Japan Data MCP

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

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:

{  "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

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

Development

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

License

Apache-2.0