AICOS OS: A Decision Governance Operating System for AI-Mediated Environments

This work presents AICOS OS, a decision governance operating system designed to function above artificial intelligence systems. The system does not generate intelligence, automate tasks, or replace human judgment. Instead, it governs whether and under what authority AI-influenced actions may proceed in environments characterized by high uncertainty, scale, and irreversible risk. AICOS OS formalizes decision contexts, authority mappings, risk and uncertainty thresholds, deterministic GO / HOLD / REJECT gating, color-state risk enforcement (Green / Yellow / Red), and audit-grade decision lineage with replay capability. By explicitly separating intelligence generation from decision authorization, the system preserves human-final authority while enabling scalable, reviewable, and legally defensible decision governance. The manuscript addresses institutional and global-scale domains including energy systems, defense, trade, critical infrastructure, and large-scale communication environments. Rather than proposing a new AI model or ethical framework, it introduces an operating-system-level architecture that translates governance requirements into enforceable system constraints. This work is intended for interdisciplinary evaluation by researchers, engineers, legal scholars, regulators, and institutional decision-makers concerned with accountability, legitimacy, and survivability in AI-mediated systems.