Refactor-Batch-Transformer

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 refactor, rationale, tests. Refactor a batch transformer to process records through explicit streaming stages without loading all records into memory.

{
  "metrics": {
    "visible": {
      "checks": [
        {
          "contains": [
            "streaming stages"
          ]
        },
        {
          "contains": [
            "batch transformer"
          ]
        },
        {
          "contains": [
            "records"
          ]
        }
      ]
    },
    "hidden": {
      "checks": [
        {
          "contains": [
            "memory"
          ]
        },
        {
          "contains": [
            "backpressure"
          ]
        },
        {
          "contains": [
            "same output"
          ]
        }
      ]
    },
    "intent": {
      "checks": [
        {
          "contains": [
            "data pipeline"
          ]
        },
        {
          "contains": [
            "scalability"
          ]
        },
        {
          "contains": [
            "refactor"
          ]
        }
      ]
    }
  }
}