plan529-superfunding

POST /api/v1/models/plan529-superfunding
{
  "contributionPerBeneficiary": 251000,
  "donors": 2,
  "beneficiaries": 6,
  "annualReturnPct": 6,
  "years": 16,
  "taxableDragPct": 1.5
}

{
  "ok": true,
  "model": "plan529-superfunding",
  "specVersion": "1.0.0",
  "contractUrl": "/api/v1/models/plan529-superfunding",
  "specUrl": "/api/v1/models/plan529-superfunding/spec",
  "inputs": {
    "contributionPerBeneficiary": 251000,
    "donors": 2,
    "beneficiaries": 6,
    "annualReturnPct": 6,
    "years": 16,
    "taxableDragPct": 1.5
  },
  "outputs": {
    "maxElectionPerBeneficiary": 190000,
    "withinElection": 190000,
    "excessUsingLifetimeExemption": 61000,
    "annualExclusionUsedPerYear": 38000,
    "fv529PerBeneficiary": 637628.272856104,
    "fvTaxablePerBeneficiary": 507614.9084105956,
    "taxFreeAdvantagePerBeneficiary": 130013.36444550834,
    "totalContribution": 1506000,
    "totalTaxFreeAdvantage": 780080.18667305
  },
  "sentinels": [],
  "assumptions": [
    "Implements model spec plan529-superfunding v1.0.0 (Concordance-tested: independently reimplemented from the spec).",
    "annualReturnPct and taxableDragPct are PERCENT points. The 529 arm assumes qualified withdrawals (spec exclusions)."
  ],
  "facts": [
    {
      "id": "irs.gift.annual-exclusion.2026",
      "label": "Annual gift tax exclusion (per recipient)",
      "value": 19000,
      "period": "TY2026",
      "source": "Rev. Proc. 2025-32, section .42(1)"
    }
  ],
  "record": {
    "sha256": "3d9ad92c3f836f223149f4a528e8a3e906e990024db4cbddd243512737f248da",
    "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."
}