Why can I only learn which coordination failure hit my agent pipeline after it already did?

The MAST taxonomy, validated on over 1,600 production agent execution traces at NeurIPS 2025, names 14 coordination failure modes that account for 79% of multi-agent system failures. Knowing the taxonomy after a failure is useful. Knowing which failure mode a specific architecture will hit before deployment does not yet exist as a tool or discipline. Current evaluation practice runs component-level tests on individual agents but has no method to characterize the emergent failure profile of the whole system under realistic coordination load. Practitioners face a consistent 37% gap between lab performance and production reliability with no diagnostic that predicts where it will open.