Supervision viability. Author-proposed term, not an established standard.
Definition. Supervision viability asks whether the human supervision an architecture claims at a supervision point actually exists. Each point has a nominal posture (what the architecture claims) and an effective posture (what a human can actually exercise). Six conditions must all hold for the claimed posture to be real: VC1 independence, VC2 latency, VC3 halt, VC4 attention, VC5 comprehensibility, VC6 authority. Where one fails, the effective posture is weaker than the nominal one.
Example. SP-005, deployment approval gate: human approval of a patch. Nominal posture in the loop. VC1 partial, VC2 pass, VC3 fail, VC4 pass, VC5 fail, VC6 pass; effective posture in the loop, weakly. Binding condition as recorded by the study: VC5 comprehensibility, because the approval request carries the agent's own description of the patch and not independent evidence. SP-006, independent reviewer, fails four of the six conditions and is effectively out of the loop. SP-007, binding approval to what runs, fails five of the six: no signal is emitted when an unapproved artefact is loaded.
Non-example. SP-024, structural test mode intercepting external dispatch, and SP-029, read-only connection identity to the System of Record, pass all six conditions (both REPORTED). They are not a human watching harder: the control acts before the action and does not depend on a human or on the agent's cooperation. Notification volume is not viability either: 19,334 automation events against 4 human-facing alerts is a volume, and operator capacity was not measured.
Limits. The six conditions are asserted, not derived; there is no proof that they are complete, independent or minimal, and the order in which they are read is a convention. Source: D2 sections 4 and 9.