diff --git a/extensions/ipynb/src/ipynbMain.ts b/extensions/ipynb/src/ipynbMain.ts
index 25aa98af6fcb2..5ac60c568e5d7 100644
--- a/extensions/ipynb/src/ipynbMain.ts
+++ b/extensions/ipynb/src/ipynbMain.ts
@@ -6,6 +6,25 @@
 import * as vscode from 'vscode';
 import { NotebookSerializer } from './notebookSerializer';
 
+// From {nbformat.INotebookMetadata} in @jupyterlab/coreutils
+type NotebookMetadata = {
+	kernelspec?: {
+		name: string;
+		display_name: string;
+		[propName: string]: unknown;
+	};
+	language_info?: {
+		name: string;
+		codemirror_mode?: string | {};
+		file_extension?: string;
+		mimetype?: string;
+		pygments_lexer?: string;
+		[propName: string]: unknown;
+	};
+	orig_nbformat: number;
+	[propName: string]: unknown;
+};
+
 export function activate(context: vscode.ExtensionContext) {
 	const serializer = new NotebookSerializer(context);
 	context.subscriptions.push(vscode.workspace.registerNotebookSerializer('jupyter-notebook', serializer, {
@@ -22,7 +41,7 @@ export function activate(context: vscode.ExtensionContext) {
 		exportNotebook: (notebook: vscode.NotebookData): string => {
 			return exportNotebook(notebook, serializer);
 		},
-		setKernelSpec: async (resource: vscode.Uri, kernelspec: unknown): Promise<boolean> => {
+		setNotebookMetadata: async (resource: vscode.Uri, metadata: Partial<NotebookMetadata>): Promise<boolean> => {
 			const document = vscode.workspace.notebookDocuments.find(doc => doc.uri.toString() === resource.toString());
 			if (!document) {
 				return false;
@@ -33,9 +52,9 @@ export function activate(context: vscode.ExtensionContext) {
 				...document.metadata,
 				custom: {
 					...(document.metadata.custom ?? {}),
-					metadata: {
+					metadata: <NotebookMetadata>{
 						...(document.metadata.custom?.metadata ?? {}),
-						kernelspec: kernelspec
+						...metadata
 					},
 				}
 			});