Why the implicit becomes fragile when humans and agents co-produce code. In the previous article, I defended a simple idea: code is not elegant prose. It is a system, to be judged by its robustness. But that idea calls for another one. If code is a system, then it is not enough for it to be pleasant to write, locally fluid to read, or elegant in appearance. Its structures must remain visible. Its boundaries, states, contracts, responsibilities, and effects must be understandable, revisitable, criticizable, and transformable. In other words: the system must be explicit. This is where a very contemporary tension appears. For a long time, part of software tooling has valued the implicit: conventions, framework magic, inferred behaviors, invisible structures, shortcuts that let us move faster. This has often been useful. It has sometimes even been very productive. But in the age of intelligences — human and artificial — the implicit changes in nature. The problem with the implicit is not only that it is hidden.…