Distinguish implementation replacement, representation change, altered promises, authority expansion, consumer compatibility and migration of outstanding work. Use the accountable owner's mandate and the project's actual workflow.
Why: one changed line can widen authority; hundreds of changed lines can preserve it. Mechanical enforcement should carry established decisions so that review can focus on their meaningful changes and remaining runtime risks.
Consequence: protect the governing boundary and its enforcement with appropriate repository controls. Rust privacy does not stop an authorized editor from changing the protected source. An instruction file points to authority; it does not replace it. Already authorized implementation does not acquire a new approval ceremony merely because this doctrine exists.
Retirement needs a disposition for consumers, history and unfinished obligations. Removing an entrance for new work does not complete old work. Preserve neither a bad abstraction nor redundant documentation solely because it has accumulated.