Agentic systems — artificial intelligence systems that plan, retrieve, invoke tools, maintain working state, and adapt task progression across time — increasingly operate inside governance frameworks designed to keep them aligned with human authority and operational intent. The HGC³AE² framework introduced in prior work positions human-governed, curated, collaboratively reconciled, and agentically engineered execution as the architecture for such alignment. The Skipjack Protocol formalizes the runtime enforcement layer. What this paper addresses is a quieter precondition. Before an agentic system can be governed, it must be capable of being *comprehended* — and, more demandingly, capable of comprehending itself. This paper argues that the load-bearing but under-specified precondition of mission-ready agentic operation is a structured Comprehension Instrument: a set of self-knowledge, situational-awareness, and intent-fidelity functions that the system runs continuously in order to remain inside the pre-authorized decision envelope its governance layer has defined. Without such an instrument, the four enforcement mechanisms of the Skipjack Protocol cannot fire reliably. The paper specifies five comprehension functions — state introspection, intent rehearsal, envelope-distance estimation, drift detection, and scope-boundary signaling — and shows where each feeds into Skipjack's enforcement mechanisms. It then argues that the Comprehension Instrument must be implemented as an architectural component bounded, testable, observable, and governable by humans, not as an emergent property of model scale or training quality.