{
  "method": "sessionUpdate",
  "args": [
    {
      "sessionId": "test-session-id",
      "update": {
        "sessionUpdate": "tool_call",
        "title": "Start subagent weather_research",
        "kind": "other",
        "toolCallId": "call-spawn-weather",
        "status": "completed",
        "rawInput": {
          "agentThreadId": "thread-paris",
          "agentPath": "/root/weather_research",
          "activityKind": "started"
        },
        "_meta": {
          "codex": {
            "subagent": {
              "threadId": "thread-paris",
              "path": "/root/weather_research",
              "activity": "started"
            }
          }
        }
      }
    }
  ]
}