@matsubokkuri/seireki-mcp

Model Context Protocol server for the Japanese calendar (西暦/和暦) and public-holiday API at https://seireki.teraren.com. Exposes the public REST endpoints (Seireki ↔ Wareki conversion, holidays, iCalendar feed) as MCP tools so AI agents can answer questions like "what era is 1997 in Japan?", "give me Japanese holidays for 2024", or "convert 平成元年 to a Western year" without scraping HTML.

Install

npm install -g @matsubokkuri/seireki-mcp
# or run on demand
npx @matsubokkuri/seireki-mcp

Configure

The server speaks MCP over stdio, so any compatible host can launch it.

Claude Desktop / Claude Code

Add the following to your claude_desktop_config.json (or the equivalent .mcp.json for Claude Code):

{
  "mcpServers": {
    "seireki": {
      "command": "npx",
      "args": ["-y", "@matsubokkuri/seireki-mcp"]
    }
  }
}

Custom base URL

Point the server at a staging deployment by setting SEIREKI_API_BASE_URL:

{
  "mcpServers": {
    "seireki": {
      "command": "npx",
      "args": ["-y", "@matsubokkuri/seireki-mcp"],
      "env": {
        "SEIREKI_API_BASE_URL": "https://staging.seireki.example.com"
      }
    }
  }
}

Tools

| Tool | Description | | --- | --- | | convert_seireki_to_wareki | Convert a Western year to its Japanese era (with age + zodiac). | | convert_wareki_to_seireki | Convert a Wareki year to its Western counterpart. | | list_seireki_years | Full Western-to-Japanese conversion table. | | list_wareki_years | Full Japanese-to-Western conversion table. | | get_holidays | Japanese national holidays for one year (1970+). | | list_holiday_years | Per-year summary (count + URL) of holidays. | | get_holidays_ics | Raw iCalendar (.ics) feed for one year. |

Develop

bun install
bun run build
bun run test
node dist/index.js   # speaks MCP over stdio

License

MIT — see LICENSE.