Debug-Object-Reference-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 config object is directly assigned to a new variable and then modified; all callers that hold the original reference see unexpected mutations. Identify the bug and fix it.

{
  "metrics": {
    "repro": {
      "checks": [
        {
          "contains": [
            "assignment"
          ]
        },
        {
          "contains": [
            "reference"
          ]
        },
        {
          "contains": [
            "config"
          ]
        },
        {
          "contains": [
            "mutation"
          ]
        }
      ]
    },
    "hidden": {
      "checks": [
        {
          "contains": [
            "Object.assign"
          ]
        },
        {
          "contains": [
            "spread"
          ]
        },
        {
          "contains": [
            "copy"
          ]
        }
      ]
    },
    "diagnose": {
      "checks": [
        {
          "contains": [
            "shared reference"
          ]
        },
        {
          "contains": [
            "same object"
          ]
        },
        {
          "contains": [
            "not a clone"
          ]
        }
      ]
    }
  }
}