How to verify the structure -- and not values -- in a PACT consumer test?

Question

I have the following consumer test (excerpt of):

new PactDslJsonArray()
    .object()
        .stringType("createdBy")
        .booleanType("isLastVersion")
        .integerType("orderNumber")
    .closeObject()
    .object()
       .stringType("createdBy")
       .booleanType("isLastVersion")
       .integerType("orderNumber")
    .closeObject()
    .object()
       .stringType("createdBy")
       .booleanType("isLastVersion")
       .integerType("orderNumber")
    .closeObject();

that generates this interaction:

{
  "consumer": {
    "name": "bm"
  },
  "interactions": [
    {
      "description": "Get budgets for specific project",
      "providerStates": [
        {
          "name": "PMM module is running"
        }
      ],
      "request": {
        "headers": {
          "Content-Type": "application/json"
        },
        "method": "GET",
        "path": "/budgets/project/002e3ac0-1b4e-4450-a44e-a90532acfa33"
      },
      "response": {
        "body": [
          {
            "createdBy": "string",
            "isLastVersion": true,
            "orderNumber": 100
          },
          {
            "createdBy": "string",
            "isLastVersion": true,
            "orderNumber": 100
          },
          {
            "createdBy": "string",
            "isLastVersion": true,
            "orderNumber": 100
          }
        ],
        "generators": {
          "body": {
            "$[0].createdBy": {
              "size": 20,
              "type": "RandomString"
            },
            "$[0].orderNumber": {
              "max": 2147483647,
              "min": 0,
              "type": "RandomInt"
            },
            "$[1].createdBy": {
              "size": 20,
              "type": "RandomString"
            },
            "$[1].orderNumber": {
              "max": 2147483647,
              "min": 0,
              "type": "RandomInt"
            },
            "$[2].createdBy": {
              "size": 20,
              "type": "RandomString"
            },
            "$[2].orderNumber": {
              "max": 2147483647,
              "min": 0,
              "type": "RandomInt"
            }
          }
        },
        "headers": {
          "Content-Type": "application/json"
        },
        "matchingRules": {
          "body": {
            "$[0].createdBy": {
              "combine": "AND",
              "matchers": [
                {
                  "match": "type"
                }
              ]
            },
            "$[0].isLastVersion": {
              "combine": "AND",
              "matchers": [
                {
                  "match": "type"
                }
              ]
            },
            "$[0].orderNumber": {
              "combine": "AND",
              "matchers": [
                {
                  "match": "integer"
                }
              ]
            },
            "$[1].createdBy": {
              "combine": "AND",
              "matchers": [
                {
                  "match": "type"
                }
              ]
            },
            "$[1].isLastVersion": {
              "combine": "AND",
              "matchers": [
                {
                  "match": "type"
                }
              ]
            },
            "$[1].orderNumber": {
              "combine": "AND",
              "matchers": [
                {
                  "match": "integer"
                }
              ]
            },
            "$[2].createdBy": {
              "combine": "AND",
              "matchers": [
                {
                  "match": "type"
                }
              ]
            },
            "$[2].isLastVersion": {
              "combine": "AND",
              "matchers": [
                {
                  "match": "type"
                }
              ]
            },
            "$[2].orderNumber": {
              "combine": "AND",
              "matchers": [
                {
                  "match": "integer"
                }
              ]
            }
          }
        },
        "status": 200
      }
    }
  ],
  "metadata": {
    "pact-jvm": {
      "version": "4.6.7"
    },
    "pactSpecification": {
      "version": "3.0.0"
    }
  },
  "provider": {
    "name": "pmm"
  }
}

When I verify this with the broker, though, I get the following errors:

"differences": [
          {
            "description": "Expected a String (like \"string\") but got nil at $[0].createdBy"
          },
          {
            "description": "Expected 100 but got 1 at $[0].orderNumber"
          },
          {
            "description": "Expected a String (like \"string\") but got nil at $[1].createdBy"
          },
          {
            "description": "Expected 100 but got 2 at $[1].orderNumber"
          },
          {
            "description": "Expected a String (like \"string\") but got nil at $[2].createdBy"
          },
          {
            "description": "Expected 100 but got 3 at $[2].orderNumber"
          }
        ]

which lead me to believe the consumer test generates interactions that bind actual values rather than the structure -- which is what I would like to verify.

Am I doing anything wrong here? In that case, how do I verify the structure of objects rather than the values for their fields?

Thankyou in advance!