TFS 2015 offers a rich (REST) API that can be used to manipulate and automate almost every aspect of Team Foundation Server. If you don’t know where to look for the documentation, here is the link https://www.visualstudio.com/en-us/integrate/api/overview.
More information:
- Getting started: https://www.visualstudio.com/integrate/get-started/rest/basics
- .NET client libraries: https://www.visualstudio.com/en-us/integrate/get-started/client-libraries/dotnet