{"model":"debt-payoff","specVersion":"1.1.0","specUrl":"/api/v1/models/debt-payoff/spec","inputs":{"extraMonthlyPayment":{"kind":"float","min":0,"max":2000}},"arrayInputs":{"debts":{"minItems":1,"maxItems":6,"itemFields":{"balance":{"kind":"float","min":500,"max":50000},"annualRate":{"kind":"float","min":0.01,"max":0.3},"minimumPayment":{"kind":"float","min":25,"max":1000}}}},"constraints":["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)"],"sentinels":[{"field":"months","value":600,"meaning":"never finished within the 600-month cap (avalanche and snowball; schedule carries 601 entries)"}],"facts":[],"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."}