A go.mod requires a mesh package at the zero version only, and the check builds it against the group's head or the latest published version (ADR 0573 §2, §4). seatfiles still named mesh-sdk at a November 4 commit; the fetch proof's new guard refuses that. Builds: design 47 G (join 11, the check's shut-off build of the group's modules) Claude-Session: https://claude.ai/code/session_01NcbgfGKaxw984XyAPfLm4h