sdd:directionCopy as claim

sdd:direction is a sdd:Port's direction — exactly one of sdd:in, sdd:out, or sdd:io (design spec §2).Copy as claim

Direction drives default border placement wherever a port's owning section doesn't already determine it. In a flat, sectionless node, sdd:in places to the left border, sdd:out to the right, and sdd:io to the top. Inside a section, a full-width or full-height strip touching a flow-axis border uses that border regardless of direction, while a side-only strip still falls back to direction: sdd:in→left, sdd:out→right, sdd:io→left (design spec §3).Copy as claim