# mpiCheckPhaseHook {#setup-hook-mpi-check} This hook can be used to setup a check phase that requires running a MPI application. It detects the used present MPI implementaion type and exports the neceesary environment variables to use `mpirun` and `mpiexec` in a Nix sandbox. Example: ```nix { mpiCheckPhaseHook, mpi, ... }: ... nativeCheckInputs = [ openssh mpiCheckPhaseHook ]; ```