{
  "session_id": "sample-123",
  "history": [
    {
      "role": "agent",
      "text": "Hello \u2014 I am your Excel mock interviewer..."
    },
    {
      "role": "agent",
      "text": "Explain the difference between VLOOKUP and INDEX+MATCH..."
    },
    {
      "role": "user",
      "text": "VLOOKUP searches left column; INDEX+MATCH is more flexible"
    }
  ],
  "results": [
    {
      "question_id": "q1",
      "answer": "VLOOKUP searches left column; INDEX+MATCH is more flexible",
      "grade": {
        "score": 3,
        "short_reason": "heuristic fallback",
        "suggestions": [
          "Be more specific"
        ]
      }
    }
  ]
}