100% this. Deciding on end user error handling in a low level is making assumptions that cannot be known at the low level. The caller decides how something is

100% this. Deciding on end user error handling in a low level is making assumptions that cannot be known at the low level. The caller decides how something is going to be handled and presented, not the callee, or you inevitably miss them in important places and silently miscategorize stuff. Far better to have that scenario lead to a 500 (unmapped error, unknown problem) so it can be fixed.