diff --git a/src/vs/code/browser/workbench/workbench.ts b/src/vs/code/browser/workbench/workbench.ts
index 2fd9c9f5fe2d0..a834fb365870b 100644
--- a/src/vs/code/browser/workbench/workbench.ts
+++ b/src/vs/code/browser/workbench/workbench.ts
@@ -1,8 +1,8 @@
+
 /*---------------------------------------------------------------------------------------------
  *  Copyright (c) Microsoft Corporation. All rights reserved.
  *  Licensed under the MIT License. See License.txt in the project root for license information.
  *--------------------------------------------------------------------------------------------*/
-
 import { create } from 'vs/workbench/workbench.web.main';
 import { URI } from 'vs/base/common/uri';
 import {
@@ -10,6 +10,12 @@ import {
 	IWorkspace,
 } from 'vs/workbench/browser/web.api';
 import { SecretStorageProvider } from 'vs/code/browser/workbench/membrane';
+import { CommandsRegistry } from 'vs/platform/commands/common/commands';
+import { IEditorService } from 'vs/workbench/services/editor/common/editorService';
+import { isCodeEditor } from 'vs/editor/browser/editorBrowser';
+import type { ServicesAccessor } from 'vs/platform/instantiation/common/instantiation';
+import { mainWindow } from 'vs/base/browser/window';
+
 declare const window: any;
 type Writeable<T> = { -readonly [P in keyof T]: T[P] };
 
@@ -30,7 +36,6 @@ type Writeable<T> = { -readonly [P in keyof T]: T[P] };
 	]);
 	delete window.extensionToGazePort;
 
-
 	const isHttps = window.location.protocol === 'https:';
 	const isDev = window.location.hostname === 'localhost';
 	const extensionUrl = {
@@ -46,13 +51,13 @@ type Writeable<T> = { -readonly [P in keyof T]: T[P] };
 		// TODO: Somehow use product.json to configure that globally
 		workspace: { workspaceUri: URI.parse('memfs:/membrane.code-workspace') },
 		payload: {
-			'skipReleaseNotes': 'true',
-			'skipWelcome': 'true',
+			skipReleaseNotes: 'true',
+			skipWelcome: 'true',
 		},
 		trusted: true,
 		open: async (
 			_workspace: IWorkspace,
-			_options?: { reuse?: boolean; payload?: object }
+			_options?: { reuse?: boolean; payload?: object },
 		) => {
 			return true;
 		},
@@ -61,17 +66,16 @@ type Writeable<T> = { -readonly [P in keyof T]: T[P] };
 	config.secretStorageProvider = SecretStorageProvider.getInstance();
 
 	config.commands = [
-		// Used to refresh the page from the extension when a new version of the IDE is known to exist.
 		{ id: 'membrane.refreshPage', handler: () => window.location.reload() },
-		// Invoked when the navigator finishes loading
 		{
-			id: 'membrane.completeInitialization', handler: () => window.completeInitialization?.()
+			id: 'membrane.completeInitialization',
+			handler: () => window.completeInitialization?.(),
 		},
-		// For product tour, emit an event to advance to the next step
 		{
-			id: 'membrane.advanceTour', handler: (cmdArgs) => window.dispatchEvent(new Event(`tour:${cmdArgs.trigger}`))
+			id: 'membrane.advanceTour',
+			handler: (cmdArgs) =>
+				window.dispatchEvent(new Event(`tour:${cmdArgs.trigger}`)),
 		},
-		// For extension panels to bubble up errors
 		{
 			id: 'membrane.reportError',
 			handler: (cmdArgs) => {
@@ -86,7 +90,7 @@ type Writeable<T> = { -readonly [P in keyof T]: T[P] };
 				(window as any).SENTRY_REPORT_ISSUE({
 					source: cmdArgs.source,
 					message: cmdArgs.message,
-					context: cmdArgs.context
+					context: cmdArgs.context,
 				});
 			},
 		},
@@ -104,8 +108,9 @@ type Writeable<T> = { -readonly [P in keyof T]: T[P] };
 		{
 			id: 'membrane.getLaunchParams',
 			handler: () => {
-				// eslint-disable-next-line no-restricted-syntax
-				const meta = document.querySelector('meta[name="membrane-launch-params"]') as HTMLMetaElement;
+				const meta = mainWindow.document.querySelector(
+					'meta[name="membrane-launch-params"]',
+				) as HTMLMetaElement;
 				return meta?.content ?? '';
 			},
 		},
@@ -117,7 +122,118 @@ type Writeable<T> = { -readonly [P in keyof T]: T[P] };
 		title: 'Membrane Home',
 	};
 
-	// eslint-disable-next-line no-restricted-syntax
-	const domElement = (window as any).vscodeTargetContainer || document.body;
+	const domElement = (window as any).vscodeTargetContainer || mainWindow.document.body;
 	create(domElement, config);
+
+	// Register Monaco commands for review decorations
+	// These allow the extension to add/remove view zones (e.g., showing removed lines during code review)
+	CommandsRegistry.registerCommand(
+		'membrane.addMonacoViewZone',
+		async (
+			accessor: ServicesAccessor,
+			args: {
+				uri: string;
+				afterLineNumber: number;
+				heightInPx: number;
+				lines: string[];
+			},
+		) => {
+			const editorService = accessor.get(IEditorService);
+			const targetUri = URI.parse(args.uri);
+
+			const activeControl = editorService.activeTextEditorControl;
+			if (!activeControl || !isCodeEditor(activeControl)) {
+				return null;
+			}
+
+			const model = activeControl.getModel();
+			if (!model) {
+				return null;
+			}
+
+			// Verify we're in the correct file
+			const modelUri = model.uri;
+			if (
+				modelUri.scheme !== targetUri.scheme ||
+				modelUri.path !== targetUri.path
+			) {
+				return null;
+			}
+
+			let zoneId: string | null = null;
+
+			activeControl.changeViewZones((accessor) => {
+				const container = document.createElement('div');
+				container.style.cssText = `
+					position: relative;
+					background: rgba(255, 0, 0, 0.15);
+					border-left: 1px solid rgba(255, 0, 0, 0.4);
+					font-family: var(--monaco-monospace-font, 'Menlo', 'Monaco', 'Courier New', monospace);
+					font-size: 12px;
+					line-height: 18px;
+					padding: 0;
+					color: rgba(255, 100, 100, 0.9);
+				`;
+
+				args.lines.forEach((line: string, idx: number) => {
+					const lineDiv = document.createElement('div');
+					lineDiv.style.cssText = `
+						position: absolute;
+						top: ${idx * 18}px;
+						left: 0;
+						right: 0;
+						white-space: pre;
+						overflow: hidden;
+						text-overflow: ellipsis;
+					`;
+
+					lineDiv.textContent = line;
+					container.appendChild(lineDiv);
+				});
+
+				zoneId = accessor.addZone({
+					afterLineNumber: args.afterLineNumber,
+					heightInPx: args.heightInPx,
+					domNode: container,
+					suppressMouseDown: false,
+				});
+			});
+
+			return { zoneId };
+		},
+	);
+
+	CommandsRegistry.registerCommand(
+		'membrane.removeMonacoViewZone',
+		async (
+			accessor: ServicesAccessor,
+			args: { uri: string; zoneId: string },
+		) => {
+			const editorService = accessor.get(IEditorService);
+			const targetUri = URI.parse(args.uri);
+
+			const activeControl = editorService.activeTextEditorControl;
+			if (!activeControl || !isCodeEditor(activeControl)) {
+				return;
+			}
+
+			const model = activeControl.getModel();
+			if (!model) {
+				return;
+			}
+
+			// Verify we're in the correct file
+			const modelUri = model.uri;
+			if (
+				modelUri.scheme !== targetUri.scheme ||
+				modelUri.path !== targetUri.path
+			) {
+				return;
+			}
+
+			activeControl.changeViewZones((accessor) => {
+				accessor.removeZone(args.zoneId);
+			});
+		},
+	);
 })();