The manual measurement of functional size is generally very time-consuming and has many precision errors. For this reason, it is necessary to automate the measurement process to obtain a solution that can be applied in a MDA industrial development. The OO-Method COSMIC Function Points (OOmCFP) is a measurement procedure that has been designed to measure the functional size of object-oriented applications generated from their conceptual models by means of model transformations. This work presents the definition of the mechanisms that are necessary to automate the OOmCFP procedure. This work also presents the OOmCFP tool that implements the OOmCFP procedure. Since this tool measures the functional size of industrial applications generated in MDA environments from their conceptual models, it is not necessary to perform the measurement task on the final code. The OOmCFP tool incorporates the benefits that the COSMIC measurement method provides. These benefits are demonstrated through a comparative analysis.