curl --request POST \
  --url https://api.retellai.com/v3/list-chats \
  --header 'Authorization: Bearer <token>' \
  --header 'Content-Type: application/json' \
  --data '
{
  "filter_criteria": {},
  "sort_order": "descending",
  "limit": 50,
  "skip": 0,
  "pagination_key": "<string>"
}
'

{
  "pagination_key": "<string>",
  "has_more": true,
  "items": [
    {
      "chat_id": "Jabr9TXYYJHfvl6Syypi88rdAHYHmcq6",
      "agent_id": "oBeDLoLOeuAbiuaMFXRtDOLriTJ5tSxD",
      "chat_status": "ongoing",
      "version": 1,
      "retell_llm_dynamic_variables": {
        "customer_name": "John Doe"
      },
      "collected_dynamic_variables": {
        "last_node_name": "Test node"
      },
      "chat_type": "api_chat",
      "custom_attributes": {},
      "start_timestamp": 1703302407333,
      "end_timestamp": 1703302428855,
      "transcript": "Agent: hi how are you doing?\nUser: Doing pretty well. How are you?\nAgent: That's great to hear! I'm doing well too, thanks! What's up?\nUser: I don't have anything in particular.\nAgent: Got it, just checking in!\nUser: Alright. See you.\nAgent: have a nice day\n",
      "message_with_tool_calls": [
        {
          "message_id": "Jabr9TXYYJHfvl6Syypi88rdAHYHmcq6",
          "role": "agent",
          "content": "hi how are you doing?",
          "created_timestamp": 1703302428855
        }
      ],
      "metadata": {},
      "chat_cost": {
        "product_costs": [
          {
            "product": "elevenlabs_tts",
            "cost": 60,
            "unit_price": 1,
            "is_transfer_leg_cost": true
          }
        ],
        "combined_cost": 70
      },
      "chat_analysis": {
        "chat_summary": "The agent messages user to ask question about his purchase inquiry. The agent asked several questions regarding his preference and asked if user would like to book an appointment. The user happily agreed and scheduled an appointment next Monday 10am.",
        "user_sentiment": "Positive",
        "chat_successful": true,
        "custom_analysis_data": {}
      }
    }
  ]
}