An audit trail is the governance mechanism that preserves evidence of actions, decisions, approvals, validation activities, and responsible parties throughout the lifecycle of an AI system. If the organization cannot establish who authorized deployment or how the system was validated, the fundamental problem is missing traceability and historical evidence. This is precisely what an audit trail should provide. CompTIA SecAI+ emphasizes governance roles, model validation, monitoring, auditing for quality and compliance, and accountability throughout the AI lifecycle. A completed threat model documents threats and attack scenarios, but it would not necessarily record deployment approval or validation evidence. Blueprint controls are not the primary mechanism for preserving historical authorization records. Organizational policies may define that approval and validation must occur, but merely having policies does not demonstrate that the required actions actually occurred. Proper audit records would identify the approver, validation method, relevant results, dates, model version, and other governance evidence. Therefore, the inability to reconstruct those decisions indicates the absence of an adequate audit trail.

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