Compounding Error

Compounding error is what chaining does to reliability. Each step in an automation succeeds with some probability, and when steps run in sequence, each depending on the one before it, those probabilities multiply rather than average. Chain ten steps at ninety-five percent each and the whole chain succeeds about sixty percent of the time (0.95 to the tenth power).

The countermeasures follow from the arithmetic: validate each step against real output before the next one runs, and monitor every decision point rather than only the final result, so a failure is visible where it happened instead of surfacing three steps later as a wrong answer.