diff --git a/src/vs/vscode.proposed.d.ts b/src/vs/vscode.proposed.d.ts
index 2d518707ad57853f27dcc2f1845cbef10d05a0a4..0cc95821510de9b202405572f03e2b8c12b61194 100644
--- a/src/vs/vscode.proposed.d.ts
+++ b/src/vs/vscode.proposed.d.ts
@@ -914,17 +914,15 @@ declare module 'vscode' {
 	 */
 	export class CustomExecution2 {
 		/**
+		 * Constructs a CustomExecution task object. The callback will be executed the task is run, at which point the
+		 * extension should return the Pseudoterminal it will "run in". The task should wait to do further execution until
+		 * [Pseudoterminal.open](#Pseudoterminal.open) is called. Task cancellation should be handled using
+		 * [Pseudoterminal.close](#Pseudoterminal.close). When the task is complete fire
+		 * [Pseudoterminal.onDidClose](#Pseudoterminal.onDidClose).
 		 * @param process The [Pseudoterminal](#Pseudoterminal) to be used by the task to display output.
 		 * @param callback The callback that will be called when the task is started by a user.
 		 */
 		constructor(callback: () => Thenable<Pseudoterminal>);
-
-		/**
-		 * The callback used to execute the task. Cancellation should be handled using
-		 * [Pseudoterminal.close](#Pseudoterminal.close). When the task is complete fire
-		 * [Pseudoterminal.onDidClose](#Pseudoterminal.onDidClose).
-		 */
-		callback: () => Thenable<Pseudoterminal>;
 	}
 
 	/**
diff --git a/src/vs/workbench/api/common/extHostTask.ts b/src/vs/workbench/api/common/extHostTask.ts
index 7667465f6bd41fd8cf6b82084d47531e2ea6114a..7cd590692fd4dd3a9bf4306a698ebd9313ee6c71 100644
--- a/src/vs/workbench/api/common/extHostTask.ts
+++ b/src/vs/workbench/api/common/extHostTask.ts
@@ -373,9 +373,9 @@ export abstract class ExtHostTaskBase implements ExtHostTaskShape {
 	protected _handleCounter: number;
 	protected _handlers: Map<number, HandlerData>;
 	protected _taskExecutions: Map<string, TaskExecutionImpl>;
-	protected _providedCustomExecutions2: Map<string, vscode.CustomExecution2>;
+	protected _providedCustomExecutions2: Map<string, types.CustomExecution2>;
 	private _notProvidedCustomExecutions: Set<string>; // Used for custom executions tasks that are created and run through executeTask.
-	protected _activeCustomExecutions2: Map<string, vscode.CustomExecution2>;
+	protected _activeCustomExecutions2: Map<string, types.CustomExecution2>;
 	private _lastStartedTask: string | undefined;
 	protected readonly _onDidExecuteTask: Emitter<vscode.TaskStartEvent> = new Emitter<vscode.TaskStartEvent>();
 	protected readonly _onDidTerminateTask: Emitter<vscode.TaskEndEvent> = new Emitter<vscode.TaskEndEvent>();
@@ -399,9 +399,9 @@ export abstract class ExtHostTaskBase implements ExtHostTaskShape {
 		this._handleCounter = 0;
 		this._handlers = new Map<number, HandlerData>();
 		this._taskExecutions = new Map<string, TaskExecutionImpl>();
-		this._providedCustomExecutions2 = new Map<string, vscode.CustomExecution2>();
+		this._providedCustomExecutions2 = new Map<string, types.CustomExecution2>();
 		this._notProvidedCustomExecutions = new Set<string>();
-		this._activeCustomExecutions2 = new Map<string, vscode.CustomExecution2>();
+		this._activeCustomExecutions2 = new Map<string, types.CustomExecution2>();
 	}
 
 	public registerTaskProvider(extension: IExtensionDescription, type: string, provider: vscode.TaskProvider): vscode.Disposable {
@@ -454,7 +454,7 @@ export abstract class ExtHostTaskBase implements ExtHostTaskShape {
 	}
 
 	public async $onDidStartTask(execution: tasks.TaskExecutionDTO, terminalId: number): Promise<void> {
-		const execution2: vscode.CustomExecution2 | undefined = this._providedCustomExecutions2.get(execution.id);
+		const execution2: types.CustomExecution2 | undefined = this._providedCustomExecutions2.get(execution.id);
 		if (execution2) {
 			if (this._activeCustomExecutions2.get(execution.id) !== undefined) {
 				throw new Error('We should not be trying to start the same custom task executions twice.');
@@ -593,7 +593,7 @@ export abstract class ExtHostTaskBase implements ExtHostTaskShape {
 		if (!isProvided && !this._providedCustomExecutions2.has(taskId)) {
 			this._notProvidedCustomExecutions.add(taskId);
 		}
-		this._providedCustomExecutions2.set(taskId, <vscode.CustomExecution2>(<vscode.Task2>task).execution2);
+		this._providedCustomExecutions2.set(taskId, <types.CustomExecution2>(<vscode.Task2>task).execution2);
 	}
 
 	protected async getTaskExecution(execution: tasks.TaskExecutionDTO | string, task?: vscode.Task): Promise<TaskExecutionImpl> {