{
  "parent_metadata": {
    "turn_id": "human-message-fixture",
    "thread_id": "main-thread",
    "source_agent": "EvoScientist",
    "workspace_dir": "/tmp/research"
  },
  "expected_child_metadata": {
    "turn_id": "human-message-fixture",
    "source_session_id": "main-thread",
    "source_agent": "EvoScientist",
    "workspace_dir": "/tmp/research",
    "usage_scope": "async_subagent"
  }
}