The Activity object

{
  "id": "act_01HX9N5AB3...",
  "object": "activity",
  "lesson_id": "lsn_01HX9...",
  "type": "quiz",
  "variant": "true_false",
  "title": "Quick check on the postulates",
  "description": "5 true/false items on the two postulates of SR.",
  "input": null,
  "questions": [
    { "id": "que_1", "prompt": "...", "type": "true_false", "correct_answer": true },
    { "id": "que_2", "prompt": "...", "type": "true_false", "correct_answer": false }
  ],
  "status": "ready",
  "ai_status": "ready",
  "evaluation": null,
  "evaluations": [],
  "created_at": "2026-05-10T12:34:56Z",
  "updated_at": "2026-05-10T12:34:56Z"
}