@User: Unfortunately, the way the rules are built, magic cannot distinguish between layers; the rule is specified for many different layers at once. Potentially, the "escape sequence" mechanism that automatically fills in the distance value might be able to be extended to include the forward and reverse edge types that triggered the rule. It would require a bit of work to encode, because those types would have to be put into a structure somewhere to be passed to the callback function that prints the DRC error text. But it seems doable.