{
  "status": "not_verified",
  "engine": "Microsoft Excel COM",
  "attempts": 3,
  "reason": "E_ACCESSDENIED in sandbox; isolated retries received RPC_E_CALL_REJECTED/timeouts",
  "existing_user_workbooks_modified": false,
  "test_created_excel_processes_closed": true,
  "alternative_verification": "Artifact Tool recalc 609 formula cells, 0 differences; 1214 source cached results matched"
}