Overview
A vertical slice is not automatically small. The first integrated path may still touch several modules. Its value comes from producing feedback, not from minimizing the number of files changed.
The decomposition requires human review because agents often revert to horizontal thinking.
A poorly specified dependency graph can also create unsafe parallel work or unnecessary serialization.
The backlog may still contain critical bug fixes, development infrastructure, polishing work, quick wins, and refactors. The goal is not to exclude those categories; it is to avoid planning the feature so that all integrated feedback is postponed until the end.