diff --git a/src/vs/workbench/api/common/extHostExtensionActivator.ts b/src/vs/workbench/api/common/extHostExtensionActivator.ts
index 970564256e5..5a3646ac4b0 100644
--- a/src/vs/workbench/api/common/extHostExtensionActivator.ts
+++ b/src/vs/workbench/api/common/extHostExtensionActivator.ts
@@ -4,6 +4,7 @@
  *--------------------------------------------------------------------------------------------*/
 
 import * as nls from 'vs/nls';
+import * as vscode from 'vscode';
 import { IDisposable } from 'vs/base/common/lifecycle';
 import { ExtensionDescriptionRegistry } from 'vs/workbench/services/extensions/common/extensionDescriptionRegistry';
 import { ExtensionIdentifier } from 'vs/platform/extensions/common/extensions';
@@ -11,28 +12,11 @@ import { ExtensionActivationError, MissingDependencyError } from 'vs/workbench/s
 
 const NO_OP_VOID_PROMISE = Promise.resolve<void>(undefined);
 
-export interface IExtensionMemento {
-	get<T>(key: string): T | undefined;
-	get<T>(key: string, defaultValue: T): T;
-	update(key: string, value: any): Promise<void>;
-}
-
-export interface IExtensionContext {
-	subscriptions: IDisposable[];
-	workspaceState: IExtensionMemento;
-	globalState: IExtensionMemento;
-	extensionPath: string;
-	storagePath: string;
-	globalStoragePath: string;
-	asAbsolutePath(relativePath: string): string;
-	readonly logPath: string;
-}
-
 /**
  * Represents the source code (module) of an extension.
  */
 export interface IExtensionModule {
-	activate?(ctx: IExtensionContext): Promise<IExtensionAPI>;
+	activate?(ctx: vscode.ExtensionContext): Promise<IExtensionAPI>;
 	deactivate?(): void;
 }
 
diff --git a/src/vs/workbench/api/common/extHostExtensionService.ts b/src/vs/workbench/api/common/extHostExtensionService.ts
index 40e90c73cc7..dab30a87016 100644
--- a/src/vs/workbench/api/common/extHostExtensionService.ts
+++ b/src/vs/workbench/api/common/extHostExtensionService.ts
@@ -13,7 +13,7 @@ import { URI } from 'vs/base/common/uri';
 import { ILogService } from 'vs/platform/log/common/log';
 import { ExtHostExtensionServiceShape, IInitData, MainContext, MainThreadExtensionServiceShape, MainThreadTelemetryShape, MainThreadWorkspaceShape, IResolveAuthorityResult } from 'vs/workbench/api/common/extHost.protocol';
 import { ExtHostConfiguration, IExtHostConfiguration } from 'vs/workbench/api/common/extHostConfiguration';
-import { ActivatedExtension, EmptyExtension, ExtensionActivatedByAPI, ExtensionActivatedByEvent, ExtensionActivationReason, ExtensionActivationTimes, ExtensionActivationTimesBuilder, ExtensionsActivator, IExtensionAPI, IExtensionContext, IExtensionModule, HostExtension, ExtensionActivationTimesFragment } from 'vs/workbench/api/common/extHostExtensionActivator';
+import { ActivatedExtension, EmptyExtension, ExtensionActivatedByAPI, ExtensionActivatedByEvent, ExtensionActivationReason, ExtensionActivationTimes, ExtensionActivationTimesBuilder, ExtensionsActivator, IExtensionAPI, IExtensionModule, HostExtension, ExtensionActivationTimesFragment } from 'vs/workbench/api/common/extHostExtensionActivator';
 import { ExtHostStorage, IExtHostStorage } from 'vs/workbench/api/common/extHostStorage';
 import { ExtHostWorkspace, IExtHostWorkspace } from 'vs/workbench/api/common/extHostWorkspace';
 import { ExtensionActivationError } from 'vs/workbench/services/extensions/common/extensions';
@@ -331,11 +331,11 @@ export abstract class AbstractExtHostExtensionService implements ExtHostExtensio
 		this._logService.info(`ExtensionService#_doActivateExtension ${extensionDescription.identifier.value} ${JSON.stringify(reason)}`);
 
 		const activationTimesBuilder = new ExtensionActivationTimesBuilder(reason.startup);
-		return Promise.all<any>([
-			this._loadCommonJSModule(joinPath(extensionDescription.extensionLocation, extensionDescription.main), activationTimesBuilder),
+		return Promise.all([
+			this._loadCommonJSModule<IExtensionModule>(joinPath(extensionDescription.extensionLocation, extensionDescription.main), activationTimesBuilder),
 			this._loadExtensionContext(extensionDescription)
 		]).then(values => {
-			return AbstractExtHostExtensionService._callActivate(this._logService, extensionDescription.identifier, <IExtensionModule>values[0], <IExtensionContext>values[1], activationTimesBuilder);
+			return AbstractExtHostExtensionService._callActivate(this._logService, extensionDescription.identifier, values[0], values[1], activationTimesBuilder);
 		});
 	}
 
@@ -353,7 +353,7 @@ export abstract class AbstractExtHostExtensionService implements ExtHostExtensio
 			this._storagePath.whenReady
 		]).then(() => {
 			const that = this;
-			return Object.freeze(<IExtensionContext>{
+			return Object.freeze<vscode.ExtensionContext>({
 				globalState,
 				workspaceState,
 				subscriptions: [],
@@ -366,7 +366,7 @@ export abstract class AbstractExtHostExtensionService implements ExtHostExtensio
 		});
 	}
 
-	private static _callActivate(logService: ILogService, extensionId: ExtensionIdentifier, extensionModule: IExtensionModule, context: IExtensionContext, activationTimesBuilder: ExtensionActivationTimesBuilder): Promise<ActivatedExtension> {
+	private static _callActivate(logService: ILogService, extensionId: ExtensionIdentifier, extensionModule: IExtensionModule, context: vscode.ExtensionContext, activationTimesBuilder: ExtensionActivationTimesBuilder): Promise<ActivatedExtension> {
 		// Make sure the extension's surface is not undefined
 		extensionModule = extensionModule || {
 			activate: undefined,
@@ -378,7 +378,7 @@ export abstract class AbstractExtHostExtensionService implements ExtHostExtensio
 		});
 	}
 
-	private static _callActivateOptional(logService: ILogService, extensionId: ExtensionIdentifier, extensionModule: IExtensionModule, context: IExtensionContext, activationTimesBuilder: ExtensionActivationTimesBuilder): Promise<IExtensionAPI> {
+	private static _callActivateOptional(logService: ILogService, extensionId: ExtensionIdentifier, extensionModule: IExtensionModule, context: vscode.ExtensionContext, activationTimesBuilder: ExtensionActivationTimesBuilder): Promise<IExtensionAPI> {
 		if (typeof extensionModule.activate === 'function') {
 			try {
 				activationTimesBuilder.activateCallStart();
diff --git a/src/vs/workbench/api/common/extHostMemento.ts b/src/vs/workbench/api/common/extHostMemento.ts
index d0e68010a17..103b8f6a785 100644
--- a/src/vs/workbench/api/common/extHostMemento.ts
+++ b/src/vs/workbench/api/common/extHostMemento.ts
@@ -3,11 +3,11 @@
  *  Licensed under the MIT License. See License.txt in the project root for license information.
  *--------------------------------------------------------------------------------------------*/
 
+import * as vscode from 'vscode';
 import { IDisposable } from 'vs/base/common/lifecycle';
-import { IExtensionMemento } from 'vs/workbench/api/common/extHostExtensionActivator';
 import { ExtHostStorage } from 'vs/workbench/api/common/extHostStorage';
 
-export class ExtensionMemento implements IExtensionMemento {
+export class ExtensionMemento implements vscode.Memento {
 
 	private readonly _id: string;
 	private readonly _shared: boolean;