This working paper introduces SCD + Security as a non-executable output reference boundary structure for the AGI era. Building on Paper 1 of the AGI Structural Alignment Series, which established BIFACE-Based Sentence Coordinate Documents as a coordinate-reference grammar, this paper addresses the next structural question: which roles, AI+AGI environments, and review contexts may reference which sentence, code, image-region, video-scene, subtitle, voice-segment, conversation, or revision-instruction coordinates, under what boundary conditions. The paper defines SCD + Security as a reference-boundary layer rather than a cybersecurity, authentication, encryption, access-control, storage, execution, evidence-confirmation, approval, consent, or legal-effect system. Its purpose is to prevent SCD/BIFACE coordinates from becoming unrestricted access paths or unintended authority references. This working paper is Paper 2 of the AGI Structural Alignment Series. This record provides the Expanded Final Publication Edition v3.0 of Paper 2 in the Structural Paper Series under the Research Program on Deterministic Infrastructure and Human-Centered AI Coordination. This version includes unified publication front matter, expanded academic structure, strengthened non-substitution boundaries, and broader cross-domain applicability.
The First Waters (2026) studied this question.