Most research on collective robotic construction (CRC) separates the architectural design and robotic path planning phases of the overall construction process. Specifically, a structure is designed and afterwards sent to a planner or compiler that returns instructions for the assembly of the structure with the robots at hand. Although this has led to the assembly of spatially complex structures, it obscures the planning process, making it inaccessible to the architect. Considering that one potential of CRC is that the architect can perform as more than a designer of static structures, this paper showcases how agent-based modelling can collapse the architectural design and robotic planning phases for CRC. As such the overall construction workflow is upended, leading to more designer control, adjustment for tolerances in the construction process, a more general understanding of the processes, and the potential for architectural reconfiguration when working with CRC systems. This is demonstrated through the presentation of an ABM for assembling a planar structure using a previously developed CRC system.