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

Use this URL when adding a remote/custom MCP connector in Claude, Claude Desktop, VS Code, Cursor, or another MCP client:

https://uk-legal-mcp.fly.dev/mcp

For clients that use mcpServers JSON:

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

For VS Code workspace config, use .vscode/mcp.json:

{
  "servers": {
    "uk-legal": {
      "type": "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?"

Local HTTP server (advanced)

Most users should connect to the hosted server above. If you specifically want to run the server locally, start it with uvx and connect to the local HTTP endpoint:

PORT=8765 uvx uk-legal-mcp

{
  "mcpServers": {
    "uk-legal": {
      "type": "http",
      "url": "http://127.0.0.1:8765/mcp"
    }
  }
}

---

Tools

Case Law

Tool	What it does
case_law_search	Full-text search of UK judgments. Filter by court, judge, party, date range.
case_law_grep_judgment	Find paragraphs in a judgment matching a pattern. Returns {eId, snippet, match} per hit.

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

URI template	Returns
judgment://{slug*}/header	Metadata header (parties, judges, citation). ~1k tokens.
judgment://{slug*}/index	Paragraph eId + first-line per row. ~4k tokens. Walk this to discover paragraphs.
judgment://{slug*}/para/{eId}	A single paragraph including its sub-paragraphs. 400–1700 tokens.

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

Legislation

Tool	What it does
legislation_search	Search Acts of Parliament and Statutory Instruments on legislation.gov.uk.
legislation_get_toc	Table of contents for an Act — parts, chapters, sections, schedules.
legislation_get_section	Retrieve a specific section with territorial extent, in-force status, and version date.

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

URI template	Returns
legislation://{type}/{year}/{number}	Full Act/SI as CLML XML.
legislation://{type}/{year}/{number}/section/{section}	A specific section as CLML XML.
legislation://{type}/{year}/{number}/toc	Flat id: title lines for the table of contents.
legislation://{type}/{year}/{number}/{date}	Point-in-time CLML for a YYYY-MM-DD date.

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

Tool	What it does
parliament_search_hansard	Search Hansard debate contributions by exact phrase.
parliament_vibe_check	Assess parliamentary reception of a policy topic. Searches Hansard, then uses LLM sampling to classify sentiment, supporters, opponents, and concerns.
parliament_find_member	Look up an MP or Lord by name. Returns member ID for use with member_debates.
parliament_member_debates	Retrieve a specific member's Hansard contributions, optionally filtered by topic.
parliament_member_interests	Get a member's registered financial interests (donations, shareholdings, etc.).
parliament_search_petitions	Search UK Parliament petitions by keyword.

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

Bills

Tool	What it does
bills_search_bills	Search current and historical parliamentary bills by keyword, session, or type.
bills_get_bill	Get full bill detail — stages, sponsors, publications.

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

Votes

Tool	What it does
votes_search_divisions	Search Commons and Lords division records by keyword or date.
votes_get_division	Get full division detail — vote counts, how each member voted.

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

Committees

Tool	What it does
committees_search_committees	Search parliamentary select committees by keyword.
committees_get_committee	Get committee detail — membership, sub-committees.
committees_search_evidence	Search oral and written evidence submissions to committees.

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

Citations

Tool	What it does
citations_parse	Extract all OSCOLA citations from free text. Resolves to canonical URLs. Disambiguates bare court codes via LLM sampling.
citations_resolve	Parse and resolve a single citation string to its canonical URL.
citations_network	Fetch a judgment from TNA and map every citation within it — cases, legislation, SIs, EU law.

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

Supported citation formats:

Format	Example
Neutral citation	[2024] UKSC 12
Law report (with or without volume)	[2024] 1 WLR 100, [1932] AC 562
Legislation section	s.47 Companies Act 2006
Statutory Instrument	SI 2018/1234
Retained EU law	Regulation (EU) 2016/679

HMRC

Tool	What it does
hmrc_get_vat_rate	VAT rate lookup for any commodity or service. Static table current as of Autumn Statement 2023.
hmrc_check_mtd_status	Check Making Tax Digital VAT mandate status for a VRN. Requires HMRC OAuth credentials.
hmrc_search_guidance	Search GOV.UK for HMRC guidance documents.

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.

---

Prompts

Four workflow prompts are available for multi-step legal research. Exposed as tools via PromptsAsTools for ChatGPT; accessible natively on protocol-aware clients (Claude, Inspector).

Prompt	Module	Description
summarise_act	legislation	Structured summary of a UK Act or SI
compare_legislation	legislation	Comparative analysis of two pieces of legislation on a topic
policy_vibe_check	parliament	Parliamentary reception assessment for a policy
member_position_analysis	parliament	A member's position and voting record on a topic

---

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):

Middleware	Purpose
ErrorHandlingMiddleware	Catches unhandled exceptions
StructuredLoggingMiddleware	JSON logging with duration and payload size
DetailedTimingMiddleware	Per-tool timing logs
ResponseLimitingMiddleware	80,000 char cap (LegalDocML XML can exceed 200k)

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 8080:8080 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

Source	API	Licence	Auth
TNA Find Case Law	caselaw.nationalarchives.gov.uk	Open Justice Licence	None
legislation.gov.uk	legislation.gov.uk	OGL v3	None
UK Parliament Hansard	hansard-api.parliament.uk	Open Parliament Licence	None
UK Parliament Members	members-api.parliament.uk	Open Parliament Licence	None
UK Parliament Petitions	petition.parliament.uk	Open Parliament Licence	None
UK Parliament Bills	bills-api.parliament.uk	Open Parliament Licence	None
UK Parliament Votes	commonsvotes-api.parliament.uk	Open Parliament Licence	None
UK Parliament Committees	committees-api.parliament.uk	Open Parliament Licence	None
HMRC	test-api.service.hmrc.gov.uk	OGL / commercial terms	OAuth 2.0
GOV.UK Search	www.gov.uk/api/search.json	OGL v3	None

---

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)