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

Source	Status	Prefix	Authentication
Bundes- & Landesrecht	✅ Available	legis:	None (public)
Rechtsprechung im Internet	✅ Available	rii:	None (public)
InfoCuria (CJEU)	✅ Available	icu:	None (public)
EUR-Lex	✅ Available	eul:	None (public)
DIP Bundestag	✅ Available	dip:	Public key included
arXiv	✅ Available	arxiv:	None (public)
nautos.de	✅ Available	nautos:	Required (IP or credentials)

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

Variable	Default	Description
GLMCP_LEGIS_ENABLED	true	Bundes- & Landesrecht
GLMCP_RII_ENABLED	true	Rechtsprechung im Internet
GLMCP_ICU_ENABLED	true	InfoCuria (CJEU)
GLMCP_EUL_ENABLED	true	EUR-Lex
GLMCP_DIP_ENABLED	true	DIP Bundestag (auto-disabled after 2026-06-01 without own key)
GLMCP_DIP_API_KEY	Public key	Override the bundled public API key
GLMCP_ARXIV_ENABLED	true	arXiv preprint search
GLMCP_NAUTOS_ENABLED	Auto	nautos.de. Auto-enabled with tenant key or credentials, auto-disabled without.

nautos.de Configuration

Variable	Required	Description
GLMCP_NAUTOS_TENANT_KEY	For IP-based	Tenant key (e.g., DWW). Enables IP-based authentication.
GLMCP_NAUTOS_USERNAME	For user-based	nautos.de account username
GLMCP_NAUTOS_PASSWORD	For user-based	nautos.de account password
GLMCP_NAUTOS_TENANT_ID	No	Tenant ID (auto-detected from login response)

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

Tool	Description
legis:search	Search federal and state legislation. Parameter: query, state (e.g., "BW", "BE"), limit. Note: BUND does not support search.
legis:get	Retrieve a specific law/norm. BUND: id = "law/section" (e.g., "bgb/823"). Länder: id from search results. Optional save_path.
legis:toc	Compact table of contents for a law — section numbers and headings. Supports from/to range and depth filter. BUND: id = law abbreviation (e.g., "bgb").
legis:states	List available jurisdictions with implementation status.

Rechtsprechung im Internet

Tool	Description
rii:search	Search for court decisions. Returns list with doc IDs, titles, and snippets. Use source: "BY" for Bavarian state courts.
rii:get_decision	Retrieve full text of a court decision by doc ID. part: K (Kurztext) or L (Langtext, default). Optional save_path to save to file. Use source: "BY" for gesetze-bayern.de IDs.

InfoCuria — CJEU

Tool	Description
icu:search	Search CJEU decisions and opinions. Returns case numbers, ECLI, dates, and document IDs.
icu:get_document	Retrieve full text by case number (C-476/17) or CELEX number. Supports section (Rn ranges, headings, line ranges) and save_path.

EUR-Lex

Tool	Description
eul:search	Search EU legislation via SPARQL. Filter by type (directive, regulation, decision, treaty).
eul:get_document	Retrieve EU legislation by CELEX number (e.g., "32016R0679" for GDPR). Supports section (Art. 5, Artikel 5-10, headings, line ranges) and save_path.

DIP Bundestag

Tool	Description
dip:search	Search Bundestagsdrucksachen by title. Filter by type (Gesetzentwurf, Anfrage, etc.), Wahlperiode, date range.
dip:get	Retrieve full text of a Drucksache by Dokumentnummer (e.g., "19/27426"). Supports section and save_path.
dip:search_vorgang	Search legislative processes (Vorgänge) with status and linked Drucksachen.
dip:search_plenarprotokoll	Full text search across parliamentary debate transcripts (BT and BR).

arXiv

Tool	Description
arxiv:search	Search preprints by keywords, author, title, abstract, or category. Returns metadata + abstract.
arxiv:get	Retrieve paper by arXiv ID. Default: metadata + abstract. With section or save_path: HTML full text as Markdown (~2024+, older: PDF link).

nautos.de

Tool	Description
nautos:search	Search DIN/EN/ISO standards by document number. Returns acCode, title, date, type.
nautos:get_document	Retrieve standard by acCode. Returns outline (metadata + TOC) by default; use section for specific parts, save_path to save full document.

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.