Phases and Gates

8.1 Artifact-gated Phase sequence #

Work must proceed through a fixed sequence of Phases declared for the Project. Each Phase must produce at least one durable artifact that becomes part of the Project Record. A Phase satisfies this requirement by producing a description of the System or a description of its Realization; a Phase whose output is Realization rather than description satisfies it by producing the description of that Realization. Progression to the next Phase requires a Verification Artifact confirming that the durable artifacts produced by the Phase are complete. No Phase may be skipped or merged in a way that removes a durable artifact produced by the Phase or the Verification Artifact that confirms it. The sequence is one pipeline, not a collection of independent activities. [GP-30]

8.2 Evidence before, verification after #

Each Phase must be preceded by a read-only evidence-gathering activity that establishes the current state of the System and must be followed by a Verification Procedure that confirms the produced artifact is internally consistent and fits with the System. Cross-artifact consistency must be verified before implementation begins. [GP-44]

8.3 Event-based Gates #

Progression between Phases must be gated by documented entrance criteria, not by calendar dates. Every Gate must carry two distinct documented criteria sets: entrance criteria, which state when the Gate may be held, and success criteria, which state what passing it means. A Gate opens when its entrance criteria are satisfied and closes only with a Decision Record that confirms its success criteria are met and that every open discrepancy is disposed of. A Gate must not be held before its inputs are mature, and must not be delayed once they are ready. [GP-49]

8.4 Gate closure is recorded #

The closure of a Gate must be recorded in the Project Record as a Decision Record (§11) naming the success criteria met and the disposition of every open discrepancy. A Gate that closed without this record is not closed. [GP-49; GP-60]

8.5 Durable human breakpoints #

The control flow of long-running work must be explicit and must contain durable breakpoints at which work can be interrupted and resumed. Breakpoints must sit between decision and action, so that human review can occur before consequential action. Breakpoints are first-class structural points, not afterthoughts. [GP-75]