QuantCalc Retirement Engine

Official6 tools

by quantcalc-app

Retirement Monte Carlo, tax-aware withdrawal and Roth-conversion plans, and a 2026 return estimate.

MCP Server: app.quantcalc/retirement-engine

This MCP server provides Monte Carlo retirement projections using a real engine, with assumptions attached. It’s described as an “app.quantcalc/retirement-engine” component and focuses on generating retirement projection outputs that incorporate user-supplied assumptions.

🛠️ Key Features

Monte Carlo retirement projections
Projections run on a real engine
Assumptions are attached to the projections

🚀 Use Cases

Estimating retirement outcomes via Monte Carlo simulations
Running scenario-based retirement planning using explicit assumptions

⚡ Developer Benefits

Clear linkage between projection results and assumptions
Suitable for automating retirement-projection workflows in MCP-connected tools

⚠️ Limitations

No additional capabilities, topics, or tool count details are provided in the source data

Topics

claude-pluginmcpmonte-carloretirement-planning

Captured live from the server via tools/list.

run_retirement_projection

Runs a Monte Carlo retirement projection on the QuantCalc engine and returns the success rate, the ending-portfolio distribution, and the assumptions that produced them. The result states the return model that ran, the number of paths, and the income assumptions it used, including when there are none. Income tax is not modelled by this tool; run_tax_aware_projection models it.

Parameters13

current_age	integer	required	Current age of the primary person.
retirement_age	integer	optional	Age work income stops. Defaults to current age.
life_expectancy	integer	optional	Age the plan must last until. Default 92.
current_savings	number	required	Total invested portfolio today, in dollars.
annual_spending	number	required	Planned yearly spending in today's dollars, before income tax (this tool runs the standard engine, which does not model tax).
monthly_contribution	number	optional	Monthly savings until retirement. Default 0.
social_security	number	optional	Yearly Social Security in today's dollars. Default 0 — and 0 is reported as an explicit assumption, not hidden.
ss_start_age	integer	optional	Age Social Security starts. Default 67.
pension	number	optional	Yearly pension income. Default 0.
pension_start_age	integer	optional	Age the pension starts. Default 65.
inflation_rate	number	optional	Annual inflation as a percent, e.g. 2.5. Default 2.5.
allocations	array	optional	Percentages summing to 100: [US stocks, international stocks, bonds, real estate, cash]. Default [60,10,25,5,0].
returns_source	string	optional	Which published return set to use (see list_return_assumption_sources). Default jpmorgan.

Raw schema

{
  "type": "object",
  "properties": {
    "current_age": {
      "type": "integer",
      "description": "Current age of the primary person."
    },
    "retirement_age": {
      "type": "integer",
      "description": "Age work income stops. Defaults to current age."
    },
    "life_expectancy": {
      "type": "integer",
      "description": "Age the plan must last until. Default 92."
    },
    "current_savings": {
      "type": "number",
      "description": "Total invested portfolio today, in dollars."
    },
    "annual_spending": {
      "type": "number",
      "description": "Planned yearly spending in today's dollars, before income tax (this tool runs the standard engine, which does not model tax)."
    },
    "monthly_contribution": {
      "type": "number",
      "description": "Monthly savings until retirement. Default 0."
    },
    "social_security": {
      "type": "number",
      "description": "Yearly Social Security in today's dollars. Default 0 — and 0 is reported as an explicit assumption, not hidden."
    },
    "ss_start_age": {
      "type": "integer",
      "description": "Age Social Security starts. Default 67."
    },
    "pension": {
      "type": "number",
      "description": "Yearly pension income. Default 0."
    },
    "pension_start_age": {
      "type": "integer",
      "description": "Age the pension starts. Default 65."
    },
    "inflation_rate": {
      "type": "number",
      "description": "Annual inflation as a percent, e.g. 2.5. Default 2.5."
    },
    "allocations": {
      "type": "array",
      "items": {
        "type": "number"
      },
      "minItems": 5,
      "maxItems": 5,
      "description": "Percentages summing to 100: [US stocks, international stocks, bonds, real estate, cash]. Default [60,10,25,5,0]."
    },
    "returns_source": {
      "type": "string",
      "description": "Which published return set to use (see list_return_assumption_sources). Default jpmorgan."
    }
  },
  "required": [
    "current_age",
    "current_savings",
    "annual_spending"
  ]
}

run_tax_aware_projection

Runs the retirement projection with the household's accounts split by tax type and returns the withdrawal order and Roth-conversion programme the engine selected, its present-value advantage and range against drawing traditional first, and the after-tax success rate. Federal and state income tax (50 states and DC), Social Security taxability, required minimum distributions, Medicare IRMAA surcharges and the early-withdrawal penalty are paid from the portfolio year by year; spending is what the household keeps after tax. The result states every assumption it used, including the defaults for inputs that were not given, and what the engine does not model.

Parameters26

current_age	integer	required	Current age of the primary person.
retirement_age	integer	optional	Age work income stops. Defaults to current age.
life_expectancy	integer	optional	Age the plan must last until. Default 92.
annual_spending	number	required	Planned yearly spending in today's dollars, after tax: what the household keeps. The engine withdraws enough each year to fund this plus that year's federal, state, Medicare-surcharge and penalty tax.
monthly_contribution	number	optional	Monthly savings until retirement. Default 0.
social_security	number	optional	Yearly Social Security in today's dollars. Default 0 — and 0 is reported as an explicit assumption, not hidden.
ss_start_age	integer	optional	Age Social Security starts. Default 67.
pension	number	optional	Yearly pension income. Default 0.
pension_start_age	integer	optional	Age the pension starts. Default 65.
inflation_rate	number	optional	Annual inflation as a percent, e.g. 2.5. Default 2.5.
allocations	array	optional	Percentages summing to 100: [US stocks, international stocks, bonds, real estate, cash]. Default [60,10,25,5,0].
returns_source	string	optional	Which published return set to use (see list_return_assumption_sources). Default jpmorgan.
traditional_balance	number	required	Pre-tax retirement accounts today (traditional IRA, 401(k), 403(b)), in dollars. 0 if none.
roth_balance	number	required	Roth IRA and Roth 401(k) balance today, in dollars. 0 if none.
taxable_balance	number	required	Taxable brokerage and savings today, in dollars. 0 if none. The three balances together are the portfolio.
filing_status	string	required	Federal filing status: single, married filing jointly (mfj), married filing separately (mfs) or head of household (hoh).
state	string	optional	Two-letter state of residence (or DC) for state income tax with that state's retirement-income rules. When absent the result states that no state tax was modelled.
cost_basis_ratio	number	optional	Percentage of the taxable account that is cost basis, 0-100. Default 40, and the result says so when it is assumed.
spouse_age	integer	optional	Spouse's current age, for married filing jointly: sets the second aged deduction and Medicare surcharge. Default: the same as current_age, stated in the result.
medicare_start_age	integer	optional	Age Medicare (and its IRMAA income surcharges) begins. Default 65. The year it begins is charged only for the months from the birthday month.
birth_year	integer	optional	Year of birth, optional. Must match current_age: 2026 minus current_age, or 2025 minus current_age when this year's birthday is still to come (then every tax rule uses the age reached in each calendar year). Sets the RMD start age (73 if born 1951-1959, 75 if born 1960 or later). Default: 2026 minus current_age, stated in the result.
birth_month	integer	optional	Month of birth, 1-12, optional. Times the half-year rules: the early-withdrawal penalty ends at 59 and a half, charitable distributions start at 70 and a half, Medicare starts in the birthday month. Default: not given, stated in the result.
annual_qcd	number	optional	Yearly qualified charitable distribution from the traditional account, in today's dollars, counted against required minimum distributions. Default 0.
roth_conversion	object	optional	The household's own Roth-conversion plan: a fixed amount per year between two ages. When given, the engine applies it on every path and searches withdrawal orders around it instead of searching its own conversion programmes.
tax_exempt_interest	number	optional	Yearly municipal-bond interest, which counts toward Social Security taxability and IRMAA income but is not itself taxed. Default 0.
spouse_split	string	optional	Married filing jointly with a state: whose IRA withdrawals, pension and Roth conversions they are on the state return: even (half each), filer (all the filer's) or spouse (all the spouse's). Arkansas, Delaware, Maryland, Minnesota, Missouri, North Dakota, Ohio and Virginia tax a couple by each spouse's own income, so there it can change the state tax; federal tax does not depend on it. Default on a joint return with a state: even (the spouse's age is then needed; when spouse_age is not given it is current_age), stated in the result. Not used off a joint return or without a state.

Raw schema

{
  "type": "object",
  "properties": {
    "current_age": {
      "type": "integer",
      "description": "Current age of the primary person."
    },
    "retirement_age": {
      "type": "integer",
      "description": "Age work income stops. Defaults to current age."
    },
    "life_expectancy": {
      "type": "integer",
      "description": "Age the plan must last until. Default 92."
    },
    "annual_spending": {
      "type": "number",
      "description": "Planned yearly spending in today's dollars, after tax: what the household keeps. The engine withdraws enough each year to fund this plus that year's federal, state, Medicare-surcharge and penalty tax."
    },
    "monthly_contribution": {
      "type": "number",
      "description": "Monthly savings until retirement. Default 0."
    },
    "social_security": {
      "type": "number",
      "description": "Yearly Social Security in today's dollars. Default 0 — and 0 is reported as an explicit assumption, not hidden."
    },
    "ss_start_age": {
      "type": "integer",
      "description": "Age Social Security starts. Default 67."
    },
    "pension": {
      "type": "number",
      "description": "Yearly pension income. Default 0."
    },
    "pension_start_age": {
      "type": "integer",
      "description": "Age the pension starts. Default 65."
    },
    "inflation_rate": {
      "type": "number",
      "description": "Annual inflation as a percent, e.g. 2.5. Default 2.5."
    },
    "allocations": {
      "type": "array",
      "items": {
        "type": "number"
      },
      "minItems": 5,
      "maxItems": 5,
      "description": "Percentages summing to 100: [US stocks, international stocks, bonds, real estate, cash]. Default [60,10,25,5,0]."
    },
    "returns_source": {
      "type": "string",
      "description": "Which published return set to use (see list_return_assumption_sources). Default jpmorgan."
    },
    "traditional_balance": {
      "type": "number",
      "description": "Pre-tax retirement accounts today (traditional IRA, 401(k), 403(b)), in dollars. 0 if none."
    },
    "roth_balance": {
      "type": "number",
      "description": "Roth IRA and Roth 401(k) balance today, in dollars. 0 if none."
    },
    "taxable_balance": {
      "type": "number",
      "description": "Taxable brokerage and savings today, in dollars. 0 if none. The three balances together are the portfolio."
    },
    "filing_status": {
      "type": "string",
      "enum": [
        "single",
        "mfj",
        "mfs",
        "hoh"
      ],
      "description": "Federal filing status: single, married filing jointly (mfj), married filing separately (mfs) or head of household (hoh)."
    },
    "state": {
      "type": "string",
      "description": "Two-letter state of residence (or DC) for state income tax with that state's retirement-income rules. When absent the result states that no state tax was modelled."
    },
    "cost_basis_ratio": {
      "type": "number",
      "description": "Percentage of the taxable account that is cost basis, 0-100. Default 40, and the result says so when it is assumed."
    },
    "spouse_age": {
      "type": "integer",
      "description": "Spouse's current age, for married filing jointly: sets the second aged deduction and Medicare surcharge. Default: the same as current_age, stated in the result."
    },
    "medicare_start_age": {
      "type": "integer",
      "description": "Age Medicare (and its IRMAA income surcharges) begins. Default 65. The year it begins is charged only for the months from the birthday month."
    },
    "birth_year": {
      "type": "integer",
      "description": "Year of birth, optional. Must match current_age: 2026 minus current_age, or 2025 minus current_age when this year's birthday is still to come (then every tax rule uses the age reached in each calendar year). Sets the RMD start age (73 if born 1951-1959, 75 if born 1960 or later). Default: 2026 minus current_age, stated in the result."
    },
    "birth_month": {
      "type": "integer",
      "description": "Month of birth, 1-12, optional. Times the half-year rules: the early-withdrawal penalty ends at 59 and a half, charitable distributions start at 70 and a half, Medicare starts in the birthday month. Default: not given, stated in the result."
    },
    "annual_qcd": {
      "type": "number",
      "description": "Yearly qualified charitable distribution from the traditional account, in today's dollars, counted against required minimum distributions. Default 0."
    },
    "roth_conversion": {
      "type": "object",
      "description": "The household's own Roth-conversion plan: a fixed amount per year between two ages. When given, the engine applies it on every path and searches withdrawal orders around it instead of searching its own conversion programmes.",
      "properties": {
        "annual_amount": {
          "type": "number",
          "description": "Dollars converted per year, today's dollars."
        },
        "start_age": {
          "type": "integer"
        },
        "end_age": {
          "type": "integer"
        }
      },
      "required": [
        "annual_amount",
        "start_age",
        "end_age"
      ]
    },
    "tax_exempt_interest": {
      "type": "number",
      "description": "Yearly municipal-bond interest, which counts toward Social Security taxability and IRMAA income but is not itself taxed. Default 0."
    },
    "spouse_split": {
      "type": "string",
      "enum": [
        "even",
        "filer",
        "spouse"
      ],
      "description": "Married filing jointly with a state: whose IRA withdrawals, pension and Roth conversions they are on the state return: even (half each), filer (all the filer's) or spouse (all the spouse's). Arkansas, Delaware, Maryland, Minnesota, Missouri, North Dakota, Ohio and Virginia tax a couple by each spouse's own income, so there it can change the state tax; federal tax does not depend on it. Default on a joint return with a state: even (the spouse's age is then needed; when spouse_age is not given it is current_age), stated in the result. Not used off a joint return or without a state."
    }
  },
  "required": [
    "current_age",
    "annual_spending",
    "traditional_balance",
    "roth_balance",
    "taxable_balance",
    "filing_status"
  ]
}

compare_return_assumptions

Runs the same plan against several published capital market assumption sets and returns the success rate and median outcome under each, showing how far the answer moves with the return forecast used.

Parameters14

current_age	integer	required	Current age of the primary person.
retirement_age	integer	optional	Age work income stops. Defaults to current age.
life_expectancy	integer	optional	Age the plan must last until. Default 92.
current_savings	number	required	Total invested portfolio today, in dollars.
annual_spending	number	required	Planned yearly spending in today's dollars, before income tax (this tool runs the standard engine, which does not model tax).
monthly_contribution	number	optional	Monthly savings until retirement. Default 0.
social_security	number	optional	Yearly Social Security in today's dollars. Default 0 — and 0 is reported as an explicit assumption, not hidden.
ss_start_age	integer	optional	Age Social Security starts. Default 67.
pension	number	optional	Yearly pension income. Default 0.
pension_start_age	integer	optional	Age the pension starts. Default 65.
inflation_rate	number	optional	Annual inflation as a percent, e.g. 2.5. Default 2.5.
allocations	array	optional	Percentages summing to 100: [US stocks, international stocks, bonds, real estate, cash]. Default [60,10,25,5,0].
returns_source	string	optional	Which published return set to use (see list_return_assumption_sources). Default jpmorgan.
sources	array	optional	Source ids to compare. Defaults to all.

Raw schema

{
  "type": "object",
  "properties": {
    "current_age": {
      "type": "integer",
      "description": "Current age of the primary person."
    },
    "retirement_age": {
      "type": "integer",
      "description": "Age work income stops. Defaults to current age."
    },
    "life_expectancy": {
      "type": "integer",
      "description": "Age the plan must last until. Default 92."
    },
    "current_savings": {
      "type": "number",
      "description": "Total invested portfolio today, in dollars."
    },
    "annual_spending": {
      "type": "number",
      "description": "Planned yearly spending in today's dollars, before income tax (this tool runs the standard engine, which does not model tax)."
    },
    "monthly_contribution": {
      "type": "number",
      "description": "Monthly savings until retirement. Default 0."
    },
    "social_security": {
      "type": "number",
      "description": "Yearly Social Security in today's dollars. Default 0 — and 0 is reported as an explicit assumption, not hidden."
    },
    "ss_start_age": {
      "type": "integer",
      "description": "Age Social Security starts. Default 67."
    },
    "pension": {
      "type": "number",
      "description": "Yearly pension income. Default 0."
    },
    "pension_start_age": {
      "type": "integer",
      "description": "Age the pension starts. Default 65."
    },
    "inflation_rate": {
      "type": "number",
      "description": "Annual inflation as a percent, e.g. 2.5. Default 2.5."
    },
    "allocations": {
      "type": "array",
      "items": {
        "type": "number"
      },
      "minItems": 5,
      "maxItems": 5,
      "description": "Percentages summing to 100: [US stocks, international stocks, bonds, real estate, cash]. Default [60,10,25,5,0]."
    },
    "returns_source": {
      "type": "string",
      "description": "Which published return set to use (see list_return_assumption_sources). Default jpmorgan."
    },
    "sources": {
      "type": "array",
      "items": {
        "type": "string"
      },
      "description": "Source ids to compare. Defaults to all."
    }
  },
  "required": [
    "current_age",
    "current_savings",
    "annual_spending"
  ]
}

list_return_assumption_sources

Returns the published capital market assumption sets the engine carries and which components each publisher provides (returns, volatilities, correlations).

Parameters

No parameters.

Raw schema

{
  "type": "object",
  "properties": {}
}

explain_methodology

Returns what the QuantCalc engine models and what it deliberately leaves out, including the tax provisions that are out of scope, and links to the published methodology.

Parameters

No parameters.

Raw schema

{
  "type": "object",
  "properties": {}
}

estimate_2026_tax_return

Estimates a household's 2026 federal and state income tax return from its 2026 income (wages, Social Security, IRA and 401(k) distributions, pensions, Roth conversions, interest, dividends, capital gains and losses), deductions, withholding and estimated payments, and returns the federal refund or amount owed, the state refund or amount owed, and both together; the main Form 1040 lines (total income, AGI, deduction, taxable income, tax, total tax) and the state's taxable income and tax; and every default assumed, the facts the state engine assumed, and what is not modelled. Computed by QuantCalc's federal and state tax APIs, the engines the website's 2026 Return Preview is checked against to the cent. Requires a connected QuantCalc PRO licence or Tax Season Pass; without one it returns no figures and names the free web calculator. An estimate, not a filed return and not tax advice.

Parameters41

filing_status	string	required	2026 filing status: single, married filing jointly (mfj), married filing separately (mfs) or head of household (hoh).
age	integer	required	The age the filer reaches in 2026 (18-110).
state	string	required	Two-letter state of residence for all of 2026, or DC. States with no income tax (e.g. TX, FL) return a state tax of 0.
birth_month	integer	optional	Filer's birth month, 1-12, optional. With it the 10% early-withdrawal tax applies only to the part of the year before 59 and a half; without it, through the year the filer reaches 59.
spouse_age	integer	optional	Joint return only: the age the spouse reaches in 2026. Default: the same as age, stated in the result.
spouse_birth_month	integer	optional	Joint return only: the spouse's birth month, 1-12, optional.
wages	number	optional	The filer's 2026 wages (Form W-2 box 1). Default 0.
spouse_wages	number	optional	Joint return only: the spouse's 2026 wages. Default 0.
qualified_overtime	number	optional	Qualified overtime compensation included in the wages: the FLSA overtime premium only (the half in time-and-a-half), deducted on Schedule 1-A (IRC 225, up to $12,500, $25,000 joint, phased out above $150,000 / $300,000 MAGI; none married filing separately). Not more than the wages. Default 0.
qualified_tips	number	optional	Qualified tips included in the wages, deducted on Schedule 1-A (IRC 224, up to $25,000, phased out above $150,000 / $300,000 MAGI; none married filing separately). Not more than the wages. Default 0.
social_security	number	optional	Gross 2026 Social Security benefits of the household (Form SSA-1099 box 5); the engine figures the taxable part. Default 0.
ira_distributions	number	optional	Taxable 2026 IRA, 401(k) and 403(b) distributions (not Roth conversions), the household's total. Default 0.
roth_conversion	number	optional	Taxable amount converted to Roth in 2026, the household's total. Default 0.
pension	number	optional	Taxable 2026 pension and annuity income, the household's total. Default 0.
pension_type	string	optional	Whether the pension is a private pension or a government (public) pension, for the state's retirement-income rules. Default private, stated in the result when a pension is given.
spouse_split	string	optional	Joint return only: whose the IRA distributions, pension and Roth conversion are on the state return: even (half each), filer, spouse, or custom (the spouse's own amounts in spouse_ira_distributions, spouse_pension and spouse_roth_conversion, the rest the filer's). Arkansas, Delaware, Maryland, Minnesota, Missouri, North Dakota, Ohio and Virginia tax a couple by each spouse's own income, so there it can change the state tax; federal tax does not depend on it. Default even, stated in the result.
spouse_ira_distributions	number	optional	spouse_split custom only: the spouse's part of ira_distributions.
spouse_pension	number	optional	spouse_split custom only: the spouse's part of pension.
spouse_roth_conversion	number	optional	spouse_split custom only: the spouse's part of roth_conversion.
taxable_interest	number	optional	Taxable interest (Form 1040 line 2b). Default 0.
tax_exempt_interest	number	optional	Tax-exempt (municipal bond) interest (line 2a): not taxed, but counts toward the taxable part of Social Security. Default 0.
ordinary_dividends	number	optional	Ordinary dividends, Form 1099-DIV box 1a (line 3b), including the qualified part. Default 0.
qualified_dividends	number	optional	The qualified part of ordinary_dividends (box 1b, line 3a), taxed at the capital-gains rates; not more than ordinary_dividends. Default 0.
capital_gain_distributions	number	optional	Capital gain distributions from funds (Form 1099-DIV box 2a). Default 0.
short_term_gains	number	optional	2026 net short-term capital gain; negative for a net loss. Default 0.
long_term_gains	number	optional	2026 net long-term capital gain; negative for a net loss. Default 0.
capital_loss_carryover_short_term	number	optional	Short-term capital loss carried over from 2025, as a positive number. Default 0.
capital_loss_carryover_long_term	number	optional	Long-term capital loss carried over from 2025, as a positive number. Default 0.
other_ordinary_income	number	optional	Other ordinary income that is not investment income (Schedule 1). Default 0.
state_local_income_tax_paid	number	optional	Itemized deduction input: state and local income tax paid in 2026 (Schedule A line 5a). Default 0.
real_estate_tax_paid	number	optional	Itemized deduction input: real estate tax paid in 2026. Default 0.
mortgage_interest	number	optional	Itemized deduction input: home mortgage interest paid in 2026. Default 0.
medical_expenses	number	optional	Itemized deduction input: medical and dental expenses paid in 2026, before the AGI floor. Default 0.
charitable_cash	number	optional	Cash gifts to charity in 2026. The engine figures the return with the standard deduction (with the 2026 deduction for non-itemizers' cash gifts) and with the itemized deductions given, and keeps the lower tax. Default 0.
federal_withholding	number	optional	Federal income tax withheld in 2026 from wages, pensions, IRA distributions and Social Security. Default 0, stated in the result.
estimated_payments	array	optional	The 2026 federal estimated tax payments, up to four installments in order (April, June, September, January). Default none.
prior_year_tax	number	optional	Total tax on the 2025 return. With it the underpayment penalty (Form 2210) is figured and subtracted; without it the penalty is not figured, stated in the result.
prior_year_agi	number	optional	2025 adjusted gross income, used with prior_year_tax: above $150,000 ($75,000 married filing separately) the prior-year safe harbor is 110%.
state_withholding	number	optional	State income tax withheld in 2026. Default 0.
state_estimated_payments	number	optional	State estimated tax paid for 2026, the total. Default 0.
marketplace_coverage	boolean	optional	True if the household had Marketplace (ACA) health coverage in 2026: the premium tax credit is not reconciled by this estimate and the result says so.

Raw schema

{
  "type": "object",
  "properties": {
    "filing_status": {
      "type": "string",
      "enum": [
        "single",
        "mfj",
        "mfs",
        "hoh"
      ],
      "description": "2026 filing status: single, married filing jointly (mfj), married filing separately (mfs) or head of household (hoh)."
    },
    "age": {
      "type": "integer",
      "description": "The age the filer reaches in 2026 (18-110)."
    },
    "state": {
      "type": "string",
      "description": "Two-letter state of residence for all of 2026, or DC. States with no income tax (e.g. TX, FL) return a state tax of 0."
    },
    "birth_month": {
      "type": "integer",
      "description": "Filer's birth month, 1-12, optional. With it the 10% early-withdrawal tax applies only to the part of the year before 59 and a half; without it, through the year the filer reaches 59."
    },
    "spouse_age": {
      "type": "integer",
      "description": "Joint return only: the age the spouse reaches in 2026. Default: the same as age, stated in the result."
    },
    "spouse_birth_month": {
      "type": "integer",
      "description": "Joint return only: the spouse's birth month, 1-12, optional."
    },
    "wages": {
      "type": "number",
      "description": "The filer's 2026 wages (Form W-2 box 1). Default 0."
    },
    "spouse_wages": {
      "type": "number",
      "description": "Joint return only: the spouse's 2026 wages. Default 0."
    },
    "qualified_overtime": {
      "type": "number",
      "description": "Qualified overtime compensation included in the wages: the FLSA overtime premium only (the half in time-and-a-half), deducted on Schedule 1-A (IRC 225, up to $12,500, $25,000 joint, phased out above $150,000 / $300,000 MAGI; none married filing separately). Not more than the wages. Default 0."
    },
    "qualified_tips": {
      "type": "number",
      "description": "Qualified tips included in the wages, deducted on Schedule 1-A (IRC 224, up to $25,000, phased out above $150,000 / $300,000 MAGI; none married filing separately). Not more than the wages. Default 0."
    },
    "social_security": {
      "type": "number",
      "description": "Gross 2026 Social Security benefits of the household (Form SSA-1099 box 5); the engine figures the taxable part. Default 0."
    },
    "ira_distributions": {
      "type": "number",
      "description": "Taxable 2026 IRA, 401(k) and 403(b) distributions (not Roth conversions), the household's total. Default 0."
    },
    "roth_conversion": {
      "type": "number",
      "description": "Taxable amount converted to Roth in 2026, the household's total. Default 0."
    },
    "pension": {
      "type": "number",
      "description": "Taxable 2026 pension and annuity income, the household's total. Default 0."
    },
    "pension_type": {
      "type": "string",
      "enum": [
        "private",
        "public"
      ],
      "description": "Whether the pension is a private pension or a government (public) pension, for the state's retirement-income rules. Default private, stated in the result when a pension is given."
    },
    "spouse_split": {
      "type": "string",
      "enum": [
        "even",
        "filer",
        "spouse",
        "custom"
      ],
      "description": "Joint return only: whose the IRA distributions, pension and Roth conversion are on the state return: even (half each), filer, spouse, or custom (the spouse's own amounts in spouse_ira_distributions, spouse_pension and spouse_roth_conversion, the rest the filer's). Arkansas, Delaware, Maryland, Minnesota, Missouri, North Dakota, Ohio and Virginia tax a couple by each spouse's own income, so there it can change the state tax; federal tax does not depend on it. Default even, stated in the result."
    },
    "spouse_ira_distributions": {
      "type": "number",
      "description": "spouse_split custom only: the spouse's part of ira_distributions."
    },
    "spouse_pension": {
      "type": "number",
      "description": "spouse_split custom only: the spouse's part of pension."
    },
    "spouse_roth_conversion": {
      "type": "number",
      "description": "spouse_split custom only: the spouse's part of roth_conversion."
    },
    "taxable_interest": {
      "type": "number",
      "description": "Taxable interest (Form 1040 line 2b). Default 0."
    },
    "tax_exempt_interest": {
      "type": "number",
      "description": "Tax-exempt (municipal bond) interest (line 2a): not taxed, but counts toward the taxable part of Social Security. Default 0."
    },
    "ordinary_dividends": {
      "type": "number",
      "description": "Ordinary dividends, Form 1099-DIV box 1a (line 3b), including the qualified part. Default 0."
    },
    "qualified_dividends": {
      "type": "number",
      "description": "The qualified part of ordinary_dividends (box 1b, line 3a), taxed at the capital-gains rates; not more than ordinary_dividends. Default 0."
    },
    "capital_gain_distributions": {
      "type": "number",
      "description": "Capital gain distributions from funds (Form 1099-DIV box 2a). Default 0."
    },
    "short_term_gains": {
      "type": "number",
      "description": "2026 net short-term capital gain; negative for a net loss. Default 0."
    },
    "long_term_gains": {
      "type": "number",
      "description": "2026 net long-term capital gain; negative for a net loss. Default 0."
    },
    "capital_loss_carryover_short_term": {
      "type": "number",
      "description": "Short-term capital loss carried over from 2025, as a positive number. Default 0."
    },
    "capital_loss_carryover_long_term": {
      "type": "number",
      "description": "Long-term capital loss carried over from 2025, as a positive number. Default 0."
    },
    "other_ordinary_income": {
      "type": "number",
      "description": "Other ordinary income that is not investment income (Schedule 1). Default 0."
    },
    "state_local_income_tax_paid": {
      "type": "number",
      "description": "Itemized deduction input: state and local income tax paid in 2026 (Schedule A line 5a). Default 0."
    },
    "real_estate_tax_paid": {
      "type": "number",
      "description": "Itemized deduction input: real estate tax paid in 2026. Default 0."
    },
    "mortgage_interest": {
      "type": "number",
      "description": "Itemized deduction input: home mortgage interest paid in 2026. Default 0."
    },
    "medical_expenses": {
      "type": "number",
      "description": "Itemized deduction input: medical and dental expenses paid in 2026, before the AGI floor. Default 0."
    },
    "charitable_cash": {
      "type": "number",
      "description": "Cash gifts to charity in 2026. The engine figures the return with the standard deduction (with the 2026 deduction for non-itemizers' cash gifts) and with the itemized deductions given, and keeps the lower tax. Default 0."
    },
    "federal_withholding": {
      "type": "number",
      "description": "Federal income tax withheld in 2026 from wages, pensions, IRA distributions and Social Security. Default 0, stated in the result."
    },
    "estimated_payments": {
      "type": "array",
      "items": {
        "type": "number"
      },
      "maxItems": 4,
      "description": "The 2026 federal estimated tax payments, up to four installments in order (April, June, September, January). Default none."
    },
    "prior_year_tax": {
      "type": "number",
      "description": "Total tax on the 2025 return. With it the underpayment penalty (Form 2210) is figured and subtracted; without it the penalty is not figured, stated in the result."
    },
    "prior_year_agi": {
      "type": "number",
      "description": "2025 adjusted gross income, used with prior_year_tax: above $150,000 ($75,000 married filing separately) the prior-year safe harbor is 110%."
    },
    "state_withholding": {
      "type": "number",
      "description": "State income tax withheld in 2026. Default 0."
    },
    "state_estimated_payments": {
      "type": "number",
      "description": "State estimated tax paid for 2026, the total. Default 0."
    },
    "marketplace_coverage": {
      "type": "boolean",
      "description": "True if the household had Marketplace (ACA) health coverage in 2026: the premium tax credit is not reconciled by this estimate and the result says so."
    }
  },
  "required": [
    "filing_status",
    "age",
    "state"
  ]
}

README.md4 KBView on GitHub

QuantCalc Retirement Engine — Claude plugin

Gives Claude the retirement engine behind quantcalc.app, so a projection is computed rather than estimated.

A language model cannot run thousands of correlated return paths against a spending plan and get the odds right. It can ask something that can.

Privacy policy · Terms · Support: hello@quantcalc.app · Documentation

Install

Install from the Claude plugin directory. The plugin installs switched off, and you enable it when you want it. Step-by-step instructions are in SETUP.md. To use the server without the plugin, add it as a custom connector:

code

https://mcp.quantcalc.app

What's in the plugin

Connector: the hosted QuantCalc engine over streamable HTTP. No account or sign-in is needed.
Skill retirement-projections: loads when a plan, withdrawal rate or success rate comes up. It keeps the assumptions attached to every number and flags differences that fall inside the margin of error.
Skill setup: connection steps, what a licence key changes, and troubleshooting.

Tools

Tool	Returns
`run_retirement_projection`	Success rate, ending-portfolio distribution, and the assumptions that produced them
`run_tax_aware_projection`	The recommended withdrawal order and Roth-conversion programme, its present-value advantage and range against traditional-first, and the after-tax success rate, with federal and state tax, RMDs, IRMAA and Social Security taxation paid from the portfolio
`compare_return_assumptions`	The same plan under each published capital market assumption set
`list_return_assumption_sources`	Which assumption sets the engine carries, and what each publisher provides
`explain_methodology`	What the engine models and what it deliberately leaves out

All five are read-only: they compute and return, and change nothing. Inputs are not kept after the run, except that a failed request is kept for two days to diagnose it.

What comes back with every number

A success rate is meaningless without its assumptions, and a summary will drop a caveat it was not handed explicitly. So each result states:

the return model that actually ran — reported by the engine, not by the request;
the number of paths and the real trial count behind the rate;
the income it assumed, including when it assumed none;
whether a correlation matrix had to be adjusted before running;
a plain warning when a run is not precise enough to show a client;
for the tax-aware tool: the spending convention (after tax — what the household keeps), every default assumed for an input that was not given, and the tax items the engine does not model.

Licence key

Optional. Without one, projections run at 2,000 paths (the 95% interval around a success rate is about ±1.5 points) and the tax-aware tool returns the first retirement year of its year-by-year schedule. A QuantCalc PRO key raises that to 10,000 paths (about ±0.7) and returns the full schedule. The tax engine itself — withdrawal order, Roth conversions, state tax — needs no key. The same key also unlocks the portfolio optimizer, glide paths, custom capital market assumptions and multi-period planning in the QuantCalc app. Those features are not tools in this plugin.

Set it in the plugin's configuration. It is sent as a connection header and never passes through the conversation.

Privacy

The server receives only the inputs of each tool call, never the conversation. A random session identifier is used to count runs for each installation. A licence key is removed before anything is logged. Details are in section 6 of the privacy policy.

Not advice

QuantCalc is calculation software, not financial advice. Methodology and the source of every figure: https://quantcalc.app/methodology.html. Tax scope and its explicit exclusions: https://quantcalc.app/tax-methodology/.

Licence

MIT — see LICENSE. This repository contains the plugin manifest, skills and documentation. The engine itself is a hosted service, published to the Official MCP Registry as app.quantcalc/retirement-engine under a DNS-verified namespace.

Install

Tools (6)

run_retirement_projectionrun_tax_aware_projectioncompare_return_assumptionslist_return_assumption_sourcesexplain_methodologyestimate_2026_tax_return

Remote endpoint

Streamable HTTP

Hosted server - connect over the network, no local install.

url

https://mcp.quantcalc.app

Add to VS Code Add to Cursor

claude_desktop_config.json

json

{
  "mcpServers": {
    "retirement-engine": {
      "command": "npx",
      "args": [
        "-y",
        "mcp-remote",
        "https://mcp.quantcalc.app"
      ]
    }
  }
}

Desktop config is stdio-only; this bridges via mcp-remote. Native remote: Settings > Connectors.

MCP Server: app.quantcalc/retirement-engine

🛠️ Key Features

🚀 Use Cases

⚡ Developer Benefits

⚠️ Limitations

Topics

run_retirement_projection

run_tax_aware_projection

compare_return_assumptions

list_return_assumption_sources

explain_methodology

estimate_2026_tax_return

QuantCalc Retirement Engine — Claude plugin

Install

What's in the plugin

Tools

What comes back with every number

Licence key

Privacy

Not advice

Licence

Install

Remote endpoint

Related servers