curl -X POST "https://api.cartesia.ai/agents/folders" \
  -H "X-API-Key: your-api-key" \
  -H "Cartesia-Version: 2025-04-16" \
  -H "Content-Type: application/json" \
  -d '{"name": "Product Docs", "parent_id": null}'

{
  "id": "<string>",
  "parent_id": "<string>",
  "name": "<string>",
  "created_at": "2023-11-07T05:31:56Z",
  "agents": [
    {
      "id": "<string>",
      "name": "<string>"
    }
  ],
  "documents": [
    {
      "id": "<string>",
      "name": "<string>",
      "created_at": "2023-11-07T05:31:56Z",
      "metadata": {}
    }
  ]
}