You could use the MxModelReflection module for this. After proper configuration of this module, one can read the content of the model. For example, the entity MxObjectMember in this module contains all the attribute in a specific entity (MxObjectType).
So you could create you own domain structure, and populate this based on the data in MxModelReflection. Then put some nice visualizations on your structure.
Hope that helps,
Thank you for the answer.
However, I did not want to specify additional tables.
As an input for my solution I found the following page.
For those interested.
I have now solved this with a JAVA action.
I have passed the objects to the action and retrieved the attributes there with the method getMembers. After that you can count the number of attributes with .size and return it as an integer.