Variable RESOURCE_URI_META_KEY`Const`

RESOURCE_URI_META_KEY: "ui/resourceUri"

Metadata key for associating a UI resource URI with a tool.

MCP servers include this key in tool definition metadata (via tools/list) to indicate which UI resource should be displayed when the tool is called. When hosts see a tool with this metadata, they fetch and render the corresponding App.

Note: This constant is provided for reference. App developers typically don't need to use it directly. Prefer using registerAppTool with the _meta.ui.resourceUri format instead.

Example: How MCP servers use this key (server-side, not in Apps)

server.registerTool(
  "weather",
  {
    description: "Get weather forecast",
    _meta: {
      [RESOURCE_URI_META_KEY]: "ui://weather/forecast",
    },
  },
  handler,
);

Example: How hosts check for this metadata (host-side)

// Check tool definition metadata (from tools/list response):
const uiUri = tool._meta?.[RESOURCE_URI_META_KEY];
if (typeof uiUri === "string" && uiUri.startsWith("ui://")) {
  // Fetch the resource and display the UI
}

Variable RESOURCE_URI_META_KEYConst

Example: How MCP servers use this key (server-side, not in Apps)

Example: How hosts check for this metadata (host-side)

Settings

Variable RESOURCE_URI_META_KEY`Const`