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MTTI (Mean Time to Intervention)

The average time between required human interventions in an agentic system. Arco's target is greater than 72 hours.

Extended Definition​

Mean Time to Intervention is the primary operational health metric for an Arco business. It measures how long the core system runs autonomously before a human decision is required. A higher MTTI indicates a more architecturally robust system.

Arco targets an MTTI greater than 72 hours for all core revenue loops. Ancillary processes (reporting, communications, minor workflows) may have lower MTTI thresholds.

MTTI should not be confused with uptime or availability. A system can be fully available but require constant human steering — that is not autonomous. MTTI specifically measures the frequency of required human judgement, not system health.

  • Stewardship Model — MTTI is the primary performance target for the Stewardship Model: a Steward whose system runs more than 72 hours between interventions is governing rather than operating.
  • Architectural Certainty — Achieving an MTTI greater than 72 hours is Arco's operational definition of Architectural Certainty: the system can run without human decisions for the target period.
  • Autonomous Business — MTTI is the operational test that distinguishes an autonomous business from an automated one: a system requiring daily human steering has not achieved autonomous operation regardless of how much automation it contains.
  • Nominal MTTI — Nominal MTTI is the failure mode that the MTTI metric cannot detect on its own: when the Steward has stopped engaging with the governance surface, long MTTI reflects unmonitored drift rather than genuine Architectural Certainty.

References​

  • Lexicon — canonical definition
  • Wiki — extended entry

Metadata​

First used: 2026-03-15
Pillar: What We've Learned

Part of the Arco Lexicon Ecosystem — maintained by Arco Venture Studio