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feat(ui): support prefersBorder option for MCP Apps #6465

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Merged
aharvard merged 3 commits into from
Jan 13, 2026
Merged

feat(ui): support prefersBorder option for MCP Apps #6465

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e01ce64
feat(ui): support prefersBorder option for MCP Apps
aharvard Jan 13, 2026
d8de8f7
refine styles
aharvard Jan 13, 2026
00e41b6
refactor(McpAppRenderer): improve loading state handling and styling
aharvard Jan 13, 2026
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64 changes: 32 additions & 32 deletions ui/desktop/src/components/McpApps/McpAppRenderer.tsx
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Original file line number Diff line number Diff line change
Expand Up @@ -32,6 +32,12 @@ interface McpAppRendererProps {
append?: (text: string) => void;
}

interface ResourceData {
html: string | null;
csp: CspMetadata | null;
prefersBorder: boolean;
}

export default function McpAppRenderer({
resourceUri,
extensionName,
Expand All @@ -42,8 +48,11 @@ export default function McpAppRenderer({
toolCancelled,
append,
}: McpAppRendererProps) {
const [resourceHtml, setResourceHtml] = useState<string | null>(null);
const [resourceCsp, setResourceCsp] = useState<CspMetadata | null>(null);
const [resource, setResource] = useState<ResourceData>({
html: null,
csp: null,
prefersBorder: true,
});
const [error, setError] = useState<string | null>(null);
const [iframeHeight, setIframeHeight] = useState(DEFAULT_IFRAME_HEIGHT);

Expand All @@ -60,11 +69,15 @@ export default function McpAppRenderer({

if (response.data) {
const content = response.data;

setResourceHtml(content.text);

const meta = content._meta as { ui?: { csp?: CspMetadata } } | undefined;
setResourceCsp(meta?.ui?.csp || null);
const meta = content._meta as
| { ui?: { csp?: CspMetadata; prefersBorder?: boolean } }
| undefined;

setResource({
html: content.text,
csp: meta?.ui?.csp || null,
prefersBorder: meta?.ui?.prefersBorder ?? true,
});
}
} catch (err) {
setError(err instanceof Error ? err.message : 'Failed to load resource');
Expand Down Expand Up @@ -161,8 +174,8 @@ export default function McpAppRenderer({
}, []);

const { iframeRef, proxyUrl } = useSandboxBridge({
resourceHtml: resourceHtml || '',
resourceCsp,
resourceHtml: resource.html || '',
resourceCsp: resource.csp,
resourceUri,
toolInput,
toolInputPartial,
Expand All @@ -174,25 +187,20 @@ export default function McpAppRenderer({

if (error) {
return (
<div className="mt-3 p-4 border border-red-500 rounded-lg bg-red-50 dark:bg-red-900/20">
<div className="p-4 border border-red-500 rounded-lg bg-red-50 dark:bg-red-900/20">
<div className="text-red-700 dark:text-red-300">Failed to load MCP app: {error}</div>
</div>
);
}

if (!resourceHtml) {
return (
<div className="mt-3 p-4 border border-borderSubtle rounded-lg bg-bgApp">
<div className="flex items-center justify-center" style={{ minHeight: '200px' }}>
Loading MCP app...
</div>
</div>
);
}

return (
<div className={cn('mt-3 bg-bgApp', 'border border-borderSubtle rounded-lg overflow-hidden')}>
{proxyUrl ? (
<div
className={cn(
'bg-bgApp overflow-hidden',
resource.prefersBorder ? 'border border-borderSubtle rounded-lg' : 'my-6'
)}
>
{resource.html && proxyUrl ? (
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@aharvard aharvard Jan 13, 2026 •
edited
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@DOsinga PTAL

I unified resource.html and proxyUrl as we don't need a discrete state for proxyUrl loading

Also, leaving this inline instead of extracting as a const. I noticed a hard-to-reproduce issue where the iframe ref might have gotten lost or something... the rendered mcp app would be sitting there w/ no messages being sent down. Maybe a closure issue? Not sure. But I think what I got works.

<iframe
ref={iframeRef}
src={proxyUrl}
Expand All @@ -205,16 +213,8 @@ export default function McpAppRenderer({
sandbox="allow-scripts allow-same-origin"
/>
) : (
<div
style={{
width: '100%',
minHeight: '200px',
display: 'flex',
alignItems: 'center',
justifyContent: 'center',
}}
>
Loading...
<div className="flex items-center justify-center p-4" style={{ minHeight: '200px' }}>
Loading MCP app...
</div>
)}
</div>
Expand Down