{
  "input": {
    "currency": "USD",
    "principal": 10000,
    "months": 12,
    "monthlyContribution": 0,
    "annualReturn": 0,
    "mode": "required-monthly",
    "goal": 50000,
    "monthlyIncome": 5000
  },
  "result": {
    "value": 3333.33,
    "summary": "Goal calculation with contributions at the beginning of each month.",
    "metrics": {
      "requiredMonthly": 3333.33,
      "monthsToGoal": null,
      "projectedBalance": 10000
    },
    "unit": "USD",
    "status": "ok"
  }
}