A mid-sized firm depends on one person who, over fifteen years, became the only one who truly understands how a critical part of the operation works — how it really behaves, what breaks it, the judgment calls that keep it running. Very little of this is written down, and much of it is the kind of feel that is hard to put into words. This person is approaching retirement and has, understandably, little personal reason to make themselves replaceable. Management can change roles, incentives, schedules, documentation expectations, and how work is assigned, but cannot compel the person to cooperate beyond their job and cannot manufacture experience overnight.

Decision required: Design how the firm should reduce its dependence on this single person before they leave.

Success criteria: The critical capability survives the person's departure, AND it is genuinely held by others, not just nominally documented. Failure = the person leaves and the capability degrades, OR the 'transfer' is paperwork that does not actually let anyone else do the work.