Aspects of the subject technology relate to systems and methods for controlling a hydraulic fracturing job. Systems and methods are provided for receiving diagnostics data of a hydraulic fracturing completion of a wellbore, accessing a fracture formation model that models formation characteristics of fractures formed through the wellbore into a formation surrounding the wellbore during the hydraulic fracture completion with respect to surface variables of the hydraulic fracturing completion, selecting one or more subsurface objective functions from a plurality of subsurface objective functions for changing one or more of the formation characteristics of the fractures, and applying the fracture formation model based on the diagnostics data to determine values of the surface variables for controlling the formation characteristics of the fractures to converge on the one or more subsurface objective functions.