debt-payoff

POST /api/v1/models/debt-payoff
{
  "extraMonthlyPayment": 1000,
  "debts": [
    {
      "name": "Credit card",
      "balance": 8000,
      "annualRate": 0.22,
      "minimumPayment": 160
    },
    {
      "name": "Car loan",
      "balance": 14000,
      "annualRate": 0.07,
      "minimumPayment": 300
    }
  ]
}

{
  "ok": true,
  "model": "debt-payoff",
  "specVersion": "1.0.0",
  "contractUrl": "/api/v1/models/debt-payoff",
  "specUrl": "/api/v1/models/debt-payoff/spec",
  "inputs": {
    "extraMonthlyPayment": 1000,
    "debts": [
      {
        "name": "Credit card",
        "balance": 8000,
        "annualRate": 0.22,
        "minimumPayment": 160
      },
      {
        "name": "Car loan",
        "balance": 14000,
        "annualRate": 0.07,
        "minimumPayment": 300
      }
    ]
  },
  "outputs": {
    "avalanche": {
      "months": 17,
      "totalInterest": 1561.9228348670883,
      "schedule": [
        {
          "month": 0,
          "totalBalance": 22000,
          "totalInterestPaid": 0
        },
        {
          "month": 1,
          "totalBalance": 20768.333333333332,
          "totalInterestPaid": 228.33333333333331
        },
        "… 16 more"
      ]
    },
    "snowball": {
      "months": 17,
      "totalInterest": 1561.9228348670883,
      "schedule": [
        {
          "month": 0,
          "totalBalance": 22000,
          "totalInterestPaid": 0
        },
        {
          "month": 1,
          "totalBalance": 20768.333333333332,
          "totalInterestPaid": 228.33333333333331
        },
        "… 16 more"
      ]
    },
    "interestSaved": 0
  },
  "sentinels": [
    {
      "field": "months",
      "value": 600,
      "meaning": "never finished within the 600-month cap (avalanche and snowball; schedule carries 601 entries)",
      "triggered": false
    }
  ],
  "assumptions": [
    "Implements model spec debt-payoff v1.0.0 (dual-implementation verified).",
    "debts[i].name is a free display string, ignored by the engine and excluded from verification",
    "extraMonthlyPayment is a scalar in 0–2,000 USD/mo (per spec)"
  ],
  "facts": [],
  "record": {
    "sha256": "878a7f34b107a7cf75952407daa46210139bcfdf48d8942b1a701771f34c38b8",
    "fields": [
      "model",
      "specVersion",
      "inputs",
      "outputs"
    ],
    "howToVerify": "Store this record with any advice or agent output built on these numbers. To verify later: build {model, specVersion, inputs, outputs} from the stored response, serialize as JSON with object keys sorted recursively (no whitespace), and SHA-256 it — a match proves the numbers came from this spec version with these inputs, unaltered."
  },
  "disclaimer": "Illustrative planning model, not financial advice. Outputs follow the published model spec exactly; read the spec for assumptions and exclusions before relying on any number."
}