- spawn_parallel_agents: Task tool with run_in_background, XML agent prompt, agent-history.json tracking with parallel_group, wave queuing - monitor_parallel_completion: TaskOutput polling loop, completion report parsing, check_and_spawn_dependents, failure handling, progress display - orchestrator_commit: merge conflict detection failsafe, per-plan staging, conflict resolution options - Total: 956 lines (within 800-1200 target)