Adaptive mini-sprint planning. Interview to zero ambiguity, then a track-shaped plan sized to the work — single-track (implement in-session) or multi-track (isolated subagents on worktrees with per-track model tiers, audited and merged in order). Accepts a described task, a requirements artifact (PRD, ticket, file, URL), or nothing: "/plan this" resolves the task from session context and the agent self-calibrates complexity. Use when the user asks to plan an implementation.
