Japan Data MCP

io.github.Mameta29Published by GitHub account Mameta29v1.1.0Updated Oct 24, 2026

30 tools for Japanese data: address, furigana, transit, Diet, holidays, weather, corporate registry

VerifiedSTDIODesktop onlyLocation & LifestyleFinanceBusiness & Commerce

Overview

AI-generated overview

A local MCP server giving assistants 28 tools for Japanese data — addresses, furigana, transit, Diet records, holidays, weather and corporate registry — paid in

What you can do
Normalize, geocode, reverse-geocode and parse Japanese addresses, and look up postal codes; convert furigana readings, get name readings and classify text; check rail station status, line disruptions, route plans, alternative routes, lines and stations; search Diet members and full-text proceedings; check holidays and do business-day math; get JMA weather forecasts, warnings and areas; look up, search and verify corporate numbers and produce KYB reports
When to use it
Useful when an assistant needs authoritative Japanese reference data in one place: address cleanup and geocoding, Japanese name readings, real-time rail disruption and route planning, public-holiday and business-day calculations, weather, Diet proceedings, or corporate-number lookups and verification.
Requirements
Runs locally over stdio, typically launched with npx, so Node.js and network access are needed. No account or API key; paid tools require the EVM_PRIVATE_KEY environment variable holding a USDC-funded wallet key. Desktop MCP clients only.
Before you install
The EVM_PRIVATE_KEY value can spend the wallet's funds, and each paid call costs roughly $0.001–$0.10 in USDC on Base; use a dedicated wallet funded only with what you intend to spend, never a primary wallet. Without the key the server starts but paid tools return a payments-disabled error. Requests go to the agentic-jp.com APIs.

Installation

In SourceWeft

  1. Open Japan Data MCP in the dashboard and add it to a workspace.
  2. Enable the server for the chats that should use its tools.

Desktop only via STDIO. STDIO servers start a local process, so they need the SourceWeft desktop host.

Other MCP clients

Follow the launch instructions in the repository.

README

japan-data-mcp

[npm version] [license] [Japan Furigana API on x402-list]

npm: @mameta/japan-data-mcp · MCP Registry: io.github.Mameta29/japan-data-mcp · transport: stdio

An MCP server that gives AI agents (Claude Desktop, Cursor, Cline, …) one-call access to the agentic-jp.com suite of Japanese data APIs. Every call is settled per-use over the x402 payment protocol — no account, no subscription, no API key.

What it covers — 28 tools across 7 APIs

APIToolsWhat it does
addressaddress_normalize, address_geocode, address_reverse_geocode, address_postal_code, address_parseJapanese address normalization, geocoding, postal-code lookup, free-form parsing
furiganafurigana_convert, furigana_name_readings, furigana_classifyReading conversion, name readings, text classification
transittransit_station_status, transit_line_disruptions, transit_route_plan, transit_alternative_routes, transit_lines, transit_stations_searchReal-time rail delays + delay-aware route planning (ODPT)
dietdiet_member, diet_members_search, diet_minutes_searchNational Diet members and full-text proceedings search
holidayholiday_is_holiday, holiday_list, holiday_add_business_days, holiday_business_days_betweenPublic holidays + business-day math
weatherweather_forecast, weather_warnings, weather_areasJMA forecasts and warnings
houjinhoujin_corporation, houjin_search, houjin_verify, houjin_kyb_reportCorporate-number (法人番号) registry — 5.78M corporations, one-call KYB report

How payment works

x402 is a buyer-pays protocol. This MCP server holds your wallet and pays each API call transparently — the agent never sees a payment prompt. Calls cost roughly $0.001–$0.10 each (mostly sub-cent), settled in USDC on Base.

  • You fund a wallet with a small amount of USDC.
  • You set EVM_PRIVATE_KEY to that wallet's key.
  • The server pays as it goes; per-call cost is well under a cent for most tools.

Without EVM_PRIVATE_KEY the server still starts and lists every tool, but a paid tool call returns a clear "payment not configured" message — nothing is charged.

Security: the key in EVM_PRIVATE_KEY can spend that wallet's funds. Use a dedicated wallet funded with only what you intend to spend — never a primary wallet.

Setup

No install step — npx fetches and runs the server on demand.

Claude Desktop

Add to claude_desktop_config.json:

json
{  "mcpServers": {    "japan-data": {      "command": "npx",      "args": ["-y", "@mameta/japan-data-mcp"],      "env": {        "EVM_PRIVATE_KEY": "0xYOUR_FUNDED_WALLET_KEY"      }    }  }}

Without EVM_PRIVATE_KEY the server still starts and lists all 28 tools; the paid tools then return a clear "payments disabled" error instead of running. Add a USDC-funded wallet key to enable them.

Cursor / Cline

Point the MCP client at npx -y @mameta/japan-data-mcp with the same EVM_PRIVATE_KEY env var. Transport is stdio.

From source

bash
git clone https://github.com/Mameta29/japan-data-mcp.gitcd japan-data-mcpnpm install && npm run build# then point the MCP client at: node /abs/path/to/dist/index.js

Example prompts

Once connected, just ask the agent in natural language:

  • "「東京都千代田区丸の内1-1」を正規化して緯度経度も出して" — address_normalize + address_geocode
  • "Is tomorrow a public holiday in Japan? If so, when is the next business day?" — holiday_is_holiday + holiday_add_business_days
  • "山手線いま遅れてる?渋谷から東京駅までの代替ルートは?" — transit_line_disruptions + transit_alternative_routes
  • "Look up the corporation with corporate number 7010401056220" — houjin_corporation
  • "国会で「デジタル庁」がいつどの委員会で議論されたか調べて" — diet_minutes_search

Configuration

Env varRequiredDescription
EVM_PRIVATE_KEYfor paid toolsPrivate key of a USDC-funded wallet (Base / Polygon). Paid tools are disabled if absent.

Development

bash
npm run dev        # run from source with tsxnpm run typecheck  # tsc --noEmitnpm run build      # compile to dist/

License

Apache-2.0

Source: README.md at commit e2c2714

Tools

0
SourceWeft has not started this package in its sandbox yet, so its tools are not known.

Version history

1
  1. v1.1.0LatestSep 16, 2026

Score

50% of the applicable checks met

How complete this listing is, computed from the registry entry, the endpoint and public sources. Not a rating of the server and not a statement that it is safe or working today: reachability is a dated check, and no installs or reviews go into the score.

  • Reached in the last 30 days25 pts

    Keep the endpoint answering the MCP handshake; SourceWeft probes it every 30 days.

  • Auth declared10 pts

    Declare the credential headers in the registry entry, or keep the endpoint answering the probe so its auth can be classified.

  • Tools listed15 pts

    Answer tools/list without a credential, or ship a package that starts in a sandbox without one.

  • DescriptionRequired15 pts
  • Logo10 pts
  • Documentation15 pts
  • License10 pts