uk-legal-mcp

A Model Context Protocol server for UK legal research. Connects AI assistants to case law, legislation, parliamentary debates, bills, votes, committees, OSCOLA citation parsing, and HMRC tax data through a single endpoint.

24 tools across 8 modules. One connection. Read-only. No API keys required for 23 of 24 tools.

MCP Client (Claude, Cursor, etc.)
        |
        v
  uk-legal-mcp gateway  (Streamable HTTP)
  +----------------------------------------------------+
  |                                                    |
  |  case_law      TNA Find Case Law API               |
  |  legislation   legislation.gov.uk Atom feed         |
  |  parliament    Hansard API + Members API            |
  |  bills         Parliamentary Bills API              |
  |  votes         Commons + Lords division records     |
  |  committees    Select committees + evidence         |
  |  citations     OSCOLA regex parser (no network)     |
  |  hmrc          HMRC sandbox/prod + GOV.UK search    |
  |                                                    |
  +----------------------------------------------------+

Quickstart

Connect to the hosted server

Add to your Claude Desktop config (~/Library/Application Support/Claude/claude_desktop_config.json):

{
  "mcpServers": {
    "uk-legal": {
      "type": "streamable-http",
      "url": "https://uk-legal-mcp.fly.dev/mcp"
    }
  }
}

Then try:

• "Search for case law about cycling accidents"
• "Get section 172 of the Companies Act 2006"
• "Parse the citations in: The court applied Donoghue v Stevenson [1932] AC 562 and s.2 Occupiers' Liability Act 1957"
• "What is parliament saying about short selling?"

Run locally

pip install -e .
python -m src.gateway
# Server starts on http://localhost:8000/mcp

Inspect with the MCP Inspector:

npx @modelcontextprotocol/inspector http://localhost:8000/mcp

Tools

Case Law

Resource templates (read via resources/read or the read_resource tool generated by ResourcesAsTools):

Upstream: TNA Find Case Law (Atom/XML). Rate limit: 1,000 req/5 min. Cached 1 hour.

Legislation

Resource templates (alternative to the tools above for clients that prefer URI-addressed reads):

Upstream: legislation.gov.uk (CLML XML + Atom feed). Cached 24 hours. Uses curl_cffi with Chrome impersonation to defeat CloudFront 437; Companies Act 2006 currently hits an AWS WAF JS challenge intermittently.

Note: Always check the extent field. A section may apply to England and Wales but not Scotland or Northern Ireland.

Parliament

Upstream: hansard-api.parliament.uk + members-api.parliament.uk + petition.parliament.uk. Not cached (live data).

Bills

Upstream: bills-api.parliament.uk. Cached 1 hour.

Votes

Upstream: commonsvotes-api.parliament.uk + lordsvotes-api.parliament.uk. Cached 24 hours.

Committees

Upstream: committees-api.parliament.uk. Cached 1 hour.

Citations

Self-contained. No external API. Zero network dependency (except citations_network which fetches the judgment XML).

Supported citation formats:

HMRC

hmrc_get_vat_rate and hmrc_search_guidance require no credentials. hmrc_check_mtd_status requires HMRC_CLIENT_ID and HMRC_CLIENT_SECRET — register at developer.service.hmrc.gov.uk. Defaults to sandbox; set HMRC_API_BASE=https://api.service.hmrc.gov.uk for production.

Architecture

src/
  gateway.py            FastMCP gateway — mounts all modules, applies middleware
  deps.py               Shared httpx clients (lifespan-managed) + error formatting
  modules/
    case_law/           TNA Find Case Law (Atom/XML parsing)
    legislation/        legislation.gov.uk (CLML XML + Atom feed)
    parliament/         Hansard API + Members API + Petitions (JSON)
    bills/              Parliamentary Bills API (JSON)
    votes/              Commons + Lords division records (JSON)
    committees/         Select committees + evidence (JSON)
    citations/          OSCOLA regex engine (compiled once, lru_cache)
    hmrc/               HMRC OAuth + GOV.UK search (JSON)
tests/
  test_citations.py     35 unit tests — regex patterns, resolution, disambiguation

Each module is a standalone FastMCP instance mounted into the gateway with a namespace prefix (case_law_, legislation_, etc.). All modules share a single httpx client pool via the gateway's lifespan context.

Middleware stack (gateway level):

Per-module caching: ResponseCachingMiddleware with TTLs — case_law (1hr), legislation (24hr), bills (1hr), votes (24hr), committees (1hr), hmrc (90 days). Parliament and citations are not cached.

Deployment

Fly.io

fly auth login
fly launch --name uk-legal-mcp --region lhr
fly deploy

Optional secrets:

fly secrets set HMRC_CLIENT_ID=your_id HMRC_CLIENT_SECRET=your_secret
# For production HMRC (default is sandbox):
fly secrets set HMRC_API_BASE=https://api.service.hmrc.gov.uk

Docker

docker build -t uk-legal-mcp .
docker run -p 8000:8000 uk-legal-mcp

Testing

pip install -e '.[test]'  # or: pip install pytest
pytest tests/test_citations.py -v

All 35 citation tests run offline with no API credentials.

Upstream APIs and Licences

Stack

• Python 3.10+
• FastMCP v3 (streamable HTTP transport)
• httpx (async HTTP with connection pooling)
• lxml (LegalDocML and CLML XML parsing)
• Pydantic v2 (input validation, output serialisation)
• Fly.io (London region, auto-stop/start)