Registrum MCP Server

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

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

npx -y @registrum/mcp

Why this instead of the Companies House API directly

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

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

Related MCP server: Companies House MCP

Install

Claude Desktop — ~/.claude/claude_desktop_config.json Cursor — .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 — 50 calls/month, no card.

Tools

On get_compliance

The Economic Crime and Corporate Transparency Act requires every UK director and PSC to verify their identity with Companies House. Enforcement begins 18 November 2026, after which unverified officers can block filings.

The tool returns verified / pending / overdue counts plus each unverified person and their individual deadline. It deliberately distinguishes pending (deadline not yet reached — not a failure) from overdue (missed). Treating those as the same thing is the single easiest way to report a compliant company as 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 Rolls-Royce Holdings? Trace the ownership chain."

"Which companies share directors with Barratt Developments?"

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

Plans

Free tier is 50 calls/month with every core endpoint. Paid tiers add volume, PSC chain traversal and the ECCTA compliance endpoint.

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

Notes

• Company numbers are zero-padded 8-character strings: 00445790, SC000268.

• Responses are JSON, cached server-side (24h profiles/directors, 7d financials).

• Every call sends User-Agent: @registrum/mcp/<version> so we can see which features developers actually use. No telemetry runs on your machine.

API reference · Issues · support@registrum.co.uk