Exposing an attribute is a design-time operation (you design the workspace), but knowing whether an attribute has a value or not is a run-time operation (data is flowing through your workspace). So if I understand your question correctly the answer is no, you cannot.

Your answer makes sense to me. I used AttributeValidation transformer to do what I want to accomplish and limit the attributes in my writer.

The inspector feature identifier tool does a good job doing it and I was hoping that there's a format parameter option in the reader that can limit format attributes in design time.

Thanks!