Incremental Guardrail Evaluation and Scoped Operating Posture for AI Agents

AI agents can gain new authority when a developer adds a tool, broadens a connector, changes a data source, enables memory, or connects another agent. A prior guardrail test may no longer support the resulting permissions. This paper proposes reassessment triggered by material capability changes, paired tests of unauthorized and authorized behavior, and a scoped Green, Yellow, or Red operating posture tied to the observed evidence. The method turns evaluation findings into explicit permission decisions. It is a proposal for organizational practice, not an empirical validation or a certification scheme.