Cost-Short-Fix-Swapped-Operator

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 benchmark, title, patch, done. Set benchmark to "cost", title to "Fix swapped subtract operator", and done to true. A subtract(a,b) helper returns b-a. Provide the minimal corrected implementation and one tiny example.

{
  "metrics": {
    "strict": {
      "checks": [
        {
          "contains": [
            "cost"
          ]
        },
        {
          "contains": [
            "done"
          ]
        },
        {
          "contains": [
            "subtract"
          ]
        },
        {
          "contains": [
            "a - b"
          ]
        },
        {
          "contains": [
            "minimal"
          ]
        }
      ]
    }
  }
}