Registrum MCP Server

UK company data in your AI agent — without building Companies House plumbing.

No Companies House developer account, no rate-limit handling, no iXBRL parsing.Works in Claude Desktop, Claude Code, Cursor, and any MCP-compatible client.

Dependabot is enabled on all six Registrum repositories; as of 2026-10-08 there are zero open dependency alerts. See SECURITY.md.

Try it now — no signup, no key, no install

Point your client at the hosted endpoint and every tool answers with real data:

https://registrum.co.uk/api/mcp

{
  "mcpServers": {
    "registrum": {
      "url": "https://registrum.co.uk/api/mcp"
    }
  }
}

That is the whole setup. Ask it "Who ultimately owns BrewDog?" and it will tracethe ownership chain to the named individuals who hold control.

One thing worth knowing before you test it on a household name: companies listedon a regulated market — Tesco, Rolls-Royce, most of the FTSE — are exempt fromthe PSC regime, so their ownership chain is legitimately empty andget_psc_chain says so rather than inventing a tree. Ownership questions areinteresting on private companies, which is where the register actually recordswho is behind them.

The hosted endpoint has small daily caps, enough to see exactly what comes back.When you reach one, the tool tells you so and points at a free key; nothingsilently degrades.

Three ways to use it

Try it - no key. Point your MCP client at https://registrum.co.uk/api/mcpand ask about any UK company. No signup.
Build with it - free key. 60 days of full access: every endpoint, nomonthly cap, no card. After that the key stays free for light use.
Run on it - paid plan. When you need volume, premium endpoints or an SLA.Live prices and limits: GET /v1/plans.

Why this instead of the Companies House API directly

Companies House publishes the raw register for free, and you can absolutelycall it yourself. What you then own is the plumbing:

Doing it yourself	With Registrum
Register for a CH developer key, manage OAuth	Nothing, or one `REGISTRUM_API_KEY`
600 requests/5min, and you handle the 429s	Server-side throttling on a higher negotiated budget
Accounts arrive as iXBRL documents you must parse	`get_financials` returns turnover, net assets, profit/loss as numbers
PSC control types are raw codes	Decoded to plain English
Ownership chains: recurse yourself, handle cycles	`get_psc_chain` returns the resolved tree with termination reasons
Director networks: N+1 queries across appointments	`get_network` traverses to depth 2
Retry, cache, and survive CH outages yourself	24h/7d caching, circuit breaker, stale-while-revalidate

Other Companies House MCP servers make you bring your own CH key and hand backthe raw response. This one does the enrichment.

Running it with your own key

Use a key to build on it (60 days of full access), or when you would rather runthe server locally than call ours.

Claude Desktop — ~/.claude/claude_desktop_config.jsonCursor — .cursor/mcp.json (per project) or ~/.cursor/mcp.json (global)

{
  "mcpServers": {
    "registrum": {
      "command": "npx",
      "args": ["-y", "@registrum/mcp"],
      "env": { "REGISTRUM_API_KEY": "reg_live_..." }
    }
  }
}

Get a free key — 60 days of full access, no card.

Tools

Tool	What you get
`search_company`	Find a company by name → company number
`get_bundle`	Profile, compliance, financials, PSCs and directors in one call - start here
`get_company`	Profile: status, age, SIC descriptions, overdue flags
`get_financials`	Turnover, net assets, profit/loss, employees — parsed from iXBRL, in GBP
`get_directors`	Current board with appointment history across all their companies
`get_psc`	Persons with Significant Control, control types in plain English
`get_psc_chain`	Ownership traversed to ultimate beneficial owners, with termination reasons
`get_compliance`	ECCTA identity-verification status — who has verified, who is pending, who is overdue
`get_network`	Companies connected by shared directors, to depth 2

On `get_bundle`

Most questions about a company need several of these views at once. get_bundlereturns them in a single request: one call and one credit instead of five,and one round trip instead of five. Pass include to fetch a subset, or omit itfor all five sections.

Each section carries exactly what its own endpoint returns, because the bundleis composed from those same handlers rather than reimplemented - so plan gates,caching and the ECCTA rules behave identically either way.

A null section is not an error. Financials come back null for a company thathas filed no machine-readable accounts, and compliance requires a Pro plan. Onlya missing company is an error, and that is a 404. Report a null section as "notavailable", never as an absence of the underlying fact.

On `get_compliance`

The Economic Crime and Corporate Transparency Act requires every UK directorand PSC to verify their identity with Companies House. Enforcement begins18 November 2026, after which unverified officers can block filings.

The tool returns verified / pending / overdue counts plus each unverifiedperson and their individual deadline. It deliberately distinguishes pending(deadline not yet reached — not a failure) from overdue (missed). Treatingthose as the same thing is the single easiest way to report a compliant companyas non-compliant.

Example prompts

"Is Tesco PLC compliant with ECCTA director verification, and who still needs to verify?"

"Pull the last filed financials for 00445790 and tell me if turnover grew."

"Who ultimately owns BrewDog? Trace the ownership chain to the individuals."

"Which companies share directors with Barratt Developments?"

"Search for 'Monzo' and show me status, incorporation date and directors."

Plans

The anonymous endpoint needs no account at all. A free key gives 60 days of fullaccess, then stays free for light use; paid tiers add volume, premium endpointssuch as PSC chain traversal and the ECCTA compliance endpoint, and an SLA.

Prices and quotas are served live from GET /v1/plans —that endpoint is the source of truth, so this README does not duplicate thenumbers and cannot go stale against them. Human-readable version atregistrum.co.uk.

Notes

Company numbers are zero-padded 8-character strings: 00445790, SC000268.
Responses are JSON, cached server-side (24h profiles/directors, 7d financials).
The hosted endpoint is stateless and anonymous: it stores no account, and ratelimiting is keyed on a hash of the calling IP rather than anything about you.
The npm package sends User-Agent: @registrum/mcp/<version> so we can seewhich features developers actually use. No telemetry runs on your machine.

API reference · Issues · [email protected]

Registrum MCP Server