MCP Apps HTML widget
Category: rendering
Mounts an interactive ui:// HTML widget (mimeType text/html;profile=mcp-app) as an inline iframe.
Support by client
| Client | Status | Notes | Verified |
|---|---|---|---|
 Claude Web | unsupported | No iframe/widget UI mounted. What renders inline is the tool's text fallback: literal 'Widget mounted (mcp-app)' label, then structuredContent JSON pretty-printed in a code block (message: 'Hello from the MCP App widget', nonce: '2fe628', renderedAt: 2026-07-05T15:49:02.774Z), then 'Done — the widget rendered inline (call id: 2fe628).' The model claims inline render but only the text fallback is visible — matches known bug #671. | 2026-07-05T15:49:35.474Z |
| Claude Desktop | supported | "Widget mounted (mcp-app)" is visibly rendered inline in the assistant message body, followed by the structuredContent JSON dump. | 2026-07-08T14:53:19.872Z |
| Claude Mobile | supported | MCP Apps widget iframe mounts INLINE in the chat: 'Widget mounted (mcp-app)' plus structuredContent nonce 6e44c3 rendered as widget content. Tool chip shows 'DoesItSupport' with a Beta badge. Automated via Mirroir, judged from screenshots. | 2026-07-09T14:23:25.122Z |
| Claude Voice | unknown | — | |
| Claude Code | unsupported | Terminal host ignores structuredContent; falls back to text. | 2026-06-30T21:36:16.590Z |
 ChatGPT Web | supported | Widget mounted (mcp-app) label rendered inline with DoesItSupport widget iframe and structuredContent JSON dump visible — surprising cross-compatibility, ChatGPT web renders MCP-Apps profile widget. | 2026-07-05T14:42:02.064Z |
| ChatGPT Mobile | unknown | — | |
| ChatGPT Voice | unknown | — | |
| ChatGPT Desktop | unknown | — | |
| Codex CLI | unsupported | Tool was called and client transcript echoed the probe's nonce — but a terminal/API surface can't render images or iframes. Default unsupported. | 2026-07-02T17:48:46.526Z |
 Siri | unknown | — | |
| Apple AI (ChatGPT) | unknown | — | |
 Gemini Web | unknown | — | |
| Gemini Mobile | unknown | — | |
| Gemini Voice | unknown | — | |
| Gemini CLI | unsupported | Tool was called and the model echoed the probe's call-id back to the user — but a terminal/code-exec surface can't render images or iframes. Default unsupported. | 2026-07-08T15:41:55.767Z |
 Antigravity | unknown | — | |
 Cursor | unknown | — | |
| Cursor CLI | unsupported | Tool was called and the model echoed the probe's call-id back to the user — but a terminal/code-exec surface can't render images or iframes. Default unsupported. | 2026-07-04T14:44:40.864Z |
 VS Code (Copilot Chat) | unknown | — | |
 GitHub Copilot CLI | unsupported | Tool was called and the model echoed the probe's call-id back to the user — but a terminal/code-exec surface can't render images or iframes. Default unsupported. | 2026-07-04T14:54:53.091Z |
 Windsurf | unknown | — | |
 Zed | unknown | — | |
 Perplexity Web | unknown | — | |
| Perplexity Mobile | unknown | — | |
| Perplexity Voice | unknown | — | |
| Comet Browser | unknown | — | |
 Grok Web | unknown | — | |
| Grok Mobile | unknown | — | |
| Grok Voice | unknown | — | |
| Grok CLI | unsupported | Tool was called and the model echoed the probe's call-id back to the user — but a terminal/code-exec surface can't render images or iframes. Default unsupported. (tool_use event and debug log both missed; inferred toolCalled from call-id echo) | 2026-07-02T18:08:58.310Z |
 Warp | unknown | — | |
 Amp | unknown | — | |
 Goose CLI | unsupported | Tool was called and the model echoed the probe's call-id back to the user — but a terminal/code-exec surface can't render images or iframes. Default unsupported. | 2026-07-04T14:52:14.409Z |
| Antigravity CLI | unsupported | Tool was called and the model echoed the probe's call-id back to the user — but a terminal/code-exec surface can't render images or iframes. Default unsupported. | 2026-07-04T14:49:42.513Z |
 JetBrains AI Assistant | unknown | — | |
 Ollama | unknown | — | |
 LM Studio | unknown | — |