diff --git a/gruntjs/gruntjs-tests.ts b/gruntjs/gruntjs-tests.ts
index 9097fa7df..84a5c22a4 100644
--- a/gruntjs/gruntjs-tests.ts
+++ b/gruntjs/gruntjs-tests.ts
@@ -3,6 +3,14 @@
 // Official code sample from 
 // http://gruntjs.com/getting-started#an-example-gruntfile
 
+interface MyTaskData {
+    repeat: number;
+}
+
+interface MyOptions {
+    sourceRoot: string;
+}
+
 // exports should work same as module.exports 
 exports = (grunt: IGrunt) => {
 
@@ -26,6 +34,17 @@ exports = (grunt: IGrunt) => {
     // Default task(s).
     grunt.registerTask('default', ['uglify']);
 
+    grunt.registerMultiTask('mytask', "short description", function() {
+        var currenttask: grunt.task.IMultiTask<MyTaskData> = this;
+        var options = currenttask.options<MyOptions>({
+            sourceRoot: "default"
+        });
+        var valid = false;
+        valid = valid && options.sourceRoot === "default";
+        valid = valid && currenttask.data.repeat > 0;
+        return valid;
+    });
+
 
     // util methods
     var testOneArg = (a: number) => a * 2;
diff --git a/gruntjs/gruntjs.d.ts b/gruntjs/gruntjs.d.ts
index 0b3d6ee2e..be08cb237 100644
--- a/gruntjs/gruntjs.d.ts
+++ b/gruntjs/gruntjs.d.ts
@@ -760,10 +760,6 @@ declare module grunt {
 
     module task {
 
-        interface TaskFunction extends ITask {
-            (...args: any[]): boolean
-        }
-
         /**
          * {@link http://gruntjs.com/api/grunt.task}
          */
@@ -784,9 +780,9 @@ declare module grunt {
              * Task-specific properties and methods are available inside the task function as properties
              * of the this object. The task function can return false to indicate that the task has failed.
              *
-             * @note taskFunction.apply(scope: grunt.task.IMultiTask, args: any[])
+             * @note taskFunction.apply(scope: grunt.task.ITask, args: any[])
              */
-            registerTask(taskName: string, description: string, taskFunction: TaskFunction): void
+            registerTask(taskName: string, description: string, taskFunction: Function): void
 
             /**
              * Register a "multi task." A multi task is a task that implicitly iterates over all of its
@@ -794,10 +790,10 @@ declare module grunt {
              * In addition to the default properties and methods, extra multi task-specific properties
              * are available inside the task function as properties of the this object.
              *
-             * @note taskFunction.apply(scope: grunt.task.IMultiTask, args: any[])
+             * @note taskFunction.apply(scope: grunt.task.IMultiTask<any>, args: any[])
              */
-            registerMultiTask(taskName: string, taskFunction: grunt.task.ITask): void
-            registerMultiTask(taskName: string, taskDescription: string, taskFunction: TaskFunction): void
+            registerMultiTask(taskName: string, taskFunction: Function): void
+            registerMultiTask(taskName: string, taskDescription: string, taskFunction: Function): void
         }
 
         /**
@@ -917,9 +913,8 @@ declare module grunt {
              * object properties, which will be further overridden in multi tasks by any target-level
              * options object properties.
              */
-            // options<T>(defaultsObj: T): ITaskOptions
-            // options<T>(defaultsObj: T): T
-            options(defaultsObj: any): any
+            options(defaultsObj: any): ITaskOptions
+            options<T>(defaultsObj: T): T
         }
 
         /**