Parallel Close

Parallel Close Skill

A user invocation (/parallel-close <parallel-slug>) forks the parallel-orchestrator agent with this procedure in context. The parallel slug of the run to terminate is:

$ARGUMENTS

This skill implements the mutation-protocol close operation (spec FR3). It terminates an open-mode run, which has no other termination signal: the mode-dependent completion semantics in the ## Mutation Protocol (F6) section of .claude/skills/parallel-orchestrate/SKILL.md state that an open-mode run never auto-completes. Read that section before applying anything here.

Prerequisites

• A parallel run is in progress and artifacts/orchestration/parallel-orchestrator-state.json tracks the parallel_slug named in $ARGUMENTS.
• The run's mode is open. A closed-mode run completes through its completion predicate — every non-withdrawn item merged or worktree_removed — and needs no close. Report that and stop rather than closing a closed-mode run to force completion.

Re-Derive Durable State Before Applying Anything

The checkpoint is a CACHE of durable state, not the source of truth (.claude/rules/parallel-orchestration.md, Cache Doctrine). Before deciding the close, re-derive the run's true per-item state and rewrite the checkpoint from it when they disagree:

• git worktree list --porcelain — worktree existence and path per item.
• git branch — branch existence and name per item.
• gh pr view <pr> --json state,mergedAt,headRefOid — pull-request state and merge outcome per item.

The close gate turns entirely on whether any item is in flight, so a stale in-flight set decides the gate wrongly. Closing while an item is genuinely running would abandon that work implicitly, which is exactly what the gate exists to prevent. The re-derivation is mandatory.

Procedure

1. Re-derive durable state as above and resolve the run's items[].

2. Gate the close on no item being in flight. Call decide_close(items) from scripts/dev_tools/parallel_mutation_protocol.py. It raises the dedicated rejection exception carrying EVERY in-flight key, so the rejection names all the work that must finish first rather than one item at a time. On rejection: report the blocking keys and stop. A rejected close appends NO mutations[] entry and makes NO state change — do not record the attempt.

3. Append exactly one run-scoped mutations[] entry for a successful close, built by build_close_entry from scripts/dev_tools/parallel_mutation_protocol.py:

   Case	op	item_key	prior_state	new_state	disposition	recolor_generation
   Close	close	null (run-scoped)	null	null	null	g (unchanged)

   The entry is run-scoped, so item_key is null: the close acts on the run, not on an item. The at timestamp comes from the engine's injected clock seam.

4. Do not recompute. Run termination changes no cohort assignment, so recolor_generation is UNCHANGED and cohorts[] is not rewritten. Do not call recolor_unstarted as part of a close.

5. Stop admitting. After the close is recorded, the run accepts no further /parallel-add. The close record is the run's final mutation; nothing may be appended to mutations[] after it.

6. Validate the checkpoint before treating the close as applied. Run the validate_orchestration_artifacts MCP tool with artifact_type: "parallel-orchestrator-state". A non-empty error list means the close was applied incorrectly; correct the checkpoint rather than proceeding.

Constraints

• One close per run, one mutations[] entry per successful close.
• No field and no enum member is added to mutations[] or to any state or merge-status enum. The nine parallel enums are owned by .claude/rules/parallel-orchestration.md and are consumed, never extended.
• The close performs no destructive side effect: it closes no pull request and removes no worktree. An item whose work should be destroyed must be removed first through /parallel-remove with --disposition abandon, which is also what makes the close gate passable.
• The close does not change any item's state. Items that never started remain in their recorded states; the close records that the run stopped admitting, not that those items were withdrawn.

Completion Requirements

• Report the parallel_slug, the gate outcome, and the single appended mutations[] entry — or, for a rejected close, the full list of in-flight keys and the explicit confirmation that nothing was appended and no state changed.
• Report the unchanged recolor_generation.
• Report the checkpoint validation result.