Houan MCP Server

@codeagentjp/houan-mcp

Local stdio MCP server for searching Japanese Diet bills (衆参議案情報) and committee Q&A records via the NDL Kokkai (国会会議録検索システム) API.

This server does not call an LLM. It only returns source-backed Diet data, with primary URLs (NDL Kokkai, 衆議院議案情報, 参議院議案情報) so your MCP client (Claude Desktop, Claude Code, Cursor, or any other agent) can cite the original source.

Sister package: @codeagentjp/egov-law-mcp for current Japanese laws (e-Gov Law Search). houan-mcp covers the legislative process side: bills under deliberation, committee questionings, and full meeting transcripts.

Status

MVP. Four tools:

• find_diet_qa — full-text search across all Diet committee speeches via the NDL Kokkai API. Filter by date, chamber, committee, speaker.
• get_meeting_record — retrieve a single committee's full transcript by issueID.
• search_bills — search current-session bills in either house by title keyword.
• get_bill — retrieve detail of one bill (proceedings timeline, committee assignment, full-text URL).

Requirements

• Node.js 20 or later
• Network access to https://kokkai.ndl.go.jp, https://www.shugiin.go.jp, https://www.sangiin.go.jp

Install

From npm:

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

From source:

git clone https://github.com/SHAYOUWORLD/houan-mcp.git
cd houan-mcp
node bin/houan-mcp.mjs

{
  "mcpServers": {
    "houan": {
      "command": "node",
      "args": ["/absolute/path/to/houan-mcp/bin/houan-mcp.mjs"]
    }
  }
}

Tools

find_diet_qa

Full-text search of Diet committee speeches via the NDL Kokkai API.

{
  "keyword": "クロード ミトス",
  "from": "2026-04-01",
  "until": "2026-04-25",
  "chamber": "衆議院",
  "committee": "外務委員会",
  "limit": 5
}

Returns matched speeches with speaker, position, committee context, and direct NDL URL.

get_meeting_record

Retrieve a single full transcript by issueID.

{
  "issueID": "122103968X00620260410"
}

search_bills

Search 衆議院議案情報 / 参議院議案情報 by title keyword.

{
  "keyword": "情報",
  "chamber": "both",
  "session": 221,
  "limit": 20
}

get_bill

Retrieve a bill detail page (proceedings timeline, committee assignment, full-text URL). The proceedingURL must be a URL returned by search_bills — it is validated against the chamber's allowed path prefix before fetching.

{
  "chamber": "shugiin",
  "proceedingURL": "https://www.shugiin.go.jp/internet/itdb_gian.nsf/html/gian/keika/1DE..."
}

Data Sources and Attribution

This package uses three Japanese public sources:

• NDL Kokkai (国会会議録検索システム) — https://kokkai.ndl.go.jp/ · API documentation. Diet records published 1947–. No auth required. Be a good neighbour: insert short delays between sequential requests, avoid concurrent bursts.
• 衆議院議案情報 — https://www.shugiin.go.jp/internet/itdb_gian.nsf/html/gian/menu.htm
• 参議院議案情報 — https://www.sangiin.go.jp/japanese/joho1/kousei/gian/index.htm

Tool results include the source URL. When you publish or redistribute output based on this package, include an appropriate attribution. Suggested:

出典: 国会会議録検索システム (https://kokkai.ndl.go.jp/) / 衆議院議案情報 / 参議院議案情報

Example: pulling a Mythos Q&A

The 4/10 2026 衆議院外務委員会 questioning by 宇佐美登 (チームみらい) on Anthropic's Claude Mythos Preview can be retrieved like this:

{
  "tool": "find_diet_qa",
  "arguments": {
    "keyword": "クロード",
    "from": "2026-04-01",
    "until": "2026-04-30"
  }
}

The response includes 花田貴裕 政府参考人's verbatim answer with meetingURL pointing to the canonical NDL record at https://kokkai.ndl.go.jp/txt/122103968X00620260410.

Safety Notes

• This package is a legislative reference tool, not legal/political advice.
• It does not execute shell commands.
• It writes JSON-RPC messages only to stdout and logs only to stderr.
• It fetches only the NDL Kokkai API and 衆/参 議案情報 endpoints.
• Diet records in NDL typically appear with a 1–2 week lag after the committee meeting. If a recent meeting cannot be found, check back later or consult the chamber's video library directly.

Related

• Sibling MCP for current laws: @codeagentjp/egov-law-mcp
• Roadmap (法令diff / 自治体条例 / 判例 MCPs): SHAYOUWORLD/egov-law-mcp#1
• Use cases (Japanese): houan-mcp の7つの実用ユースケース (codeagent.jp)
• From bills to current law (Japanese): houan-mcpとe-Gov法令MCPの調査フロー (codeagent.jp)
• Other Japanese public-data APIs and MCP servers: codeagent.jp/guides/public-data-api/

License

MIT © codeagent.jp