USR369 said 'new sop' after the DoughCalc build-diary confusion resolved. Checked TASKGATE first (per PROCESS-INDEX-FIRST) rather than assuming none existed - it matched SOP-HANDOFF.md, a real SOP but for a different topic (session-continuity files, not build handoffs) - 4th false TASKGATE match this session. Confirmed no real SOP covers cross-system build/artifact handoffs. Wrote SOP-ARTIFACT-HANDOFF.md: build diary lives with the artifact (not a shared unscoped folder), ARTIFACTS registration required on both sending and receiving system, handoff message must state exact paths with no ambiguous pronouns, task must close with a real decision + sys_id rather than a verbal done claim, receiving system verifies live before treating handoff complete. Added to SOP-INDEX.md with a cross-reference note distinguishing it from SOP-HANDOFF.md. Broadcast platform-wide (id 42), verified live per D671. Logged the 4th-false-match pattern (K239) as its own finding for Server 40's TASKGATE fix.