tools · POST /v1/tools/calculate_fiduciary_tax

calculate_fiduciary_tax

Form 1041 § 1(e) rate schedule and § 642(b) exemption.

Call it

bash

curl -s https://opentax.invaro.ai/v1/tools/calculate_fiduciary_tax \
  -H "Authorization: Bearer $OPENTAX_KEY" \
  -H "Content-Type: application/json" \
  -d '{
  "fiduciaryType": "trust",
  "fiduciaryIncomeBeforeExemption": 45000,
  "asOf": "2025-12-31"
}'

What it does

Compute US federal income tax for an ESTATE or TRUST (Form 1041): the § 1(e) compressed brackets and § 642(b) exemption. Input is taxable income before the exemption, after the §§ 651/661 distribution deduction. Retained capital gains refuse loudly (§ 1(h) trust breakpoints not modeled). Grantor trusts belong on the grantor's individual return via calculate_tax.

This is the description the MCP server hands to a model. The imperative sentences are addressed to the model; the facts about scope apply to every caller.

Inputs

Nothing is syntactically required, but computation needs asOf, and the engine names any fact the target depends on with NEEDS_FACTS.

field	type	description
fiduciaryType	"estate" \| "simple-trust" \| "complex-trust"	Form 1041 filer type for the § 642(b) exemption: estate ($600), simple trust required to distribute all income currently ($300), or complex trust ($100). Grantor trusts do not file their own tax — use the grantor's individual return.
fiduciaryIncomeBeforeExemption	number \| string	The estate/trust's taxable income BEFORE the § 642(b) exemption but AFTER the §§ 651/661 income-distribution deduction (the DNI machinery is attested by this input). In dollars.
fiduciaryLongTermGains	number \| string	Net long-term capital gain retained by the estate/trust. Any positive amount REFUSES — the § 1(h) preferential breakpoints for estates and trusts are not modeled. In dollars.
target	string	rule to derive (default: us.federal.fiduciary.income_tax).
asOf	string	REQUIRED for computation: the law-in-force date — use the intended tax year's year-end (e.g. "2025-12-31" for TY2025). Omitting it is an error, never a default. pattern ^\d{4}-\d{2}-\d{2}$
includeProof	boolean	include the full proof artifact in the response as `proof` (PROOF-FORMAT v2: every applied rule, input, assumption and rounding, verifiable offline against corpusMerkleRoot; ~200 KB). Default false — the hashes alone are returned.

Example

No captured example for this tool yet; the call above is a valid request. The examples page has ten end-to-end pairs including two refusals.