{
  "assumptions": "Original synthetic fixture. Labels are declared finalized records, not inferred from the feature-event list. Outcome window is [predict_at, predict_at + 24 hours).",
  "assemble_at": "2026-01-11T12:00:00Z",
  "later_assemble_at": "2026-01-15T12:00:00Z",
  "observations": [
    {
      "id": "user-01-day-08",
      "entity": "user-01",
      "predict_at": "2026-01-08T12:00:00Z"
    },
    {
      "id": "user-02-day-08",
      "entity": "user-02",
      "predict_at": "2026-01-08T12:00:00Z"
    },
    {
      "id": "user-03-day-09",
      "entity": "user-03",
      "predict_at": "2026-01-09T12:00:00Z"
    },
    {
      "id": "user-04-day-10",
      "entity": "user-04",
      "predict_at": "2026-01-10T12:00:00Z"
    },
    {
      "id": "user-05-day-12",
      "entity": "user-05",
      "predict_at": "2026-01-12T12:00:00Z"
    },
    {
      "id": "user-06-day-08",
      "entity": "user-06",
      "predict_at": "2026-01-08T12:00:00Z"
    }
  ],
  "events": [
    {
      "id": "u1-known",
      "entity": "user-01",
      "event_at": "2026-01-07T14:00:00Z",
      "arrived_at": "2026-01-07T15:00:00Z"
    },
    {
      "id": "u1-late",
      "entity": "user-01",
      "event_at": "2026-01-08T11:00:00Z",
      "arrived_at": "2026-01-08T13:00:00Z"
    },
    {
      "id": "u1-cutoff",
      "entity": "user-01",
      "event_at": "2026-01-08T12:00:00Z",
      "arrived_at": "2026-01-08T12:00:00Z"
    },
    {
      "id": "u1-after",
      "entity": "user-01",
      "event_at": "2026-01-08T13:00:00Z",
      "arrived_at": "2026-01-08T13:30:00Z"
    },
    {
      "id": "u2-start",
      "entity": "user-02",
      "event_at": "2026-01-07T12:00:00Z",
      "arrived_at": "2026-01-07T12:00:00Z"
    },
    {
      "id": "u2-old",
      "entity": "user-02",
      "event_at": "2026-01-07T11:00:00Z",
      "arrived_at": "2026-01-07T11:00:00Z"
    },
    {
      "id": "u2-arrival-cutoff",
      "entity": "user-02",
      "event_at": "2026-01-08T11:00:00Z",
      "arrived_at": "2026-01-08T12:00:00Z"
    },
    {
      "id": "u3-known",
      "entity": "user-03",
      "event_at": "2026-01-09T10:00:00Z",
      "arrived_at": "2026-01-09T10:00:00Z"
    }
  ],
  "labels": [
    {
      "id": "user-01-day-08",
      "value": 1,
      "ready_at": "2026-01-09T13:00:00Z"
    },
    {
      "id": "user-02-day-08",
      "value": 0,
      "ready_at": "2026-01-10T12:00:00Z"
    },
    {
      "id": "user-03-day-09",
      "value": 0,
      "ready_at": "2026-01-12T12:00:00Z"
    },
    {
      "id": "user-04-day-10",
      "value": 1,
      "ready_at": "2026-01-12T12:00:00Z"
    },
    {
      "id": "user-05-day-12",
      "value": 0,
      "ready_at": "2026-01-14T12:00:00Z"
    }
  ]
}