Worktree Execution Skill

Architecture

Two isolated worktrees enable parallel prompt execution.

Orchestrator
    │
    ├── Create Worktrees (in ${TMPDIR:-/tmp}/)
    │       ├── worktree-rashomon-original-{timestamp}
    │       └── worktree-rashomon-optimized-{timestamp}
    │
    ├── Parallel Execution (Task tool)
    │       ├── Execution 1 → worktree-rashomon-original
    │       └── Execution 2 → worktree-rashomon-optimized
    │
    ├── Collect Results (await both)
    │
    └── Cleanup Worktrees (always)

Worktree Management

Creation

Script: scripts/worktree-create.sh

# Default labels (original/optimized) for prompt eval
./scripts/worktree-create.sh [repo_root]

# Custom labels for skill eval
./scripts/worktree-create.sh [repo_root] baseline with-skill
./scripts/worktree-create.sh [repo_root] old-version new-version

Output (stdout):

/tmp/worktree-rashomon-{label_a}-20260114-123456
/tmp/worktree-rashomon-{label_b}-20260114-123456

Properties:

• Location: ${TMPDIR:-/tmp}/
• Naming: worktree-rashomon-{label}-{timestamp}
• Branch: Detached HEAD at current commit
• Labels default to original / optimized if not specified

Cleanup

Script: scripts/worktree-cleanup.sh

# Remove all rashomon worktrees
./scripts/worktree-cleanup.sh [repo_root]

# Remove specific worktrees
./scripts/worktree-cleanup.sh [repo_root] path1 path2

# Remove only orphaned worktrees (age > 1 hour)
./scripts/worktree-cleanup.sh --orphans [repo_root]

Cleanup Triggers:

• After successful report generation
• In finally block on any failure
• On timeout
• On startup (orphan detection)

Parallel Execution Principle

Key: To achieve true parallel execution, spawn both Task calls in a single message.

The calling command determines which agents to invoke and how to structure the Task calls. This skill provides only the worktree infrastructure.

Error Handling (Worktree Operations)

Scenario	Behavior
Creation fails	Report git error, suggest checking repository state
Cleanup fails	Log warning, attempt orphan cleanup on next run
Orphan detected	Force remove worktrees older than 1 hour

Scripts Reference

worktree-create.sh

Exit Code	Meaning
0	Success
1	Not a git repository
2	Creation failed

worktree-cleanup.sh

Exit Code	Meaning
0	Success (or nothing to clean)
1	Not a git repository
2	Cleanup partially failed

Constraints

• No concurrent comparisons: One rashomon execution per repository
• Git required: git 2.5+ for worktree support
• Disk space: Sufficient space for worktree copies