Could not load file or assembly 'Microsoft.Office.SharePoint.Tools, Version=15.0.0.0, Culture=neutral, PublicKeyToken=71e9bce111e9429c' or one of its dependencies. The system cannot find the file specified.

I have created a simple provider hosted app for SharePoint online. I did not add any code to it, the only change I made is Permissions.

When I hit F5, I get to see following error

Could not load file or assembly 'Microsoft.Office.SharePoint.Tools, Version=15.0.0.0, Culture=neutral, PublicKeyToken=71e9bce111e9429c' or one of its dependencies. The system cannot find the file specified.

If I build the entire solution, no error are seen. I am using following 

Visual Studio 2015 Community

Windows 10 x64 OS

SharePoint Online

Do I have to do something in GAC? or in Visual Studio Project? Please help.