Not something I am familiar with I am afraid. I suspect you can’t do it… but someone may know something I don’t…
I presume you are looking for something like the Visual Studio GUI Interface hooks, or the Apple Interface Builder IBOutlet type things… But I am not aware of them in Shader Builder… Then again… I don’t use Shader Builder much at all, apart from as a handy shader validator.
The Lighthouse 3D website has a very nice tutorial on how to build and link GLSL shaders, and how to hook the attributes into your code… Maybe that would be a better approach? It is certainly not a lot more typing than using IBOutlets, or IBActions for GUI stuff, which is perhaps why it’s not such a high priority for Apple.
They still have to integrate Geometry Shader recognition into Shader Builder after all!