Halluc-Edge-Nan-Equality

The model receives the prompt (and optional system message). The run uses scorer rubric_json_metrics with the JSON configuration below. Pass/fail and partial credit are determined entirely by that scorer against the model output; no human grading.

Return JSON only with keys answer, supported_facts, uncertainty. In JavaScript, does NaN === NaN evaluate to true or false? What is the correct way to check if a value is NaN? Avoid claiming == or === can reliably detect NaN.

{
  "metrics": {
    "accuracy": {
      "checks": [
        {
          "contains": [
            "false"
          ]
        },
        {
          "contains": [
            "Number.isNaN"
          ]
        },
        {
          "contains": [
            "NaN !== NaN"
          ]
        }
      ]
    },
    "fabricated": {
      "checks": [
        {
          "contains": [
            "cannot detect NaN with ==="
          ]
        },
        {
          "contains": [
            "use Number.isNaN"
          ]
        },
        {
          "contains": [
            "equality cannot detect"
          ]
        }
      ]
    }
  }
}