gsd-mvp-phase

$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.

1. Prompts for an "As a / I want to / So that" user story (three structured questions)
2. Runs SPIDR splitting check — if the story is too large, walks through Spike/Paths/Interfaces/Data/Rules and offers to split into multiple phases
3. Writes **Mode:** mvp and the reformatted **Goal:** to the phase's ROADMAP.md section
4. Delegates to /gsd-plan-phase <N> which auto-detects MVP mode via the roadmap field

Phase 1 of the vertical-mvp-slice PRD shipped the planner-side machinery; this command is the user entry point for it.