日本の給与・社会保険・労働法
io.github.kishida-devil/jp-payroll-mcpJapan payroll & social insurance. 日本の給与計算・社会保険。47都道府県の料率、源泉所得税、割増賃金、有給、標準報酬月額の改定、最低賃金。根拠の条文つき。
Score: 100/100
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Tools · 30
Full monthly deduction breakdown for one employee: health insurance, long-term care, pension, child support, employment insurance, withholding income tax and net pay, with the employer share as well. …
Workers compensation (労災保険) rates by business type, and the employer premium on a given 賃金総額. The whole premium falls on the employer — nothing is deducted from the employee, unlike every other statu…
Premiums and income tax on a 賞与. Both work differently from monthly pay and are routinely got wrong. Premiums are charged on 標準賞与額 (the bonus truncated to the thousand yen) under two caps that behave…
Income tax to withhold from a payment, from the National Tax Agency tables. The taxable amount is pay AFTER social insurance has been deducted, not gross. Pick the table with `period`: "monthly" for …
Decides whether a pay change forces the standard remuneration to be revised, and answers SEPARATELY for health insurance and pension — the tables differ, so a change routinely moves one and not the ot…
The yearly redetermination of standard remuneration, effective each September through the following August. Months below the payment-basis-day threshold drop OUT of the average entirely — they are no…
A separate route with a lower bar than 随時改定, and the one people forget. ONE grade of movement is enough, and fixed pay need not have changed at all — which matters because returning to shorter hours u…
Runs calculate_payslip for many employees in one call and returns the run totals: gross, employee deductions, net, and employer cost. Reach for this the moment more than two or three people are in pl…
Runs the annual 定時決定 for a whole payroll in one call, and reports which employees moved grade. 健康保険法第41条 puts every insured employee on the same schedule — the average of April, May and June pay, ove…
For work whose April-June happens to be its busiest or quietest quarter, where the ordinary calculation would fix a grade that is wrong for eleven months of the year. Available for 定時決定 (since April 2…
Maps a monthly amount to its health grade (1-50) and pension grade (1-32), with the standard remuneration each resolves to and whether the pension grade was clamped. Use it to check a grade, not to co…
For anyone outside employee cover: the self-employed, freelancers, people between jobs. Use this instead of calculate_payslip when the person is not an employee. Running a freelancer through the pays…
What one employee costs an employer over a year, bonuses included. Reach for this rather than multiplying a payslip by twelve, because the two do not agree once a bonus is paid. 健康保険法第45条 caps the st…
Works out how many days of paid leave someone has been granted, and whether the employer still owes the five days it must direct. 労働基準法第39条 grants ten working days once six months of service are comp…
Decides whether someone is covered by health and pension insurance, and on which payment-basis day count their annual determination runs. Call this before decide_regular_remuneration or judge_monthly…
The single most expensive month-end mistake in Japanese payroll, and one an assistant will get wrong from memory. Coverage ends the day AFTER the last day worked, not on it. So an employee leaving on…
Maternity and childcare leave look alike and behave differently. Maternity leave has no day-count test and exempts bonus premiums unconditionally; childcare leave gained a 14-day rule in October 2022 …
Returns the exact date each threshold is crossed and which premium starts or stops: long-term care begins at 40 and ends at 65, pension ends at 70, health insurance ends at 75 (transfer to 後期高齢者医療). …
Year-end adjustment (年末調整) for 2026 from the National Tax Agency's 令和8年分 booklet: the printed 給与所得控除後の給与等の金額 table (1,103 rows), the income-adjustment deduction, social/life/earthquake insurance deduc…
Estimate of next fiscal year's resident tax (住民税: 道府県民税 + 市町村民税 + 森林環境税) from the previous year's income and the municipality: employment income from the NTA table for that year, resident-tax deductio…
Health insurance, long-term care, pension and child-support rates for a prefecture, plus the bonus caps and the employer-only child-care contribution. Health rates differ by prefecture and change each…
Hourly 地域別最低賃金 for a prefecture. Revisions take effect prefecture by prefecture from October, on different days, so a date matters — pass one when checking a past payroll rather than assuming the curr…
Count business days in a range, shift a date by N business days, or check one date. Covers 1955-2027 including substitute holidays, 国民の休日 (a weekday that is a holiday only because it sits between two …
Checks the National Tax Agency check digit on many qualified-invoice registration numbers in one call. Be careful how you report the result. A passing check digit means the shape of the number is rig…
Checks the National Tax Agency check digit on a 13-digit 法人番号, or on a qualified invoice registration number (the same 13 digits prefixed with T). This proves the number is well formed. It does NOT p…
The consumption tax rate in force on a date, with the national and local parts, and the reduced 8% rate for food and newspapers. Pass amount to have the tax worked out. Japan changed the rate four ti…
Returns the full text of a Japanese statutory provision, as published by e-Gov. The judgement tools name the statute or notice their answer rests on, but not its words. Use this to quote the provisio…
Works out statutory premium pay under 労働基準法第37条 — overtime, night work and work on a statutory holiday. The rates do not simply add up, and getting this wrong under-pays wages. A night premium stacks…
Works out how much of a commuting allowance escapes income tax, and states the amount that still counts as remuneration for social insurance. These are two different bases, and that asymmetry is the …
Japanese statutory figures change on fixed dates — insurance rates each March, employment insurance each April, minimum wage each October — and a stale table produces numbers that look plausible and a…
How to use
Claude Desktop or claude.ai: add a custom connector (Customize → Connectors; on Team and Enterprise plans an owner adds it under Organization settings → Connectors) with this server URL: https://japan-payroll-api.tsumugi.workers.dev/mcp
Cursor or Cline: add to your MCP config:
{
"mcpServers": {
"\u65e5\u672c\u306e\u7d66\u4e0e\u30fb\u793e\u4f1a\u4fdd\u967a\u30fb\u52b4\u50cd\u6cd5": {
"url": "https://japan-payroll-api.tsumugi.workers.dev/mcp",
"transport": "streamable-http"
}
}
}