模型真实性不能靠猜：用多信号复验

{
  "protocol": "jbb-model-authenticity-v1",
  "protocol_version": "1.1.0",
  "test_id": "<RANDOM_TEST_ID>",
  "captured_at_utc": "<ISO_8601_UTC>",
  "sample_count": 3,
  "scope": {
    "base_url": "https://jbbt.pages.dev/v1",
    "endpoint": "/chat/completions",
    "requested_model": "<MODEL_ID_FROM_/v1/models>",
    "alias_used": "<TRUE_OR_FALSE>",
    "resolved_or_pinned_model": "<VALUE_OR_NOT_OBSERVED>",
    "api_version": "<VALUE_OR_NOT_APPLICABLE>",
    "region": "<VALUE_OR_NOT_OBSERVED>",
    "official_model_doc_url": "<HTTPS_URL>",
    "official_doc_snapshot_sha256": "<SHA256>",
    "sdk": "<SDK_NAME>",
    "sdk_version": "<SDK_VERSION>"
  },
  "request_control": {
    "probe_request_description": "One advertised capability probe with the one-time nonce embedded in the expected payload",
    "canonical_body_encoding": "UTF-8 JSON with stable key ordering and no Authorization header",
    "request_body_sha256": "<SHA256_OF_EXACT_CANONICAL_BODY_SENT>",
    "nonce_sha256": "<SHA256_OF_ONE_TIME_NONCE>",
    "temperature": 0,
    "seed": "<INTEGER_OR_NOT_SUPPORTED>",
    "max_tokens": 64,
    "stream": false
  },
  "capability_probe": {
    "capability": "<ONE_ADVERTISED_CAPABILITY>",
    "official_contract_url": "<HTTPS_URL>",
    "nonce_binding_rule": "<MACHINE_RULE_THAT_REQUIRES_ONE_TIME_NONCE_IN_EXPECTED_PAYLOAD>",
    "acceptance_rule": "<PRE_REGISTERED_MACHINE_CHECKABLE_RULE>"
  },
  "observations": [
    {
      "attempt": 1,
      "attempted_at_utc": "<ISO_8601_UTC>",
      "retry_of": null,
      "local_request_id_private": "<STORE_PRIVATELY_NOT_IN_PUBLIC_REPORT>",
      "local_request_id_sha256": "<SHA256_FOR_PUBLIC_REPORT>",
      "upstream_request_id": "<PRESENT_HASHED_OR_NOT_OBSERVED>",
      "http_status": 200,
      "response_id_sha256": "<SHA256>",
      "response_model": "<VALUE_OR_NOT_OBSERVED>",
      "system_fingerprint_sha256": "<SHA256_OR_NOT_OBSERVED>",
      "response_body_sha256": "<SHA256_OF_RAW_BODY_OR_SSE_TRANSCRIPT>",
      "usage_raw": {
        "prompt_tokens": "<INTEGER_OR_NOT_OBSERVED>",
        "completion_tokens": "<INTEGER_OR_NOT_OBSERVED>",
        "completion_tokens_details.reasoning_tokens": "<INTEGER_OR_NOT_OBSERVED>"
      },
      "usage_provenance": "<UPSTREAM_REPORTED_OR_JBB_ESTIMATED_OR_JBB_CONVERTED_OR_NOT_OBSERVED>",
      "probe_rule_pass": "<TRUE_OR_FALSE>",
      "jbb_log_correlation": "<MATCHED_OR_NOT_MATCHED_OR_NOT_CHECKED>"
    },
    {
      "attempt": 2,
      "attempted_at_utc": "<ISO_8601_UTC>",
      "retry_of": null,
      "local_request_id_private": "<STORE_PRIVATELY_NOT_IN_PUBLIC_REPORT>",
      "local_request_id_sha256": "<SHA256_FOR_PUBLIC_REPORT>",
      "upstream_request_id": "<PRESENT_HASHED_OR_NOT_OBSERVED>",
      "http_status": 200,
      "response_id_sha256": "<SHA256>",
      "response_model": "<VALUE_OR_NOT_OBSERVED>",
      "system_fingerprint_sha256": "<SHA256_OR_NOT_OBSERVED>",
      "response_body_sha256": "<SHA256_OF_RAW_BODY_OR_SSE_TRANSCRIPT>",
      "usage_raw": {
        "prompt_tokens": "<INTEGER_OR_NOT_OBSERVED>",
        "completion_tokens": "<INTEGER_OR_NOT_OBSERVED>",
        "completion_tokens_details.reasoning_tokens": "<INTEGER_OR_NOT_OBSERVED>"
      },
      "usage_provenance": "<UPSTREAM_REPORTED_OR_JBB_ESTIMATED_OR_JBB_CONVERTED_OR_NOT_OBSERVED>",
      "probe_rule_pass": "<TRUE_OR_FALSE>",
      "jbb_log_correlation": "<MATCHED_OR_NOT_MATCHED_OR_NOT_CHECKED>"
    },
    {
      "attempt": 3,
      "attempted_at_utc": "<ISO_8601_UTC>",
      "retry_of": null,
      "local_request_id_private": "<STORE_PRIVATELY_NOT_IN_PUBLIC_REPORT>",
      "local_request_id_sha256": "<SHA256_FOR_PUBLIC_REPORT>",
      "upstream_request_id": "<PRESENT_HASHED_OR_NOT_OBSERVED>",
      "http_status": 200,
      "response_id_sha256": "<SHA256>",
      "response_model": "<VALUE_OR_NOT_OBSERVED>",
      "system_fingerprint_sha256": "<SHA256_OR_NOT_OBSERVED>",
      "response_body_sha256": "<SHA256_OF_RAW_BODY_OR_SSE_TRANSCRIPT>",
      "usage_raw": {
        "prompt_tokens": "<INTEGER_OR_NOT_OBSERVED>",
        "completion_tokens": "<INTEGER_OR_NOT_OBSERVED>",
        "completion_tokens_details.reasoning_tokens": "<INTEGER_OR_NOT_OBSERVED>"
      },
      "usage_provenance": "<UPSTREAM_REPORTED_OR_JBB_ESTIMATED_OR_JBB_CONVERTED_OR_NOT_OBSERVED>",
      "probe_rule_pass": "<TRUE_OR_FALSE>",
      "jbb_log_correlation": "<MATCHED_OR_NOT_MATCHED_OR_NOT_CHECKED>"
    }
  ],
  "decision_rule": {
    "l2_requires": [
      "exactly 3 independently timed observations",
      "identical request_body_sha256 across attempts",
      "retry_of is null and local_request_id_sha256 is unique for every attempt",
      "http_status is successful and probe_rule_pass is true for every attempt",
      "jbb_log_correlation is MATCHED for every attempt",
      "no unexplained model, metadata, schema, usage provenance or capability mismatch"
    ],
    "unexplained_mismatch_count": "<NON_NEGATIVE_INTEGER>",
    "l2_rule_pass": "<TRUE_ONLY_IF_EVERY_REQUIREMENT_PASSES>"
  },
  "verdict": {
    "evidence_level": "<0_TO_4>",
    "consistency": "<CONSISTENT_OR_INCONSISTENT_OR_INSUFFICIENT>",
    "external_vendor_correlation": "<VERIFIED_OR_NOT_VERIFIED_OR_NOT_AVAILABLE>",
    "cryptographic_attestation": {
      "available_in_current_jbb_review": false,
      "verified": false,
      "requires": [
        "vendor-controlled signature over canonical request hash, response hash and nonce",
        "immutable resolved model ID plus model artifact or measurement hash",
        "documented signing-key provenance, verifier, expiry and revocation checks"
      ]
    },
    "limitations": [
      "A compatible intermediary can rewrite model labels and metadata.",
      "Three samples cannot establish fleet-wide or time-invariant routing.",
      "Missing metadata is not proof of substitution."
    ]
  },
  "redaction_checklist": {
    "authorization_removed": true,
    "api_key_removed": true,
    "prompt_and_personal_data_removed_from_public_copy": true,
    "channel_account_and_route_removed": true,
    "raw_local_and_upstream_identifiers_private": true
  }
}