fix: added a normalization step for MathJax-style \[\] and \(\) delimiters

So inline and block equations are converted before KaTeX rendering,
enabling proper display of model-generated LaTeX in the WebUI

Added a dedicated remarkMathJaxDelimiters plugin that rewrites MathJax
bracket delimiters into KaTeX-friendly dollar math while limiting the
normalization to text nodes so code blocks and other literals remain untouched

Wired the new plugin into the existing Markdown processor ahead of remark-math
and dropped the prior global string replace, keeping the established
remark/rehype pipeline intact while still rendering centered and inline
equations correctly

Author: ServeurpersoCom

tools/server/webui/src/lib/components/app/misc/MarkdownContent.svelte

@@ -15,6 +15,7 @@
 	import githubLightCss from 'highlight.js/styles/github.css?inline';
 	import { mode } from 'mode-watcher';
 	import { remarkLiteralHtml } from '$lib/markdown/literal-html';
+	import { remarkMathJaxDelimiters } from '$lib/markdown/mathjax-delimiters';
 
 	interface Props {
 		content: string;
@@ -49,6 +50,7 @@
 	let processor = $derived(() => {
 		return remark()
 			.use(remarkGfm) // GitHub Flavored Markdown
+			.use(remarkMathJaxDelimiters) // Normalize \[\] and \(\) delimiters inside text nodes
 			.use(remarkMath) // Parse $inline$ and $$block$$ math
 			.use(remarkBreaks) // Convert line breaks to <br>
 			.use(remarkLiteralHtml) // Treat raw HTML as literal text with preserved indentation
@@ -154,9 +156,20 @@
 		return mutated ? tempDiv.innerHTML : html;
 	}
 
+	function normalizeMathDelimiters(text: string): string {
+		return text
+			.replace(/(^|[^\\])\\\[((?:\\.|[\s\S])*?)\\\]/g, (_, prefix: string, content: string) => {
+				return `${prefix}$$${content}$$`;
+			})
+			.replace(/(^|[^\\])\\\(((?:\\.|[\s\S])*?)\\\)/g, (_, prefix: string, content: string) => {
+				return `${prefix}$${content}$`;
+			});
+	}
+
 	async function processMarkdown(text: string): Promise<string> {
 		try {
-			const result = await processor().process(text);
+			const normalized = normalizeMathDelimiters(text);
+			const result = await processor().process(normalized);
 			const html = String(result);
 			const enhancedLinks = enhanceLinks(html);
 

tools/server/webui/src/lib/markdown/mathjax-delimiters.ts

@@ -0,0 +1,33 @@
+import type { Plugin } from 'unified';
+import { visit } from 'unist-util-visit';
+import type { Root, Text } from 'mdast';
+
+const BLOCK_REGEX = /(^|[^\\])\\\[((?:\\.|[\s\S])*?)\\\]/g;
+const INLINE_REGEX = /(^|[^\\])\\\(((?:\\.|[\s\S])*?)\\\)/g;
+
+/**
+ * remark plugin that normalizes MathJax bracket delimiters into KaTeX-compatible
+ * dollar-delimited math nodes. The transformation only touches plain text nodes,
+ * preserving code blocks, inline code, and other literal sections handled
+ * elsewhere in the pipeline.
+ */
+
+export const remarkMathJaxDelimiters: Plugin<[], Root> = () => {
+	return (tree) => {
+		visit(tree, 'text', (node: Text) => {
+			const value = node.value;
+
+			if (!value || (!value.includes('\\[') && !value.includes('\\('))) {
+				return;
+			}
+
+			node.value = value
+				.replace(BLOCK_REGEX, (_, prefix: string, content: string) => {
+					return `${prefix}$$${content}$$`;
+				})
+				.replace(INLINE_REGEX, (_, prefix: string, content: string) => {
+					return `${prefix}$${content}$`;
+				});
+		});
+	};
+};