tools · POST /v1/tools/find_tax_cliffs

find_tax_cliffs

Sweep one input across a range; every discontinuity in the target.

Call it

bash

curl -s https://opentax.invaro.ai/v1/tools/find_tax_cliffs \
  -H "Authorization: Bearer $OPENTAX_KEY" \
  -H "Content-Type: application/json" \
  -d '{
  "facts": {
    "filing": {
      "filingStatus": "mfj"
    },
    "credits": {
      "qualifyingChildren": 2
    },
    "asOf": "2025-12-31"
  },
  "vary": "wages",
  "fromDollars": 0,
  "toDollars": 80000,
  "stepDollars": 500
}'

What it does

Find exact dollar amounts where one more cent of an input costs MORE than a cent of tax (marginal rate over 100%) — e.g. the EITC investment-income kill switch, CTC phase-out steps. Every probe is a real evaluation.

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

Required: facts, vary, fromDollars, toDollars. Everything else is optional and defaults are disclosed in assumptions.

field	type	description
factsrequired	object · any keys	facts for the computation: either flat corpus fact ids (see list_input_facts) or the same group objects calculate_tax accepts (filing, income, retirement, …), plus optional target and asOf. Business/fiduciary/dependent facts are accepted flat. Unknown keys are rejected by name — nothing is ever silently dropped. Takes every field listed on calculate_tax, grouped or flat, plus asOf and target.
varyrequired	string	money fact to vary, e.g. "wages" or "taxableInterest"
fromDollarsrequired	number
toDollarsrequired	number
stepDollars	number	coarse scan step, default 1000

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.