feat: add hostInfo and hostCapabilities props to AppRenderer by Copilot · Pull Request #179 · MCP-UI-Org/mcp-ui

Copilot · 2026-02-06T21:16:38Z

Implementation Complete ✅

Summary

Successfully implemented hostInfo and hostCapabilities props for the AppRenderer component with proper cleanup handling.

Latest Changes:

Added proper AppBridge cleanup in useEffect to prevent message listener accumulation when dependencies change
Added close() mock to tests for proper cleanup testing
Fixed documentation example to inline define sandboxUrl for copy-pastable code

Testing:
✅ 35 AppRenderer tests passing
✅ Linting clean
✅ Build successful

Original prompt

This section details on the original issue you should resolve

<issue_title>AppRenderer: Add hostInfo and hostCapabilities props</issue_title>
<issue_description>## Problem

The AppRenderer component currently hardcodes hostInfo and capabilities when creating the internal AppBridge:
const bridge = new AppBridge(
  client ?? null,
  {
    name: 'MCP-UI Host',  // Hardcoded
    version: '1.0.0',     // Hardcoded
  },
  {
    openLinks: {},
    serverTools: serverCapabilities?.tools,
    serverResources: serverCapabilities?.resources,
  },
);
This means MCP apps receive generic host information in McpUiInitializeResult instead of the actual host application's identity and capabilities.

Use Case

We're integrating @mcp-ui/client into goose and we'd like MCP apps to know they're running in goose and what capabilities are available:

hostInfo.name: "goose" (not "MCP-UI Host")

hostInfo.version: goose's actual version

hostCapabilities: goose-specific capabilities (e.g., sampling, logging)

Proposed Solution

Add optional hostInfo and hostCapabilities props to AppRendererProps:
interface AppRendererProps {
  // ... existing props ...
  
  /** Host application identification (name and version). Defaults to { name: 'MCP-UI Host', version: '1.0.0' } */
  hostInfo?: { name: string; version: string };
  
  /** Host capabilities to advertise to the MCP app */
  hostCapabilities?: McpUiHostCapabilities;
}
Workaround

Currently, we could use AppFrame + AppBridge directly for full control, but AppRenderer is much more convenient for common use cases.

Related

This would allow hosts to properly identify themselves per the MCP UI spec's McpUiInitializeResult type.</issue_description>

Comments on the Issue (you are @copilot in this section)

Fixes AppRenderer: Add hostInfo and hostCapabilities props #175

💡 You can make Copilot smarter by setting up custom instructions, customizing its development environment and configuring Model Context Protocol (MCP) servers. Learn more Copilot coding agent tips in the docs.

Co-authored-by: idosal <18148989+idosal@users.noreply.github.com>

Copilot

Pull request overview

This PR enhances the TypeScript client SDK’s AppRenderer so host applications can provide real host identity (hostInfo) and explicitly control advertised capabilities (hostCapabilities), instead of relying on hardcoded defaults and implicit derivation.

Changes:

Added hostInfo and hostCapabilities props to AppRenderer with defaults matching the previous behavior.
Re-exported Implementation and McpUiHostCapabilities types from @mcp-ui/client for consumer convenience.
Added tests and documentation updates covering default and custom prop behavior.

Reviewed changes

Copilot reviewed 4 out of 4 changed files in this pull request and generated 2 comments.

File	Description
`sdks/typescript/client/src/components/AppRenderer.tsx`	Adds `hostInfo` / `hostCapabilities` props and uses them when constructing `AppBridge`.
`sdks/typescript/client/src/index.ts`	Re-exports `Implementation` and `McpUiHostCapabilities` types for easier consumption.
`sdks/typescript/client/src/components/__tests__/AppRenderer.test.tsx`	Adds unit tests for default vs custom `hostInfo` and `hostCapabilities`.
`docs/src/guide/mcp-apps.md`	Documents the new props and provides an example for customizing host identity/capabilities.

Copilot · 2026-02-06T23:51:58Z

    createBridge();

    return () => {
      mounted = false;
    };
-  }, [client]);
+  }, [client, hostInfo, hostCapabilities]);


The AppBridge is recreated whenever client, hostInfo, or hostCapabilities change, but the effect cleanup only flips mounted to false and does not tear down the previous bridge/connection. With hostInfo/hostCapabilities commonly passed as object literals, this can lead to repeated bridge re-creation and lingering transports/event handlers. Please add a proper cleanup that disposes the previous bridge connection (and avoid unnecessary re-creates by ensuring these deps are stable or memoized).

Fixed in commit 9e6d54e. Added proper cleanup that calls bridge.close() in the useEffect cleanup function to dispose the previous bridge connection when dependencies change. Also stored the bridge reference locally in the effect to ensure cleanup happens correctly.

Copilot · 2026-02-06T23:51:58Z

+    <AppRenderer
+      client={client}
+      toolName={toolName}
+      sandbox={{ url: sandboxUrl }}
+      hostInfo={hostInfo}
+      hostCapabilities={hostCapabilities}
+      onOpenLink={async ({ url }) => window.open(url)}
+    />


The example uses sandbox={{ url: sandboxUrl }} but sandboxUrl is not defined in the snippet, which makes the docs example non-copy-pastable. Consider defining sandboxUrl (e.g., new URL(...)) in the example or inlining it, consistent with the earlier AppRenderer example in this guide.

@copilot apply changes based on this feedback

Fixed in commit 9e6d54e. Changed the example to inline define the sandbox URL: sandbox={{ url: new URL('http://localhost:8765/sandbox_proxy.html') }} to match the earlier example in the guide.

Co-authored-by: idosal <18148989+idosal@users.noreply.github.com>

aharvard

thanks LGTM

aharvard · 2026-04-21T13:16:27Z

@idosal can we get this up in 7.1? TYSM!

idosal · 2026-04-21T13:19:38Z

@idosal can we get this up in 7.1? TYSM!

Sure, I'll do it today. Thanks for the reminder!

aharvard · 2026-04-28T16:10:56Z

hey @idosal, sry to bother again! It looks like the merge commit to main failed the release step: https://github.com/MCP-UI-Org/mcp-ui/actions/runs/24823858027/job/72654919151

…7.1.0) (2026-05-01) ### Features * add hostInfo and hostCapabilities props to AppRenderer ([#179](#179)) ([87e2436](87e2436))

github-actions · 2026-05-01T13:43:12Z

🎉 This PR is included in version 7.1.0 🎉

The release is available on:

Your semantic-release bot 📦🚀

Initial plan

14a4805

Copilot AI assigned Copilot and idosal Feb 6, 2026

Copilot started work on behalf of idosal February 6, 2026 21:16 View session

Copilot AI and others added 3 commits February 6, 2026 21:21

feat: add hostInfo and hostCapabilities props to AppRenderer

72bc1f4

Co-authored-by: idosal <18148989+idosal@users.noreply.github.com>

docs: document hostInfo and hostCapabilities props in AppRenderer

bc97603

Co-authored-by: idosal <18148989+idosal@users.noreply.github.com>

fix: remove trailing whitespace in AppRenderer

2029dc4

Co-authored-by: idosal <18148989+idosal@users.noreply.github.com>

Copilot AI changed the title ~~[WIP] Add hostInfo and hostCapabilities props to AppRenderer~~ Add hostInfo and hostCapabilities props to AppRenderer Feb 6, 2026

Copilot AI requested a review from idosal February 6, 2026 21:25

Copilot finished work on behalf of idosal February 6, 2026 21:25

idosal marked this pull request as ready for review February 6, 2026 23:46

Copilot AI review requested due to automatic review settings February 6, 2026 23:46

Copilot started reviewing on behalf of idosal February 6, 2026 23:47 View session

Copilot AI reviewed Feb 6, 2026

View reviewed changes

Copilot started work on behalf of idosal February 7, 2026 00:20 View session

fix: add AppBridge cleanup to prevent memory leaks and fix docs example

9e6d54e

Co-authored-by: idosal <18148989+idosal@users.noreply.github.com>

Copilot finished work on behalf of idosal February 7, 2026 00:26

infoxicator approved these changes Feb 7, 2026

View reviewed changes

aharvard approved these changes Feb 19, 2026

View reviewed changes

aharvard mentioned this pull request Feb 26, 2026

feat(client): add hostCapabilities prop to AppRenderer #183

Closed

idosal approved these changes Apr 23, 2026

View reviewed changes

idosal changed the title ~~Add hostInfo and hostCapabilities props to AppRenderer~~ feat: add hostInfo and hostCapabilities props to AppRenderer Apr 23, 2026

idosal added 2 commits April 23, 2026 00:48

Merge branch 'main' into copilot/add-hostinfo-hostcapabilities-props

bb35fc9

fix build

69bce02

idosal merged commit 87e2436 into main Apr 23, 2026
13 checks passed

idosal deleted the copilot/add-hostinfo-hostcapabilities-props branch April 23, 2026 07:57

github-actions Bot added the released label May 1, 2026

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feat: add hostInfo and hostCapabilities props to AppRenderer#179

feat: add hostInfo and hostCapabilities props to AppRenderer#179
idosal merged 7 commits intomainfrom
copilot/add-hostinfo-hostcapabilities-props

Copilot AI commented Feb 6, 2026 •

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Copilot AI commented Feb 6, 2026 • edited Loading Uh oh! There was an error while loading. Please reload this page.

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Implementation Complete ✅

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Copilot AI commented Feb 6, 2026 •

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