In order to keep a project on track and viable PRINCE2 uses stage boundaries as major control points to assess the current status of the project.
Ideally this process should not interrupt the natural flow of a project using agile. Although this is an important point in the project to formalize its continuation, this should still be carried out with as little ceremony as possible because the team interactions and transparency of information will make the situation obvious and therefore the decision easy to make.
Throughout the stage the frequent delivery of products in an iterative and incremental style will mean that it will be clear how many features have been delivered and their level of quality. This will give a clearer indication of progress than information relating to time and cost.
The continual use of ‘inspect and adapt’ will in turn allow the team to continually and gradually improve how they work with the stage boundary, giving team members the opportunity to consolidate their learnings across the organization as a whole.
Ultimately this gives the project board the confidence to continue on the current successful path or to stop the project and use its resources elsewhere.