Customers in research are enthusiastic about a shared inbox for client messages. Support says it would make them accountable for disputes they cannot see, and legal flags the retention rules it would trigger. Which of Cagan's risks is this?

The principle — a solution has to work for the people who sell, support, defend and account for it, not only for the people who use it.

Why the key is correct — Cagan's fourth risk asks whether this solution also works for the various aspects of our business Support being made accountable for disputes it cannot see, and a retention obligation nobody has planned for, are exactly those aspects.

Why the others are wrong — value is about whether customers will buy it or users will choose to use it, and in this scenario they are enthusiastic, so the value evidence runs the opposite way. Feasibility concerns what the engineers can build, and nothing here says the inbox cannot be built. And narrowing viability to revenue drops most of what the question covers, including the parts that sink features.

Remember this — when the objection comes from inside your own company, you are usually looking at viability.

Sources — Marty Cagan on the four big risks, Silicon Valley Product Group.