fix(AI Agent Node): Escape curly brackets in tools description for non Tool agents (#11772)

packages/@n8n/nodes-langchain/utils/helpers.ts

@@ -165,10 +165,29 @@ export function serializeChatHistory(chatHistory: BaseMessage[]): string {
 		.join('\n');
 }
 
+export function escapeSingleCurlyBrackets(text?: string): string | undefined {
+	if (text === undefined) return undefined;
+
+	let result = text;
+
+	result = result
+		// First handle triple brackets to avoid interference with double brackets
+		.replace(/(?<!{){{{(?!{)/g, '{{{{')
+		.replace(/(?<!})}}}(?!})/g, '}}}}')
+		// Then handle single brackets, but only if they're not part of double brackets
+		// Convert single { to {{ if it's not already part of {{ or {{{
+		.replace(/(?<!{){(?!{)/g, '{{')
+		// Convert single } to }} if it's not already part of }} or }}}
+		.replace(/(?<!})}(?!})/g, '}}');
+
+	return result;
+}
+
 export const getConnectedTools = async (
 	ctx: IExecuteFunctions,
 	enforceUniqueNames: boolean,
 	convertStructuredTool: boolean = true,
+	escapeCurlyBrackets: boolean = false,
 ) => {
 	const connectedTools =
 		((await ctx.getInputConnectionData(NodeConnectionType.AiTool, 0)) as Tool[]) || [];
@@ -189,6 +208,10 @@ export const getConnectedTools = async (
 		}
 		seenNames.add(name);
 
+		if (escapeCurlyBrackets) {
+			tool.description = escapeSingleCurlyBrackets(tool.description) ?? tool.description;
+		}
+
 		if (convertStructuredTool && tool instanceof N8nTool) {
 			finalTools.push(tool.asDynamicTool());
 		} else {