Automation and Extensibility for Visual Studio
Visual Studio add-ins are deprecated in Visual Studio 2013. You should upgrade your add-ins to VSPackage extensions. For more information about upgrading, see How to: Convert an Add-in to a VSPackage.
You can extend Visual Studio by using VSPackages and Managed Extensibility Framework (MEF) extensions.
To use VSPackages and the Managed Extensibility Framework, you must install the Visual Studio SDK. For information about how to download the Visual Studio SDK, see Visual Studio Extensibility Developer Center on the MSDN Web site.
For information about how to extend Visual Studio by using the Visual Studio SDK, see Developing Visual Studio Extensions on the MSDN Web site.