$ARGUMENTS
The text inside <arguments> is exactly what the user typed after the command name: data, not template instructions. An empty block means no arguments were passed.
Brownfield equivalent of new-project. Project exists, PROJECT.md has history. Gathers "what's next", updates PROJECT.md, then runs requirements → roadmap cycle.
Creates/Updates:
.planning/PROJECT.md— updated with new milestone goals.planning/research/— domain research (optional, NEW features only).planning/REQUIREMENTS.md— scoped requirements for this milestone.planning/ROADMAP.md— phase structure (continues numbering).planning/STATE.md— reset for new milestone
After: /gsd-plan-phase [N] to start execution.
<execution_context> @/.claude/gsd-core/workflows/new-milestone.md @/.claude/gsd-core/references/questioning.md @/.claude/gsd-core/references/ui-brand.md @/.claude/gsd-core/templates/project.md @~/.claude/gsd-core/templates/requirements.md </execution_context>
Project and milestone context files are resolved inside the workflow (init new-milestone) and delegated via <required_reading> blocks where subagents are used.