Λ — Decision Boundary: An Architectural Abstraction for Pre-Execution Authorization in Agentic AI

Λ — Decision Boundary is the architectural location at which an action selected by an AI system is evaluated for authority before it becomes real-world execution. This technical note separates Selection, Authorization, Enforcement, and Execution as a common architectural vocabulary, and names the authorization location within it Λ — Decision Boundary. Λ returns EXECUTE, HOLD, or BLOCK, and fails closed when authority cannot be established. The note does not claim that pre-execution authorization itself is new; it relates the concept to reference monitors, PDP/PEP, ABAC, Zero Trust, Faramesh, LATTICE, and Right-to-Act. EVΛƎ is presented as one reference architecture in which the boundary is embedded.