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TapTax

REMOTE · API.TAPTAX.CO.UK · SCANNED OCT 7

UK tax: take-home pay, self-employed and company tax, VAT, stamp duty, invoices and MTD.

Available components

69 Trust /100
Trust breakdown (7 categories)

How this component scores in each security and reliability category. Every signal is checked automatically against the live server, and we only credit what we can confirm. How we score → Why this is hard to score →

Endpoint Security66
Transport & Reachability100
Schema Quality & AI Usability78
  • 100% of prompts and resources have a non-trivial description (not blank, and not just the item's name).Pass
  • AI-judged instruction clarity (good).Pass
  • Context-footprint check failed: tool/resource definitions use about 7034 tokens (~143/item across 49 items; 48 tools + 1 resources), over budget; trim descriptions and params. See how to fix → Fail
  • Usage-examples check failed: none of the tools include examples. See how to fix → Fail
Stability & Change Management13
  • Stability observed for 4 of 30 days with no destabilising changes; credit accrues until the full window elapses.Partial
Tool Coverage93
  • 100% of tools have a non-trivial description (not blank, and not just the tool's name).Pass
  • 80% of tool parameters carry a description.Partial
Tool Safety81
  • No prompt-injection markers were found in the server instructions, tool names or descriptions we captured.Pass
  • 1 of 4 tool(s) whose name or description implies an irreversible operation declare an MCP destructiveHint annotation; "calculate_take_home_pay" implies "pay" and declares readOnlyHint instead, contradicting what its own name says it does. See how to fix → Partial
  • An AI judge read all 50 captured unit(s) of tool text and found none that tries to manipulate the model reading it.Pass
Capabilities100
  • Implements a current MCP spec version (2026-07-28).Pass
  • Supports UI / widget rendering.Pass
Install

How do I install the TapTax MCP server?

TapTax is a hosted endpoint at https://api.taptax.co.uk/mcp, so there is nothing to install locally. Ready-made configuration for Claude, Cursor, VS Code, Codex and 5 more is on this page, copied from each client's own documentation.

remote · api.taptax.co.uk

# add to Claude Code
claude mcp add --transport http uk-co-taptax-taptax 'https://api.taptax.co.uk/mcp'
// .cursor/mcp.json
{
  "mcpServers": {
    "uk-co-taptax-taptax": {
      "url": "https://api.taptax.co.uk/mcp"
    }
  }
}
// .vscode/mcp.json
{
  "servers": {
    "uk-co-taptax-taptax": {
      "type": "http",
      "url": "https://api.taptax.co.uk/mcp"
    }
  }
}
# ~/.codex/config.toml
[mcp_servers.uk-co-taptax-taptax]
url = "https://api.taptax.co.uk/mcp"
// opencode.json
{
  "$schema": "https://opencode.ai/config.json",
  "mcp": {
    "uk-co-taptax-taptax": {
      "type": "remote",
      "url": "https://api.taptax.co.uk/mcp",
      "enabled": true
    }
  }
}
# add to OpenClaw
openclaw mcp add uk-co-taptax-taptax --url 'https://api.taptax.co.uk/mcp' --transport streamable-http
# ~/.hermes/config.yaml
mcp_servers:
  uk-co-taptax-taptax:
    url: "https://api.taptax.co.uk/mcp"
// ~/.netclaw/config/netclaw.json
{
  "McpServers": {
    "uk-co-taptax-taptax": {
      "Transport": "http",
      "Url": "https://api.taptax.co.uk/mcp"
    }
  }
}
# add to Vellum
assistant mcp add uk-co-taptax-taptax -t streamable-http -u 'https://api.taptax.co.uk/mcp'
// mcp.json
{
  "mcpServers": {
    "uk-co-taptax-taptax": {
      "type": "http",
      "url": "https://api.taptax.co.uk/mcp"
    }
  }
}

The mcpServers block is a cross-client convention. Remote transports vary, so check your client's docs.

Changelog

Every change we have recorded for this component, newest first. Security-relevant changes are always shown. ▲ marks a change for the better, ▼ a change for the worse; unmarked changes are neutral.

  • 7 Oct 26 +2
    • DNSSEC: fail → pass ▲ security
  • 5 Oct 26 +1
    • Tool “create_invoice” rewrote its description, which is the text the model reads security
    • Tool “get_mileage_summary” rewrote its description, which is the text the model reads security
    • Tool “get_tax_position” rewrote its description, which is the text the model reads security
    • Tool “list_invoices” rewrote its description, which is the text the model reads security
    • Tool “list_transactions” rewrote its description, which is the text the model reads security
    • “calculate_capital_gains_tax” added an optional parameter “disposalDate” cosmetic
  • 4 Oct 26 −1
    • Schema quality: 2235 → 6911 ▼ functional
    • Tool coverage: 52% → 80% ▲ functional
    • Stability: unverified → 0.03 ▲ functional
    • Schema quality: excellent → good functional
    • Destructive annotations: 1 of 4 tool(s) whose name or description implies an irreversible operation declare an MCP destructiveHint annotation; "calculate_take_home_pay" implies "pay" and declares readOnlyHint instead, contradicting what its own name says it does. functional
    • Server version: 1.0.0 → 1.1.0 functional
    • New tool “calculate_tax_on_multiple_incomes” functional
    • New tool “calculate_capital_gains_tax” functional
    • New tool “calculate_child_benefit_charge” functional
    • New tool “calculate_cis_deduction” functional
    • New tool “calculate_contractor_day_rate” functional
    • New tool “calculate_corporation_tax” functional
    • New tool “calculate_dividend_tax” functional
    • New tool “calculate_gross_salary_for_take_home” functional
    • New tool “calculate_invoice_due_date” functional
    • New tool “calculate_late_payment_interest” functional
    • New tool “calculate_markup” functional
    • New tool “calculate_mileage_allowance” functional
    • New tool “calculate_pension_tax_relief” functional
    • New tool “calculate_pro_rata_salary” functional
    • New tool “calculate_profit_margin” functional
    • New tool “calculate_rental_income_tax” functional
    • New tool “calculate_salary_sacrifice” functional
    • New tool “calculate_savings_interest_tax” functional
    • New tool “calculate_stamp_duty” functional
    • New tool “calculate_student_loan_repayment” functional
    • New tool “calculate_take_home_pay” functional
    • New tool “calculate_vat” functional
    • New tool “check_vat_registration” functional
    • New tool “check_vat_reverse_charge” functional
    • New tool “compare_inside_and_outside_ir35” functional
    • New tool “compare_limited_company_and_sole_trader” functional
    • New tool “compare_salary_and_dividends” functional
    • New tool “convert_hourly_rate_to_salary” functional
    • New tool “convert_salary_to_hourly_rate” functional
    • New tool “estimate_self_assessment_penalties” functional
    • New tool “generate_invoice_numbers” functional
    • New tool “plan_quarterly_tax_set_aside” functional
    • New tool “prepare_business_document” functional
  • 3 Oct 26 67

    First indexed and scored.

Diagnostics

Diagnostic detail from the automated scan of this channel: what the scanner observed at each step, so you can see exactly where a check passed or failed. It is informational only and never changes the trust score.

Captured 8 Oct 2026 · Probed https://api.taptax.co.uk/mcp

TLS valid

Negotiated TLS 1.3 with TLS_AES_128_GCM_SHA256 .

Subject Issuer Valid from Valid until Key Signature Serial
CN=taptax.co.uk CN=WE1,O=Google Trust Services,C=US 28 Aug 2026 26 Nov 2026 ECDSA 256 ECDSA-SHA256 4e351366101092240ebc42c9ef4a0780
SANs: taptax.co.uk, *.taptax.co.uk
CN=WE1,O=Google Trust Services,C=US (CA) CN=GTS Root R4,O=Google Trust Services LLC,C=US 13 Dec 2023 20 Feb 2029 ECDSA 256 ECDSA-SHA384 7ff31977972c224a76155d13b6d685e3
CN=GTS Root R4,O=Google Trust Services LLC,C=US (CA) CN=GlobalSign Root CA,OU=Root CA,O=GlobalSign nv-sa,C=BE 15 Nov 2023 28 Jan 2028 ECDSA 384 SHA256-RSA 7fe530bf331343bedd821610493d8a1b

Background: What to check on a remote MCP endpoint →

DNSSEC secure

Validation of api.taptax.co.uk. — Secure

Zone DS Keys Algorithms Outcome
. trust_anchor 20326, 38696 8, 8 Verified
uk. present 43876 8 Verified
co.uk. present 11810 8 Verified
taptax.co.uk. present 2371 13 Verified
api.taptax.co.uk. Verified address RRset verified with the apex keys
Authentication No authorisation required

The endpoint answered without asking for a token. Anyone who knows the URL can reach it.

Result No authorisation required
HTTP status 200
Header Value
strict-transport-security max-age=31536000; includeSubDomains
content-security-policy default-src 'self';base-uri 'self';font-src 'self' https: data:;form-action 'self';frame-ancestors 'self';img-src 'self' data:;object-src 'none';script-src 'self';script-src-attr 'none';style-src 'self' https: 'unsafe-inline';upgrade-insecure-requests
x-content-type-options nosniff
x-frame-options SAMEORIGIN
referrer-policy no-referrer

Background: How OAuth 2.1 works in the 2026 MCP spec →

Transports 2 probes
Transport URL Outcome Status Location
streamable-http https://api.taptax.co.uk/mcp Verified 200
http (plaintext) http://api.taptax.co.uk/mcp HTTPS enforced 301 https://api.taptax.co.uk/mcp
MCP tools · 49 exposed · ~6,938 tokens

The tools this component advertises to a client, with an estimated token cost for each. Expand a tool to see its parameters and schema. The per-tool counts are indicative and are not scored directly; the schema's total context footprint is one signal in Schema Quality & AI Usability. A tool's description is untrusted text the model reads on every call, which is what makes this list a security surface and not just an inventory: how tool poisoning works →

Tool Tokens
add_transaction ~476

Record a business income or expense in the signed-in person's TapTax, such as a receipt or a payment. The category is the HMRC self-employment box it belongs in. The same entry added twice within 10 minutes is recorded once.

NameTypeReqDescription
amountnumberyesIn pounds, VAT included
categorystringyesFor an expense, its HMRC self-employment box (SA103F): costOfGoods: materials, parts and stock used in the work or sold on, e.g. trade and building suppliers such as Screwfix, Toolstation, City Elect…
datestringyesThe date on the receipt or of the payment
descriptionstringyesSupplier or client, and what it was for
personalboolean–True for a personal (non-business) payment
typestringyes–

No output schema declared.

No examples provided.

calculate_capital_gains_tax ~208

Calculate UK Capital Gains Tax on selling an asset (residential property, shares, a business qualifying for Business Asset Disposal Relief, or other assets) for a tax year: the gain after costs, losses and the annual exempt amount, tax at each rate given other income, and the payment deadline.

NameTypeReqDescription
allowableCostsnumber–Costs of buying, improving and selling
assetTypestringyesbadr: Business Asset Disposal Relief
costBasisnumberyesWhat the asset cost
disposalDatestring–Disposal date; only matters in 2024-25, when rates changed on 30 October 2024
lossesnumber–Capital losses to offset
otherIncomenumber–Taxable income in the year, which sets the rate
proceedsnumberyesSale proceeds
taxYearstring–UK tax year, e.g. "2026-27". Defaults to the current one.

No output schema declared.

No examples provided.

calculate_child_benefit_charge ~110

Calculate the High Income Child Benefit Charge on an adjusted net income and the Child Benefit received in a tax year: the charge, the benefit kept, and the income the charge starts from.

NameTypeReqDescription
adjustedNetIncomenumberyesThe higher earner's adjusted net income for the year
annualChildBenefitnumberyesChild Benefit received in the year
taxYearstring–UK tax year, e.g. "2026-27". Defaults to the current one.

No output schema declared.

No examples provided.

calculate_cis_deduction ~166

Calculate the Construction Industry Scheme deduction on a payment (labour only, materials excluded) at the registered, unregistered or gross-payment rate, the amount received, and whether the year's deductions are likely to be more or less than the tax actually due.

NameTypeReqDescription
annualIncomenumber–Expected self-employed income for the year
cisStatusstringyesregistered (20%), unregistered (30%) or gross payment status (0%)
expensesnumber–Expected business expenses for the year
grossPaymentnumberyesThe payment before deduction
materialsAmountnumber–Part of the payment that is materials
taxYearstring–UK tax year, e.g. "2026-27". Defaults to the current one.

No output schema declared.

No examples provided.

calculate_contractor_day_rate ~171

Turn a contractor day rate into annual and monthly income, an hourly equivalent, and take-home pay as a sole trader, through a company outside IR35 and inside IR35, with the best route and the PAYE salary that would take home as much, for a tax year.

NameTypeReqDescription
accountancyCostnumber–Accountancy cost a year
billableDaysnumberyesDays billed in a year after holidays, sickness and gaps
businessExpensesnumber–Business expenses a year
dayRatenumberyesDay rate charged
hoursPerDaynumber–Hours in a working day; defaults to 7.5
taxYearstring–UK tax year, e.g. "2026-27". Defaults to the current one.

No output schema declared.

No examples provided.

calculate_corporation_tax ~85

Calculate UK corporation tax on a company's taxable profit for a tax year, including marginal relief between the small profits and main rates, with profit after tax and the effective rate.

NameTypeReqDescription
taxYearstring–UK tax year, e.g. "2026-27". Defaults to the current one.
taxableProfitnumberyesCompany's taxable profit for the year

No output schema declared.

No examples provided.

calculate_dividend_tax ~104

Calculate UK tax on dividends for a tax year, given the dividends and other income: the dividend allowance, tax at the basic, higher and additional dividend rates, and the effective rate.

NameTypeReqDescription
dividendIncomenumberyesDividends received in the year
otherIncomenumber–Other taxable income, such as a salary
taxYearstring–UK tax year, e.g. "2026-27". Defaults to the current one.

No output schema declared.

No examples provided.

calculate_gross_salary_for_take_home ~163

Work out the gross UK salary needed to take home a given amount a year after income tax, employee National Insurance, student loan and a pension percentage, for a tax year (net to gross).

NameTypeReqDescription
pensionPercentnumber–Employee pension as a percentage of gross, e.g. 5
scottishTaxpayerboolean–True for a Scottish taxpayer (Scottish bands)
studentLoanPlanstring–Student loan plan, if any (plan4 is Scotland, postgrad the postgraduate loan)
targetTakeHomenumberyesTake-home pay wanted a year, in pounds
taxYearstring–UK tax year, e.g. "2026-27". Defaults to the current one.

No output schema declared.

No examples provided.

calculate_invoice_due_date ~143

Calculate the date an invoice is due from its date and the payment terms (on receipt, a number of days, end of month, days after month end, a day of the following month, or the statutory 30-day default), with the weekday and whether the terms exceed the statutory limit.

NameTypeReqDescription
customerstring––
dayOfMonthinteger–Day, for day-of-following-month terms
daysinteger–Days, for net and net-end-of-month terms
invoiceDatestringyesInvoice date, or the day the customer received it (YYYY-MM-DD)
termsstringyesThe payment terms

No output schema declared.

No examples provided.

calculate_late_payment_interest ~107

Calculate the statutory interest (Bank of England base rate plus 8%) and fixed compensation a business can claim on a late-paid commercial invoice under the Late Payment of Commercial Debts Act, from the amount, the due date and the payment date.

NameTypeReqDescription
amountnumberyesUnpaid invoice amount, VAT included if charged
dueDatestringyesThe last day payment was due
paidOnstring–The day it was paid; defaults to today

No output schema declared.

No examples provided.

calculate_markup ~56

Calculate the selling price, profit and the equivalent profit margin from a cost and a markup percentage.

NameTypeReqDescription
costnumberyesCost of the item or job
markupPercentnumberyesMarkup on cost, as a percentage

No output schema declared.

No examples provided.

calculate_mileage_allowance ~127

Calculate the tax-free business mileage allowance for a year at HMRC's approved mileage rates for a car or van, motorcycle or bicycle, including the passenger rate, and the tax it saves at the basic or higher rate.

NameTypeReqDescription
annualBusinessMilesnumberyesBusiness miles in the year
averageMilesPerPassengerTripnumber––
passengerTripsinteger–Business trips with a passenger
taxBandstring–Income tax band, for the saving; defaults to basic
vehicleTypestring–Defaults to car (cars and vans)

No output schema declared.

No examples provided.

calculate_pension_tax_relief ~142

Compare a self-employed person's tax with their current and a higher personal pension contribution in a tax year: the basic-rate relief added to the pension, the reduction in the tax bill, and the net cost of the extra contribution.

NameTypeReqDescription
businessExpensesnumber–Allowable business expenses
currentPensionContributionnumber–Personal pension contributions now, a year
grossIncomenumberyesSelf-employed income before expenses
targetPensionContributionnumberyesPersonal pension contributions planned, a year
taxYearstring–UK tax year, e.g. "2026-27". Defaults to the current one.

No output schema declared.

No examples provided.

calculate_pro_rata_salary ~181

Work out a part-time salary from the full-time salary and the hours or days worked compared with full time, with the take-home pay on the pro rata salary for a tax year.

NameTypeReqDescription
actualUnitsnumberyesHours (or days) actually worked a week, in the same unit
fullTimeSalarynumberyesFull-time annual salary
fullTimeUnitsnumberyesFull-time hours (or days) a week, e.g. 37.5
scottishTaxpayerboolean–True for a Scottish taxpayer (Scottish bands)
studentLoanPlanstring–Student loan plan, if any (plan4 is Scotland, postgrad the postgraduate loan)
taxYearstring–UK tax year, e.g. "2026-27". Defaults to the current one.

No output schema declared.

No examples provided.

calculate_profit_margin ~72

Calculate the profit margin and markup from a cost and a selling price, or the selling price needed for a target margin.

NameTypeReqDescription
costnumberyesCost of the item or job
pricenumber–Selling price
targetMarginPercentnumber–Margin wanted, as a percentage of price

No output schema declared.

No examples provided.

calculate_rental_income_tax ~126

Calculate UK income tax on rental profit for a landlord in a tax year, given rent, allowable expenses, mortgage interest (relieved as a 20% tax credit) and other income.

NameTypeReqDescription
allowableExpensesnumber–Allowable expenses, not mortgage interest
grossRentnumberyesRent received in the year
mortgageInterestPaidnumber–Mortgage interest paid
otherIncomenumber–Other taxable income
taxYearstring–UK tax year, e.g. "2026-27". Defaults to the current one.

No output schema declared.

No examples provided.

calculate_salary_sacrifice ~255

Compare pay before and after a salary sacrifice for a pension or an electric company car: income tax, National Insurance and student loan saved, employer National Insurance saved and passed back, benefit-in-kind tax for a car, the drop in take-home pay, and for a pension the cost per pound added and the saving against paying in from net pay.

NameTypeReqDescription
carP11dValuenumber–List (P11D) value of the car; electric car only
employerNIPassbacknumber–Share (0 to 1) of the employer NI saving added to the pension; pension only
grossSalarynumberyesGross annual salary before the sacrifice
sacrificeAmountnumberyesAmount given up from gross pay each year
sacrificeTypestringyespension, or ev-car for an electric car scheme
scottishTaxpayerboolean–True for a Scottish taxpayer (Scottish bands)
studentLoanPlanstring–Student loan plan, if any (plan4 is Scotland, postgrad the postgraduate loan)
taxYearstring–UK tax year, e.g. "2026-27". Defaults to the current one.

No output schema declared.

No examples provided.

calculate_savings_interest_tax ~118

Calculate UK tax on savings interest for a tax year, given the interest, any tax already deducted and other income: the starting rate for savings, the Personal Savings Allowance and the tax due.

NameTypeReqDescription
grossInterestnumberyesSavings interest in the year
otherIncomenumber–Other taxable income
taxDeductedAtSourcenumber–Tax already deducted from the interest
taxYearstring–UK tax year, e.g. "2026-27". Defaults to the current one.

No output schema declared.

No examples provided.

calculate_stamp_duty ~178

Calculate the tax on buying property: Stamp Duty Land Tax in England and Northern Ireland, Land and Buildings Transaction Tax in Scotland or Land Transaction Tax in Wales, by band, with first-time buyer relief, the additional property surcharge and the non-resident surcharge where they apply.

NameTypeReqDescription
companyboolean–True when a company is buying
completionDatestring–Completion date; defaults to today
countrystring–Where the property is; defaults to England or Northern Ireland
firstTimeBuyerboolean––
ownsOtherResidentialPropertyboolean–Drives the additional property surcharge
pricenumberyesPurchase price
propertyUsestring––
replacingMainResidenceboolean––
ukResidentboolean–False adds the non-resident surcharge (England and NI)

No output schema declared.

No examples provided.

calculate_student_loan_repayment ~101

Calculate yearly, monthly and weekly UK student loan repayments on an income for a repayment plan (Plan 1, 2, 4 or the postgraduate loan) in a tax year.

NameTypeReqDescription
annualIncomenumberyesIncome a year that repayments are taken from
planstringyesRepayment plan
taxYearstring–UK tax year, e.g. "2026-27". Defaults to the current one.

No output schema declared.

No examples provided.

calculate_take_home_pay ~171

Calculate take-home pay from a UK salary for a tax year: income tax by band (England, Wales and Northern Ireland, or Scotland), employee National Insurance, student loan repayment and pension contributions, with yearly, monthly and weekly take-home and the employer National Insurance and total cost to the employer.

NameTypeReqDescription
grossSalarynumberyesGross annual salary in pounds
pensionContributionsnumber–Employee pension contributions a year, in pounds
scottishTaxpayerboolean–True for a Scottish taxpayer (Scottish bands)
studentLoanPlanstring–Student loan plan, if any (plan4 is Scotland, postgrad the postgraduate loan)
taxYearstring–UK tax year, e.g. "2026-27". Defaults to the current one.

No output schema declared.

No examples provided.

calculate_tax_on_multiple_incomes ~203

Calculate the combined UK tax on income from several sources in one tax year (employment, self-employment, rental profit, dividends and savings interest), allowing for PAYE tax already deducted: income tax, National Insurance, student loan, what is left to pay and take-home.

NameTypeReqDescription
dividendIncomenumber–Dividends
employmentnumber–Employment income (salary)
payeTaxDeductednumber–Income tax already deducted through PAYE
pensionContributionsnumber–Personal pension contributions
rentalProfitnumber–Rental profit
savingsInterestnumber–Savings interest
selfEmploymentnumber–Self-employed profit
studentLoanPlanstring–Student loan plan, if any (plan4 is Scotland, postgrad the postgraduate loan)
taxYearstring–UK tax year, e.g. "2026-27". Defaults to the current one.

No output schema declared.

No examples provided.

calculate_vat ~94

Add VAT to a net price or take it out of a gross price at the standard (20%), reduced (5%) or any other rate, with the net, VAT and gross amounts.

NameTypeReqDescription
amountnumberyesThe price
directionstringyesadd: the amount is net; remove: the amount includes VAT
ratePercentnumber–VAT rate as a percentage; defaults to 20

No output schema declared.

No examples provided.

check_mtd_status ~73

Say whether and when Making Tax Digital for Income Tax applies to someone, from their qualifying income: self-employment turnover plus property income, before expenses, as on their Self Assessment return. Employment and pension income do not count.

NameTypeReqDescription
propertyIncomenumber––
selfEmploymentTurnovernumberyes–

No output schema declared.

No examples provided.

check_tax_code ~267

Check whether a UK PAYE tax code (e.g. 1257L, BR, K475, 1257L W1/M1) looks right for a salary and circumstances, explain what it means, and estimate any over- or under-payment. Flat-rate codes (BR, D0, D1) are only judged when hasMultipleJobs is known; without it the verdict is needs_info. Returns a verdict tier; refund figures are estimates, not amounts owed.

NameTypeReqDescription
grossSalarynumberyesAnnual gross pay from this job, in pounds
hasCompanyCarboolean––
hasMarriageAllowanceboolean––
hasMultipleJobsboolean–Whether the person has another job or pension; omitted when unknown
hasPrivateMedicalboolean––
marriageAllowanceDirectionstring––
monthsOnCodeinteger–For emergency codes: how many monthly payslips were paid on it so far
receivesStatePensionboolean––
scotlandboolean–True for a Scottish taxpayer
taxCodestringyesThe code as printed on a payslip or P45
taxYearstring–Tax year the code applies to; defaults to the current one

No output schema declared.

No examples provided.

check_vat_registration ~156

Check whether a turnover is over the UK VAT registration threshold for a tax year, and compare VAT payable under the standard scheme with the Flat Rate Scheme for the business's sector rate, including the first-year discount, with the cheaper scheme and the difference.

NameTypeReqDescription
annualTurnovernumberyesVAT taxable turnover over 12 months
firstYearOfVatRegistrationboolean––
flatRatePercentnumber–Flat Rate Scheme percentage for the sector, e.g. 14.5 for IT consultancy
taxYearstring–UK tax year, e.g. "2026-27". Defaults to the current one.
vatablePurchasesnumber–Purchases with VAT a year

No output schema declared.

No examples provided.

check_vat_reverse_charge ~103

Work out whether the domestic VAT reverse charge for construction services applies to an invoice, by HMRC's decision steps. Takes the yes or no answers known so far and returns the next question to answer, or the outcome with what the invoice must say.

NameTypeReqDescription
answersobject–Answers so far, keyed by question id: supplier-vat, construction-service, vat-rate, employment-business, customer-vat, customer-cis, end-user, five-percent

No output schema declared.

No examples provided.

compare_inside_and_outside_ir35 ~145

Compare a contractor's take-home pay working inside IR35 (deemed employment payment, employer National Insurance) with working outside IR35 through a limited company, from the day rate and working days, for a tax year. It compares pay; it does not decide IR35 status.

NameTypeReqDescription
accountancyCostnumber–Accountancy cost a year
businessExpensesnumber–Business expenses a year
dayRatenumberyesDay rate charged
taxYearstring–UK tax year, e.g. "2026-27". Defaults to the current one.
workingDaysnumberyesDays worked in the year

No output schema declared.

No examples provided.

compare_limited_company_and_sole_trader ~122

Compare take-home pay as a sole trader with running the same profit through a limited company (salary plus dividends, corporation tax and accountancy cost) for a tax year, with the annual difference and an approximate break-even profit.

NameTypeReqDescription
accountancyCostnumber–Extra accountancy cost of a company a year; defaults to 2000
annualProfitnumberyesBusiness profit a year
taxYearstring–UK tax year, e.g. "2026-27". Defaults to the current one.

No output schema declared.

No examples provided.

compare_salary_and_dividends ~111

For a limited company director, work out take-home pay from a chosen salary plus dividends paid from the remaining profit after employer National Insurance and corporation tax, with every tax and the effective rate, for a tax year.

NameTypeReqDescription
companyProfitBeforeSalarynumberyesCompany profit before the director's salary
salarynumberyesDirector's salary for the year
taxYearstring–UK tax year, e.g. "2026-27". Defaults to the current one.

No output schema declared.

No examples provided.

convert_hourly_rate_to_salary ~168

Convert an hourly rate to the annual salary it adds up to for the hours a week and paid weeks a year given, with take-home pay on that salary for a tax year.

NameTypeReqDescription
hourlyRatenumberyesGross pay per hour
hoursPerWeeknumberyesHours worked a week
paidWeeksPerYearnumber–Paid weeks a year; defaults to 52 (holiday is paid)
scottishTaxpayerboolean–True for a Scottish taxpayer (Scottish bands)
studentLoanPlanstring–Student loan plan, if any (plan4 is Scotland, postgrad the postgraduate loan)
taxYearstring–UK tax year, e.g. "2026-27". Defaults to the current one.

No output schema declared.

No examples provided.

convert_salary_to_hourly_rate ~161

Convert an annual salary to its gross hourly rate and the take-home pay per hour, for the hours a week and paid weeks a year given, in a tax year.

NameTypeReqDescription
annualSalarynumberyesGross annual salary
hoursPerWeeknumberyesHours worked a week
paidWeeksPerYearnumber–Paid weeks a year; defaults to 52
scottishTaxpayerboolean–True for a Scottish taxpayer (Scottish bands)
studentLoanPlanstring–Student loan plan, if any (plan4 is Scotland, postgrad the postgraduate loan)
taxYearstring–UK tax year, e.g. "2026-27". Defaults to the current one.

No output schema declared.

No examples provided.

create_invoice ~212

Create and save a draft invoice in the signed-in person's TapTax account from a client name and one or more line items. No saved client, earlier invoice or client email is needed to create it; an email is only needed later, to send it. It is numbered in their sequence, uses their saved business details, and is not sent. Free plans include 3 invoices; paid plans are unlimited.

NameTypeReqDescription
clientAddressstring––
clientEmailstring–The client email; required to send the invoice
clientNamestringyes–
dueDatestring–Exact due date; otherwise dueInDays applies
dueInDaysinteger–Payment terms in days when no dueDate is given (0 = due on receipt)
issueDatestring–Defaults to today
itemsarrayyes–
notesstring––
vatRatePercentnumber–VAT rate for a VAT-registered business, e.g. 20

No output schema declared.

No examples provided.

estimate_self_assessment_penalties ~121

Estimate Self Assessment late filing penalties, late payment penalties and late payment interest on the tax due, from how many days late the return was filed and the tax was paid.

NameTypeReqDescription
annualInterestRatePercentnumber–HMRC's late payment interest rate a year; defaults to 7.75
filingDaysLateintegeryesDays after the filing deadline the return was filed
paymentDaysLateintegeryesDays after the payment deadline the tax was paid
taxDuenumberyesTax due on the return

No output schema declared.

No examples provided.

estimate_self_employed_tax ~245

Estimate UK income tax and Class 4 National Insurance for a sole trader from turnover and allowable expenses, with the take-home figure, effective and marginal rates, payments on account and tailored tips, from HMRC's published rates for the tax year. Works from the figures given, without a TapTax account.

NameTypeReqDescription
businessMilesnumber–Business miles driven in a car or van, claimed at the approved mileage rate
expensesnumber–Allowable business expenses, in pounds (excluding mileage if businessMiles is given)
otherIncomenumber–Other taxable income such as a salary or pension, in pounds
pensionContributionsnumber–Personal pension contributions paid (relief at source), in pounds
studentLoanPlanstring––
taxDeductedAtSourcenumber–Tax already paid through PAYE or CIS deductions this year
taxYearstring–UK tax year, e.g. "2026-27" (6 April 2026 to 5 April 2027). Defaults to the current one.
turnovernumberyesSelf-employed income before expenses, in pounds

No output schema declared.

No examples provided.

generate_invoice_numbers ~156

Generate invoice numbers: the next number after a given one (keeping its prefix and zero padding), or a run of numbers in a chosen format (prefix, separator, optional year or month, number of digits) from a starting number.

NameTypeReqDescription
countinteger–How many; defaults to 1
datePartstring––
digitsinteger–Digits in the number; defaults to 4
lastNumberstring–The last number used, e.g. INV-0041
prefixstring–Letters, numbers and single hyphens, e.g. INV
separatorstring––
startinteger–First number; defaults to 1

No output schema declared.

No examples provided.

get_mileage_summary ~53

Read the signed-in person's own mileage log in their TapTax account for a tax year: total miles, the deductible amount at the approved rates, and the most recent trips.

NameTypeReqDescription
taxYearstring––

No output schema declared.

No examples provided.

get_mtd_deadlines ~55

List the standard Making Tax Digital quarterly update periods and deadlines for a tax year, and which one is next. Updates are cumulative from 6 April.

NameTypeReqDescription
taxYearstring–Defaults to the current tax year

No output schema declared.

No examples provided.

get_tax_position ~107

Read the signed-in person's own TapTax account: their tax year so far, as their dashboard shows it: business income, expenses and profit counted by the filing rule, the estimated income tax and Class 4 NI, how many transactions still need a business-or-personal decision, which quarterly updates they have filed through TapTax, and the next deadline. Needs no figures from the person: everything comes from their records.

NameTypeReqDescription
taxYearstring–Defaults to the current tax year

No output schema declared.

No examples provided.

list_invoices ~77

Read the signed-in person's own invoices from their TapTax account, newest first, with each one's live status (a sent invoice past its due date reads as overdue) and the totals outstanding and overdue. Needs no details from the person.

NameTypeReqDescription
limitinteger––
statusstring–unpaid = sent, viewed or overdue

No output schema declared.

No examples provided.

list_transactions ~143

Read and search the signed-in person's own income and expense records in their TapTax account, newest first. Filter by tax year or dates, type, text in the description, or needsReview=true for the ones still waiting for a business-or-personal decision (the review queue). Needs no details from the person beyond what to look for.

NameTypeReqDescription
fromstring–On or after this date
limitinteger––
needsReviewboolean––
searchstring–Text to find in the description
taxYearstring––
tostring–On or before this date
typestring––

No output schema declared.

No examples provided.

log_mileage_trip ~117

Record a business journey in the signed-in person's mileage log. TapTax prices it at the approved mileage rate for the tax year (tiered after 10,000 car miles). Commuting to a permanent workplace is not business mileage. Mileage tracking is on the Pro plan.

NameTypeReqDescription
datestringyes–
fromstringyes–
milesnumberyesBusiness miles for this trip
purposestringyes–
tostringyes–
vehiclestring–Vans count as car

No output schema declared.

No examples provided.

mark_invoice_paid ~34

Record that the client has paid an invoice (dated today). Stops any payment reminders.

NameTypeReqDescription
invoiceIdstringyes–

No output schema declared.

No examples provided.

plan_quarterly_tax_set_aside ~162

Plan how much to set aside for tax as a sole trader under Making Tax Digital, from the year's profit or each quarter's profit: the income tax, Class 4 National Insurance and student loan due, monthly and weekly amounts to put away, running totals by quarter with each update deadline, and any first payment on account.

NameTypeReqDescription
annualProfitnumber–Expected profit for the year (split evenly across quarters)
firstYearOfTradingboolean–True in the first year, when the first payment on account is also due
quarterlyProfitsarray–Profit for each quarter, Q1 to Q4, instead of an annual figure
studentLoanPlanstring–Student loan plan, if any

No output schema declared.

No examples provided.

prepare_business_document ~220

Prepare an invoice, quote, receipt, credit note or pro forma invoice in TapTax's free document generator, without a TapTax account. Returns the totals and a link that opens the generator with the document filled in, where the person checks it, adds a logo if they like, and downloads the PDF. The details travel in the link itself and are not stored by TapTax.

NameTypeReqDescription
clientAddressstring––
clientEmailstring––
clientNamestring––
datestring–Issue date, YYYY-MM-DD; defaults to today
fromAddressstring––
fromNamestring–The business issuing it
kindstringyesWhich document
linesarrayyes–
notesstring––
numberstring–Document number, e.g. INV-0042
paymentTermsstring––
templatestring–Design; defaults to the generator default
vatRatePercent––Defaults to 0

No output schema declared.

No examples provided.

prepare_quarterly_update ~143

Get the signed-in person's Making Tax Digital quarterly update ready: the cumulative income, expenses and profit from 6 April to the end of the quarter, what still needs reviewing, and a card with a button that opens TapTax to check and file it. Filing itself always happens in the TapTax app, never from the chat, so HMRC receives the details of the device the person files from.

NameTypeReqDescription
quarterinteger–1 = to 5 July, 2 = to 5 October, 3 = to 5 January, 4 = to 5 April
taxYearstring–Defaults to the current tax year

No output schema declared.

No examples provided.

send_invoice ~84

Get one of the signed-in person’s invoices ready to email, with its PDF, to the client address on it from their business name. It opens a card showing exactly what the client will receive (who it goes to, the lines and the total) with a Send button. Nothing is emailed until the person presses Send on that card.

NameTypeReqDescription
invoiceIdstringyes–

No output schema declared.

No examples provided.

send_invoice_from_card ~59

Emails the invoice shown on a TapTax send card to its client, when the person presses Send on that card. Needs the one-time token the card was given.

NameTypeReqDescription
invoiceIdstringyes–
sendTokenstringyes–

No output schema declared.

No examples provided.

update_transaction ~87

Change a transaction the signed-in person owns: mark it business or personal (this is how the review queue is cleared), or correct its category, description, amount or date.

NameTypeReqDescription
amountnumber––
businessOrPersonalstring––
categorystring––
datestring––
descriptionstring––
idstringyes–

No output schema declared.

No examples provided.

Common questions

What is the TapTax MCP server?

TapTax is an MCP server listed in the public MCP registry as uk.co.taptax/taptax. UK tax: take-home pay, self-employed and company tax, VAT, stamp duty, invoices and MTD. This page covers its hosted endpoint (https://api.taptax.co.uk/mcp).

Is the TapTax MCP server safe to use?

TapTax scores 69 out of 100 on VerifyMCP. That is a record of what we were able to check automatically, not an endorsement. The category breakdown on this page shows every signal behind the number, including the ones we could not confirm.

What tools does the TapTax MCP server expose?

TapTax exposes 49 tools: estimate_self_employed_tax, check_tax_code, check_mtd_status, get_mtd_deadlines, calculate_take_home_pay, and 44 more. Their descriptions and schemas cost roughly 6,938 tokens of context every time the server is loaded.

Does the TapTax MCP server require authentication?

No. We connected to TapTax without credentials and it answered, so anything it exposes is reachable by anyone who knows the address.

Is the TapTax MCP server still maintained?

TapTax is still listed as active in the MCP registry. We last reached this channel on 7 October 2026. Those dates come from our own scans of the registry and the channel itself, not from anything the publisher announced.