quarterly-estimates

POST /api/v1/models/quarterly-estimates
{
  "expectedCurrentYearTax": 250000,
  "priorYearTax": 250000,
  "priorYearAgi": 1500000,
  "expectedWithholding": 250000
}

{
  "ok": true,
  "model": "quarterly-estimates",
  "specVersion": "1.0.0",
  "contractUrl": "/api/v1/models/quarterly-estimates",
  "specUrl": "/api/v1/models/quarterly-estimates/spec",
  "inputs": {
    "expectedCurrentYearTax": 250000,
    "priorYearTax": 250000,
    "priorYearAgi": 1500000,
    "expectedWithholding": 250000
  },
  "outputs": {
    "requiredAnnualPayment": 225000,
    "safeHarborUsed": "90% of current year",
    "requiredAfterWithholding": 0,
    "quarterlyPayment": 0,
    "balanceDueAtFiling": 0,
    "deMinimisNoPenalty": true
  },
  "sentinels": [],
  "assumptions": [
    "Implements model spec quarterly-estimates v1.0.0 (Concordance-tested: independently reimplemented from the spec).",
    "IRC §6654 safe harbors with the non-MFS 110% AGI trigger ($150,000); four equal installments — the annualized-income method is out of scope."
  ],
  "facts": [
    {
      "id": "irs.6654.safe-harbor.current-year-pct",
      "label": "Estimated-tax safe harbor: share of current-year tax",
      "value": 0.9,
      "period": "statutory (IRC §6654(d)(1)(B)(i), not indexed)",
      "source": "IRC §6654(d)(1)(B)(i); IRS Form 1040-ES instructions"
    },
    {
      "id": "irs.6654.safe-harbor.prior-year-pct",
      "label": "Estimated-tax safe harbor: share of prior-year tax (AGI ≤ $150,000)",
      "value": 1,
      "period": "statutory (IRC §6654(d)(1)(B)(ii), not indexed)",
      "source": "IRC §6654(d)(1)(B)(ii); IRS Form 1040-ES instructions"
    },
    {
      "id": "irs.6654.safe-harbor.prior-year-pct.high-agi",
      "label": "Estimated-tax safe harbor: share of prior-year tax when prior-year AGI exceeds $150,000",
      "value": 1.1,
      "period": "statutory (IRC §6654(d)(1)(C), not indexed)",
      "source": "IRC §6654(d)(1)(C); IRS Form 1040-ES instructions"
    },
    {
      "id": "irs.6654.high-agi-threshold",
      "label": "Estimated-tax safe harbor: prior-year AGI threshold for the 110% rule",
      "value": 150000,
      "period": "statutory (IRC §6654(d)(1)(C)(i), not indexed)",
      "source": "IRC §6654(d)(1)(C)(i); IRS Form 1040-ES instructions"
    },
    {
      "id": "irs.6654.de-minimis-balance",
      "label": "Estimated-tax de minimis: no payments required when balance after withholding is under this",
      "value": 1000,
      "period": "statutory (IRC §6654(e)(1), not indexed)",
      "source": "IRC §6654(e)(1); IRS Form 1040-ES instructions"
    }
  ],
  "record": {
    "sha256": "f970e8672bdc401067b50d8296e514e1446506f57aa09a5e5250da6869da1a20",
    "fields": [
      "model",
      "specVersion",
      "inputs",
      "outputs"
    ],
    "model": "quarterly-estimates",
    "specVersion": "1.0.0",
    "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."
}