Workflow Checkpoint Skill

Overview

Save and mutate persistent workflow state that survives context auto-summarization.

State files store: task details, worktree locations, PR URLs, and review status. This skill owns the write side of workflow state — initializing a workflow, updating fields, transitioning phases, and capturing a structured handoff. For the read/restore side (resuming after a break, reconciling against git, verifying a workflow exists), see @skills/rehydrate/SKILL.md.

Triggers

Activate this skill when:

• Starting a new workflow (ideate)
• Transitioning between workflow phases
• Saving progress for later continuation (checkpoint)

Phase Transitions

Valid transitions, guards, and prerequisites for all workflow types are documented in references/phase-transitions.md. CRITICAL: Phase mutation is a separate action from field mutation. When a transition has a guard, action: "update" the prerequisite fields first, then action: "transition" — guards read the most recent state, so updates land before guards evaluate. Attempting to mutate phase via action: "update" returns a RESERVED_FIELD error pointing at transition (see "Reserved fields" below).