Why does the decision come first in Decision, Delta, Check?#
Because the decision sets how much has to be understood. A reversible configuration change and an irreversible data migration demand very different depths of understanding from the same reviewer. Starting from the waiting decision sizes each brief to what rests on it.
Why does Decision, Delta, Check weigh decision impact over change size?#
A thousand-line refactor that preserves every interface may need less understanding than a three-line change to an authorisation rule. Explanations sized by the diff are too long for trivial changes and too thin where the risk is. AI pull request summaries start from the branch base instead of from what a named person last understood, and they never check that anything transferred.
Each part has its own artefact: the decision queue entry, the delta and the comprehension check.