{"model":"extra-payment","specVersion":"1.0.0","specUrl":"/api/v1/models/extra-payment/spec","inputs":{"currentBalance":{"kind":"float","min":1000,"max":2000000},"annualRate":{"kind":"float","min":0.001,"max":0.3},"remainingTermMonths":{"kind":"int","min":6,"max":480},"extraMonthlyPayment":{"kind":"float","min":0,"max":10000}},"arrayInputs":{},"constraints":[],"sentinels":[],"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."}