In my previous article, Mystery Meat vs. Breadcrumb Systems, I argued that organizing code by feature reduces unnecessary exploration. Feature-based packages make it easier to navigate to the right place in the system. But navigation alone doesn't produce comprehension. You can open service.pricing immediately and still have no idea what you're looking at. Finding the file only solves the location problem. Understanding it requires something else. The Single Responsibility Principle is usually framed as a design rule: "a class should have one reason to change." But that framing doesn't explain why classes that follow it are often easier to understand. The SRP protects working memory by limiting the number of responsibilities within a boundary. Usually the SRP applies to the boundary of a class, but the same constraint can be applied to packages and methods. When a boundary contains one responsibility, understanding is easier. When it mixes responsibilities, reading turns into code simulation.…