Failure localization test for step granularity — if a step…

When This Fires

• When decomposing workflows and deciding how fine-grained to make each step
• When a workflow step fails and you realize you don't know which sub-operation caused the failure
• When reviewing workflow documentation that has steps spanning multiple distinct operations
• Complements Competent stranger test for workflow steps — could someone… (competent stranger test) with the failure-diagnostic perspective on granularity

Common Failure Mode

Compound steps that bundle distinct failure modes: "Review and approve the document." If this step fails, did the review find problems (expected, fixable) or did the approval process break (unexpected, systemic)? Two completely different failure modes are hidden inside one step, requiring investigation to distinguish them.

The Protocol

(1) For each workflow step, simulate failure: "If this step fails, what would I know?" (2) If the answer is "I'd know exactly what went wrong" → granularity is correct. (3) If the answer is "I'd need to investigate further" → the step bundles multiple failure modes. Decompose until each sub-step has a single, identifiable failure mode. (4) Apply the split test: can the step fail in two or more genuinely different ways? If yes, it's at least two steps. "Send email" has one failure mode (email doesn't send). "Draft and send email" has two (draft quality failure vs. sending failure). (5) Stop decomposing when further splits would separate operations that always succeed or fail together — there's no diagnostic value in splitting inseparable operations.