json field coverage audit derived

{
  "input": {
    "body": {
      "documents": [
        {
          "id": "a",
          "email": "a@example.com",
          "profile": {
            "phone": "+61400000000"
          }
        },
        {
          "id": "b",
          "email": "",
          "profile": {}
        },
        {
          "id": 3,
          "profile": {
            "phone": null
          }
        }
      ],
      "expect_pointers": [
        "/id",
        "/email",
        "/profile/phone"
      ]
    },
    "type": "http",
    "method": "POST",
    "bodyType": "json"
  },
  "output": {
    "type": "json",
    "example": {
      "limits": {
        "maxLines": 2000,
        "maxHeaders": 100,
        "maxFindings": 500,
        "maxPointers": 2000,
        "maxTextBytes": 262144,
        "maxBatchItems": 500,
        "maxDocumentBytes": 262144
      },
      "passed": false,
      "complete": true,
      "coverage": [
        {
          "types": {
            "string": 2
          },
          "pointer": "/email",
          "present_in": 2,
          "type_count": 1,
          "populated_in": 1,
          "presence_rate": 0.666667,
          "population_rate": 0.333333
        },
        {
          "types": {
            "string": 2,
            "integer": 1
          },
          "pointer": "/id",
          "present_in": 3,
          "type_count": 2,
          "populated_in": 3,
          "presence_rate": 1,
          "population_rate": 1
        },
        {
          "types": {
            "object": 3
          },
          "pointer": "/profile",
          "present_in": 3,
          "type_count": 1,
          "populated_in": 2,
          "presence_rate": 1,
          "population_rate": 0.666667
        }
      ],
      "findings": [
        {
          "code": "INCONSISTENT_TYPE",
          "detail": "/id appears as string and integer across the batch, so a typed consumer cannot rely on it.",
          "pointer": "/id"
        },
        {
          "code": "INCONSISTENT_TYPE",
          "detail": "/profile/phone appears as string and null across the batch, so a typed consumer cannot rely on it.",
          "pointer": "/profile/phone"
        },
        {
          "code": "EXPECTED_POINTER_PARTIAL",
          "detail": "/email is present in only 2 of 3 documents.",
          "pointer": "/email",
          "present_in": 2
        }
      ],
      "request_id": "example-request",
      "service_id": "json_field_coverage_audit",
      "assumptions": [
        "A location counts as present when it exists and as populated when it holds something. An empty string, an empty array and an empty object are present but not populated, and null is absent by default.",
        "Rates are over the documents actually examined, which is reported separately from the number supplied."
      ],
      "limitations": [
        "Observed population across the batch supplied. Whether the batch represents real traffic is not knowable here.",
        "passed is true only when every expectation held and every document was fully examined."
      ],
      "observed_at": "2026-10-02T00:00:00.000Z",
      "not_examined": [],
      "finding_count": 4,
      "always_present": [
        "/id",
        "/profile"
      ],
      "document_count": 3,
      "never_populated": [],
      "service_version": "1.0.0",
      "findings_by_code": {
        "INCONSISTENT_TYPE": 2,
        "EXPECTED_POINTER_PARTIAL": 2
      },
      "distinct_pointer_count": 4,
      "examined_document_count": 3
    }
  }
}