Worked on the macports/macports-ports repository to address a targeted bug affecting MPI-enabled builds of VTK when used with HDF5. Focused on CMake configuration and library integration, the developer introduced a missing CMake argument to ensure VTK correctly recognizes and enables MPI support. This adjustment resolved configuration errors that previously disrupted scientific workflows relying on MPI and HDF5, leading to more reliable and reproducible builds. The work demonstrated attention to traceability by linking the fix to an internal ticket and providing clear documentation. Skills applied included CMake scripting, MPI support, and cross-library build management within a collaborative open-source environment.