Research in process-centered environments (PCEs) has focused on project management support and has neglected method guidance for the engineers performing the (software) engineering process. It has been dominated by the search for suitable process-modeling languages and enactment mechanisms. The consequences of process orientation on the computer-based engineering environments, i.e., the interactive tools used during process performance, have been studied much less. In this article, we present the PRIME (Process Integrated Modeling Environments) framework which empowers method guidance through process-integrated tools. In contrast to the tools of PCEs, the process-integrated tools of PRIME adjust their behavior according to the current process situation and the method definitions. Process integration of PRIME tools is achieved through (1) the definition of tool models; (2) the integration of the tool models and the method definitions; (3) the interpretation of the integrated environment model by the tools, the process-aware control integration mechanism, and the enactment mechanism; and (4) the synchronization of the tools and the enactment mechanism based on a comprehensive interaction protocol. We sketch the implementation of PRIME as a reusable implementation framework which facilitates the realization of process-integrated tools as well as the process integration of external tools. We define a six-step procedure for building a PRIME-based process-integrated environment (PIE) and illustrate how PRIME facilitates change integration on an easy-to-adapt modeling level.