diff --git a/src/lib/components/chat/Messages/Markdown/ColonFenceBlock.svelte b/src/lib/components/chat/Messages/Markdown/ColonFenceBlock.svelte
index 2206a8735d..71f9d4f2d3 100644
--- a/src/lib/components/chat/Messages/Markdown/ColonFenceBlock.svelte
+++ b/src/lib/components/chat/Messages/Markdown/ColonFenceBlock.svelte
@@ -18,9 +18,12 @@
 	export let onTaskClick: Function = () => {};
 	export let onSourceClick: Function = () => {};
 
-	const fenceType: string = token.fenceType ?? 'default';
+	$: fenceType = token.fenceType ?? 'default';
+	$: attributes = token.attributes ?? {};
 
-	const label = fenceType.replace(/_/g, ' ').replace(/\b\w/g, (c) => c.toUpperCase());
+	$: label =
+		attributes.subject || fenceType.replace(/_/g, ' ').replace(/\b\w/g, (c) => c.toUpperCase());
+	$: header = attributes.recipient ? `${label} · ${attributes.recipient}` : label;
 
 	let copied = false;
 
@@ -34,13 +37,16 @@
 </script>
 
 <div class="relative group my-2 rounded-2xl border border-gray-100 dark:border-gray-800 px-4 py-3">
-	<!-- Header row: type badge + copy button -->
-	<div class="flex items-center justify-between mb-2">
-		<span class="text-xs font-normal text-gray-500 dark:text-gray-400">
-			{label}
+	<div class="flex items-center justify-between gap-2 mb-2">
+		<span
+			class="text-xs font-normal text-gray-500 dark:text-gray-400 truncate"
+			dir="auto"
+			title={header}
+		>
+			{header}
 		</span>
 
-		<div class="invisible group-hover:visible flex gap-0.5">
+		<div class="invisible group-hover:visible flex gap-0.5 shrink-0">
 			<Tooltip content={copied ? $i18n.t('Copied') : $i18n.t('Copy')}>
 				<button
 					class="p-1 rounded-lg bg-transparent hover:bg-black/5 dark:hover:bg-white/5 transition"
diff --git a/src/lib/utils/marked/colon-fence-extension.test.ts b/src/lib/utils/marked/colon-fence-extension.test.ts
new file mode 100644
index 0000000000..a82ebd663d
--- /dev/null
+++ b/src/lib/utils/marked/colon-fence-extension.test.ts
@@ -0,0 +1,69 @@
+import { describe, expect, it } from 'vitest';
+import { Marked } from 'marked';
+
+import colonFenceExtension from './colon-fence-extension';
+
+type ColonFenceToken = {
+	type: string;
+	fenceType: string;
+	attributes: Record<string, string>;
+	text: string;
+};
+
+const firstFence = (src: string) => {
+	const marked = new Marked();
+	marked.use(colonFenceExtension());
+	const tokens = marked.lexer(src) as unknown as ColonFenceToken[];
+	return tokens.find((token) => token.type === 'colonFence') as ColonFenceToken;
+};
+
+describe('colon fence extension', () => {
+	it('tokenizes a block without attributes', () => {
+		const token = firstFence(':::writing\n\nHello\n:::\n');
+
+		expect(token.fenceType).toBe('writing');
+		expect(token.attributes).toEqual({});
+		expect(token.text).toBe('Hello');
+	});
+
+	it('parses the attributes on the opening line', () => {
+		const token = firstFence(
+			':::writing{variant="email" id="48173" subject="Short question" recipient="mail@example.com"}\n\nHello\n:::\n'
+		);
+
+		expect(token.attributes).toEqual({
+			variant: 'email',
+			id: '48173',
+			subject: 'Short question',
+			recipient: 'mail@example.com'
+		});
+		expect(token.text).toBe('Hello');
+	});
+
+	it('does not read attributes from unbraced trailing text', () => {
+		const token = firstFence(':::writing{variant="document"} draft subject="junk"\n\nHello\n:::\n');
+
+		expect(token.attributes).toEqual({ variant: 'document' });
+	});
+
+	it('ignores an opening line that has no braces at all', () => {
+		const token = firstFence(
+			':::note prose mentioning recipient="evil@example.com"\n\nHello\n:::\n'
+		);
+
+		expect(token.fenceType).toBe('note');
+		expect(token.attributes).toEqual({});
+	});
+
+	it('ignores an unclosed brace', () => {
+		const token = firstFence(':::writing{subject="Short question"\n\nHello\n:::\n');
+
+		expect(token.attributes).toEqual({});
+	});
+
+	it('allows braces inside an attribute value', () => {
+		const token = firstFence(':::writing{subject="use {x} here"}\n\nHello\n:::\n');
+
+		expect(token.attributes.subject).toBe('use {x} here');
+	});
+});
diff --git a/src/lib/utils/marked/colon-fence-extension.ts b/src/lib/utils/marked/colon-fence-extension.ts
index 329614462e..609ded4130 100644
--- a/src/lib/utils/marked/colon-fence-extension.ts
+++ b/src/lib/utils/marked/colon-fence-extension.ts
@@ -1,5 +1,5 @@
 /**
- * Marked extension for colon-fence blocks (:::type ... :::)
+ * Marked extension for colon-fence blocks (:::type{key="value"} ... :::)
  *
  * Used by newer OpenAI chat models to wrap semantically distinct content:
  *   :::writing    – reusable prose (letters, articles, docs)
@@ -9,12 +9,21 @@
  * The extension is generic and will tokenize any :::<identifier> block.
  */
 
+function parseAttributes(attributeList: string): Record<string, string> {
+	const attributes: Record<string, string> = {};
+	for (const [, key, value] of attributeList.matchAll(/([\w-]+)="([^"]*)"/g)) {
+		attributes[key] = value;
+	}
+	return attributes;
+}
+
 function colonFenceTokenizer(this: any, src: string) {
 	// Match :::type at the start of a line, optionally followed by content, then closing :::
-	const match = /^:::([\w-]+)[^\n]*\n([\s\S]*?)(?:\n:::(?:\s*(?:\n|$)))/.exec(src);
+	const match = /^:::([\w-]+)(?:\{([^\n]*)\})?[^\n]*\n([\s\S]*?)(?:\n:::(?:\s*(?:\n|$)))/.exec(src);
 	if (match) {
 		const fenceType = match[1];
-		const text = match[2].trim();
+		const attributes = parseAttributes(match[2] ?? '');
+		const text = match[3].trim();
 		const raw = match[0];
 
 		const tokens: any[] = [];
@@ -24,6 +33,7 @@ function colonFenceTokenizer(this: any, src: string) {
 			type: 'colonFence',
 			raw,
 			fenceType,
+			attributes,
 			text,
 			tokens
 		};