Is Decisionscalc free?

Yes, Decisionscalc is free to use.

How do I install Decisionscalc?

Decisionscalc supports both local and remote installation. For local use, install it via the provided package manager and add the configuration to your AI app. For remote access, add the server URL to your MCP configuration.

Is Decisionscalc safe to use?

Decisionscalc scored 6.7/10 (moderate risk) in MCP Marketplace's automated security scan. It has 1 high or critical finding to review. It's listed, but review the security report on this page before installing.

What AI apps work with Decisionscalc?

Decisionscalc uses the Model Context Protocol (MCP) and works with any MCP-compatible AI app, including Claude, ChatGPT / Codex, Gemini, Copilot, Cursor, and more.

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Decisionscalc MCP Server

by Admin3007

Developer ToolsModerate6.7MCP RegistryLocalRemote

Free

Server data from the Official MCP Registry

Official-rule calculators: Irish tax/welfare, US paid leave, UK NI, stamp duty, CA/QC, AU, NZ.

About

Official-rule calculators: Irish tax/welfare, US paid leave, UK NI, stamp duty, CA/QC, AU, NZ.

Remote endpoints: streamable-http: https://decisionscalc.com/mcp

Security Report

6.7

Moderate6.7Moderate Risk

This is a read-only, stateless MCP server exposing tax, benefit and pension calculators with no authentication required by design (documented as free and keyless). Code is clean: no shell execution, no outbound network calls from tool logic, no secrets, and input size is capped at 64KB with batch limits. Permissions are minimal and match the stated purpose; the only notable observation is the intentional lack of auth, which is documented. Supply chain analysis found 2 known vulnerabilities in dependencies (1 critical, 0 high severity).

6 files analyzed · 5 issues found

Security scores are indicators to help you make informed decisions, not guarantees. Always review permissions before connecting any MCP server.

Permissions Required

This plugin requests these system permissions. Most are normal for its category.

HTTP Network Access

Connects to external APIs or services over the internet.

How to Install & Connect

Available as Local & Remote

This plugin can run on your machine or connect to a hosted endpoint. during install.

Documentation

View on GitHub

From the project's GitHub README.

DecisionsCalc MCP server

Calculators built on official rules, for AI agents. Free, no key, read-only.

Endpoint: https://decisionscalc.com/mcp (Model Context Protocol, Streamable HTTP, JSON responses)
Official MCP Registry: com.decisionscalc/calculators
Docs for agents: https://decisionscalc.com/for-agents/
Server card: https://decisionscalc.com/.well-known/mcp/server-card.json

Every result includes the calculator page a person can open and the official sources (gov.ie, Revenue, Citizens Information, GOV.UK, Canada.ca, Québec.ca, ATO, IRD…) it is based on, so an agent can cite them. Rates are dated and re-checked when budgets change.

Use it

{ "mcpServers": { "decisionscalc": { "type": "http", "url": "https://decisionscalc.com/mcp" } } }

Example call:

curl -s https://decisionscalc.com/mcp -H 'Content-Type: application/json' \
  -d '{"jsonrpc":"2.0","id":1,"method":"tools/call","params":{"name":"ireland_rent_tax_credit","arguments":{"monthlyRent":1500}}}'

Tools

Tool	What it does	Calculator
`ireland_what_can_i_claim`	Ireland: list the social welfare payments and tax credits a household may get (Child Benefit, New Baby Grant, Working Family Payment, Maternity Benefit, Carer’s Allowance, State Pension, Fuel Allowance, Rent Tax Credit) with estimated amounts, using official 2026/2027 rates.	page
`ireland_working_family_payment`	Ireland: estimate the Working Family Payment (weekly, tax-free) for a family, from gross pay, number of children and hours worked, using the official income limits (2026, and +€30 from January 2027) and the 60% rule.	page
`ireland_rent_tax_credit`	Ireland: how much Rent Tax Credit a renter can claim for each year 2022–2026 (20% of rent, capped per year), including back-claims. Claims for 2022 must be made by 31 December 2026 (Revenue four-year rule).	page
`ireland_carers_allowance`	Ireland: estimate the weekly Carer’s Allowance from the official means test (income disregard €1,000/€2,000 from July 2026, €1,150/€2,300 from July 2027; savings bands; Department rate table).	page
`ireland_fuel_allowance`	Ireland: check the Fuel Allowance means test (66+: €534 a week single, €640.80 from January 2027; under 66 needs a qualifying payment) and the 2026/27 season amount (€38, then €43 a week; €1,134 in lump sums).	page
`ireland_state_pension_contributory`	Ireland: estimate the State Pension (Contributory) weekly rate under the Department’s Total Contributions Approach (paid PRSI + up to 520 credits + HomeCaring Periods; 2,080 for the full rate).	page
`ireland_budget_2027_take_home`	Ireland: take-home pay in 2026 against 2027 after Budget 2027 (income tax bands and credits, USC, PRSI, rent credit), line by line.	page
`ireland_maternity_leave_pay`	Ireland: each parent’s take-home pay in the year of maternity/paternity/parent’s leave against a normal year (Maternity Benefit €299 a week in 2026, €309 from 2027; taxed but no USC or PRSI), the household gap and a monthly saving target.	page
`ireland_help_to_buy`	Ireland: Help to Buy refund for a first-time buyer of a new build or self-build: the lesser of €35,000 (contracts from 7 October 2026; €30,000 before), 10% of the price, or income tax + DIRT paid in the previous 4 years; price limit €500,000; mortgage at least 70% of the price. Scheme runs to the end of 2029.	page
`ireland_capital_gains_tax`	Ireland: capital gains tax on a disposal (shares, crypto, property other than your home): 31% for disposals from 7 October 2026 (33% before), 33% on development land, €1,270 annual exemption, losses, and the payment deadline (15 December for January–November disposals). Not for Irish/EU ETFs or funds, which pay exit tax.	page
`ireland_inheritance_gift_tax`	Ireland: Capital Acquisitions Tax (CAT) on a gift or inheritance: group threshold by relationship (A child €420,000, B sibling/niece/nephew/grandchild/parent €44,000, C everyone else €22,000 from 7 October 2026; €400,000/€40,000/€20,000 before), 33% above the unused threshold after earlier benefits in the same group since 5 December 1991, the €3,000 small gift exemption, whether an IT38 return is needed (above 80% of the threshold) and the 31 October pay-and-file date. Spouses and civil partners are exempt; reliefs (dwelling house, agricultural, business, favourite nephew) are not applied.	page
`ireland_myfuturefund_pension`	Ireland: MyFutureFund (pension auto-enrolment, started January 2026): what you, your employer and the State pay in (1.5/1.5/0.5% rising to 6/6/2% by year 10, on pay up to €80,000) and the projected pot at retirement.	page
`ireland_where_to_put_savings`	Ireland: compare where a lump sum ends up after tax over a number of years: State Savings (tax-free), a bank deposit (DIRT 33%), ETFs (exit tax with 8-year deemed disposal), shares (CGT 31%) and a pension (tax relief). Growth for market products is an assumption you set.	page
`ireland_pension_tax_relief`	Ireland: income tax relief on personal pension contributions and AVCs (occupational scheme, PRSA, RAC, PEPP): the age-related limit (under 30 15%, 30-39 20%, 40-49 25%, 50-54 30%, 55-59 35%, 60+ 40% of earnings up to €115,000), relief at the marginal rate (2026 or Budget 2027 bands; no USC or PRSI relief), the net cost and the room left this year.	page
`ireland_landlord_rental_tax`	Ireland: tax on residential rental income for an individual landlord: profit after mortgage interest (deductible only for RTB-registered tenancies), other expenses and 12.5% wear and tear, income tax at the marginal rate on top of salary (2026 or Budget 2027 bands), the Residential Premises Rental Income Relief (up to €1,000, 20% of profit), USC with the 3% surcharge on non-PAYE income over €100,000, and PRSI on unearned income over €5,000 for employees under 66.	page
`uk_stamp_duty_england_ni`	UK: Stamp Duty Land Tax for England and Northern Ireland at 2026/27 rates, band by band: standard, first-time buyer relief (nil to £300,000, up to £500,000) or additional property (+5% on every band), plus the 2% non-resident surcharge.	page
`scotland_lbtt`	Scotland: Land and Buildings Transaction Tax at 2026/27 rates, band by band, with first-time buyer relief (nil band to £175,000) or the 8% Additional Dwelling Supplement.	page
`wales_ltt`	Wales: Land Transaction Tax at 2026/27 rates, band by band (nil band £225,000 for everyone; no first-time buyer relief) or the higher rates for additional properties.	page
`canada_ei_maternity_parental`	Canada (outside Quebec): EI maternity and parental benefits for 2026: 55% of insurable earnings up to $729 a week (standard) or 33% up to $437 (extended), 15 weeks maternity, parental weeks, one-week waiting period.	page
`quebec_qpip`	Quebec: QPIP (RQAP) parental insurance for 2026 for both parents: basic or special plan, birth or adoption, earnings up to $103,000, weekly amounts and totals, with the shareable weeks split between parents.	page
`australia_private_health_rebate_mls`	Australia: private health insurance rebate (1 April 2026 – 31 March 2027) and Medicare Levy Surcharge for 2026–27 by income tier, single or family, and age band: whether hospital cover saves you tax.	page
`new_zealand_kiwisaver`	New Zealand: KiwiSaver balance at 65 under the 2026 rules (default and employer minimum 3.5%, 4% from April 2028; government contribution 25c per $1 up to $260.72; ESCT on employer contributions; PIR tax on returns). Returns are an assumption you set.	page
`parental_leave_income_gap`	Statutory parental leave pay for a birth parent and the income gap against normal pay (gross, before tax) in the UK (Statutory Maternity Pay), Ireland (Maternity Benefit), Canada (EI), Quebec (QPIP), Australia (Parental Leave Pay) or a US state’s paid family and medical leave (us-CA, us-NY, us-NJ, us-WA, us-MA and the rest; us-XX = no state program, FMLA unpaid), with an optional employer top-up.	page
`uk_voluntary_ni_from_abroad`	UK State Pension for people living outside the UK: which gap years (2020–21 to 2026–27) can still be filled with voluntary National Insurance after the 6 April 2026 change, at Class 2 (£3.65/wk, years to 2025–26 only) or Class 3 (£18.40/wk), each year’s cost and 5 April deadline, and the State Pension gain (1/35 of £241.30 a week per year, up to 35 years) with payback.	page

What is in this repository

src/lib/agent-tools.ts: the tool definitions (input schemas, which calculation each runs, sources).
src/lib/mcp-server.ts + functions/mcp.ts: the stateless MCP server (JSON-RPC: initialize, tools/list, tools/call, ping) running as a Cloudflare Pages Function.
src/lib/webmcp.ts: the same tools registered for in-browser agents (WebMCP) on decisionscalc.com.
src/lib/calc/*.ts: the calculations, each with its official sources in the header and a test file reproducing the government's own worked examples where one exists. Run npm install && npm test.

This is a read-only mirror of the code running on decisionscalc.com, published so it can be audited. Licence: source available, all rights reserved (see LICENSE.md). Using the hosted endpoint is free.

Results are general information, not financial, tax or legal advice. The relevant government department decides.

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