The Human Layer Architecture: A Specification for Human-AI System Design

Title: The Human Layer Architecture: A Specification for Human-AI System Design Series: Paper 2 of The Human Layer Architecture Version: 1.0 (March 2026) Abstract: The first paper in this series established the economic and institutional case for the Human Layer: the argument that AI systems designed to amplify human judgment outperform those designed for full replacement. This paper delivers the formal specification. It defines five architectural components required for accountable human-AI interaction in regulated, safety-critical, or trust-dependent environments: decision gates, escalation protocols, accountability structures, override mechanisms, and trust calibration interfaces. Each component is grounded in peer-reviewed research, operational precedent, and regulatory requirements now in force or approaching enforcement under the EU AI Act, NIST AI RMF, and ISO/IEC 42001. The five components form a dependency graph, not a checklist. Removing any one breaks the guarantees provided by the others. This is not a policy recommendation. It is a design document for any system where human oversight must be structural, not decorative. Keywords: Systems Architecture, AI Specification, EU AI Act Compliance, Human-in-the-loop (HITL), AI Governance, RAIR (Reasoned AI Response), RSR (Reasoned System Response), NIST AI RMF. Author: Ahmad Noureddine, Founder & CXO at AtivoLabs. ORCID: 0009-0003-1669-4553 Related Work: This paper provides the technical implementation for the economic framework established in Paper 1: "The Human Layer: Why the Most Critical Infrastructure in AI Isn't Artificial" (DOI: 10.5281/zenodo.19119699).