json structural drift derived

{
  "input": {
    "body": {
      "documents": [
        {
          "id": "a",
          "meta": {
            "source": "api"
          },
          "items": [
            {
              "qty": 1,
              "sku": "s1"
            },
            {
              "qty": 2,
              "sku": "s2"
            }
          ],
          "amount": 2
        },
        {
          "id": "b",
          "meta": {
            "source": "api",
            "trace_id": "x"
          },
          "items": [
            {
              "sku": "s3"
            }
          ],
          "amount": "3"
        }
      ],
      "reference": {
        "id": "r",
        "meta": {
          "source": "api"
        },
        "items": [
          {
            "qty": 1,
            "sku": "s"
          }
        ],
        "amount": 1
      }
    },
    "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,
      "stable": false,
      "complete": true,
      "findings": [
        {
          "code": "REFERENCE_POINTER_MISSING",
          "detail": "/items/*/qty is in the reference but absent from 1 of 2 documents.",
          "pointer": "/items/*/qty",
          "documents": 1
        },
        {
          "code": "TYPE_DRIFT",
          "detail": "/amount is integer in the reference but string in the batch.",
          "pointer": "/amount",
          "observed": {
            "string": 1
          },
          "reference_type": "integer"
        },
        {
          "code": "UNDECLARED_POINTER",
          "detail": "/meta/trace_id appears in 1 of 2 documents and is not in the reference.",
          "pointer": "/meta/trace_id",
          "documents": 1
        }
      ],
      "request_id": "example-request",
      "service_id": "json_structural_drift",
      "assumptions": [
        "Array indices are generalised to * so a two-item list and a three-item list are the same shape rather than a difference at every position.",
        "integer and number are treated as the same shape, because JSON does not distinguish 1 from 1.0."
      ],
      "limitations": [
        "Shape comparison against the supplied reference only. Values are not compared, and whether the reference is the right shape is not assessed.",
        "stable is true only when every document was fully examined and nothing drifted."
      ],
      "observed_at": "2026-10-02T00:00:00.000Z",
      "not_examined": [],
      "finding_count": 3,
      "document_count": 2,
      "service_version": "1.0.0",
      "findings_by_code": {
        "TYPE_DRIFT": 1,
        "UNDECLARED_POINTER": 1,
        "REFERENCE_POINTER_MISSING": 1
      },
      "type_drift_count": 1,
      "additional_pointers": [
        "/meta/trace_id"
      ],
      "missing_pointer_count": 1,
      "examined_document_count": 2,
      "reference_pointer_count": 8,
      "additional_pointer_count": 1
    }
  }
}