Legal MCP - German Legal Texts Search System

A comprehensive system for searching and analyzing German legal texts using vector embeddings and semantic search, consisting of:

• Store API: FastAPI backend with PostgreSQL, pgvector, and Ollama embeddings

• MCP Server: FastMCP server providing tools for AI assistants to query legal texts

• CLI Tool: Command-line interface for importing and querying legal texts

• Web Scraper: Automatic extraction of legal texts from gesetze-im-internet.de

• XML Parser: Comprehensive parser for German legal XML format (gii-norm.dtd)

Table of Contents

• Features

• Architecture

• Quick Start

• CLI Tool

• Environment Configuration

• API Documentation

• Legal Text Features

• XML Parser

• Development

• Docker Commands

• Troubleshooting

• Project Structure

• Technology Stack

Features

Store API Features

• 🗄️ PostgreSQL + pgvector - Vector database for semantic search

• 🤖 Ollama Integration - Generate embeddings for legal texts

• 🌐 Web Scraping - Automatic extraction from gesetze-im-internet.de

• 📄 XML Parsing - Comprehensive parser for German legal XML format

• 🔍 Semantic Search - Vector-based similarity search for legal texts

• 📊 Metadata Tracking - Full document metadata and versioning

• 📝 RESTful API - FastAPI with automatic documentation

• 🐳 Docker Support - Easy deployment with containerization

MCP Server Features

• 🔧 FastMCP - Modern MCP server implementation

• 🤝 AI Assistant Integration - Provides tools for querying legal texts

• 🔌 HTTP API Client - Connects to Store API for data access

CLI Tool Features

• 📋 List Commands - View imported codes and available catalog

• 📥 Import Commands - Import legal codes with progress indication

• 🔍 Query Commands - Retrieve texts by code, section, and sub-section

• 🔎 Search Commands - Semantic search with similarity scoring

• 📊 Multiple Output Formats - Table view or JSON output

• ⚙️ Configurable - Custom API URL support via flag or environment variable

Architecture

┌──────────────────────────────────────────────────┐
│                                                  │
│  Docker Network: legal-mcp-network               │
│                                                  │
│  ┌────────────────┐                              │
│  │  MCP Server    │ :8001                        │
│  │  (FastMCP)     │                              │
│  └───────┬────────┘                              │
│          │                                       │
│          │ LEGAL_API_BASE_URL                    │
│          │ http://store-api:8000                 │
│          │                                       │
│          ▼                                       │
│  ┌────────────────┐                              │
│  │  Store API     │ :8000                        │
│  │  (FastAPI)     │                              │
│  └───────┬────────┘                              │
│          │                                       │
│          │ DATABASE_URL                          │
│          │ postgresql://postgres:5432            │
│          │ OLLAMA_BASE_URL                       │
│          │                                       │
│          ▼                                       │
│  ┌────────────────┐                              │
│  │  PostgreSQL    │ :5432                        │
│  │  + pgvector    │                              │
│  └────────────────┘                              │
│                                                  │
└──────────────────────────────────────────────────┘
         │
         │ External Ollama Service
         │ (for embeddings)
         ▼
┌────────────────┐
│  Ollama API    │
│  (Remote/Local)│
└────────────────┘

Quick Start

Prerequisites

• Docker and Docker Compose

• Ollama (local or remote endpoint for embeddings)

• Git

⚠️ Important: Ollama Embedding Model

By default, this project uses the embedding model: ryanshillington/Qwen3-Embedding-4B:latest

You must pull this model (or your configured alternative) before importing legal texts:

ollama pull ryanshillington/Qwen3-Embedding-4B:latest

You can use a different model by setting the OLLAMA_EMBEDDING_MODEL environment variable, but the model must produce 2560-dimensional vectors. Using a model with different dimensions will cause errors, as the database schema is fixed at 2560 dimensions. Changing to a model with different dimensions would require database schema modifications and re-importing all legal texts.

1. Clone and Setup

# Clone the repository
git clone <repository-url>
cd legal-mcp

# Copy environment file
cp .env.example .env

# Edit .env with your configuration
# Update OLLAMA_BASE_URL and OLLAMA_AUTH_TOKEN if needed

2. Start All Services

# Build and start all services
docker-compose up -d

# Check service status
docker-compose ps

This will start:

• PostgreSQL (port 5432) - Database with pgvector extension

• Store API (port 8000) - FastAPI backend for legal texts

• MCP Server (port 8001) - FastMCP server for AI assistants

3. Run Database Migrations

# Run Alembic migrations to set up the database
docker-compose exec store-api alembic upgrade head

4. Import Legal Texts

# Import a test legal code (e.g., rag_1)
curl -X POST http://localhost:8000/legal-texts/gesetze-im-internet/rag_1

# Import German Civil Code (BGB)
curl -X POST http://localhost:8000/legal-texts/gesetze-im-internet/bgb

# Import other legal codes
curl -X POST http://localhost:8000/legal-texts/gesetze-im-internet/stgb  # Criminal Code
curl -X POST http://localhost:8000/legal-texts/gesetze-im-internet/gg    # Constitution

5. Test the API

# Check API health
curl http://localhost:8000/health

# Query legal texts by section
curl "http://localhost:8000/legal-texts/gesetze-im-internet/rag_1?section=%C2%A7%201"

# Semantic search (requires embeddings)
curl "http://localhost:8000/legal-texts/gesetze-im-internet/rag_1/search?q=Versicherung&limit=5"

# Access interactive API documentation
open http://localhost:8000/docs

CLI Tool

The CLI provides a convenient command-line interface for managing legal texts without writing code.

Installation

# Install in development mode (from project root)
pip install -e .

# Verify installation
legal-mcp --help

Prerequisites

The CLI requires the Store API to be running:

# Start all services
docker-compose up -d

# Verify Store API is running
curl http://localhost:8000/health

Available Commands

List Commands

List Imported Codes

# Show all imported legal codes in table format
legal-mcp list codes

# Output as JSON
legal-mcp list codes --json

List Available Catalog

# Show all available legal codes that can be imported
legal-mcp list catalog

# Output as JSON
legal-mcp list catalog --json

Import Command

# Import a single legal code
legal-mcp import --code bgb

# Import multiple legal codes
legal-mcp import --code bgb --code stgb --code gg

# Import with JSON output
legal-mcp import --code bgb --json

The import command displays a spinner while processing and shows progress for each code.

Query Command

# Query all texts for a legal code
legal-mcp query bgb

# Query specific section
legal-mcp query bgb --section "§ 1"

# Query specific sub-section
legal-mcp query bgb --section "§ 1" --sub-section "1"

# Output as JSON
legal-mcp query bgb --section "§ 1" --json

Search Command

# Semantic search in a legal code
legal-mcp search bgb "Kaufvertrag"

# Limit number of results
legal-mcp search bgb "Kaufvertrag" --limit 5

# Set similarity cutoff threshold (0-2, lower = stricter)
legal-mcp search bgb "Kaufvertrag" --cutoff 0.5

# Output as JSON
legal-mcp search bgb "Kaufvertrag" --json

Configuration

Default API URL: http://localhost:8000

Override with environment variable:

export LEGAL_API_BASE_URL=http://custom-host:8000
legal-mcp list codes

Override with command flag:

legal-mcp list codes --api-url http://custom-host:8000

Output Formats

Table Format (default):

• Clean, formatted tables with Rich library

• Text truncation for readability

• Color-coded output

JSON Format:

• Complete data with full text content

• Machine-readable for scripting

• Use --json flag with any command

Example Workflow

# 1. Check available legal codes
legal-mcp list catalog

# 2. Import desired codes
legal-mcp import --code bgb --code stgb

# 3. Verify imports
legal-mcp list codes

# 4. Query specific sections
legal-mcp query bgb --section "§ 433"

# 5. Perform semantic search
legal-mcp search bgb "Kaufvertrag" --limit 10

Environment Configuration

The application uses a .env file for configuration. See .env.example for a template.

Required Environment Variables

# Ollama Configuration
OLLAMA_BASE_URL=https://your-ollama-endpoint.com
OLLAMA_AUTH_TOKEN=your-auth-token-here
OLLAMA_EMBEDDING_MODEL=ryanshillington/Qwen3-Embedding-4B:latest  # Optional, this is the default

# PostgreSQL Configuration
POSTGRES_HOST=postgres  # Use 'postgres' in Docker, 'localhost' for local dev

Note: The OLLAMA_EMBEDDING_MODEL variable allows you to use a different embedding model. However, any alternative model must produce 2560-dimensional vectors to be compatible with the database schema. The default model (ryanshillington/Qwen3-Embedding-4B:latest) is recommended.

Additional Configuration (set in docker-compose.yml)

# Database URL (automatically constructed)
DATABASE_URL=postgresql+asyncpg://legal_mcp:legal_mcp_password@postgres:5432/legal_mcp_db

# MCP Server Configuration
LEGAL_API_BASE_URL=http://store-api:8000

API Documentation

Once running, access the interactive API documentation:

• Swagger UI: http://localhost:8000/docs

• ReDoc: http://localhost:8000/redoc

Main Endpoints

Legal Texts

• POST /legal-texts/gesetze-im-internet/{book} - Import legal text with embeddings

• GET /legal-texts/gesetze-im-internet/{code} - Query legal texts by code/section

• GET /legal-texts/gesetze-im-internet/{code}/search - Semantic search with embeddings

System

• GET /health - Health check endpoint

• GET / - API information

MCP Server

The MCP Server provides tools for AI assistants to interact with the legal text database through the Model Context Protocol.

Available Tools

The MCP Server exposes the following tools:

• search_legal_texts - Perform semantic search on legal texts

  • Parameters: query, code, limit (1-20), cutoff (0-2)

  • Returns: List of matching legal text sections with similarity scores

• get_legal_section - Retrieve specific legal text sections

  • Parameters: code, section, sub_section (optional)

  • Returns: List of legal text sections matching the criteria

• import_legal_code - Import a complete legal code from Gesetze im Internet

  • Parameters: code

  • Returns: Success message with import statistics

• get_available_codes - Get all available legal codes in the database

  • Returns: List of legal code identifiers

Using the MCP Server

The MCP Server runs on port 8001 and can be accessed by MCP-compatible clients:

# Check MCP server is running
curl http://localhost:8001/health

# The MCP server automatically connects to the Store API
# using LEGAL_API_BASE_URL environment variable

For AI assistants, configure the MCP client to connect to http://localhost:8001 (or the appropriate host/port for your deployment).

Legal Text Features

Importing Legal Texts

The system automatically:

1. Scrapes legal text XML from gesetze-im-internet.de

2. Parses the XML into structured legal text sections

3. Generates embeddings for each text section using Ollama

4. Stores the texts with their embeddings in PostgreSQL with pgvector

Querying Legal Texts

Query by section identifier:

curl "http://localhost:8000/legal-texts/gesetze-im-internet/bgb?section=%C2%A7%201"

Semantic Search

Search using natural language with vector similarity:

curl "http://localhost:8000/legal-texts/gesetze-im-internet/bgb/search?q=Kaufvertrag&limit=5&cutoff=0.7"

Parameters:

• q - Search query (required)

• limit - Maximum results (1-100, default: 10)

• cutoff - Similarity threshold (0-2, default: 0.5)

  • Lower values = stricter matching

  • 0.3-0.5: Very strict

  • 0.6-0.7: Good balance

  • 0.8-1.0: More permissive

XML Parser

The system includes a comprehensive parser for the gii-norm.dtd format used by gesetze-im-internet.de.

Parser Features

• Complete DTD Coverage - All major elements from gii-norm.dtd

• Structured Data - Type-safe dataclasses for all structures

• Text Extraction - Handles complex nested text with formatting

• Table Support - Captures table structures

• Footnote Handling - Extracts footnotes with references

• Metadata Parsing - Complete metadata extraction

Using the Parser

from app.scrapers import GesetzteImInternetScraper

# The scraper automatically uses the XML parser
scraper = GesetzteImInternetScraper()
legal_texts = scraper.scrape('bgb')

for text in legal_texts:
    print(f"Section: {text.section}")
    print(f"Text: {text.text}")

Parsed Metadata

The parser extracts:

• Legal abbreviations (jurabk, amtabk)

• Dates (ausfertigung-datum)

• Citations (fundstelle)

• Titles (kurzue, langue, titel)

• Structural classification (gliederungseinheit)

• Section designations (enbez)

• Version information (standangabe)

Development

Local Development (without Docker)

1. Install dependencies:

   python -m venv .venv
   source .venv/bin/activate  # On Windows: .venv\Scripts\activate
   pip install -r requirements.txt
   
   # Install CLI tool in development mode
   pip install -e .

2. Set up local database:

   # Start only PostgreSQL
   docker-compose up postgres -d
   
   # Update .env to use localhost
   # POSTGRES_HOST=localhost

3. Run migrations:

   cd store
   alembic upgrade head

4. Start Store API:

   cd store
   uvicorn app.main:app --reload --host 0.0.0.0 --port 8000

5. Start MCP Server:

   cd mcp
   export LEGAL_API_BASE_URL=http://localhost:8000
   python -m server.main

Running Tests

# Run all tests
pytest

# Run with coverage
pytest --cov=app tests/

# Run specific test file
pytest tests/test_main.py -v

# Run CLI tests specifically
pytest tests/cli/ -v

Contributing

We welcome contributions from the community! Please see our Contributing Guidelines for details on:

• How to report bugs

• How to suggest features

• How to submit pull requests

• Development setup instructions

• Code style guidelines

Code of Conduct

This project adheres to the Contributor Covenant Code of Conduct. By participating, you are expected to uphold this code. Please report unacceptable behavior through the project's reporting mechanisms.

Security

Security is important to us. If you discover a security vulnerability, please follow our Security Policy for responsible disclosure. Do not open public issues for security vulnerabilities.

License

This project is licensed under the MIT License - see the LICENSE file for details.

Acknowledgments

• Legal texts sourced from Gesetze im Internet

• Built with FastAPI, FastMCP, and Ollama

• Vector similarity search powered by pgvector

Support

• Issues: Open an issue on GitHub for bugs or feature requests

• Discussions: Use GitHub Discussions for questions and community chat

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