German Legal MCP Server

⚠️ WARNING: Work in Progress
This project is currently under active development and not production-ready. APIs may change without notice, and features may be incomplete or unstable. Use at your own risk.

A Model Context Protocol (MCP) server for German legal research, providing unified access to multiple legal databases.

Supported Sources

Features

Bundes- & Landesrecht (legis:* tools)

• Federal and state legislation — BUND (all federal laws) + 16 Länder (all states)
• No authentication — free public access, no rate limits
• Unified interface — one set of tools for all jurisdictions
• Full text search — search across state legislation (Länder only)
• Resilient input — BUND accepts "§ 823", "823", "Art. 1", "Paragraph 51"
• Pandoc-compatible Markdown — clean conversion with Turndown
• Save to file — save_path parameter to avoid context pollution
• Available states: BUND, BB, BW, BY, BE, HB, HE, HH, MV, NI, NW, RP, SL, SN, ST, SH, TH

Rechtsprechung im Internet (rii:* tools)

• Federal court decisions — BVerfG, BGH, BVerwG, BFH, BAG, BSG, BPatG (from 2010)
• Bavarian state courts — AG, LG, OLG, VG, VGH, FG, ArbG, LAG, BayVerfGH via gesetze-bayern.de
• No authentication — free public access
• Full text search — search across all federal court decisions
• Kurztext/Langtext — summary or full text via part parameter
• Randnummern — formatted as [Rn. 5]{.rn} (pandoc spans)
• Save to file — save_path parameter to avoid context pollution

InfoCuria — CJEU (icu:* tools)

• EU Court of Justice case law — judgments, opinions, orders from CJEU and General Court
• No authentication — free public access via InfoCuria API
• Multilingual — documents available in all EU languages (default: DE)
• Flexible case lookup — accepts case numbers (C-476/17), CELEX numbers, or internal IDs
• Randnummern — formatted as [Rn. 5]{.rn}
• Partial content — section parameter for Rn ranges, headings, or line ranges
• Save to file — save_path parameter to avoid context pollution

EUR-Lex (eul:* tools)

• EU legislation — directives, regulations, decisions, treaties (TFEU, TEU)
• No authentication — free public access via Cellar REST API and SPARQL
• Multilingual — documents available in all EU languages (default: DE)
• CELEX lookup — retrieve by CELEX number (e.g., "32016R0679" for GDPR)
• SPARQL search — search by title keywords, filter by resource type
• Partial content — section parameter for articles (Art. 5), headings, or line ranges
• Save to file — save_path parameter to avoid context pollution

DIP Bundestag (dip:* tools)

• Parliamentary documents — Bundestagsdrucksachen (Gesetzentwürfe, Beschlussempfehlungen, Anfragen)
• Legislative processes — Vorgänge with status tracking and linked documents
• Debate transcripts — full text search across Plenarprotokolle (BT and BR)
• Full text retrieval — extracted text including Gesetzesbegründungen, with section support
• Public API key included — works out of the box (key expires 2026-06-01, override via env var)
• Save to file — save_path parameter to avoid context pollution

arXiv (arxiv:* tools)

• Preprint search — search by keywords, author, title, abstract, or category
• Metadata + abstract — default response without full text fetch (token-efficient)
• HTML full text — Markdown conversion for papers from ~2024+ (LaTeXML HTML)
• PDF fallback — older papers without HTML return abstract + PDF link
• No authentication — free public API, no rate limits beyond ~1 req/3s
• Save to file — save_path parameter to avoid context pollution

nautos.de (nautos:* tools)

• DIN/EN/ISO standards — search and retrieve technical standards from nautos.de
• Two-phase document retrieval — outline (metadata + TOC) first, then sections on demand
• Automatic authentication — IP-based login (auto-detected), user-based login fallback
• Structured TOC — hierarchical table of contents with section IDs for navigation
• File cache — 30-day TTL, persistent across restarts (~/.local/share/german-legal-mcp/cache/nautos/)
• Save to file — save_path parameter to dump full document to disk

Quick Start with npx

npx @metaneutrons/german-legal-mcp

or add your MCP client config (e.g., claude_desktop_config.json):

{
  "mcpServers": {
    "german-legal": {
      "command": "npx",
      "args": ["-y", "@metaneutrons/german-legal-mcp"]
    }
  }
}

Environment Variables

Provider Enablement

nautos.de Configuration

Authentication: IP-based login is tried first (requires GLMCP_NAUTOS_TENANT_KEY). If it fails and credentials are set, user-based login is attempted as fallback.

Tools

Bundes- & Landesrecht

Rechtsprechung im Internet

InfoCuria — CJEU

EUR-Lex

DIP Bundestag

arXiv

nautos.de

Two-Phase Document Retrieval

All document tools use a two-phase approach to avoid flooding the LLM context:

1. Outline — first call returns title, metadata, table of contents, and a preview
2. Section — request specific parts by Randnummer, heading, or line range (served from cache)
3. Save to file — write full document to disk, return metadata only

Section formats: "Rn 5", "Rn 5-12", "lines:100-200", or any heading text (fuzzy match).

Markdown Output

Documents are converted to pandoc-compatible Markdown:

• Randnummern: [Rn. 5]{.rn} (bracketed spans)
• Footnotes: ^[inline footnote text] (pandoc inline footnotes)

Development

npm test              # Run tests
npm run test:watch    # Watch mode
npm run test:coverage # Coverage report

MCP Inspector

npx @modelcontextprotocol/inspector node dist/index.js

Commit Convention

This repo uses Conventional Commits enforced via Husky + commitlint.

Types: feat, fix, docs, style, refactor, perf, test, chore, ci, build, revert

Scopes: legis, rii, icu, eul, dip, nautos, core, deps, config

Architecture

• Dynamic provider loading — providers auto-discovered from src/providers/*/
• Cheerio + Turndown for HTML → pandoc Markdown conversion
• Zod for input validation
• Axios for HTTP requests (Legis, RII, InfoCuria, EUR-Lex, DIP, arXiv, nautos)
• Structured JSON errors — all providers return BaseError.toJSON() with code, userMessage, recoveryHint; Axios errors auto-wrapped; DNS failures fail fast
• Conversion validation — all HTML→Markdown providers validate output is non-empty; detects upstream layout changes early
• Tools namespaced by source (legis:, rii:, icu:, eul:, dip:, arxiv:, nautos:)

License

GPL-3.0 - See LICENSE for details.