# PlugRail Japanese Calendar

Works out Japanese holidays and business days from Cabinet Office data. Useful when deadlines or schedules in your project follow the Japanese calendar.

- MCP server · `type=mcp` · Claude Code, Codex, Cursor, GitHub Copilot, Windsurf (Devin Desktop), Cline, Zed, Gemini CLI
- Author: plugrail
- License: MIT · policy=link-only · description only; the file stays with the author
- Source: https://github.com/plugrail/servers
- Updated: 2026-10-07
- HTML: https://affpapa.org/en/nevibecode/mcp/plugrail-japanese-calendar

## What it does

Four tools ship with the server: `is_holiday`, `list_holidays`, `business_days_between` and `add_business_days`. Your agent can ask whether a given date is a day off, pull the holiday list for a range, count business days between two dates, or shift a date forward by a number of business days.

Holiday data sits in Cloudflare D1, with Cloudflare KV handling the cache. The hosted endpoint is `https://jp-calendar.plugrail.dev/mcp`, and that is the quickest way in. Authentication, rate limiting and usage metering exist only on the hosted side, so a self-hosted copy does not inherit them.

Self-hosting means copying `wrangler.example.jsonc` to `wrangler.jsonc` under `packages/servers/jp-calendar/`, filling in your own Cloudflare resource IDs, creating the D1 database and KV namespace, then running `pnpm --filter @plugrail/jp-calendar deploy`. The project is independent of Japanese government bodies and carries no guarantee from them, so for anything legally binding check the primary source.

## Requirements
- Remote server: `https://jp-calendar.plugrail.dev/mcp`

## Install

### Claude Code (native platform)

**Platform CLI: remote server**
```bash
claude mcp add --transport http jp-calendar https://jp-calendar.plugrail.dev/mcp
```

### Codex

**Platform CLI: remote server**
```bash
codex mcp add plugrail-japanese-calendar --url https://jp-calendar.plugrail.dev/mcp
```

### Cursor

**Config file**
File `.cursor/mcp.json`:
```json
{
    "mcpServers": {
        "plugrail-japanese-calendar": {
            "url": "https://jp-calendar.plugrail.dev/mcp"
        }
    }
}
```

### GitHub Copilot

**Config file**
File `.vscode/mcp.json`:
```json
{
    "servers": {
        "plugrail-japanese-calendar": {
            "type": "http",
            "url": "https://jp-calendar.plugrail.dev/mcp"
        }
    }
}
```

### Gemini CLI

**Platform CLI: remote server**
```bash
gemini mcp add -t http plugrail-japanese-calendar https://jp-calendar.plugrail.dev/mcp
```

## When to use it
- check whether a date falls on a Japanese public holiday
- count business days between two dates, skipping days off
- push a deadline forward by a set number of business days
- list Japanese holidays across a date range
- keep a Japanese day off from being treated as a working day

## Example prompts
- Check with jp-calendar whether May 3 is a holiday and tell me which one
- Count the business days between April 1 and June 30 on the Japanese calendar
- Add five business days to December 20 and give me the resulting date

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