Data Butler MCP

Current UK (2026-27) rates and thresholds, verified against gov.uk with source URLs and verification dates. Categories: income-tax, national-insurance, minimum-wage, student-loans, vat, isa, state-pension, state-pension-age, stamp-duty, capital-gains, pensions, dividends, savings, marriage-allowance, statutory-sick-pay, statutory-parental-pay, child-benefit. Covers UK income tax, National Insurance, minimum wage, student loans, VAT, ISAs, pensions, stamp duty, capital gains, dividends, savings, the State Pension and State Pension age, statutory sick/maternity/paternity pay and Child Benefit.

{
  "type": "object",
  "properties": {
    "category": {
      "type": "string",
      "description": "one of: income-tax, national-insurance, minimum-wage, student-loans, vat, isa, state-pension, state-pension-age, stamp-duty, capital-gains, pensions, dividends, savings, marriage-allowance, statutory-sick-pay, statutory-parental-pay, child-benefit (omit to list all)"
    }
  }
}

{
  "title": "UK rates lookup",
  "readOnlyHint": true,
  "openWorldHint": false,
  "idempotentHint": true,
  "destructiveHint": false
}

Which exam paper is a topic on? The canonical student revision question ("is electricity paper 2 AQA?" — answer: no, Paper 1). Input a topic plus optional board/subject/level; returns the paper, sibling topics on that paper, spec code, and the official spec URL. Knows quirks like AQA Combined Science Trilogy Physics Paper 2 having no Space physics. Coverage: AQA GCSE Physics (8463); AQA GCSE Biology (8461); AQA GCSE Chemistry (8462); AQA GCSE Combined Science: Trilogy (8464); AQA GCSE Mathematics (8300).

{
  "type": "object",
  "required": [
    "topic"
  ],
  "properties": {
    "board": {
      "type": "string",
      "description": "e.g. aqa"
    },
    "level": {
      "type": "string",
      "description": "e.g. gcse"
    },
    "topic": {
      "type": "string",
      "description": "e.g. electricity, forces, ecology, organic chemistry"
    },
    "subject": {
      "type": "string",
      "description": "e.g. physics, combined science"
    }
  }
}

{
  "title": "Exam topic → paper",
  "readOnlyHint": true,
  "openWorldHint": false,
  "idempotentHint": true,
  "destructiveHint": false
}

Who runs this domain? Live RDAP lookup: registration date and age, registrar, nameservers, status, whether the registrant is redacted, plus a typosquat check (edit-distance / brand-substring) against high-value brands. A very recently registered domain resembling a bank or big brand is a classic phishing signal — but report it as a signal, not a conclusion.

{
  "type": "object",
  "required": [
    "domain"
  ],
  "properties": {
    "domain": {
      "type": "string",
      "description": "e.g. example.com"
    }
  }
}

{
  "title": "Domain provenance",
  "readOnlyHint": true,
  "openWorldHint": true,
  "idempotentHint": true,
  "destructiveHint": false
}

Who publishes this package, and is it a typosquat? Live npm or PyPI lookup: first-publish date and age, release count, latest version, maintainers/author, linked repo, plus a typosquat check against popular package names. Use when an agent is about to install or recommend an unfamiliar dependency.

{
  "type": "object",
  "required": [
    "ecosystem",
    "name"
  ],
  "properties": {
    "name": {
      "type": "string",
      "description": "package name, e.g. express or requests"
    },
    "ecosystem": {
      "enum": [
        "npm",
        "pypi"
      ],
      "type": "string",
      "description": "npm or pypi"
    }
  }
}

{
  "title": "Package provenance",
  "readOnlyHint": true,
  "openWorldHint": true,
  "idempotentHint": true,
  "destructiveHint": false
}

Net salary after income tax and social contributions for an employee in one of ten countries (uk, us, ca, au, in, br, pl, fr, de, es), computed live by the LifeByNumbers salary calculators (same operator). Takes a gross salary in local currency (annual by default, or monthly with period) and a country code, plus optional state and filingStatus for the US, province for Canada, region (england|scotland) for the UK and region (madrid|cataluna) for Spain. Returns gross, net and total deductions (each annual and monthly), a line-by-line breakdown typed as tax / social / contribution / repayment, effectiveRate, the tax year the figures apply to, currency, the assumptions behind the estimate and the upstream calculator page as source.

{
  "type": "object",
  "required": [
    "country",
    "gross"
  ],
  "properties": {
    "gross": {
      "type": "number",
      "description": "gross salary in local currency, annual unless period is monthly, e.g. 50000"
    },
    "state": {
      "type": "string",
      "description": "US only: two-letter state code, e.g. TX (default CA)"
    },
    "period": {
      "enum": [
        "annual",
        "monthly"
      ],
      "type": "string",
      "description": "period of gross (default annual); results always give both annual and monthly"
    },
    "region": {
      "enum": [
        "england",
        "scotland",
        "wales",
        "northern-ireland",
        "madrid",
        "cataluna"
      ],
      "type": "string",
      "description": "UK: england | scotland | wales | northern-ireland (scotland applies Scottish income tax bands; default england). Spain: madrid | cataluna, the autonomous community whose IRPF scale applies (default madrid)"
    },
    "country": {
      "enum": [
        "uk",
        "us",
        "ca",
        "au",
        "in",
        "br",
        "pl",
        "fr",
        "de",
        "es"
      ],
      "type": "string",
      "description": "ISO 3166-1 alpha-2, lower case: uk, us, ca, au, in, br, pl, fr, de, es"
    },
    "province": {
      "type": "string",
      "description": "Canada only: two-letter province/territory code, e.g. BC (default ON)"
    },
    "filingStatus": {
      "enum": [
        "single",
        "married_joint",
        "head_of_household"
      ],
      "type": "string",
      "description": "US only (default single)"
    }
  }
}

{
  "title": "Take-home pay",
  "readOnlyHint": true,
  "openWorldHint": true,
  "idempotentHint": true,
  "destructiveHint": false
}

What has changed in Data Butler's verified datasets since a date — pass your training-cutoff date to learn which UK tax/NI/benefit thresholds, exam-spec facts, official vehicle datasets (UK DVSA, French RappelConso and Japanese MLIT recalls), software end-of-life dates (Node.js, Python, Ubuntu, Debian, Android, iOS, macOS, Windows, Java, Go, Ruby, PHP, PostgreSQL, React — cycles that reached end of life or whose dates moved), central-bank policy rates (Bank of England, Fed, ECB), US federal tax thresholds (IRS inflation adjustments, Social Security wage base, retirement and HSA limits), German tax and social-insurance thresholds (Grundfreibetrag, Beitragsbemessungsgrenzen, Zusatzbeitrag, Mindestlohn, Kindergeld, Umsatzsteuer), UK vehicle tax (VED) rates and MOT rules, UK exam dates (results days, summer timetable paper dates, entry deadlines and late-fee dates, announced specification changes), calendar facts (public holidays for the UK, US, Germany and France; tax-year and daylight-saving rules for nine countries — new years published, holidays added or moved), UK government service fees and rules (passports, ETA, Universal Credit, eVisa), Japanese vehicle statutory costs (車検 inspection fees, 自賠責 insurance rates), Japanese minimum wages by prefecture, 協会けんぽ health insurance rates, 雇用保険料率 and income-tax deductions, UK CPI and CPIH inflation rates (ONS, monthly) and US inflation (BLS CPI-U 12-month rate and index, each monthly release) changed after your knowledge ends. Each entry: from → to, effectiveFrom, official source, verifiedDate, and a maintainer note (e.g. which Budget). Areas: uk-rates, uk-exams, vehicles, software-eol, policy-rates, us-rates, de-rates, uk-vehicle-rules, uk-exam-dates, calendar, uk-gov-process, jp-vehicle-costs, jp-living-costs, uk-inflation, us-inflation, or all. Coverage starts 2026-08-31. The same changelog is published for humans at https://databutler.dev/changes, with feeds at https://databutler.dev/changes.rss and https://databutler.dev/changes.atom. Output is a Verified Changes protocol document (verified-changes/0.1, spec https://databutler.dev/protocol); an entry whose figure is a Verified Fact carries factKey for get_fact.

{
  "type": "object",
  "required": [
    "since"
  ],
  "properties": {
    "area": {
      "enum": [
        "uk-rates",
        "uk-exams",
        "vehicles",
        "software-eol",
        "policy-rates",
        "us-rates",
        "de-rates",
        "uk-vehicle-rules",
        "uk-exam-dates",
        "calendar",
        "uk-gov-process",
        "jp-vehicle-costs",
        "jp-living-costs",
        "uk-inflation",
        "us-inflation",
        "all"
      ],
      "type": "string",
      "description": "default all"
    },
    "since": {
      "type": "string",
      "description": "ISO date YYYY-MM-DD, e.g. your training cutoff"
    }
  }
}

{
  "title": "What changed since",
  "readOnlyHint": true,
  "openWorldHint": false,
  "idempotentHint": true,
  "destructiveHint": false
}

The current value of one official figure by key — a tax threshold, rate, allowance, fee, deadline, limit or policy rate — with the date it was verified, the official source URL, the period it applies to and a signature. Keys are `<country>/<topic>/<fact>`, e.g. `uk/income-tax/personal-allowance`, `uk/national-insurance/primary-threshold`, `us/social-security/wage-base`, `de/income-tax/grundfreibetrag`, `uk/bank-rate`, `eu/ecb/deposit-facility`, `uk/gov/passport-renewal-adult/fee-online-uk`. A loose key is resolved when unambiguous; otherwise the answer lists candidate keys. `max_age` (e.g. `30d`) marks the answer `stale` when the verification is older than that. `nextExpectedChange` is the next date the source's calendar allows the value to move; `status` is `stale` when that date has passed since verification. Several keys separated by commas return a batch. Covers UK, US and German rates and thresholds, UK vehicle tax and MOT rules, UK government service fees, UK exam dates and central-bank policy rates; `coverage` lists the rest.

{
  "type": "object",
  "required": [
    "key"
  ],
  "properties": {
    "key": {
      "type": "string",
      "description": "one key, or several separated by commas (max 50), e.g. uk/income-tax/personal-allowance"
    },
    "as_of": {
      "type": "string",
      "format": "date",
      "description": "optional YYYY-MM-DD: the value in force that day"
    },
    "period": {
      "type": "string",
      "description": "optional period label instead of as_of, e.g. 2025-26"
    },
    "max_age": {
      "type": "string",
      "description": "optional freshness bar: 30d, 12w, 6m, 1y or ISO 8601 (P30D)"
    }
  }
}

{
  "title": "Get a verified fact",
  "readOnlyHint": true,
  "openWorldHint": false,
  "idempotentHint": true,
  "destructiveHint": false
}

Ranked canonical fact keys for a plain-language question or a guessed key — "NI primary threshold", "ECB deposit rate", "passport renewal fee" — each with label, unit, period and verification date, and the full record of the top match when it is unambiguous. The keys feed `get_fact`. Filter by `namespace` (`uk`, `us`, `de`, `eu`).

{
  "type": "object",
  "required": [
    "q"
  ],
  "properties": {
    "q": {
      "type": "string",
      "description": "question or guessed key"
    },
    "limit": {
      "type": "integer",
      "maximum": 20,
      "minimum": 1,
      "description": "default 5"
    },
    "namespace": {
      "enum": [
        "de",
        "eu",
        "jp",
        "uk",
        "us"
      ],
      "type": "string",
      "description": "optional jurisdiction filter"
    }
  }
}

{
  "title": "Find the key for a fact",
  "readOnlyHint": true,
  "openWorldHint": false,
  "idempotentHint": true,
  "destructiveHint": false
}

Exactly what Data Butler covers and does not, per area, including figures it does not serve yet. Areas: uk-rates, uk-exams, provenance, stats, vehicles, tax, software-eol, policy-rates, us-rates, de-rates, uk-vehicle-rules, uk-exam-dates, calendar, uk-gov-process, jp-vehicle-costs, jp-living-costs, uk-inflation, us-inflation (omit for all). Returns rate categories and tax years, boards/subjects, package ecosystems, stats operations, vehicle datasets, take-home-pay countries, the 14 software products with end-of-life data, central-bank policy rates (boe, fed, ecb), US federal rate categories and tax year, German rate categories and Veranlagungszeitraum, UK vehicle tax (VED) and MOT rule categories, UK exam dates (results, timetable, deadlines, spec-changes for jcq, aqa, pearson, ocr, wjec-eduqas; sqa results day), calendar facts: public holidays (uk, us, de, fr), tax years and daylight saving (uk, us, de, fr, au, in, ca, br, pl) for 2026–2028, UK government services (passports, DVLA, voting, registrations, Self Assessment, benefits, eVisa, ETA), Japanese vehicle statutory cost categories (weight tax, 自賠責, inspection fees, car taxes), Japanese daily-life figure categories (minimum wage, health insurance, pension, employment insurance, benefits, holidays, consumption tax, income tax, resident tax), UK inflation categories (cpi, cpih), US CPI-U inflation (latest month, prior month, annual averages), and an explicit notCovered list.

{
  "type": "object",
  "properties": {
    "area": {
      "type": "string",
      "description": "one of uk-rates, uk-exams, provenance, stats, vehicles, tax, software-eol, policy-rates, us-rates, de-rates, uk-vehicle-rules, uk-exam-dates, calendar, uk-gov-process, jp-vehicle-costs, jp-living-costs, uk-inflation, us-inflation"
    }
  }
}

{
  "title": "Coverage",
  "readOnlyHint": true,
  "openWorldHint": false,
  "idempotentHint": true,
  "destructiveHint": false
}

Every tool across all Data Butler servers (UK rates; UK exams; provenance; exact statistics; vehicles: UK MOT, UK, French and Japanese recalls; take-home pay for ten countries; software support status and end-of-life timelines for 14 runtimes and operating systems; central-bank policy rates: Bank of England, Fed, ECB; US federal rates and thresholds (us_rates_lookup: income tax, Social Security, Medicare, retirement, HSA, estate and gift, capital gains, IRMAA, RMD); German tax and social-insurance figures (de_rates_lookup: Einkommensteuertarif, Sozialversicherung, Mindestlohn, Minijob, Kindergeld, Kinderfreibetrag, Pauschbeträge, Entfernungspauschale, Umsatzsteuer); UK vehicle tax (VED) and MOT rules; UK exam dates and spec changes: results days, the summer 2027 timetable, entry deadlines, new specifications; calendar facts: public holidays, tax-year starts and daylight-saving switches for 2026–2028; UK government services: passport, driving licence, vehicle tax/SORN, voting, birth/death registration, Blue Badge, Self Assessment, NI number, Universal Credit, EU Settlement Scheme, eVisa, ETA; Japan vehicle statutory costs (jp_vehicle_costs_lookup: 自動車重量税, エコカー減税, 自賠責保険, 検査手数料, 自動車税, 軽自動車税); Japan daily-life official figures (jp_living_costs_lookup: 最低賃金, 健康保険料率, 年金, 雇用保険, 児童手当, 高額療養費, 祝日, 消費税, 基礎控除, 住民税); UK inflation: CPI and CPIH 12-month rates, CPI index and annual averages (ONS); US inflation (us_inflation_lookup: BLS CPI-U 12-month rate, index level, annual averages)), with input schemas — including tools not listed at this front door. Optional query filters by keyword. Run any of them with call, or connect to serverUrl directly.

{
  "type": "object",
  "properties": {
    "query": {
      "type": "string",
      "description": "keyword filter, e.g. regression, exam, npm"
    }
  }
}

{
  "title": "Tool catalogue",
  "readOnlyHint": true,
  "openWorldHint": false,
  "idempotentHint": true,
  "destructiveHint": false
}

Run any Data Butler tool by name — the long tail not listed here: exam_spec_lookup, exam_paper_index; exact statistics (distribution, hypothesis_test, confidence_interval, bayes_update, linear_regression, descriptive_stats); the vehicles hub (uk_mot_reliability, uk_recalls_for_model, uk_recalls_search, fr_recalls_for_model, fr_recalls_search, jp_recalls_for_model, jp_complaints_summary); software end-of-life (support_status {product, version}, support_timeline {product} for nodejs, python, ubuntu, debian, android, ios, macos, windows, oracle-jdk, go, ruby, php, postgresql, react); policy_rate (Bank of England Bank Rate, Fed federal funds target range, ECB key rates — committed data verified against the banks' own pages); us_rates_lookup (US federal rates and thresholds for the current tax year: income-tax, social-security, medicare, retirement, hsa, estate-gift, social-security-benefits, medicare-costs, capital-gains); de_rates_lookup (German tax and social-insurance figures for the current Veranlagungszeitraum: income-tax, social-insurance, minimum-wage, minijob, kindergeld, kinderfreibetrag, sparer-pauschbetrag, arbeitnehmer-pauschbetrag, entfernungspauschale, vat); uk_vehicle_rules_lookup (UK car tax: first-year CO2 bands, standard rate, expensive car supplement, 2001–2017 bands, pre-2001 rates, electric cars, historic vehicles; MOT due dates, fees, retests, penalties — verified against gov.uk); UK exam dates (uk_exam_dates {kind: results|timetable|deadlines|spec-changes, board?, qualification?}); calendar facts (calendar_facts {country, kind: holidays|tax-year|dst, year?, region?} and next_holiday {country, from?} — holidays for uk, us, de, fr; tax years and DST for uk, us, de, fr, au, in, ca, br, pl; 2026–2028); uk_gov_process (UK government services — passport and ETA fees, driving licence renewal, SORN, register to vote, birth/death registration, Self Assessment deadlines, NI number, Universal Credit, EU Settlement Scheme, eVisa — fees, processing times, start URLs, dated changes, verified against gov.uk); jp_vehicle_costs_lookup (Japan 車検 statutory costs and car taxes: weight-tax, weight-tax-eco, cali, inspection-fee, auto-tax, kei-tax — verified against MLIT, FSA, NALTEC and local-government pages); jp_living_costs_lookup (Japan minimum wage by prefecture, 協会けんぽ rates, pensions, employment insurance, benefits, 2027 holidays, consumption tax, income-tax deductions, resident tax — verified against MHLW, NTA, 総務省, 内閣府, こども家庭庁, 日本年金機構 and 協会けんぽ pages); uk_inflation_lookup (UK CPI and CPIH inflation from the ONS); us_inflation_lookup (US CPI-U from the BLS: 12-month percent change, index level 1982-84=100, annual averages from 2021, with release dates). uk_rates_lookup, domain_provenance, package_provenance and take_home_pay are listed directly. See catalogue for schemas. The result carries the inner tool's freshness and cite.

{
  "type": "object",
  "required": [
    "tool"
  ],
  "properties": {
    "tool": {
      "type": "string",
      "description": "tool name from catalogue"
    },
    "arguments": {
      "type": "object",
      "description": "that tool's arguments"
    }
  }
}

{
  "title": "Call any tool",
  "readOnlyHint": true,
  "openWorldHint": true,
  "idempotentHint": true,
  "destructiveHint": false
}