SOUTH: Stochastic Authorization for Agent and Service Requests

SOUTH defines an authorization protocol for evaluating requests issued by users, services, or autonomous agents. SOUTH allows a server to return a deterministic decision or an allow decision that is issued with a probability determined by local policy. This enables servers to incorporate uncertainty, contextual information, and load conditions into authorization decisions. SOUTH is transport independent and can be composed with existing authentication mechanisms such as OAuth, OpenID Connect, mutual TLS, or DPoP. This document describes the request and response objects, decision semantics, and an HTTP binding for interoperable deployment.