US Tax Estimator — MCP connector

Connecting

• Endpoint: https://my.yz-cpa.com/mcp
• Transport: MCP Streamable HTTP, stateless (no session id), JSON responses. POST only; GET and DELETE answer 405.
• Authentication: none. There is no user data behind the tools, so there is nothing to authorize.
• Rate limit: 600 requests per IP address per hour; above that, HTTP 429 with a JSON-RPC error.
• Errors: invalid arguments return JSON-RPC error -32602 naming the problem. Values outside what a tool covers (for example an unsupported tax year) return a tool result with isError: true and a plain-language reason.
• Scope: U.S. federal tax only (no state tax, AMT, capital-gain rates or QBI). The estimate covers tax years 2025–2026; the offshore comparison covers 2019–2025.

Data handling

Tools ask only for the figures a calculation needs (amounts, filing status, tax year; age and sex of the insured for the §7702 screen) and have no fields for names, emails, tax IDs or account numbers. Inputs and results are not stored or logged, not shared, and not used for advertising, profiling or model training. Like any request to our website, the web server's access log records the time and IP address (not the figures). Full policy: yz-cpa.com/tax-estimator-privacy · Terms: yz-cpa.com/terms

Estimate federal income and self-employment tax

estimate_federal_tax · Read (readOnlyHint true, destructiveHint false, idempotentHint true, openWorldHint false) · side effects: none

Estimates a year's U.S. federal income tax plus self-employment tax, the refund or balance due after withholding and estimated payments, marginal and effective rates, a bracket-by-bracket breakdown and, when prior-year figures are given, the safe-harbor quarterly estimated payment. Uses the standard deduction unless larger itemized deductions are given; child tax credit with phase-out; Social Security wage base and Additional Medicare tax. Federal only: no state tax, AMT, capital-gain rates, QBI deduction or other credits.

Inputs

• estimated_payments_made number · optional · default 0 · min 0, max 10000000000
  Federal estimated tax payments already made for this year, USD.
• federal_withholding number · optional · default 0 · min 0, max 10000000000
  Federal income tax withheld for the year (W-2 box 2, 1099 withholding), USD.
• filing_status "single" | "married_filing_jointly" | "married_filing_separately" | "head_of_household" · required
  Federal filing status.
• itemized_deductions number · optional · min 0, max 10000000000
  Total itemized deductions (Schedule A), USD. Used only when larger than the standard deduction.
• prior_year_agi number · optional · min 0, max 10000000000
  Last year's adjusted gross income, USD (decides 100% vs 110% safe harbor).
• prior_year_total_tax number · optional · min 0, max 10000000000
  Last year's total federal tax, USD. Give it to get the quarterly safe-harbor payment.
• qualifying_children integer · optional · default 0 · min 0, max 20
  Children under 17 who qualify for the child tax credit.
• self_employment_profit number · optional · default 0 · min 0, max 10000000000
  Net self-employment profit (Schedule C), USD. Already included in total_income; used for self-employment tax.
• tax_year integer · required · min 2000, max 2100
  Tax year: 2025 or 2026.
• total_income number · required · min 0, max 10000000000
  Total income for the year before deductions, USD: wages, interest, dividends, other income and self-employment profit together.
• w2_wages number · optional · default 0 · min 0, max 10000000000
  W-2 wages (Social Security / Medicare wages), USD; reduces the self-employment Social Security tax room. 0 if none.

Upcoming federal tax deadlines

list_federal_tax_deadlines · Read (readOnlyHint true, destructiveHint false, idempotentHint true, openWorldHint false) · side effects: none

Lists upcoming U.S. federal tax deadlines with days remaining: quarterly estimated payments (1040-ES), individual return and extension dates, and optionally S-corporation, partnership and C-corporation return and estimated-tax dates. Dates are already moved off weekends and holidays.

Inputs

• from_date string · optional
  List deadlines on or after this date (YYYY-MM-DD). Default: today (U.S. Central).
• include_business boolean · optional · default false
  Also list business return and C-corporation estimated tax dates.
• limit integer · optional · default 8 · min 1, max 30
  Maximum number of deadlines to return.

Check FBAR, Form 8938 and Form 3520 thresholds

check_foreign_reporting_requirements · Read (readOnlyHint true, destructiveHint false, idempotentHint true, openWorldHint false) · side effects: none

Checks a U.S. person's foreign-asset figures against the filing thresholds for FBAR (FinCEN Form 114), Form 8938 (FATCA) and Form 3520 (gifts or bequests from a foreign individual or estate). Only the forms whose figures are given are checked. Thresholds only: it does not decide which accounts or assets count; the descriptions of each input say what to include.

Inputs

• filing_status "single" | "married_filing_jointly" | "married_filing_separately" | "head_of_household" · required
  Federal filing status.
• foreign_accounts_max_aggregate number · optional · min 0, max 10000000000
  FBAR: the highest combined value of all foreign financial accounts at any time in the year, USD.
• foreign_gifts_received number · optional · min 0, max 10000000000
  Form 3520: total gifts and bequests received in the year from nonresident alien individuals or foreign estates, USD.
• lives_abroad boolean · optional · default false
  Form 8938: true if the taxpayer meets the bona fide residence or physical presence test abroad (higher thresholds).
• specified_foreign_assets_max number · optional · min 0, max 10000000000
  Form 8938: the highest value of specified foreign financial assets at any time in the year, USD.
• specified_foreign_assets_year_end number · optional · min 0, max 10000000000
  Form 8938: value of specified foreign financial assets on the last day of the year, USD.

Screen a non-U.S. life insurance policy under IRC §7702

screen_foreign_life_insurance_7702 · Read (readOnlyHint true, destructiveHint false, idempotentHint true, openWorldHint false) · side effects: none

Preliminary screen of whether a non-U.S. savings-type life insurance policy (for example a Hong Kong whole-life or savings plan) meets the U.S. definition of life insurance under IRC §7702, using the cash value accumulation test (CVAT) and the cash value corridor, from the policy's cash value table. A policy that fails is taxed each year on its inside growth (§7702(g)). Values in any one currency (ratios do not depend on currency). Does not check the guideline premium limit.

Inputs

• increasing_benefit_rule object · optional
  For policies whose death benefit grows by a fixed rate: lets years without a death_benefit be computed.
  • annual_premium number · required
    Annual premium.
  • basic_sum_insured number · required
    Basic sum insured at issue.
  • growth_rate number · required · min 0, max 0.1
    Yearly growth of the sum insured as a decimal (0.035 = 3.5%).
  • pay_years integer · required · min 1, max 40
    Number of premium-paying years.
• issue_age integer · required · min 0, max 90
  Insured's age at issue, completed years.
• issue_year integer · required · min 1985, max 2100
  Calendar year the policy was issued.
• policy_years array of objects · required
  Rows from the policy's illustration / cash value table; a few years such as 1, 5, 10, 20 are enough.
  • cash_value number · required
    Cash (surrender) value at the end of that policy year.
  • death_benefit number · optional
    Death benefit at the end of that policy year (omit only when increasing_benefit_rule is given).
  • policy_year integer · required · min 1, max 100
• sex "M" | "F" · required
  Insured's sex (mortality table).

Compare catch-up options for unreported foreign assets

compare_offshore_compliance_options · Read (readOnlyHint true, destructiveHint false, idempotentHint true, openWorldHint false) · side effects: none

For a U.S. taxpayer who missed FBAR or Form 8938 filings or left foreign income unreported, estimates and compares the cost of three catch-up paths: A) delinquent information return procedures (only when no income went unreported), B) amended returns with tax and interest plus a reasonable-cause statement (with the statutory penalty exposure if reasonable cause is rejected), and C) the Streamlined Domestic Offshore Procedures (tax, interest and the 5% penalty). Also adds the 1% Form 720 excise tax on premiums paid to foreign insurers. Tax years 2019–2025. Assumes non-willful conduct; it does not decide eligibility.

Inputs

• filing_status "single" | "married_filing_jointly" · required
  Filing status used on the original returns.
• years array of objects · required
  One entry per affected tax year.
  • agi number · required · min 0, max 10000000000
    Adjusted gross income as originally filed, USD (for the 3.8% net investment income tax).
  • fbar_filed_complete boolean · optional · default false
    FBAR for that year was filed on time and listed every account and policy.
  • foreign_insurance_premiums number · optional · default 0 · min 0, max 10000000000
    Premiums paid that year to foreign life insurers or annuity issuers, USD (1% excise tax).
  • form_8938_filed_complete boolean · optional · default false
    Form 8938 for that year was filed and complete.
  • taxable_income number · required · min 0, max 10000000000
    Taxable income as originally filed, USD.
  • unreported_income number · optional · default 0 · min 0, max 10000000000
    Income that should have been reported but was not, USD (e.g. foreign interest, dividends, §7702(g) policy growth).
  • year integer · required · min 2000, max 2100
    Tax year (2019–2025).
  • year_end_unreported_foreign_assets number · optional · default 0 · min 0, max 10000000000
    Year-end value of foreign assets that were not properly reported, USD (the base for the Streamlined 5% penalty).

Example requests

• “We're married filing jointly with two kids and made $142,000 in 2026, $26,000 of it from my side business. $13,800 was withheld and we paid $2,000 in estimates. Will we get a refund?” — about $12,450 total federal tax, refund about $3,350.
• “What federal tax deadlines are coming up for my business?”
• “I'm single and live in the U.S. My foreign accounts peaked at $12,000; my foreign assets were $49,000 at year end and $80,000 at most. Do I need an FBAR or Form 8938?” — both.
• “Does my Hong Kong savings policy (issued 2021 at 40, male; cash values 5,000 / 95,000 / 130,000 / 200,000 at years 1 / 5 / 10 / 20) meet §7702?”
• “I never reported foreign interest for 2023 and 2024. What would the Streamlined procedure cost compared with amending?”