The author proposes a new paradigm in software development called Grey Box Engineering, which combines elements of traditional white box and black box engineering. In this approach, the focus shifts from writing code to verifying outcomes through automated tests or AI systems. The author describes their experience with a data migration crisis, where they used an unreviewed 375-line Python script to rescue telemetry data, highlighting the benefits of this new paradigm in terms of efficiency, cognitive unburdening, and expertise reallocation. The author argues that trust is not built through reviewing code but rather through verifying outcomes, which parallels how we interact with complex systems in our daily lives. This approach transforms what it means to be a technical professional, shifting from implementing solutions to architecting validation measures and assessing outputs against expectations.