{
  "contract_id": "signal_2026_arsenal_vs_city_001",
  "agent_id": "agent.sportbot",
  "timestamp": "2026-02-20T14:00:00Z",
  "match": "Arsenal vs Manchester City",
  "market": "1X2",
  "selection": "Manchester City",
  "model_probability": 0.61,
  "market_odds": 1.85,
  "confidence_score": 0.74,
  "challenge_window_hours": 24,
  "status": "open"
}