{
  "context": "Evaluates how well the solution uses github.com/prometheus/client_model/go and protobuf helpers to build a counter metric payload that carries exemplar value, timestamp, and labels, and serializes it correctly.",
  "type": "weighted_checklist",
  "checklist": [
    {
      "name": "Counter struct",
      "description": "Builds a dto.MetricFamily with Type set via dto.MetricType_COUNTER.Enum(), containing exactly one dto.Metric whose Counter uses dto.Counter.Value set from the requested counterValue.",
      "max_score": 20
    },
    {
      "name": "Exemplar value/time",
      "description": "Creates a dto.Exemplar attached to the counter with Value set from exemplarValue and Timestamp populated using timestamppb.New(exemplarTime); fails fast when exemplarTime.IsZero().",
      "max_score": 25
    },
    {
      "name": "Exemplar labels",
      "description": "Populates exemplar context using dto.LabelPair entries for each exemplar label key/value (e.g., trace_id, span_id), ensuring they live under dto.Exemplar.Label and nowhere else.",
      "max_score": 20
    },
    {
      "name": "Metric labels",
      "description": "Maps base labels into dto.LabelPair entries placed on dto.Metric.Label, keeping them separate from exemplar labels and preserving provided name/value pairs.",
      "max_score": 15
    },
    {
      "name": "Serialization",
      "description": "Returns protobuf bytes by calling proto.Marshal on the assembled dto.MetricFamily and propagates marshal errors instead of hiding them.",
      "max_score": 20
    }
  ]
}