{"model":"renovation","specVersion":"1.1.0","specUrl":"/api/v1/models/renovation/spec","inputs":{"renovationCost":{"kind":"float","min":5000,"max":300000},"estimatedValueIncrease":{"kind":"float","min":0,"max":0.3},"currentHomeValue":{"kind":"float","min":100000,"max":3000000},"fundingMethod":{"kind":"choice","values":["savings","heloc"]},"helocRate":{"kind":"float","min":0.04,"max":0.15},"helocTermMonths":{"kind":"int","min":12,"max":120},"appreciationRate":{"kind":"float","min":0.01,"max":0.1},"annualReturn":{"kind":"float","min":0.02,"max":0.12},"yearsHorizon":{"kind":"int","min":1,"max":20}},"arrayInputs":{},"constraints":["helocRate must stay > 0 (NaN at 0)"],"sentinels":[{"field":"breakEvenYears","value":999,"meaning":"never — annualized gain ≤ 0 (note: 999, not relocation's 9999)"}],"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."}