To face the major challenges posed by the increasing product variants with shortening life cycles and fluctuating market conditions, modular and adaptable assembly systems are used. Their strong dependency on software creates a new void in the planning and implementation processes of these assembly systems. Usually, the programmer fills this void based on his knowledge, which leads to frequent and large adaptations of the code base. This is rather counter-productive. To address this challenge, we developed a generic user-friendly graphical API (Application Programming Interface) for a process owner in our previous work (Müller et al, Proc CIRP 81:730–735, 2019, [1]). This API can describe any assembly system and the associated task and is used to get the boilerplate code needed to execute the process on a programmable logic controller (PLC)—the standard hardware used in the industry. In this paper, the virtual description of an assembly system used by the API is extended to include a goal-oriented task description by defining the process and the structure. We believe that this extension provides the proper abstraction needed by the process owner. In addition, this extension significantly reduces the modeling effort.