HomeCalc Connector Developer Docs — MCP Endpoint & Tools

Last reviewed: October 2026.

The HomeCalc Connector is a free, read-only Model Context Protocol (MCP) server for HomeCalc.ca’s Canadian mortgage, tax and real-estate calculators. This page is for developers and anyone wiring it into an MCP client: the endpoint, the protocol details, every tool’s input schema, and real requests with the exact responses they return.

Every example on this page is real

Each request below was sent to https://homecalc.ca/api/mcp on 2026-10-26, and each response is shown exactly as the server returned it. HomeCalc’s automated tests re-run every request against the connector’s code and fail if any response changes.

Overview

HomeCalc Connector at a glance
	Value
Endpoint	https://homecalc.ca/api/mcp
Transport	MCP Streamable HTTP — JSON-RPC 2.0 over POST; responses arrive as text/event-stream
Protocol revisions	2026-07-28, and the 2025-era revisions 2025-11-25, 2025-06-18, 2025-03-26, 2024-11-05, 2024-10-07
Authentication	None — no account, no API key
Sessions	Stateless — no mcp-session-id is issued; every request stands alone
Tools	12 calculation tools, all marked readOnlyHint: true and openWorldHint: false
Server	homecalc 0.1.0
Browser clients	CORS allows any origin (Access-Control-Allow-Origin: *)
Price	Free

There is no published rate limit, quota or service-level agreement. The tools only compute and return numbers — nothing is created, changed or deleted.

Health check

A plain GET on the endpoint answers without an MCP client, so you can check it from a browser:

Request

curl -sS https://homecalc.ca/api/mcp

Response (HTTP 200)

{"name":"homecalc","status":"ok","transport":"streamable-http","endpoint":"/api/mcp","docs":"https://homecalc.ca/connector"}

A CORS preflight (OPTIONS) returns HTTP 204 with no body.

Connect an MCP client

Claude: open Settings → Connectors, choose Add custom connector, paste https://homecalc.ca/api/mcp and leave authentication set to None. The connector page has the same steps.

Other MCP clients: clients that support remote Streamable HTTP servers connect with the same URL and no credentials. We test the endpoint with the official MCP TypeScript SDK client in both protocol eras: a client pinned to 2026-07-28 (no initialize handshake) and a default 2025-era client (with initialize). Both list the same 12 tools and return identical results. SDK clients negotiate the protocol version for you.

Raw HTTP quick start

You don’t need an SDK. Every request is a JSON-RPC 2.0 body sent with POST and these headers:

content-type: application/json
accept: application/json, text/event-stream — both are required (see 406)
mcp-protocol-version: 2025-06-18 — the revision these examples use

The response is a single server-sent event: an event: message line followed by a data: line that carries the JSON-RPC response.

1. initialize (optional on a stateless server)

A 2025-era client usually starts with initialize. Because the server is stateless, nothing from it has to be sent on later requests.

Request

curl -sS https://homecalc.ca/api/mcp \
  -H 'content-type: application/json' \
  -H 'accept: application/json, text/event-stream' \
  -H 'mcp-protocol-version: 2025-06-18' \
  -d '{"jsonrpc":"2.0","id":1,"method":"initialize","params":{"protocolVersion":"2025-06-18","capabilities":{},"clientInfo":{"name":"my-client","version":"1.0.0"}}}'

Response

event: message
data: {"result":{"protocolVersion":"2025-06-18","capabilities":{"tools":{"listChanged":true}},"serverInfo":{"name":"homecalc","version":"0.1.0"},"instructions":"HomeCalc.ca provides accurate, source-backed Canadian mortgage and real-estate calculators. Use these tools to answer Canadian home-buying, mortgage, and tax math questions with 2026 figures: mortgage payments, minimum down payment + CMHC, land transfer tax, income tax / take-home, mortgage break penalty (IRD), BC home flipping tax, and rent-increase guidelines. Every result includes a source link on homecalc.ca and is an estimate, not financial advice — surface both to the user."},"jsonrpc":"2.0","id":1}

2. tools/list

Request

curl -sS https://homecalc.ca/api/mcp \
  -H 'content-type: application/json' \
  -H 'accept: application/json, text/event-stream' \
  -H 'mcp-protocol-version: 2025-06-18' \
  -d '{"jsonrpc":"2.0","id":2,"method":"tools/list","params":{}}'

The response lists all 12 tools with their JSON Schema (2020-12) input schemas. The first entry is shown in full below; the tool reference covers the rest. Default values for optional parameters are included in the live tools/list response — read them from there, because some follow the rates HomeCalc updates weekly.

First entry of result.tools (defaults omitted)

{
  "name": "mortgage_payment",
  "title": "Canadian Mortgage Payment Calculator",
  "description": "Calculate the periodic mortgage payment for a Canadian home. Call it ONE of two ways: (a) if the user gave a PURCHASE PRICE, pass homePrice + downPayment and CMHC insurance is applied when the down payment is under 20%; (b) if the user gave a MORTGAGE / LOAN AMOUNT (e.g. \"payment on a $500,000 mortgage\"), pass loanAmount on its own. Do NOT invent a purchase price in order to reach a loan amount — use loanAmount. Inventing a price changes the answer by several percent and attaches a CMHC premium the user does not owe.",
  "inputSchema": {
    "type": "object",
    "$schema": "https://json-schema.org/draft/2020-12/schema",
    "properties": {
      "homePrice": {
        "description": "Purchase price in CAD, e.g. 650000. Use with downPayment. Omit if the user gave you the mortgage amount instead.",
        "type": "number",
        "exclusiveMinimum": 0
      },
      "loanAmount": {
        "description": "The mortgage amount itself in CAD, when the user stated the loan rather than the purchase price. Mutually exclusive with homePrice. No CMHC premium is applied on this path — the amount is taken as the principal.",
        "type": "number",
        "exclusiveMinimum": 0
      },
      "downPayment": {
        "description": "Down payment amount in CAD (or percent if downPaymentType='percent'). Required when homePrice is used.",
        "type": "number",
        "minimum": 0
      },
      "annualInterestRatePct": {
        "type": "number",
        "minimum": 0,
        "maximum": 25,
        "description": "Annual interest rate as a percent, e.g. 5.25"
      },
      "amortizationYears": {
        "description": "Amortization in years (max 25 insured, 30 uninsured/first-time new builds)",
        "type": "number",
        "minimum": 1,
        "maximum": 30
      },
      "downPaymentType": {
        "type": "string",
        "enum": [
          "amount",
          "percent"
        ]
      },
      "paymentFrequency": {
        "type": "string",
        "enum": [
          "monthly",
          "semi-monthly",
          "biweekly",
          "accelerated-biweekly",
          "weekly",
          "accelerated-weekly"
        ]
      },
      "rateType": {
        "type": "string",
        "enum": [
          "fixed",
          "variable"
        ]
      },
      "termYears": {
        "type": "number",
        "minimum": 1,
        "maximum": 10
      },
      "province": {
        "description": "Province name, used only for CMHC PST on the premium",
        "type": "string"
      }
    },
    "required": [
      "annualInterestRatePct"
    ]
  },
  "annotations": {
    "readOnlyHint": true,
    "openWorldHint": false,
    "title": "Canadian Mortgage Payment Calculator"
  }
}

3. tools/call

Request

curl -sS https://homecalc.ca/api/mcp \
  -H 'content-type: application/json' \
  -H 'accept: application/json, text/event-stream' \
  -H 'mcp-protocol-version: 2025-06-18' \
  -d '{"jsonrpc":"2.0","id":3,"method":"tools/call","params":{"name":"mortgage_payment","arguments":{"homePrice":650000,"downPayment":65000,"annualInterestRatePct":5.25,"amortizationYears":25}}}'

Response

event: message
data: {"result":{"content":[{"type":"text","text":"{\n  \"basis\": \"homePrice\",\n  \"monthlyPayment\": 3594.19,\n  \"paymentAmount\": 3594.19,\n  \"paymentLabel\": \"Monthly\",\n  \"mortgagePrincipal\": 585000,\n  \"downPaymentAmount\": 65000,\n  \"downPaymentPercent\": 10,\n  \"cmhcRequired\": true,\n  \"cmhcInsurancePremium\": 18135,\n  \"cmhcInsuranceRate\": 0.031,\n  \"source\": \"https://homecalc.ca/tools/mortgage-payment-calculator\",\n  \"disclaimer\": \"Estimate only, based on 2026 Canadian rules. Not financial advice. Confirm with your lender, lawyer, or the CRA.\"\n}"}],"structuredContent":{"basis":"homePrice","monthlyPayment":3594.19,"paymentAmount":3594.19,"paymentLabel":"Monthly","mortgagePrincipal":585000,"downPaymentAmount":65000,"downPaymentPercent":10,"cmhcRequired":true,"cmhcInsurancePremium":18135,"cmhcInsuranceRate":0.031,"source":"https://homecalc.ca/tools/mortgage-payment-calculator","disclaimer":"Estimate only, based on 2026 Canadian rules. Not financial advice. Confirm with your lender, lawyer, or the CRA."}},"jsonrpc":"2.0","id":3}

Tool reference

All 12 tools, in the order tools/list returns them:

mortgage_payment
minimum_down_payment
land_transfer_tax
income_tax
mortgage_penalty
bc_home_flipping_tax
rent_increase
capital_gains_tax
heloc_second_mortgage
mortgage_affordability
cap_rate
house_flipping

`mortgage_payment`

Canadian Mortgage Payment Calculator

Calculate the periodic mortgage payment for a Canadian home. Call it ONE of two ways: (a) if the user gave a PURCHASE PRICE, pass homePrice + downPayment and CMHC insurance is applied when the down payment is under 20%; (b) if the user gave a MORTGAGE / LOAN AMOUNT (e.g. "payment on a $500,000 mortgage"), pass loanAmount on its own. Do NOT invent a purchase price in order to reach a loan amount — use loanAmount. Inventing a price changes the answer by several percent and attaches a CMHC premium the user does not owe.

Input parameters for mortgage_payment
Parameter	Type	Required	Allowed values	Description
homePrice	number	No	> 0	Purchase price in CAD, e.g. 650000. Use with downPayment. Omit if the user gave you the mortgage amount instead.
loanAmount	number	No	> 0	The mortgage amount itself in CAD, when the user stated the loan rather than the purchase price. Mutually exclusive with homePrice. No CMHC premium is applied on this path — the amount is taken as the principal.
downPayment	number	No	≥ 0	Down payment amount in CAD (or percent if downPaymentType='percent'). Required when homePrice is used.
annualInterestRatePct	number	Yes	≥ 0, ≤ 25	Annual interest rate as a percent, e.g. 5.25
amortizationYears	number	No	≥ 1, ≤ 30	Amortization in years (max 25 insured, 30 uninsured/first-time new builds)
downPaymentType	string	No	amount, percent
paymentFrequency	string	No	monthly, semi-monthly, biweekly, accelerated-biweekly, weekly, accelerated-weekly
rateType	string	No	fixed, variable
termYears	number	No	≥ 1, ≤ 10
province	string	No		Province name, used only for CMHC PST on the premium

See a live example of mortgage_payment

`minimum_down_payment`

Minimum Down Payment Calculator (Canada)

Calculate the minimum down payment for a Canadian home under the Dec 2024 CMHC rules (5% on the first $500k, 10% on the portion from $500k–$1.5M, 20% at/above $1.5M), plus whether CMHC insurance applies and the premium rate.

Input parameters for minimum_down_payment
Parameter	Type	Required	Allowed values	Description
homePrice	number	Yes	> 0	Purchase price in CAD, e.g. 800000

See a live example of minimum_down_payment

`land_transfer_tax`

Canadian Land Transfer Tax Calculator

Estimate land transfer tax on a home purchase for all 13 provinces and territories (incl. Toronto MLTT, Montreal welcome tax), first-time buyer rebates, plus the transfer registration fee (the government fee to register the deed) and the total due at registration. Alberta, Saskatchewan, Newfoundland & Labrador and the three territories charge no land transfer tax, only the registration fee. The mortgage registration fee is separate and not included.

Input parameters for land_transfer_tax
Parameter	Type	Required	Allowed values	Description
price	number	Yes	> 0	Purchase price in CAD
province	string	Yes	Ontario, British Columbia, Quebec, Alberta, Manitoba, Nova Scotia, New Brunswick, Saskatchewan, PEI, Newfoundland & Labrador, Northwest Territories, Nunavut, Yukon	Province or territory
inToronto	boolean	No		Ontario only: property is within the City of Toronto (adds the municipal LTT)
isFirstTimeBuyer	boolean	No
quebecMunicipality	string	No	montreal, other	Quebec only: 'montreal' uses Montreal's welcome-tax brackets (the website's Quebec default); 'other' uses the provincial base schedule for municipalities without higher rates above $500,000

See a live example of land_transfer_tax

`income_tax`

Canadian Income Tax & Take-Home Calculator

Calculate 2026 Canadian federal + provincial income tax, CPP/QPP, EI, QPIP (Quebec), Ontario surtax and Health Premium where applicable, plus net (take-home) pay for any province.

Input parameters for income_tax
Parameter	Type	Required	Allowed values	Description
annualIncome	number	Yes	≥ 0	Gross annual employment income in CAD
province	string	Yes	Ontario, British Columbia, Alberta, Quebec, Manitoba, Saskatchewan, Nova Scotia, New Brunswick, PEI, Newfoundland & Labrador	Province of residence
employmentType	string	No	employed, self_employed
rrspContribution	number	No	≥ 0	Annual RRSP contribution in CAD

See a live example of income_tax

`mortgage_penalty`

Mortgage Prepayment Penalty Calculator (IRD)

Estimate the penalty to break a Canadian mortgage: three months' interest vs the interest rate differential (IRD), including the big-bank posted-rate method. Fixed = greater of the two; variable = usually three months' interest. IMPORTANT: the three rate inputs below are lender-specific and are NOT supplied by most users. If they are omitted, this tool falls back to illustrative site defaults and the answer can be several times too low or too high — the response reports exactly which values were assumed in `assumedInputs`. Always surface those assumptions to the user and tell them to confirm the real figures with their lender.

Input parameters for mortgage_penalty
Parameter	Type	Required	Allowed values	Description
balance	number	Yes	> 0	Outstanding mortgage balance in CAD
rateType	string	No	fixed, variable
contractRatePct	number	Yes	≥ 0, ≤ 25	Your contract rate as a percent, e.g. 5.25
monthsRemaining	number	Yes	≥ 0, ≤ 120	Months remaining in the term
lenderMethod	string	No	big-bank, monoline	Big banks use the posted-rate IRD, monolines use actual rates. Which is larger depends on the gap between the discount originally received and today's posted rate — it is NOT always the big bank.
currentRateForRemainingTermPct	number	No	≥ 0, ≤ 25	Monoline method: today's rate for the remaining term (percent). Lender-specific — omit if unknown and the reply will say it was assumed.
postedAtOriginationPct	number	No	≥ 0, ≤ 25	Big-bank method: posted (not discounted) rate when you signed, from your mortgage documents. HIGH IMPACT — this single value can change the penalty several-fold. Omit if unknown and the reply will say it was assumed.
todaysPostedForClosestTermPct	number	No	≥ 0, ≤ 25	Big-bank method: your lender's posted rate today for the closest term. Omit if unknown and the reply will say it was assumed.

See a live example of mortgage_penalty

`bc_home_flipping_tax`

BC Home Flipping Tax Calculator

Estimate British Columbia's home flipping tax on a property sold within 730 days: 20% tapering to 0% between 366 and 730 days, with a $20,000 primary-residence deduction (only if held at least 365 days).

Input parameters for bc_home_flipping_tax
Parameter	Type	Required	Allowed values	Description
taxableIncome	number	Yes		Proceeds minus cost to acquire minus cost to improve (may be negative)
daysHeld	number	Yes	≥ 0	Number of days the property was owned before sale
isPrimaryResidence	boolean	No		Lived in it as a primary residence

See a live example of bc_home_flipping_tax

`rent_increase`

Rent Increase Guideline Calculator (ON / BC / MB)

Calculate the maximum allowable annual rent increase under the Ontario LTB, BC RTB or Manitoba RTB guideline for a given year, and the resulting new rent.

Input parameters for rent_increase
Parameter	Type	Required	Allowed values	Description
currentRent	number	Yes	> 0	Current monthly rent in CAD
province	string	Yes	Ontario, British Columbia, Manitoba
year	string	Yes		Guideline year, e.g. '2026'. Use the rent_increase tool's supported years if unsure.

See a live example of rent_increase

`capital_gains_tax`

Canadian Capital Gains Tax Calculator

Estimate Canadian capital gains tax on a disposition (real estate, stocks, crypto, a business, or a rental property). Applies the flat 50% inclusion rate, the principal-residence exemption, the lifetime capital gains exemption for QSBC shares, capital-loss offsets, and rental CCA recapture — then taxes the taxable gain on top of your other income at federal + provincial brackets.

Input parameters for capital_gains_tax
Parameter	Type	Required	Allowed values	Description
salePrice	number	Yes	≥ 0	Gross sale proceeds in CAD
purchasePrice	number	Yes	≥ 0	Original purchase price in CAD
province	string	No	Ontario, British Columbia, Alberta, Quebec, Manitoba, Saskatchewan, Nova Scotia, New Brunswick, PEI, Newfoundland & Labrador, Northwest Territories, Nunavut, Yukon	Province/territory of residence
annualIncome	number	No	≥ 0	Your other annual income in CAD — the gain stacks on top of this
assetType	string	No	real-estate, stocks, crypto, business, rental, other
sellingCosts	number	No	≥ 0	Realtor commission, legal fees, and other costs of selling
buyingCosts	number	No	≥ 0	Land transfer tax, legal fees, and other costs of acquiring
capitalImprovements	number	No	≥ 0	Capital improvements added to the adjusted cost base
isPrincipalResidence	boolean	No		Real estate only: claim the principal residence exemption
yearsOwned	number	No	≥ 0	Years the property was owned (principal-residence proration)
yearsDesignated	number	No	≥ 0	Years designated as your principal residence
isQSBC	boolean	No		Business only: qualified small business corporation shares (LCGE)
lcgeRemaining	number	No	≥ 0	Remaining lifetime capital gains exemption room in CAD
capitalLosses	number	No	≥ 0	Prior/current capital losses available to offset the gain
taxpayerType	string	No	individual, corporation, trust
taxYear	number	No	≥ 2020, ≤ 2035	Tax year of the disposition
landValue	number	No	≥ 0	Rental only: land portion of the sale price (splits land vs building gain)
originalBuildingCost	number	No	≥ 0	Rental only: original building cost for CCA recapture
ccaClaimedToDate	number	No	≥ 0	Rental only: total CCA claimed to date

See a live example of capital_gains_tax

`heloc_second_mortgage`

HELOC & Second Mortgage Calculator (Canada)

Compare a HELOC against a second mortgage for tapping home equity in Canada. Returns how much you can borrow (revolving HELOC capped at 65% LTV, total secured borrowing to 80% with an A lender), monthly payments, TDS qualification at the OSFI stress-test rate, and the equivalent numbers for B and private lenders.

Input parameters for heloc_second_mortgage
Parameter	Type	Required	Allowed values	Description
homeValue	number	Yes	> 0	Current market value of the home in CAD
outstandingFirstMortgage	number	Yes	≥ 0	Balance remaining on the first mortgage in CAD
amountToBorrow	number	Yes	≥ 0	Amount you want to borrow in CAD
annualHouseholdIncome	number	Yes	≥ 0	Gross annual household income in CAD
province	string	No	Ontario, British Columbia, Alberta, Quebec, Manitoba, Saskatchewan, Nova Scotia, New Brunswick, Newfoundland and Labrador, Prince Edward Island
existingMonthlyDebts	number	No	≥ 0	Other monthly debt payments (car, cards, loans)
purposeOfFunds	string	No	Home Renovation, Debt Consolidation, Investment Property Down Payment, Education, Emergency Funds, Other
secondMortgageLenderTier	string	No	A, B, Private	A = bank/credit union, B = trust/MIC, Private = individual investor
helocPrimeRatePct	number	No	≥ 0, ≤ 25	Prime rate as a percent; defaults to the site's current prime
helocSpreadPct	number	No	≥ 0, ≤ 10	Lender spread over prime as a percent, e.g. 0.5
secondMortgageRatePct	number	No	≥ 0, ≤ 30	Second mortgage rate as a percent; defaults to the tier's typical rate
secondMortgageAmortYears	number	No	≥ 1, ≤ 30
secondMortgageTermYears	number	No	≥ 1, ≤ 10
extraMonthlyPrincipal	number	No	≥ 0	Optional extra principal paid monthly on the HELOC

See a live example of heloc_second_mortgage

`mortgage_affordability`

Mortgage Affordability Calculator (Canada)

Work out the maximum home price a Canadian buyer qualifies for: binary-searches the price that keeps both the GDS (39%) and TDS (44%) ratios satisfied at the OSFI stress-test rate, honouring the Dec-2024 minimum down payment tiers and the $1.5M CMHC insurability ceiling. Returns max price, max mortgage, CMHC premium, monthly payment, and the GDS/TDS ratios.

Input parameters for mortgage_affordability
Parameter	Type	Required	Allowed values	Description
annualIncome	number	Yes	≥ 0	Primary applicant gross annual income in CAD
downPayment	number	Yes	≥ 0	Down payment — dollars, or a percent if downPaymentMode='percent'
coApplicantIncome	number	No	≥ 0	Co-applicant gross annual income in CAD (0 = none)
downPaymentMode	string	No	dollar, percent
monthlyDebts	number	No	≥ 0	Other monthly debt payments (car, cards, student loans)
annualPropertyTax	number	No	≥ 0	Estimated annual property tax in CAD
monthlyHeating	number	No	≥ 0	Estimated monthly heating cost in CAD
propertyType	string	No	single-family, condo, townhouse
condoFees	number	No	≥ 0	Monthly condo fees — 50% counts toward GDS/TDS for condos
province	string	No
interestRatePct	number	No	≥ 0, ≤ 25	Contract mortgage rate as a percent, e.g. 4.79
amortizationYears	any	No

See a live example of mortgage_affordability

`cap_rate`

Cap Rate & Rental Property Calculator (Canada)

Analyze a Canadian rental property: capitalization rate, net operating income, gross rent multiplier, expense ratio, annual cash flow and cash-on-cash return, plus how the cap rate compares to typical yields in the local market. Mortgage math uses Canadian semi-annual compounding.

Input parameters for cap_rate
Parameter	Type	Required	Allowed values	Description
purchasePrice	number	Yes	> 0	Purchase price in CAD
monthlyGrossRent	number	Yes	≥ 0	Total gross monthly rent across all units in CAD
annualOperatingExpenses	number	Yes	≥ 0	Total annual operating expenses in CAD (property tax, insurance, management, maintenance, landlord utilities) — excludes mortgage payments
downPayment	number	Yes	≥ 0	Down payment in CAD. Set equal to purchasePrice for an all-cash purchase.
interestRatePct	number	No	≥ 0, ≤ 25	Mortgage rate as a percent, e.g. 5.49
amortizationYears	number	No	≥ 1, ≤ 30
vacancyRatePct	number	No	≥ 0, ≤ 100	Vacancy allowance as a percent of gross rent
city	string	No	toronto, vancouver, calgary, edmonton, ottawa, montreal, halifax, winnipeg, hamilton, kitchener-waterloo, other	City used for the cap-rate benchmark range
propertyType	string	No	single-family, multi-unit, commercial, mixed-use

See a live example of cap_rate

`house_flipping`

House Flipping Profit Calculator (Canada)

Estimate the profit on a Canadian house flip: land transfer tax (with first-time buyer rebate), renovation cost with contingency, holding costs, realtor commission, and closing costs — then the tax bill. Flags the CRA residential property flipping rule (held under 12 months = 100% business income, no capital gains treatment) and shows the tax saving from waiting past the 12-month line.

Input parameters for house_flipping
Parameter	Type	Required	Allowed values	Description
purchasePrice	number	Yes	> 0	Purchase price in CAD
afterRepairValue	number	Yes	> 0	Expected resale price after renovation (ARV) in CAD
renovationCost	number	Yes	≥ 0	Budgeted renovation cost in CAD, before contingency
province	string	No	Ontario, British Columbia, Alberta, Quebec, Manitoba, Saskatchewan, Nova Scotia, New Brunswick, PEI, Newfoundland
city	string	No		City name — include 'Toronto' to add the Toronto municipal land transfer tax
contingencyPct	number	No	≥ 0, ≤ 100	Renovation contingency as a percent of the renovation budget
holdingPeriodMonths	number	No	≥ 0, ≤ 120	Months held from purchase to sale — under 12 triggers the CRA flipping rule
monthlyHoldingCosts	number	No	≥ 0	Monthly carrying costs: mortgage interest, property tax, insurance, utilities
realtorCommissionPct	number	No	≥ 0, ≤ 15	Realtor commission on the sale as a percent of ARV
closingCostsBuy	number	No	≥ 0	Legal and inspection costs on the purchase, excluding land transfer tax
closingCostsSell	number	No	≥ 0	Legal and staging costs on the sale, excluding commission
marginalTaxRatePct	number	No	≥ 0, ≤ 60	Your combined marginal tax rate as a percent
isFirstTimeBuyer	boolean	No		Eligible for the first-time buyer land transfer tax rebate

See a live example of house_flipping

Live examples

One call per tool. Each shows the params of the tools/call request and the structuredContent of the result. The result’s content[0].text carries the same JSON as text.

`mortgage_payment`

Monthly payment on a $650,000 home with 10% down at 5.25%, 25-year amortization.

params

{
  "name": "mortgage_payment",
  "arguments": {
    "homePrice": 650000,
    "downPayment": 65000,
    "annualInterestRatePct": 5.25,
    "amortizationYears": 25
  }
}

result.structuredContent

{
  "basis": "homePrice",
  "monthlyPayment": 3594.19,
  "paymentAmount": 3594.19,
  "paymentLabel": "Monthly",
  "mortgagePrincipal": 585000,
  "downPaymentAmount": 65000,
  "downPaymentPercent": 10,
  "cmhcRequired": true,
  "cmhcInsurancePremium": 18135,
  "cmhcInsuranceRate": 0.031,
  "source": "https://homecalc.ca/tools/mortgage-payment-calculator",
  "disclaimer": "Estimate only, based on 2026 Canadian rules. Not financial advice. Confirm with your lender, lawyer, or the CRA."
}

`minimum_down_payment`

Minimum down payment on an $850,000 home.

params

{
  "name": "minimum_down_payment",
  "arguments": {
    "homePrice": 850000
  }
}

result.structuredContent

{
  "homePrice": 850000,
  "minimumDownPayment": 60000,
  "minimumDownPercent": 7.1,
  "cmhcInsurable": true,
  "cmhcPremiumRatePercent": 4,
  "source": "https://homecalc.ca/tools/down-payment-calculator",
  "disclaimer": "Estimate only, based on 2026 Canadian rules. Not financial advice. Confirm with your lender, lawyer, or the CRA."
}

`land_transfer_tax`

Land transfer tax on a $1,200,000 purchase in the City of Toronto.

params

{
  "name": "land_transfer_tax",
  "arguments": {
    "price": 1200000,
    "province": "Ontario",
    "inToronto": true,
    "isFirstTimeBuyer": false
  }
}

result.structuredContent

{
  "province": "Ontario",
  "provincialLandTransferTax": 20475,
  "torontoMunicipalLandTransferTax": 20475,
  "firstTimeBuyerRebate": 0,
  "totalLandTransferTax": 40950,
  "transferRegistrationFee": 86.42,
  "totalDueAtRegistration": 41036.42,
  "note": null,
  "source": "https://homecalc.ca/tools/land-transfer-tax-calculator/toronto",
  "disclaimer": "Estimate only, based on 2026 Canadian rules. Not financial advice. Confirm with your lender, lawyer, or the CRA."
}

`income_tax`

Income tax and take-home pay on $95,000 of employment income in Ontario.

Developer note: provincialTax already includes the Ontario surtax and the Ontario Health Premium. ontarioSurtax and ontarioHealthPremium are a breakdown of that total — do not add them again.

params

{
  "name": "income_tax",
  "arguments": {
    "annualIncome": 95000,
    "province": "Ontario"
  }
}

result.structuredContent

{
  "grossIncome": 95000,
  "federalTax": 12276.5972,
  "provincialTax": 6239.4567400000005,
  "ontarioSurtax": 0,
  "ontarioHealthPremium": 750,
  "cpp": 4646.45,
  "ei": 1123.07,
  "qpip": 0,
  "totalDeductions": 24285.573940000002,
  "netPay": 70714.42606,
  "effectiveRatePercent": 25.6,
  "marginalRatePercent": 29.7,
  "source": "https://homecalc.ca/tools/income-tax-calculator",
  "disclaimer": "Estimate only, based on 2026 Canadian rules. Not financial advice. Confirm with your lender, lawyer, or the CRA."
}

`mortgage_penalty`

Penalty to break a $400,000 fixed mortgage at 4.5% with 30 months left (big-bank posted-rate IRD).

params

{
  "name": "mortgage_penalty",
  "arguments": {
    "balance": 400000,
    "rateType": "fixed",
    "contractRatePct": 4.5,
    "monthsRemaining": 30,
    "lenderMethod": "big-bank",
    "currentRateForRemainingTermPct": 4.29,
    "postedAtOriginationPct": 6.49,
    "todaysPostedForClosestTermPct": 5.79
  }
}

result.structuredContent

{
  "applicablePenalty": 7000,
  "applicableMethod": "posted-rate-ird",
  "threeMonthInterest": 4500,
  "irdStandardMethod": 2100,
  "irdPostedRateMethod": 7000,
  "assumedInputs": {},
  "estimateOnly": false,
  "source": "https://homecalc.ca/tools/mortgage-penalty-calculator",
  "disclaimer": "Estimate only, based on 2026 Canadian rules. Not financial advice. Confirm with your lender, lawyer, or the CRA."
}

`bc_home_flipping_tax`

BC home flipping tax on a $120,000 gain from a property held 300 days.

params

{
  "name": "bc_home_flipping_tax",
  "arguments": {
    "taxableIncome": 120000,
    "daysHeld": 300,
    "isPrimaryResidence": false
  }
}

result.structuredContent

{
  "applies": true,
  "taxRatePercent": 20,
  "primaryResidenceDeduction": 0,
  "netTaxableIncome": 120000,
  "taxOwing": 24000,
  "note": null,
  "source": "https://homecalc.ca/tools/house-flip-tax-calculator/bc",
  "disclaimer": "Estimate only, based on 2026 Canadian rules. Not financial advice. Confirm with your lender, lawyer, or the CRA."
}

`rent_increase`

Maximum 2026 guideline increase on $2,000/month rent in Ontario.

params

{
  "name": "rent_increase",
  "arguments": {
    "currentRent": 2000,
    "province": "Ontario",
    "year": "2026"
  }
}

result.structuredContent

{
  "province": "Ontario",
  "year": "2026",
  "guidelinePercent": 2.1,
  "increaseAmount": 42,
  "newRent": 2042,
  "availableYears": [
    "2024",
    "2025",
    "2026",
    "2027"
  ],
  "source": "https://homecalc.ca/tools/rent-increase-calculator",
  "disclaimer": "Estimate only, based on 2026 Canadian rules. Not financial advice. Confirm with your lender, lawyer, or the CRA."
}

`capital_gains_tax`

Capital gains tax on selling a property that is not a principal residence, bought for $600,000 and sold for $900,000 in Ontario.

params

{
  "name": "capital_gains_tax",
  "arguments": {
    "salePrice": 900000,
    "purchasePrice": 600000,
    "province": "Ontario",
    "annualIncome": 100000,
    "assetType": "real-estate",
    "sellingCosts": 40000,
    "taxYear": 2026
  }
}

result.structuredContent

{
  "netProceeds": 860000,
  "adjustedCostBase": 600000,
  "capitalGain": 260000,
  "isLoss": false,
  "exemptAmount": 0,
  "lcgeApplied": 0,
  "lossesApplied": 0,
  "gainAfterExemptions": 260000,
  "inclusionRatePercent": 50,
  "taxableCapitalGain": 130000,
  "federalTaxOnGain": 34319,
  "provincialTaxOnGain": 15252,
  "estimatedTax": 49571,
  "ccaRecapture": 0,
  "taxOnRecapture": 0,
  "netAfterTax": 810429,
  "effectiveRateOnGainPercent": 19.1,
  "marginalRatePercent": 42.2,
  "isFullExemption": false,
  "source": "https://homecalc.ca/tools/capital-gains-tax-calculator",
  "disclaimer": "Estimate only, based on 2026 Canadian rules. Not financial advice. Confirm with your lender, lawyer, or the CRA."
}

`heloc_second_mortgage`

Can a homeowner borrow $75,000 against a $900,000 home with $450,000 owing?

params

{
  "name": "heloc_second_mortgage",
  "arguments": {
    "homeValue": 900000,
    "outstandingFirstMortgage": 450000,
    "amountToBorrow": 75000,
    "annualHouseholdIncome": 160000,
    "province": "Ontario",
    "helocPrimeRatePct": 4.95,
    "helocSpreadPct": 0.5,
    "secondMortgageRatePct": 7.5
  }
}

result.structuredContent

{
  "homeValue": 900000,
  "currentEquity": 450000,
  "currentLtvPercent": 50,
  "heloc": {
    "maxAvailable": 270000,
    "requestFits": true,
    "effectiveRatePercent": 5.45,
    "revolvingPortion": 75000,
    "termPortion": 0,
    "monthlyInterestOnlyPayment": 340.63,
    "monthlyBlendedPayment": 340.63,
    "stressTestRatePercent": 7.45,
    "stressTestMonthlyPayment": 465.63,
    "tdsRatioPercent": 33.25,
    "tdsQualifies": true,
    "combinedLtvPercent": 58.33
  },
  "secondMortgage": {
    "lenderTier": "A",
    "maxAvailable": 270000,
    "requestFits": true,
    "ratePercent": 7.5,
    "monthlyPayment": 548.67,
    "totalInterestPaid": 89599.86,
    "amortizationYears": 25,
    "balanceAtEndOfTerm": 73918.97,
    "tdsRatioPercent": 34.6,
    "tdsQualifies": true,
    "combinedLtvPercent": 58.33
  },
  "maxAvailableByLenderTier": {
    "A": 270000,
    "B": 270000,
    "Private": 360000
  },
  "baseGdsRatioPercent": 29.76,
  "baseTdsRatioPercent": 29.76,
  "estimatedMonthlyPropertyTax": 750,
  "source": "https://homecalc.ca/tools/heloc-second-mortgage-calculator",
  "disclaimer": "Estimate only, based on 2026 Canadian rules. Not financial advice. Confirm with your lender, lawyer, or the CRA."
}

`mortgage_affordability`

Maximum purchase price on $120,000 income with $100,000 down at 4.5%.

params

{
  "name": "mortgage_affordability",
  "arguments": {
    "annualIncome": 120000,
    "downPayment": 100000,
    "interestRatePct": 4.5,
    "amortizationYears": 25,
    "province": "Ontario"
  }
}

result.structuredContent

{
  "maxHomePrice": 582878,
  "maxMortgage": 496398.58,
  "monthlyPayment": 2747.43,
  "totalMonthlyHousing": 3322.43,
  "stressTestRatePercent": 6.5,
  "gdsRatioPercent": 39,
  "tdsRatioPercent": 39,
  "downPaymentAmount": 100000,
  "downPaymentPercent": 17.16,
  "minimumDownPaymentRequired": 33287.8,
  "downPaymentBelowMinimum": false,
  "cmhcRequired": true,
  "cmhcPremium": 13520.58,
  "cmhcPremiumRatePercent": 2.8,
  "cmhcNotAvailable": false,
  "amortizationWarning": false,
  "source": "https://homecalc.ca/tools/mortgage-affordability-calculator",
  "disclaimer": "Estimate only, based on 2026 Canadian rules. Not financial advice. Confirm with your lender, lawyer, or the CRA."
}

`cap_rate`

Cap rate on a $600,000 rental renting for $3,200/month with $9,000 of annual expenses.

params

{
  "name": "cap_rate",
  "arguments": {
    "purchasePrice": 600000,
    "monthlyGrossRent": 3200,
    "annualOperatingExpenses": 9000,
    "downPayment": 120000,
    "interestRatePct": 5,
    "amortizationYears": 25
  }
}

result.structuredContent

{
  "capRatePercent": 4.58,
  "netOperatingIncome": 27480,
  "grossRentalIncome": 38400,
  "vacancyLoss": 1920,
  "effectiveGrossIncome": 36480,
  "operatingExpenses": 9000,
  "grossRentMultiplier": 15.63,
  "expenseRatioPercent": 24.67,
  "mortgagePrincipal": 480000,
  "monthlyMortgagePayment": 2791.7,
  "annualDebtService": 33500.45,
  "annualCashFlow": -6020.45,
  "cashInvested": 120000,
  "cashOnCashReturnPercent": -5.02,
  "benchmark": {
    "market": "Your Market",
    "typicalRangePercent": {
      "low": 3.75,
      "high": 5.75
    },
    "position": "lower-typical",
    "message": "This cap rate is within the typical range for Your Market — a reasonable deal if appreciation potential is strong."
  },
  "warnings": [],
  "source": "https://homecalc.ca/tools/cap-rate-calculator",
  "disclaimer": "Estimate only, based on 2026 Canadian rules. Not financial advice. Confirm with your lender, lawyer, or the CRA."
}

`house_flipping`

Profit on a flip bought for $500,000, renovated for $60,000 and resold for $650,000 after 6 months.

params

{
  "name": "house_flipping",
  "arguments": {
    "purchasePrice": 500000,
    "afterRepairValue": 650000,
    "renovationCost": 60000,
    "province": "Ontario",
    "holdingPeriodMonths": 6,
    "monthlyHoldingCosts": 2500,
    "marginalTaxRatePct": 43.41
  }
}

result.structuredContent

{
  "provincialLandTransferTax": 6475,
  "torontoMunicipalLandTransferTax": 0,
  "firstTimeBuyerRebate": 0,
  "totalLandTransferTax": 6475,
  "renovationWithContingency": 69000,
  "holdingCosts": 15000,
  "realtorCommission": 32500,
  "totalCosts": 622975,
  "grossProfit": 27025,
  "craFlippingRuleApplies": true,
  "taxableAmount": 27025,
  "estimatedTax": 11732,
  "netProfit": 15293,
  "roiPercent": 2.7,
  "breakEvenSalePrice": 634707,
  "monthsToCapitalGainsTreatment": 6,
  "taxSavingIfHeldPast12Months": 6000,
  "source": "https://homecalc.ca/tools/house-flipping-calculator",
  "disclaimer": "Estimate only, based on 2026 Canadian rules. Not financial advice. Confirm with your lender, lawyer, or the CRA."
}

Result format and source links

A successful result has both content (one text item) and structuredContent. Every successful result also includes two fields to show the user:

source — the HomeCalc page for that calculator, where the user can check or change the inputs.
disclaimer — currently: “Estimate only, based on 2026 Canadian rules. Not financial advice. Confirm with your lender, lawyer, or the CRA.”

The source links returned by the examples above:

Source URL returned by each example
Tool	source
mortgage_payment	https://homecalc.ca/tools/mortgage-payment-calculator
minimum_down_payment	https://homecalc.ca/tools/down-payment-calculator
land_transfer_tax	https://homecalc.ca/tools/land-transfer-tax-calculator/toronto
income_tax	https://homecalc.ca/tools/income-tax-calculator
mortgage_penalty	https://homecalc.ca/tools/mortgage-penalty-calculator
bc_home_flipping_tax	https://homecalc.ca/tools/house-flip-tax-calculator/bc
rent_increase	https://homecalc.ca/tools/rent-increase-calculator
capital_gains_tax	https://homecalc.ca/tools/capital-gains-tax-calculator
heloc_second_mortgage	https://homecalc.ca/tools/heloc-second-mortgage-calculator
mortgage_affordability	https://homecalc.ca/tools/mortgage-affordability-calculator
cap_rate	https://homecalc.ca/tools/cap-rate-calculator
house_flipping	https://homecalc.ca/tools/house-flipping-calculator

The link can depend on the inputs — for example, a Toronto purchase returns the Toronto land transfer tax page.

Errors and troubleshooting

There are two kinds of error. Tool errors come back as a normal result with isError: true; protocol errors come back as a JSON-RPC error.

A calculation the tool refuses

When the premise is impossible (here, a down payment below the legal minimum), the tool returns isError: true and a reason instead of a number. Relay the reason to the user.

params

{
  "name": "mortgage_payment",
  "arguments": {
    "homePrice": 650000,
    "downPayment": 10000,
    "annualInterestRatePct": 5.25
  }
}

Response

{
  "result": {
    "content": [
      {
        "type": "text",
        "text": "{\n  \"error\": \"A down payment of $10,000 is below the legal minimum for a $650,000 home, which is $40,000 (5% on the first $500,000, 10% from $500,000 to $1.5M, 20% at or above $1.5M). There is no zero-down or below-minimum insured mortgage in Canada, so no payment is returned. Tell the user the minimum, and re-run with a down payment of at least that amount.\"\n}"
      }
    ],
    "structuredContent": {
      "error": "A down payment of $10,000 is below the legal minimum for a $650,000 home, which is $40,000 (5% on the first $500,000, 10% from $500,000 to $1.5M, 20% at or above $1.5M). There is no zero-down or below-minimum insured mortgage in Canada, so no payment is returned. Tell the user the minimum, and re-run with a down payment of at least that amount."
    },
    "isError": true
  },
  "jsonrpc": "2.0",
  "id": 15
}

Missing or invalid arguments

Arguments are validated against the tool's inputSchema. A missing required field or an out-of-range value comes back as an error result naming the problem.

params

{
  "name": "minimum_down_payment",
  "arguments": {}
}

Response

{
  "result": {
    "content": [
      {
        "type": "text",
        "text": "Input validation error: Invalid arguments for tool minimum_down_payment: homePrice: Invalid input: expected number, received undefined"
      }
    ],
    "isError": true
  },
  "jsonrpc": "2.0",
  "id": 16
}

A tool name that does not exist

Only the names returned by tools/list exist. Any other name is rejected.

params

{
  "name": "stress_test",
  "arguments": {
    "annualIncome": 100000
  }
}

Response

{
  "jsonrpc": "2.0",
  "id": 17,
  "error": {
    "code": -32602,
    "message": "Tool stress_test not found"
  }
}

406 Not Acceptable

The Accept header must list both application/json and text/event-stream. Sending only one (or none) returns 406 before the request reaches any tool.

Request

curl -sS https://homecalc.ca/api/mcp \
  -H 'content-type: application/json' \
  -H 'accept: application/json' \
  -H 'mcp-protocol-version: 2025-06-18' \
  -d '{"jsonrpc":"2.0","id":2,"method":"tools/list","params":{}}'

Response (HTTP 406)

{"jsonrpc":"2.0","error":{"code":-32000,"message":"Not Acceptable: Client must accept both application/json and text/event-stream"},"id":null}

400 Unsupported protocol version

An unknown MCP-Protocol-Version header returns 400, and the error lists the 2025-era revisions the server accepts. Official MCP SDK clients negotiate the version for you.

Request

curl -sS https://homecalc.ca/api/mcp \
  -H 'content-type: application/json' \
  -H 'accept: application/json, text/event-stream' \
  -H 'mcp-protocol-version: 1999-01-01' \
  -d '{"jsonrpc":"2.0","id":2,"method":"tools/list","params":{}}'

Response (HTTP 400)

{"jsonrpc":"2.0","error":{"code":-32000,"message":"Bad Request: Unsupported protocol version: 1999-01-01 (supported versions: 2025-11-25, 2025-06-18, 2025-03-26, 2024-11-05, 2024-10-07)"},"id":null}

Privacy and data

No personal data. The connector has no login and never stores names, emails, IP addresses, exact figures, account identifiers or conversation text. For each calculation we keep anonymous, rounded usage statistics: which calculator, which assistant (Claude or ChatGPT), the time, whether it succeeded or returned an error, the province, rounded ranges of the inputs (for example the price in $100,000 bands, income in $25,000 bands, the interest rate rounded down to the nearest 0.25%) and yes/no outcomes (for example whether CMHC insurance applies). Our hosting provider keeps standard request logs, including IP addresses, for about a day for security and operations. Usage statistics are deleted after 24 months. We use them only to improve the calculators and to publish aggregate market research, and we never sell them.

Calls from your own client — including any you make to try these examples — are counted in those anonymous usage statistics. See the Privacy Policy for the full details.

Questions

The connector is built and maintained by Hami Tahm, founder of HomeCalc.ca, on the same calculator cores as the website (see our methodology). Questions or issues? Email hami@homecalc.ca.

HomeCalc Connector — developer documentation

🔑Every example on this page is real

Overview

Health check

Connect an MCP client

Raw HTTP quick start

1. initialize (optional on a stateless server)

2. tools/list

3. tools/call

Tool reference

mortgage_payment

minimum_down_payment

land_transfer_tax

income_tax

mortgage_penalty

bc_home_flipping_tax

rent_increase

capital_gains_tax

heloc_second_mortgage

mortgage_affordability

cap_rate

house_flipping

Live examples

mortgage_payment

minimum_down_payment

land_transfer_tax

income_tax

mortgage_penalty

bc_home_flipping_tax

rent_increase

capital_gains_tax

heloc_second_mortgage

mortgage_affordability

cap_rate

house_flipping

Result format and source links

Errors and troubleshooting

A calculation the tool refuses

Missing or invalid arguments

A tool name that does not exist

406 Not Acceptable

400 Unsupported protocol version

Privacy and data

Questions

Stay Ahead of the Market

Every example on this page is real

`mortgage_payment`

`minimum_down_payment`

`land_transfer_tax`

`income_tax`

`mortgage_penalty`

`bc_home_flipping_tax`

`rent_increase`

`capital_gains_tax`

`heloc_second_mortgage`

`mortgage_affordability`

`cap_rate`

`house_flipping`

`mortgage_payment`

`minimum_down_payment`

`land_transfer_tax`

`income_tax`

`mortgage_penalty`

`bc_home_flipping_tax`

`rent_increase`

`capital_gains_tax`

`heloc_second_mortgage`

`mortgage_affordability`

`cap_rate`

`house_flipping`