The design of safety-critical systems and business-critical services necessitates to coordinate between a large variety of tools used in different phases of the development process. As certification frequently prescribes to achieve justified compliance with regulations of authorities, integrated tool chain should strictly adhere to the development process itself. In order to manage complexity, we follow a model-driven approach where the development process is captured using a precise domain-specific modeling language. Each individual step within this process is represented transparently as a service. Moreover, to carry out individual tasks, systems engineers are guided by semi-automated transformation steps and well-formedness constraint checking. Both of them are formalized by graph patterns and graph transformation rules as provided by the Viatra2 framework. In our prototype implementation, we use the popular JBPM workflow engine as orchestration means between different design and verification tools. We also give some insights how this tool integration approach was applied in recent projects.