UK Companies House (Registrum) no API key

What UK Companies House (Registrum) - no API key MCP server does

UK Companies House (Registrum) - no API key connects an MCP-compatible AI client to UK company information without requiring a Companies House developer account. Its tools cover company identification, corporate profiles, accounts data, officers, persons with significant control, ownership traversal, director relationships, and Economic Crime and Corporate Transparency Act (ECCTA) identity-verification status.

The service is intended for questions such as finding a company number from a name, reviewing filing and status information, extracting financial metrics, identifying controlling individuals, or examining links between companies. Company numbers use eight-character, zero-padded formats, including prefixes such as SC for Scottish companies.

How it works

The hosted MCP endpoint is:

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

A client can connect to that URL without an account, API key, or local installation. The hosted service is anonymous and stateless, with rate limits based on a hash of the caller’s IP address. It applies server-side caching, including 24-hour caching for profiles and directors and seven-day caching for financial data. A circuit breaker and stale-while-revalidate behavior are also described for handling source-service interruptions.

For local execution, the npm package is launched with npx and can receive a REGISTRUM_API_KEY. A free key provides 60 days of full access and then remains available for light use; paid plans add higher-volume access and selected premium endpoints. Current plan limits are provided by Registrum’s live plans endpoint rather than fixed values in the project documentation.

Tools and capabilities

• search_company finds a company by name and returns its company number.
• get_bundle combines profile, compliance, financial, PSC, and director sections in one request. An include parameter can limit the returned sections.
• get_company returns status, company age, SIC descriptions, and overdue indicators.
• get_financials parses machine-readable iXBRL accounts into GBP values for turnover, net assets, profit or loss, and employees.
• get_directors returns the current board and appointment history across the directors’ companies.
• get_psc lists persons with significant control and explains control types in plain English.
• get_psc_chain follows ownership to ultimate beneficial owners and reports why a chain terminates.
• get_compliance reports ECCTA verification counts, unverified people, and individual deadlines, distinguishing pending from overdue status.
• get_network finds companies connected through shared directors to a depth of two.

A missing company is an error, while an unavailable data section can be returned as null. For example, financials may be unavailable when a company has not filed machine-readable accounts. Compliance data may require a plan that includes that endpoint.

Setup and configuration

For a hosted connection, add the endpoint to the MCP client configuration:

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

For local use, configure the npm package and pass the key as an environment variable:

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

The README gives configuration locations for Claude Desktop and Cursor. The package sends its own versioned user-agent; no telemetry runs on the user’s machine.

Limitations and notes

The no-key hosted endpoint has daily caps. When a cap is reached, the tool reports it and directs the user to a free key rather than silently returning reduced results. Regulated-market companies can be exempt from the PSC regime, so an empty ownership chain may be an expected result rather than evidence that ownership data is missing.

ECCTA enforcement for identity verification begins on 18 November 2026. Pending means a deadline has not yet passed; overdue means the deadline was missed. These states should not be treated as equivalent.