Jp Calendar MCP server

mcp-jp-calendar

日本語版はこちら (Japanese README)

Give your AI agent correct answers about Japanese business days. An MCP server that tells Claude (or any MCP client) whether a date is a working day in Japan, what date payment is actually due, and which fiscal quarter you're in — accounting for national holidays, substitute holidays, and conventions no simple weekday check gets right. No API keys, no network calls: all holiday data (2020–2030) is embedded in the package.

Contents

• Why this exists
• Install
• Tools
• Supported range & data source
• The meta field
• Versioning policy
• Maintenance policy
• Disclaimer
• Development
• Related tools

Why this exists

A naive "is it a weekday" check gets Japanese business dates wrong more often than you'd expect. A few real examples this server handles correctly:

Get any of these wrong in a scheduling or invoicing agent and you'll pick a bank holiday as a due date, or misreport a quarter. This server encodes the actual rules so your agent doesn't have to guess.

Install

Option 1 — npx (recommended)

No install step required. Add this to your Claude Desktop config (claudedesktopconfig.json):

• Windows: %APPDATA%\Claude\claudedesktopconfig.json
• macOS: ~/Library/Application Support/Claude/claudedesktopconfig.json

{
  "mcpServers": {
    "jp-calendar": {
      "command": "npx",
      "args": ["-y", "mcp-jp-calendar"]
    }
  }
}

Restart Claude Desktop and the tools become available. You can also run it directly:

npx mcp-jp-calendar

Or install it globally:

npm install -g mcp-jp-calendar

Option 2 — .mcpb bundle (one-click install for Claude Desktop)

MCP Bundles let you install a local MCP server with a single double-click, no terminal required. Build one from source:

git clone https://github.com/skypier-jp-works/mcp-jp-calendar.git
cd mcp-jp-calendar
npm install
npm run build
mkdir -p mcpb-dist/server && cp build/*.js mcpb-dist/server/
cd mcpb-dist
npm install --omit=dev
npm install -g @anthropic-ai/mcpb
mcpb pack . mcp-jp-calendar.mcpb

Then double-click the resulting mcp-jp-calendar.mcpb file to install it in Claude for macOS/Windows.

Tools

Shortened. The full README is on GitHub.