Another big change in TFS 15 Preview is the new Build Agent.
This doesn’t mean there is yet another build server (the new Team Build is here to stay 
), the big news here is that the new Agent is cross-platform by default, because it is written in .NET Core!
You can set it up as usual from the main _admin page. Once you add the new Agent, you can select Windows (preview):
You need to add a user as Agent Pool Administrator to run this new agent, as per documentation:
Once you start it, you would be prompted for some configuration settings. It is very easy and similar to the old agent:
All done!
Remember it is a preview, and if you want to start using it that this agent is a replacement for the Node.JS agent. So if you want to keep using TFS 2015 in the meantime do not replace the Windows Agent that comes with it.
As usual, the code for the agent is on GitHub.