Model-driven engineering (MDE) addresses the complexity of modern-day embedded system design. Multiple MDE frameworks are often integrated into a design process to use each MDE framework's state-of-the-art tools for increased productivity. However, this integration requires substantial development effort. In this paper, we propose an MDE, framework based on a formalism of system graphs and trait hierarchies for programming-language-agnostic integration between tools within our framework and with tools of other MDE frameworks. Implementing our framework for each programming language is a one-time development effort. We evaluate our proposal in an MDE design process by developing a Java supporting library and an AMALTHEA connector. Then we perform an MDE, industrial avionics case study with both. The evaluation shows that our framework facilitates the integration of different tools and the independent development of different system parts. Therefore, our framework is a reliable MDE, framework that lowers the effort of integrating tools to benefit from their combined state-of-the-art.