{"model":"down-payment","specVersion":"1.0.0","specUrl":"/api/v1/models/down-payment/spec","inputs":{"homePrice":{"kind":"float","min":100000,"max":2000000},"downPaymentPct":{"kind":"float","min":0.03,"max":0.3},"currentSavings":{"kind":"float","min":0,"max":500000},"monthlySavings":{"kind":"float","min":100,"max":10000},"annualReturn":{"kind":"float","min":0,"max":0.12}},"arrayInputs":{},"constraints":[],"sentinels":[{"field":"monthsToGoal","value":600,"meaning":"goal not reached within 600 months (yearsToGoal = 50 exactly)"}],"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."}