curl --request GET \
  --url https://api.agentmark.co/v1/spans/{spanId} \
  --header 'Authorization: Bearer <token>' \
  --header 'X-Agentmark-App-Id: <api-key>'

{
  "data": {
    "cost": 123,
    "duration_ms": 123,
    "id": "<string>",
    "input": "<string>",
    "input_tokens": 1,
    "metadata": {},
    "model": "<string>",
    "name": "<string>",
    "output": "<string>",
    "output_object": "<string>",
    "output_tokens": 1,
    "parent_id": "<string>",
    "prompt_name": "<string>",
    "service_name": "<string>",
    "span_kind": "<string>",
    "status_message": "<string>",
    "timestamp": "2023-11-07T05:31:56Z",
    "tokens": 1,
    "tool_calls": "<string>",
    "trace_id": "<string>",
    "type": "<string>"
  }
}