Drill

Lock the next seam. Write only that seam.

Method

Work one level at a time. A higher lock that moves drops the in-flight slice.

1. Language. Name the thing in the project's words. Stop until the name is shared.
2. Obligation. Name what the slice guarantees: the behavior a caller can now rely on, and what must stay true that already was. Then verify-with and rollback for each. Machinery is not implied by the guarantee. Do not open a staged transformation artifact.
3. Place. Name the files, symbols, and runtime boundary. When coupling is unproven, trace the path to closure first.
4. Slice. Name the smallest write that keeps the obligation. Reuse first: search for the existing rule and call it. Duplicate only with a named reason, and proximity is not a reason. Do not extract a wrapper that restates an existing operation. Then write it.