If you're ever assigned to manage a single person, it's better to go big picture and wonder if this is a reasonable way to run a company (imo). If a single person is working on a project that requires oversight that person should be senior enough to "manage themselves". If they are too junior, the team should be bigger (because it's important enough to require oversight). If it's oversight due to legal issues that's fine but then the management can be hands of and should basically spot check that everything is following said legal requirements.
At least that's my humble opinion. I treat one on one manager to technical role relations as an organizational smell.