UK legal API for AI agents and researchers. Access comprehensive UK legislation and caselaw data with semantic search and Model Context Protocol integration.

Lex provides programmatic access to millions of UK legal documents, court decisions, and statutory instruments with advanced semantic search capabilities.

This is an experimental service and should not be used as a production dependency.

• Legislation - Acts and Statutory Instruments (1267-present, complete from 1963)
• Case Law - Court judgments and decisions (2001-present)
• Explanatory Notes - Legislative context and guidance
• Amendments - Changes and modifications over time
• PDF Digitisation - Historical legislation digitised using AI

• Legal Research - Find precedents and relevant legislation in seconds
• Policy Analysis - Track legislative changes over time
• AI Grounding - Ground AI assistants in authoritative UK legal sources

Connect AI assistants to Lex via Model Context Protocol. See the live documentation for setup instructions for:

• Claude Desktop
• Claude Code
• Cursor
• Microsoft Copilot Studio
• VS Code + GitHub Copilot

• Python 3.12+
• uv
• Docker & Docker Compose
• Azure OpenAI credentials

# Clone and setup
git clone https://github.com/i-dot-ai/lex.git && cd lex
cp .env.example .env  # Add your Azure OpenAI keys
# Start services and load sample data
docker compose up -d
make ingest-all-sample
# Visit https://localhost:8000/docs for API documentation

# Quick samples (recommended for testing)
make ingest-legislation-sample
make ingest-caselaw-sample
make ingest-all-sample
# Full datasets (production use)
make ingest-legislation-full
make ingest-caselaw-full
make ingest-all-full
# Create indexes for fast filtering
uv run python scripts/create_payload_indexes.py

make install          # Install dependencies
make test             # Run tests
make run              # Start API locally (without Docker)
uv run ruff format .  # Format code

lex/
├── src/
│   ├── lex/          # Data pipeline (scraping, parsing, indexing)
│   └── backend/      # API server (FastAPI + MCP)
├── tools/            # Export utilities (Parquet/JSONL)
└── docs/             # Documentation

• Deployment Guide
• Data Pipeline Guide
• API Reference
• Troubleshooting
• Contributing

Built with support from The National Archives and Ministry of Justice.

MIT - See LICENSE for details.