Inputs
| Field | Type | Valid domain |
|---|---|---|
| annualContribution | float | 500 – 25,000 |
| discountPct | float | 0 – 0.15 |
| priceAtGrant | float | 5 – 500 |
| priceAtPurchase | float | 5 – 500 |
| lookback | choice | yes | no |
| marginalOrdinaryRate | float | 0.1 – 0.37 |
- Immediate-sale (disqualifying disposition) scenario only; domain edges approximate §423 limits (15% max discount; the $25,000 cap is on grant-date FMV, which the contribution-only domain does not recompute — see spec exclusions).
All fields required. Out-of-domain values are rejected with per-field errors — never clamped. Unknown fields are rejected.
Live example — generated from the real engine
Request
POST /api/v1/models/espp
{
"annualContribution": 13000,
"discountPct": 0.08,
"priceAtGrant": 253,
"priceAtPurchase": 253,
"lookback": "yes",
"marginalOrdinaryRate": 0.24
}Response (chart arrays compacted)
{
"ok": true,
"model": "espp",
"specVersion": "1.0.0",
"contractUrl": "/api/v1/models/espp",
"specUrl": "/api/v1/models/espp/spec",
"inputs": {
"annualContribution": 13000,
"discountPct": 0.08,
"priceAtGrant": 253,
"priceAtPurchase": 253,
"lookback": "yes",
"marginalOrdinaryRate": 0.24
},
"outputs": {
"purchasePrice": 232.76000000000002,
"sharesPurchased": 55.85152087987626,
"marketValueAtPurchase": 14130.434782608694,
"bargainElement": 1130.4347826086941,
"ordinaryIncomeTax": 271.3043478260866,
"afterTaxProfit": 859.1304347826076,
"preTaxReturnRate": 0.08695652173913032,
"afterTaxReturnRate": 0.06608695652173904
},
"sentinels": [],
"assumptions": [
"Implements model spec espp v1.0.0 (dual-implementation verified).",
"Immediate-sale (disqualifying disposition) scenario only; domain edges approximate §423 limits (15% max discount; the $25,000 cap is on grant-date FMV, which the contribution-only domain does not recompute — see spec exclusions)."
],
"facts": [],
"record": {
"sha256": "40369267c54487f8cae78aa214e53210b7ca3baefbfcdc9683415b442e639351",
"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."
}This example is executed against the production engine when the page builds — it cannot drift from the API's real behavior.