The customer calls: 'The model got worse and we changed nothing.' Walk me through your first two hours.
The signature production-ML incident, and a pure FDE test: a ranked differential diagnosis run live on a call, because 'nothing changed' is always false, and one hypothesis explains half of all cases.
Updated Sep 2026 · Grounded in real Forward Deployed Engineer interview loops and written to a senior-engineer editorial bar.
The signature production-ML incident, and a pure FDE test: a ranked differential diagnosis run live on a call, because 'nothing changed' is always false, and one hypothesis explains half of all cases.
Lead with where the obvious approach breaks, because that is the judgment they are screening for — most candidates jump straight to the happy path and lose the room.
Then walk the failure back through the pipeline in order, naming the one metric the customer's exec sponsor actually cares about before you propose the fix.
