpUiHostStylesSchema → McpUiHostStylesSchema
McpUiInitializedNotification → McpUiInitializedNotification
McpUiInitializedNotificationSchema → McpUiInitializedNotificationSchema
McpUiInitializeRequest → McpUiInitializeRequest
McpUiInitializeRequestSchema → McpUiInitializeRequestSchema
McpUiInitializeResult → McpUiInitializeResult
McpUiInitializeResultSchema → McpUiInitializeResultSchema
McpUiMessageRequest → McpUiMessageRequest
McpUiMessageRequestSchema → McpUiMessageRequestSchema
McpUiMessageResult → McpUiMessageResult
McpUiMessageResultSchema → McpUiMessageResultSchema
McpUiOpenLinkRequest → McpUiOpenLinkRequest
McpUiOpenLinkRequestSchema → McpUiOpenLinkRequestSchema
McpUiOpenLinkResult → McpUiOpenLinkResult
McpUiOpenLinkResultSchema → McpUiOpenLinkResultSchema
McpUiRequestDisplayModeRequest → McpUiRequestDisplayModeRequest
McpUiRequestDisplayModeRequestSchema → McpUiRequestDisplayModeRequestSchema
McpUiRequestDisplayModeResult → McpUiRequestDisplayModeResult
McpUiRequestDisplayModeResultSchema → McpUiRequestDisplayModeResultSchema
McpUiResourceCsp → McpUiResourceCsp
McpUiResourceCspSchema → McpUiResourceCspSchema
McpUiResourceMeta → McpUiResourceMeta
McpUiResourceMetaSchema → McpUiResourceMetaSchema
McpUiResourcePermissions → McpUiResourcePermissions
McpUiResourcePermissionsSchema → McpUiResourcePermissionsSchema
McpUiResourceTeardownRequest → McpUiResourceTeardownRequest
McpUiResourceTeardownRequestSchema → McpUiResourceTeardownRequestSchema
McpUiResourceTeardownResult → McpUiResourceTeardownResult
McpUiResourceTeardownResultSchema → McpUiResourceTeardownResultSchema
McpUiSandboxProxyReadyNotification → McpUiSandboxProxyReadyNotification
McpUiSandboxProxyReadyNotificationSchema → McpUiSandboxProxyReadyNotificationSchema
McpUiSandboxResourceReadyNotification → McpUiSandboxResourceReadyNotification
McpUiSandboxResourceReadyNotificationSchema → McpUiSandboxResourceReadyNotificationSchema
McpUiSizeChangedNotification → McpUiSizeChangedNotification
McpUiSizeChangedNotificationSchema → McpUiSizeChangedNotificationSchema
McpUiStyles → McpUiStyles
McpUiStyleVariableKey → McpUiStyleVariableKey
McpUiSupportedContentBlockModalities → McpUiSupportedContentBlockModalities
McpUiSupportedContentBlockModalitiesSchema → McpUiSupportedContentBlockModalitiesSchema
McpUiTheme → McpUiTheme
McpUiThemeSchema → McpUiThemeSchema
McpUiToolCancelledNotification → McpUiToolCancelledNotification
McpUiToolCancelledNotificationSchema → McpUiToolCancelledNotificationSchema
McpUiToolInputNotification → McpUiToolInputNotification
McpUiToolInputNotificationSchema → McpUiToolInputNotificationSchema
McpUiToolInputPartialNotification → McpUiToolInputPartialNotification
McpUiToolInputPartialNotificationSchema → McpUiToolInputPartialNotificationSchema
McpUiToolMeta → McpUiToolMeta
McpUiToolMetaSchema → McpUiToolMetaSchema
McpUiToolResultNotification → McpUiToolResultNotification
McpUiToolResultNotificationSchema → McpUiToolResultNotificationSchema
McpUiToolVisibility → McpUiToolVisibility
McpUiToolVisibilitySchema → McpUiToolVisibilitySchema
McpUiUpdateModelContextRequest → McpUiUpdateModelContextRequest
McpUiUpdateModelContextRequestSchema → McpUiUpdateModelContextRequestSchema
MESSAGE_METHOD → MESSAGE_METHOD
OPEN_LINK_METHOD → OPEN_LINK_METHOD
PostMessageTransport → PostMessageTransport
REQUEST_DISPLAY_MODE_METHOD → REQUEST_DISPLAY_MODE_METHOD
RESOURCE_MIME_TYPE → RESOURCE_MIME_TYPE
RESOURCE_TEARDOWN_METHOD → RESOURCE_TEARDOWN_METHOD
RESOURCE_URI_META_KEY → RESOURCE_URI_META_KEY
SANDBOX_PROXY_READY_METHOD → SANDBOX_PROXY_READY_METHOD
SANDBOX_RESOURCE_READY_METHOD → SANDBOX_RESOURCE_READY_METHOD
SIZE_CHANGED_METHOD → SIZE_CHANGED_METHOD
TOOL_CANCELLED_METHOD → TOOL_CANCELLED_METHOD
TOOL_INPUT_METHOD → TOOL_INPUT_METHOD
TOOL_INPUT_PARTIAL_METHOD → TOOL_INPUT_PARTIAL_METHOD
TOOL_RESULT_METHOD → TOOL_RESULT_METHOD