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Japanese Law MCP Server

Queries Japanese law data and EU cross-references from MCP clients with remote or local hosting.

Installation

Add the following to your MCP client configuration file.

Configuration

{
  "mcpServers": {
    "ansvar-systems-japan-law-mcp": {
      "url": "https://japan-law-mcp.vercel.app/mcp"
    }
  }
}

You can query Japanese law directly from MCP clients to access up-to-date provisions, cross-references, and AI-friendly context. This server provides fast, verifiable statute text and EU cross-references for data protection, cybersecurity, corporate law, and more, enabling legal researchers, compliance officers, and developers to work with Japanese law in an AI-enabled workflow.

How to use

You connect your MCP client to one or more MCP endpoints exposed by this server. The hosted endpoint offers direct remote access for Claude, Claude Code, Claude Desktop, and compatible clients. You can also run the server locally via npm or npx when you want an on-machine setup. Once connected, you can run natural language queries such as asking for specific provisions, checking if a statute is currently in force, or finding EU cross-references implemented by Japanese law.

How to install

Prerequisites: you need Node.js and npm installed on your system. Ensure you are using a modern environment capable of running SQLite-based full-text search and JavaScript tooling.

Option A — Use remotely (no install required): connect to the hosted MCP endpoint directly from your client.

Option B — Run locally with npm: clone the project, install dependencies, build if needed, and start the server.

Step-by-step commands to run locally:

git clone https://github.com/Ansvar-Systems/Japan-law-mcp
cd Japan-law-mcp
npm install
npm run build
npm run dev

Use locally with npx for quick start

You can start the MCP server directly with npm or npx without long setup steps.

To start with npx, run this command in your terminal.

npx @ansvar/japan-law-mcp

Configure clients to connect

Remote endpoint (recommended for quick access): use the hosted URL in your MCP client configuration.

Local startup via npm (example): add this to your client’s configuration to use the local server.

Quick start configuration examples

{
  "mcpServers": {
    "japan_law_http": {
      "type": "http",
      "url": "https://japan-law-mcp.vercel.app/mcp",
      "args": []
    }
  }
}

Available tools

search_legislation

Perform full-text search across all provisions with BM25 ranking to locate relevant statutes and sections.

get_provision

Retrieve a specific provision by statute identifier along with its chapter and section for precise citation.

check_currency

Determine whether a statute is in force, amended, or repealed, to ensure you reference current law.

validate_citation

Validate a legal citation against the database to reduce citation errors and hallucinations.

build_legal_stance

Aggregate citations from multiple statutes to build a legal position on a topic.

format_citation

Format citations according to Japanese conventions, including full, short, or pinpoint formats.

list_sources

List all available statutes with metadata for quick reference.

about

Provide server information, capabilities, and coverage summary for quick assessment.

get_eu_basis

Retrieve EU directives or regulations referenced by a Japanese statute.

get_japanese_implementations

Find Japanese laws that implement a given EU act.

search_eu_implementations

Search EU documents with counts of Japanese implementations.

get_provision_eu_basis

Get EU law references associated with a specific provision.

validate_eu_compliance

Check the implementation status of EU directives within Japanese law.