Preventing Conflicting Business Logic in Growing Software Systems

Most large systems do not fail because individual requirements were implemented incorrectly. They fail because many requirements were implemented correctly — but inconsistently. When software evolves story by story, business rules accumulate. Each new feature works in isolation. Tests pass. Code reviews succeed. Deployment looks stable. And yet, over time, the system’s behavior becomes contradictory. The root cause is structural: business rules are implemented without a mechanism that forces them to reconcile. The Structural Risk of Story-Driven Development Story-driven development optimizes for delivering isolated behavior: A story defines a scenario. A service implements that scenario. Tests verify the scenario. This process is efficient. It is also structurally dangerous in larger systems. User stories describe cases . They do not define invariants . Consider an Order concept: Closed orders cannot be modified. VIP customers may modify any order. Orders older than 30 days cannot be c