Debug-Number-Parse-Empty-V2

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 diagnosis, fix, tests. A numeric parser uses Number(value || 0), silently converting empty strings and null to zero when they should be invalid. Identify the bug and fix.

{
  "metrics": {
    "repro": {
      "checks": [
        {
          "contains": [
            "empty string"
          ]
        },
        {
          "contains": [
            "null"
          ]
        },
        {
          "contains": [
            "zero"
          ]
        },
        {
          "contains": [
            "invalid"
          ]
        }
      ]
    },
    "hidden": {
      "checks": [
        {
          "contains": [
            "validate"
          ]
        },
        {
          "contains": [
            "Number.isFinite"
          ]
        },
        {
          "contains": [
            "reject empty"
          ]
        }
      ]
    },
    "diagnose": {
      "checks": [
        {
          "contains": [
            "Number"
          ]
        },
        {
          "contains": [
            "fallback"
          ]
        },
        {
          "contains": [
            "parser"
          ]
        }
      ]
    }
  }
}