Error Handling Stops Scaling When It Is Treated as a Local Coding Habit Many systems become hard to maintain later not because the business is inherently complex, but because error handling was never designed as part of the system. At prototype stage, error handling is often just "bubble it up if something fails." But once a system enters long-term evolution, failure paths stop being local control flow. They carry retry decisions, degradation behavior, alert routing, user responses, troubleshooting context, and compatibility expectations. If errors are still just ad hoc strings, local enums, or incidental wrappers, the system becomes brittle. From a system builder's perspective, the central question is not "how do we throw or return errors?" It is this: How do we make errors converge for governance while preserving useful information for diagnosis? This is the problem I have been trying to solve with what I call the Wukong Error Governance Model , and in Rust, with the orion-error crate.…