Nominal MTTI

The condition in which a system's measured Mean Time to Intervention is long not because it has achieved genuine Architectural Certainty but because the Steward has stopped engaging with the audit surface — producing a metric that appears to confirm autonomous operation while the system is in fact running unmonitored and unrefined.

MTTI measures the frequency of required human interventions in an agentic system. It cannot measure whether the absence of intervention reflects system health or Steward withdrawal. These two states are observationally identical: both report long MTTI, both show low Escalation Rates, and both appear from the outside to confirm that the system is governing itself correctly. Nominal MTTI names the failure mode that the MTTI metric cannot detect on its own.

The mechanism is cognitive arithmetic rather than negligence. A Steward governing an autonomous business at production volume must review the Proof of Action trail, validate exception resolutions, confirm Escalation Rate stability across task classes, and identify leading indicators of Knowledge Debt accumulation — rising Escalation Rates for specific exception classes, narrowing MTTI segments, Execution Divergence patterns that signal context drift. The complete Proof of Action trail contains all of this information. When the cognitive cost of reviewing that trail exceeds the Steward's available attention budget, the Steward stops reviewing it — not negligently but practically. No interventions surface because nothing is surfacing them. The MTTI appears to extend because the governance that would measure it has quietly withdrawn.

The diagnostic implication is direct: long MTTI is a necessary but not sufficient condition for Architectural Certainty. The sufficient condition requires confirmation that the Steward is actively monitoring the audit surface, that recent exception resolutions are consistent with the Intervention Threshold parameters, and that no Execution Divergence patterns are accumulating undetected. The distinction between genuine and Nominal MTTI is not observable in the MTTI metric. It is observable only in the presence and quality of Steward engagement with the system's governance surface.

First used: May 2026