kaisha-mcp
MCP server for the Kaisha API, providing official Japanese company-registry data including corporate numbers and qualified invoice registrations, with pay-per-call via USDC micropayments.
README
kaisha-mcp
MCP server for the Kaisha API — official Japanese company-registry data for AI agents, paid per call with x402 (USDC on Base or Solana). No API keys, no signup — the paying wallet is the account.
Data comes from Japan's National Tax Agency open datasets: all ~5.8M registered corporations (法人番号) and ~5M qualified-invoice registrations (適格請求書). Individual proprietors' names are never returned.
Install
Add it to any MCP client (Claude Code, Cursor, OpenClaw, …) in one line:
claude mcp add kaisha -e EVM_PRIVATE_KEY=0x<base-wallet-with-usdc> -- npx -y kaisha-mcp
Or run it directly:
EVM_PRIVATE_KEY=0x... npx -y kaisha-mcp
Configuration
Set at least one signing key — a wallet holding a small amount of USDC (calls cost $0.002–$0.01):
| Env var | Meaning |
|---|---|
EVM_PRIVATE_KEY |
Base wallet private key holding USDC (0x…) |
SVM_PRIVATE_KEY |
Solana wallet private key holding USDC (base58) |
EVM_RPC_URL |
(optional) Base RPC, default https://mainnet.base.org |
KAISHA_BASE_URL |
(optional) API base, default https://kaisha-api.hp-vladic.workers.dev |
Keep your private key in your MCP client's env config — never commit it.
Tools
| Tool | Description | Price |
|---|---|---|
resolve_japanese_company |
Company name (fuzzy) or 13-digit corporate number → canonical name, address, entity type, active/closed | $0.005 |
verify_japan_invoice_number |
Qualified-invoice number (T+13 digits) → active / cancelled / not-found, registration date, name |
$0.01 |
japan_new_companies |
Daily feed of newly registered companies (新設法人), closures, moves, renames, mergers from NTA diff data | $0.01 |
japan_business_days |
Business-day check / add N days / count a range (weekends + national holidays) | $0.002 |
japan_holidays |
Japanese national holidays for a year (1955–2027) | $0.002 |
kaisha_catalog |
Machine-readable catalog of endpoints, prices, and payment networks | free |
How payment works
Each priced call triggers the x402 flow automatically: the API replies 402 Payment Required with a price, your wallet signs a USDC payment, the request is retried, and the data comes back with an on-chain settlement proof. Every challenge offers both Base (eip155:8453) and Solana mainnet.
Links
- API & docs: https://kaisha-api.hp-vladic.workers.dev
- npm: https://www.npmjs.com/package/kaisha-mcp
- Catalog (free): https://kaisha-api.hp-vladic.workers.dev/catalog
License
MIT
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