Plan milestone slices from overview + narrative alone (no system GDDs required), create per-milestone directory skeletons and briefs, and write gat/milestone/milestone.md. Runs before per-system design. Stops before technical design, task breakdown, or implementation.
Plan milestone slices from overview + narrative alone (no system GDDs required), create per-milestone directory skeletons and briefs, and write gat/milestone/milestone.md. Runs before per-system design. Stops before technical design, task breakdown, or implementation.