External AI systems increasingly generate decision-relevant representations of enterprises for customers, investors, counterparties, and regulators. These representations occur outside organizational control and typically leave no durable record. When such outputs later become relevant in board review, litigation, audit, or regulatory inquiry, enterprises are often unable to evidence what was said, when it was said, or how leadership responded at the time. This technical note describes AIVO Evidentia, an operational evidence-layer system developed to address this evidentiary gap. Evidentia records how external AI systems describe an enterprise at defined points in time and preserves those representations as immutable records suitable for later legal, audit, and governance review. The system does not attempt to control AI behavior, assert legal duties, or imply regulatory obligation. This note is descriptive, not normative, and should be read alongside the companion governance paper on evidentiary gaps arising from external AI representations.