Microsoft made it possible from the beginning to extend TFS or do some basic programming against a TFS server by using the TFS object model. The only problem(next to the lack of good documentation) is that you had to install Visual Studio or Team Explorer to be able to use this.
In TFS 2012, Microsoft finally create a stand-alone installer that would just install the programmability components – making for a faster, smaller and less impactful install.
You can download the installer here: http://visualstudiogallery.msdn.microsoft.com/f30e5cc7-036e-449c-a541-d522299445aa
Remark: you still need proper licenses/CALs.