ArgoSPE: Model-based software performance engineering Stochastic Petri nets (SPNs) have been proved useful for the quantitative analysis of systems. This paper introduces ArgoSPE, a tool for the performance evaluation of software systems in the first stages of the life-cycle. ArgoSPE implements a performance evaluation process that builds on the principles of the software performance engineering (SPE). The theory behind the tool, i.e. the underlying SPE process, has been presented in previous papers and consists in translating some performance annotated UML diagrams into SPN models. Therefore, ArgoSPE prevents software engineers to model with SPN since they are obtained as a by-product of their UML models. The design of the tool follows the architecture proposed by OMG in the UML Profile for Schedulability, Performance and Time specification