  This extended abstract reports on previous work of the CamFort project in
which we developed an external units-of-measure type system for Fortran code,
targeted at scientists. Our approach can guide the programmer in adding
specifications (type annotations) to existing code, with the aim of easing
adoption on legacy code. Pertinent to the topics of the HATRA workshop, we
discuss the human-aspects of the tool here. CamFort is open-source and freely
available online.
