{
  "unit": "user session and calendar day",
  "development": "2026-04-01/2026-04-09 inclusive",
  "test": "2026-04-10/2026-04-14 inclusive",
  "new_users": [
    "usr_0151",
    "usr_0152",
    "usr_0153",
    "usr_0154",
    "usr_0155",
    "usr_0156",
    "usr_0157",
    "usr_0158",
    "usr_0159",
    "usr_0160"
  ],
  "leakage_controls": [
    "No random row split inside one labeled event",
    "User id, device id, IP, country, and raw hour are not model features",
    "History is computed only from earlier successful logins",
    "Threshold T is not fit on the test split",
    "New users are scored and reported separately"
  ]
}