Debug-Cache-Key-Collision-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 cache uses userId + action as a composite key with no separator; userId 'ab' with action 'cd' produces the same key as userId 'a' with action 'bcd', causing cache hits to return data belonging to the wrong user. Identify the key collision and fix it.

{
  "metrics": {
    "repro": {
      "checks": [
        {
          "contains": [
            "collision"
          ]
        },
        {
          "contains": [
            "separator"
          ]
        },
        {
          "contains": [
            "composite key"
          ]
        },
        {
          "contains": [
            "concatenation"
          ]
        }
      ]
    },
    "hidden": {
      "checks": [
        {
          "contains": [
            ":"
          ]
        },
        {
          "contains": [
            "delimiter"
          ]
        },
        {
          "contains": [
            "`${userId}:${action}`"
          ]
        }
      ]
    },
    "diagnose": {
      "checks": [
        {
          "contains": [
            "key collision"
          ]
        },
        {
          "contains": [
            "no separator"
          ]
        },
        {
          "contains": [
            "ambiguous key"
          ]
        }
      ]
    }
  }
}