feat: refactor and normalise props

README.md

@@ -98,6 +98,8 @@ It accepts the following props:
   - **`iframeProps`**: Optional props passed to the iframe element
   - **`iframeRenderData`**: Optional `Record<string, unknown>` to pass data to the iframe upon rendering. This enables advanced use cases where the parent application needs to provide initial state or configuration to the sandboxed iframe content.
   - **`autoResizeIframe`**: Optional `boolean | { width?: boolean; height?: boolean }` to automatically resize the iframe to the size of the content.
+- **`mcpContextProps`**: Optional MCP invocation context forwarded to HTML resources (e.g., `toolInput`, `toolOutput`, `toolName`, `toolResponseMetadata`). Providing `toolOutput` here overrides `iframeRenderData` for the sandbox payload.
+- **`clientContextProps`**: Optional host context (e.g., `theme`, `userAgent`, `model`) exposed to sandboxed HTML content. Both context props can also be supplied via `htmlProps` when you need HTML-specific overrides.
 - **`remoteDomProps`**: Optional props for the internal `<RemoteDOMResourceRenderer>`
   - **`library`**: Optional component library for Remote DOM resources (defaults to `basicComponentLibrary`)
   - **`remoteElements`**: remote element definitions for Remote DOM resources.

docs/src/guide/client/html-resource.md

@@ -6,13 +6,16 @@ The `<HTMLResourceRenderer />` component is an internal component used by `<UIRe
 
 ```typescript
 import type { Resource } from '@modelcontextprotocol/sdk/types';
+import type { MCPContextProps, ClientContextProps } from '@mcp-ui/client';
 
 export interface HTMLResourceRendererProps {
   resource: Partial<Resource>;
   onUIAction?: (result: UIActionResult) => Promise<any>;
   style?: React.CSSProperties;
   proxy?: string;
   iframeRenderData?: Record<string, unknown>;
+  mcpContextProps?: MCPContextProps;
+  clientContextProps?: ClientContextProps;
   autoResizeIframe?: boolean | { width?: boolean; height?: boolean };
   sandboxPermissions?: string;
   iframeProps?: Omit<React.HTMLAttributes<HTMLIFrameElement>, 'src' | 'srcDoc' | 'ref' | 'style'>;
@@ -40,6 +43,7 @@ The component accepts the following props:
 - **`style`**: (Optional) Custom styles for the iframe.
 - **`proxy`**: (Optional) A URL to a proxy script. This is useful for hosts with a strict Content Security Policy (CSP). When provided, external URLs will be rendered in a nested iframe hosted at this URL. For example, if `proxy` is `https://my-proxy.com/`, the final URL will be `https://my-proxy.com/?url=<encoded_original_url>`. For your convenience, mcp-ui hosts a proxy script at `https://proxy.mcpui.dev`, which you can use as a the prop value without any setup (see `examples/external-url-demo`).
 - **`iframeProps`**: (Optional) Custom props for the iframe.
+- **`iframeRenderData`**: (Optional) Additional data merged into the render payload forwarded to the iframe. When `mcpContextProps.toolOutput` is provided, it takes precedence over this merged object.
 - **`autoResizeIframe`**: (Optional) When enabled, the iframe will automatically resize based on messages from the iframe's content. This prop can be a boolean (to enable both width and height resizing) or an object (`{width?: boolean, height?: boolean}`) to control dimensions independently.
 - **`sandboxPermissions`**: (Optional) Additional iframe sandbox permissions to add to the defaults. These are merged with:
   - External URLs (`text/uri-list`): `'allow-scripts allow-same-origin'`

docs/src/guide/client/resource-renderer.md

@@ -42,13 +42,16 @@ The `UIResourceRenderer` automatically detects and uses metadata from resources
 
 ```typescript
 import type { Resource } from '@modelcontextprotocol/sdk/types';
+import type { MCPContextProps, ClientContextProps } from '@mcp-ui/client';
 
 interface UIResourceRendererProps {
   resource: Partial<Resource>;
   onUIAction?: (result: UIActionResult) => Promise<unknown>;
   supportedContentTypes?: ResourceContentType[];
   htmlProps?: Omit<HTMLResourceRendererProps, 'resource' | 'onUIAction'>;
   remoteDomProps?: Omit<RemoteDOMResourceProps, 'resource' | 'onUIAction'>;
+  mcpContextProps?: MCPContextProps;
+  clientContextProps?: ClientContextProps;
 }
 ```
 
@@ -76,6 +79,8 @@ interface UIResourceRendererProps {
     - **`ref`**: Optional React ref to access the underlying iframe element
   - **`iframeRenderData`**: Optional `Record<string, unknown>` to pass data to the iframe upon rendering. This enables advanced use cases where the parent application needs to provide initial state or configuration to the sandboxed iframe content.
   - **`autoResizeIframe`**: Optional `boolean | { width?: boolean; height?: boolean }` to automatically resize the iframe to the size of the content.
+- **`mcpContextProps`**: Optional MCP invocation context forwarded to HTML resources (e.g., `toolInput`, `toolOutput`, `toolName`, `toolResponseMetadata`). These can also be provided via `htmlProps` for HTML-only overrides.
+- **`clientContextProps`**: Optional host context for HTML resources (e.g., `theme`, `userAgent`, `model`). When unspecified, defaults are used. Like `mcpContextProps`, these can be supplied in `htmlProps` to scope them to HTML resources.
 - **`remoteDomProps`**: Optional props for the `<RemoteDOMResourceRenderer>`
   - **`library`**: Optional component library for Remote DOM resources (defaults to `basicComponentLibrary`)
   - **`remoteElements`**: Optional remote element definitions for Remote DOM resources. REQUIRED for Remote DOM snippets.

sdks/typescript/client/README.md

@@ -98,6 +98,8 @@ It accepts the following props:
   - **`iframeProps`**: Optional props passed to the iframe element
   - **`iframeRenderData`**: Optional `Record<string, unknown>` to pass data to the iframe upon rendering. This enables advanced use cases where the parent application needs to provide initial state or configuration to the sandboxed iframe content.
   - **`autoResizeIframe`**: Optional `boolean | { width?: boolean; height?: boolean }` to automatically resize the iframe to the size of the content.
+- **`mcpContextProps`**: Optional MCP invocation context forwarded to HTML resources (e.g., `toolInput`, `toolOutput`, `toolName`, `toolResponseMetadata`). Providing `toolOutput` here overrides `iframeRenderData` for the sandbox payload.
+- **`clientContextProps`**: Optional host context (e.g., `theme`, `userAgent`, `model`) exposed to sandboxed HTML content. Both context props can also be supplied via `htmlProps` when you need HTML-specific overrides.
 - **`remoteDomProps`**: Optional props for the internal `<RemoteDOMResourceRenderer>`
   - **`library`**: Optional component library for Remote DOM resources (defaults to `basicComponentLibrary`)
   - **`remoteElements`**: remote element definitions for Remote DOM resources.

sdks/typescript/client/src/components/HTMLResourceRenderer.tsx

@@ -1,6 +1,6 @@
 import React, { useCallback, useEffect, useImperativeHandle, useMemo, useRef } from 'react';
 import type { Resource } from '@modelcontextprotocol/sdk/types.js';
-import { UIActionResult, UIMetadataKey } from '../types';
+import { UIActionResult, UIMetadataKey, MCPContextProps, ClientContextProps } from '../types';
 import { processHTMLResource } from '../utils/processResource';
 import { getUIResourceMetadata } from '../utils/metadataUtils';
 
@@ -10,9 +10,8 @@ export type HTMLResourceRendererProps = {
   style?: React.CSSProperties;
   proxy?: string;
   iframeRenderData?: Record<string, unknown>;
-  toolInput?: Record<string, unknown>;
-  toolName?: string;
-  toolResponseMetadata?: Record<string, unknown>;
+  mcpContextProps?: MCPContextProps;
+  clientContextProps?: ClientContextProps;
   autoResizeIframe?: boolean | { width?: boolean; height?: boolean };
   sandboxPermissions?: string;
   iframeProps?: Omit<React.HTMLAttributes<HTMLIFrameElement>, 'src' | 'srcDoc' | 'style'> & {
@@ -46,9 +45,8 @@ export const HTMLResourceRenderer = ({
   style,
   proxy,
   iframeRenderData,
-  toolInput,
-  toolName,
-  toolResponseMetadata,
+  mcpContextProps,
+  clientContextProps,
   autoResizeIframe,
   sandboxPermissions,
   iframeProps,
@@ -60,7 +58,7 @@ export const HTMLResourceRenderer = ({
   const preferredFrameSize = uiMetadata[UIMetadataKey.PREFERRED_FRAME_SIZE] ?? ['100%', '100%'];
   const metadataInitialRenderData = uiMetadata[UIMetadataKey.INITIAL_RENDER_DATA] ?? undefined;
 
-  const initialRenderData = useMemo(() => {
+  const combinedRenderData = useMemo(() => {
     if (!iframeRenderData && !metadataInitialRenderData) {
       return undefined;
     }
@@ -70,17 +68,20 @@ export const HTMLResourceRenderer = ({
     };
   }, [iframeRenderData, metadataInitialRenderData]);
 
+  const initialRenderData = useMemo(
+    () => mcpContextProps?.toolOutput ?? combinedRenderData,
+    [mcpContextProps?.toolOutput, combinedRenderData],
+  );
+
   const { error, iframeSrc, iframeRenderMode, htmlString } = useMemo(
     () =>
-      processHTMLResource(
-        resource,
+      processHTMLResource(resource, {
         proxy,
         initialRenderData,
-        toolInput,
-        toolName,
-        toolResponseMetadata
-      ),
-    [resource, proxy]
+        mcpContextProps,
+        clientContextProps,
+      }),
+    [resource, proxy, initialRenderData, mcpContextProps, clientContextProps]
   );
 
 

sdks/typescript/client/src/components/UIResourceRenderer.tsx

@@ -1,5 +1,5 @@
 import type { EmbeddedResource } from '@modelcontextprotocol/sdk/types.js';
-import { ResourceContentType, UIActionResult } from '../types';
+import { ResourceContentType, UIActionResult, ClientContextProps, MCPContextProps } from '../types';
 import { HTMLResourceRenderer, HTMLResourceRendererProps } from './HTMLResourceRenderer';
 import { RemoteDOMResourceProps, RemoteDOMResourceRenderer } from './RemoteDOMResourceRenderer';
 import { basicComponentLibrary } from '../remote-dom/component-libraries/basic';
@@ -8,8 +8,10 @@ export type UIResourceRendererProps = {
   resource: Partial<EmbeddedResource>;
   onUIAction?: (result: UIActionResult) => Promise<unknown>;
   supportedContentTypes?: ResourceContentType[];
-  htmlProps?: Omit<HTMLResourceRendererProps, 'resource' | 'onUIAction'>;
-  remoteDomProps?: Omit<RemoteDOMResourceProps, 'resource' | 'onUIAction'>;
+  htmlProps?: Omit<HTMLResourceRendererProps, 'resource' | 'onUIAction' | 'mcpContextProps' | 'clientContextProps'>;
+  remoteDomProps?: RemoteDOMResourceProps;
+  mcpContextProps?: MCPContextProps;
+  clientContextProps?: ClientContextProps;
 };
 
 function getContentType(
@@ -34,7 +36,7 @@ function getContentType(
 }
 
 export const UIResourceRenderer = (props: UIResourceRendererProps) => {
-  const { resource, onUIAction, supportedContentTypes, htmlProps, remoteDomProps } = props;
+  const { resource, onUIAction, supportedContentTypes, htmlProps, remoteDomProps, mcpContextProps, clientContextProps } = props;
   const contentType = getContentType(resource);
 
   if (supportedContentTypes && contentType && !supportedContentTypes.includes(contentType)) {
@@ -45,7 +47,15 @@ export const UIResourceRenderer = (props: UIResourceRendererProps) => {
     case 'rawHtml':
     case 'skybridge':
     case 'externalUrl': {
-      return <HTMLResourceRenderer resource={resource} onUIAction={onUIAction} {...htmlProps} />;
+      return (
+        <HTMLResourceRenderer
+          resource={resource}
+          onUIAction={onUIAction}
+          {...htmlProps}
+          {...mcpContextProps}
+          {...clientContextProps}
+        />
+      );
     }
     case 'remoteDom':
       return (

sdks/typescript/client/src/components/__tests__/HTMLResourceRenderer.test.tsx

@@ -71,7 +71,7 @@ describe('HTMLResource component', () => {
     render(<HTMLResourceRenderer {...props} />);
     expect(
       screen.getByText(
-        'Resource must be of type text/html (for HTML content) or text/uri-list (for URL content).',
+        'Resource must be of type text/html (for HTML content), text/html+skybridge, or text/uri-list (for URL content).',
       ),
     ).toBeInTheDocument();
   });
@@ -359,7 +359,7 @@ describe('HTMLResource iframe communication', () => {
     // Error message should be displayed
     expect(
       await screen.findByText(
-        'Resource must be of type text/html (for HTML content) or text/uri-list (for URL content).',
+        'Resource must be of type text/html (for HTML content), text/html+skybridge, or text/uri-list (for URL content).',
       ),
     ).toBeInTheDocument();
 
@@ -534,6 +534,40 @@ describe('HTMLResource metadata', () => {
     );
   });
 
+  it('should prioritize toolOutput from mcpContextProps over other render data', () => {
+    const iframeRenderData = { priority: 'iframe', foo: 'bar' };
+    const metadataInitialRenderData = { priority: 'metadata', baz: 'qux' };
+    const toolOutput = { priority: 'context', extra: 'value' };
+    const resource = {
+      mimeType: 'text/uri-list',
+      text: 'https://example.com/app',
+      _meta: { [`${UI_METADATA_PREFIX}initial-render-data`]: metadataInitialRenderData },
+    };
+    const ref = React.createRef<HTMLIFrameElement>();
+    render(
+      <HTMLResourceRenderer
+        resource={resource}
+        iframeProps={{ ref }}
+        iframeRenderData={iframeRenderData}
+        mcpContextProps={{ toolOutput }}
+      />,
+    );
+    expect(ref.current).toBeInTheDocument();
+    const iframeWindow = ref.current?.contentWindow as Window;
+    const spy = vi.spyOn(iframeWindow, 'postMessage');
+    dispatchMessage(iframeWindow, {
+      type: InternalMessageType.UI_LIFECYCLE_IFRAME_READY,
+    });
+    expect(spy).toHaveBeenCalledWith(
+      {
+        type: InternalMessageType.UI_LIFECYCLE_IFRAME_RENDER_DATA,
+        payload: { renderData: toolOutput },
+        messageId: undefined,
+      },
+      '*',
+    );
+  });
+
   it('should respond to ui-request-render-data with render data', () => {
     const iframeRenderData = { theme: 'dark', user: { id: '123' } };
     const resource = {

sdks/typescript/client/src/components/__tests__/UIResourceRenderer.test.tsx

@@ -29,15 +29,15 @@ describe('<UIResourceRenderer />', () => {
     render(<UIResourceRenderer resource={resource} />);
     expect(screen.getByTestId('html-resource')).toBeInTheDocument();
     expect(RemoteDOMResourceRenderer).not.toHaveBeenCalled();
-    expect(HTMLResourceRenderer).toHaveBeenCalledWith({ resource }, {});
+    expect(HTMLResourceRenderer).toHaveBeenCalledWith(expect.objectContaining({ resource }), {});
   });
 
   it('should render HTMLResourceRenderer for "text/uri-list" mimeType', () => {
     const resource = { ...baseResource, mimeType: 'text/uri-list' };
     render(<UIResourceRenderer resource={resource} />);
     expect(screen.getByTestId('html-resource')).toBeInTheDocument();
     expect(RemoteDOMResourceRenderer).not.toHaveBeenCalled();
-    expect(HTMLResourceRenderer).toHaveBeenCalledWith({ resource }, {});
+    expect(HTMLResourceRenderer).toHaveBeenCalledWith(expect.objectContaining({ resource }), {});
   });
 
   it('should render RemoteDOMResourceRenderer for "remote-dom" mimeType', () => {
@@ -75,7 +75,7 @@ describe('<UIResourceRenderer />', () => {
     render(<UIResourceRenderer resource={resource} supportedContentTypes={['rawHtml']} />);
     expect(screen.getByTestId('html-resource')).toBeInTheDocument();
     expect(RemoteDOMResourceRenderer).not.toHaveBeenCalled();
-    expect(HTMLResourceRenderer).toHaveBeenCalledWith({ resource }, {});
+    expect(HTMLResourceRenderer).toHaveBeenCalledWith(expect.objectContaining({ resource }), {});
   });
 
   it('should pass proxy prop to HTMLResourceRenderer for external URLs', () => {
@@ -85,7 +85,7 @@ describe('<UIResourceRenderer />', () => {
     );
     expect(screen.getByTestId('html-resource')).toBeInTheDocument();
     expect(HTMLResourceRenderer).toHaveBeenCalledWith(
-      { resource, proxy: 'https://proxy.mcpui.dev/' },
+      expect.objectContaining({ resource, proxy: 'https://proxy.mcpui.dev/' }),
       {},
     );
   });
@@ -97,7 +97,41 @@ describe('<UIResourceRenderer />', () => {
     );
     expect(screen.getByTestId('html-resource')).toBeInTheDocument();
     expect(HTMLResourceRenderer).toHaveBeenCalledWith(
-      { resource, proxy: 'https://proxy.mcpui.dev/' },
+      expect.objectContaining({ resource, proxy: 'https://proxy.mcpui.dev/' }),
+      {},
+    );
+  });
+
+  it('should forward context props to HTMLResourceRenderer', () => {
+    const resource = { ...baseResource, mimeType: 'text/html' };
+    const mcpContextProps = { toolName: 'demo-tool', toolInput: { foo: 'bar' } };
+    const clientContextProps = { theme: 'light', model: 'gpt-5' };
+    render(
+      <UIResourceRenderer
+        resource={resource}
+        mcpContextProps={mcpContextProps}
+        clientContextProps={clientContextProps}
+      />,
+    );
+    expect(HTMLResourceRenderer).toHaveBeenCalledWith(
+      expect.objectContaining({ resource, mcpContextProps, clientContextProps }),
+      {},
+    );
+  });
+
+  it('should use htmlProps context when top-level context is undefined', () => {
+    const resource = { ...baseResource, mimeType: 'text/html' };
+    const htmlProps = {
+      mcpContextProps: { toolName: 'html-only', toolInput: { bar: 'baz' } },
+      clientContextProps: { theme: 'dark', userAgent: 'jest' },
+    };
+    render(<UIResourceRenderer resource={resource} htmlProps={htmlProps} />);
+    expect(HTMLResourceRenderer).toHaveBeenCalledWith(
+      expect.objectContaining({
+        resource,
+        mcpContextProps: htmlProps.mcpContextProps,
+        clientContextProps: htmlProps.clientContextProps,
+      }),
       {},
     );
   });

sdks/typescript/client/src/types.ts

@@ -102,3 +102,16 @@ export type UIResourceMetadata = {
   [UIMetadataKey.PREFERRED_FRAME_SIZE]?: [string, string];
   [UIMetadataKey.INITIAL_RENDER_DATA]?: Record<string, unknown>;
 };
+
+export type MCPContextProps = {
+  toolInput?: Record<string, unknown>;
+  toolOutput?: Record<string, unknown>;
+  toolName?: string;
+  toolResponseMetadata?: Record<string, unknown>;
+};
+
+export type ClientContextProps = {
+  theme?: string;
+  userAgent?: string;
+  model?: string;
+};