span attribute contract audit derived

{
  "input": {
    "body": {
      "spans": "[\n {\n  \"trace_id\": \"t1\",\n  \"span_id\": \"a\",\n  \"name\": \"GET /orders\",\n  \"kind\": \"SPAN_KIND_SERVER\",\n  \"start_time\": \"2026-10-02T12:00:00.000Z\",\n  \"end_time\": \"2026-10-02T12:00:00.500Z\",\n  \"attributes\": {\n   \"http.request.method\": \"GET\",\n   \"http.route\": \"/orders\"\n  }\n },\n {\n  \"trace_id\": \"t1\",\n  \"span_id\": \"b\",\n  \"parent_span_id\": \"a\",\n  \"name\": \"SELECT orders\",\n  \"kind\": \"SPAN_KIND_CLIENT\",\n  \"start_time\": \"2026-10-02T11:59:59.960Z\",\n  \"end_time\": \"2026-10-02T12:00:00.200Z\",\n  \"attributes\": {}\n },\n {\n  \"trace_id\": \"t1\",\n  \"span_id\": \"c\",\n  \"parent_span_id\": \"zz\",\n  \"name\": \"cache.get\",\n  \"start_time\": \"2026-10-02T12:00:00.100Z\",\n  \"end_time\": \"2026-10-02T12:00:00.110Z\",\n  \"attributes\": {}\n },\n {\n  \"trace_id\": \"t2\",\n  \"span_id\": \"d\",\n  \"name\": \"GET /orders/8827341/items\",\n  \"kind\": \"HTTP_SERVER\",\n  \"start_time\": \"2026-10-02T12:00:01.000\",\n  \"end_time\": \"2026-10-02T12:00:01.300Z\",\n  \"attributes\": {\n   \"http.request.method\": \"GET\"\n  }\n }\n]",
      "contract": {
        "required_by_kind": {
          "SPAN_KIND_CLIENT": [
            "db.system"
          ],
          "SPAN_KIND_SERVER": [
            "http.request.method",
            "http.route"
          ]
        },
        "require_known_kind": true,
        "required_attributes": [
          "service.name"
        ],
        "forbidden_attributes": [
          "http.request.header.authorization"
        ],
        "forbid_high_cardinality_names": true
      }
    },
    "type": "http",
    "method": "POST",
    "bodyType": "json"
  },
  "output": {
    "type": "json",
    "example": {
      "limits": {
        "maxLines": 20000,
        "maxSpans": 10000,
        "maxFields": 500,
        "maxSamples": 20000,
        "maxFindings": 500,
        "maxJsonBytes": 2097152
      },
      "passed": false,
      "checked": {
        "known_kind": true,
        "required_by_kind": 2,
        "required_attributes": 1,
        "forbidden_attributes": 1,
        "high_cardinality_names": true
      },
      "complete": true,
      "findings": [
        {
          "code": "REQUIRED_ATTRIBUTE_ABSENT",
          "span": "a",
          "detail": "a is missing service.name.",
          "attribute": "service.name"
        },
        {
          "code": "REQUIRED_ATTRIBUTE_ABSENT",
          "span": "b",
          "detail": "b is missing service.name.",
          "attribute": "service.name"
        },
        {
          "code": "REQUIRED_ATTRIBUTE_ABSENT",
          "span": "b",
          "detail": "b is a SPAN_KIND_CLIENT span and is missing db.system, which the contract requires for that kind.",
          "attribute": "db.system"
        }
      ],
      "conformant": false,
      "request_id": "example-request",
      "service_id": "span_attribute_contract_audit",
      "span_count": 4,
      "assumptions": [
        "The contract is the caller’s, so this holds spans to a team convention rather than to an opinion. Which checks ran is published, so a contract that checked nothing is visible rather than reading as a ...",
        "A span name embedding an identifier is reported because the name is the aggregation key: a name per call means no latency distribution exists for the operation. Identifiers belong in attributes, where...",
        "A forbidden attribute is reported by key and never by value, since the reason to forbid one is usually what it contains."
      ],
      "limitations": [
        "The spans supplied against the contract supplied. Whether an attribute’s value is correct, and what a backend does with it, are outside this.",
        "conformant is true only when every check that ran found nothing and every rule applied to something."
      ],
      "observed_at": "2026-10-02T00:00:00.000Z",
      "not_examined": [],
      "finding_count": 7,
      "attribute_keys": [
        {
          "key": "http.request.method",
          "spans": 2
        },
        {
          "key": "http.route",
          "spans": 1
        }
      ],
      "service_version": "1.0.0",
      "findings_by_code": {
        "SPAN_KIND_NOT_RECOGNISED": 1,
        "REQUIRED_ATTRIBUTE_ABSENT": 5,
        "SPAN_NAME_CARRIES_AN_IDENTIFIER": 1
      },
      "distinct_name_count": 4,
      "distinct_attribute_key_count": 2
    }
  }
}