Cost-Generation-Fibonacci

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, code, done. Set benchmark to "cost", title to "Implement nth Fibonacci number", and done to true. Implement an iterative nth Fibonacci function for n >= 0 with compact code.

{
  "metrics": {
    "strict": {
      "checks": [
        {
          "contains": [
            "cost"
          ]
        },
        {
          "contains": [
            "done"
          ]
        },
        {
          "contains": [
            "fibonacci"
          ]
        },
        {
          "contains": [
            "iterative"
          ]
        },
        {
          "contains": [
            "n"
          ]
        }
      ]
    }
  }
}