Connect UK Companies House to Codex
Query UK Companies House directly from Codex. Arlet links the two through one MCP connection and takes care of API keys.
Connects your AI client to the Companies House Public Data API (api.company-information.service.gov.uk), the official register of companies in England, Wales, Scotland and Northern Ireland.
Tools (all read-only):
- search_companies: search the register by name or number and get company numbers, status, type, incorporation date and registered address.
- get_company_profile: full profile of one company (status, type, SIC codes, accounts and confirmation statement due dates, registered office, previous names).
- list_officers: current and resigned directors and secretaries with role, appointment/resignation dates, nationality and occupation.
- list_filing_history: filings (accounts, confirmation statements, officer changes, charges, resolutions ...) with an optional category filter.
- list_persons_with_significant_control: PSC register entries (individuals, corporate entities, legal persons) with their natures of control.
Authentication: HTTP Basic with your own API key (free registration at the Companies House Developer Hub; 600 requests per 5 minutes per key).
Licence: Companies House data is Crown copyright and reusable under the Open Government Licence v3.0. Each response carries the source and licence.
How to connect UK Companies House to Codex
- 1
In the Arlet dashboard, open Data tools, find UK Companies House, set the API key issued by UK Companies House and switch it on.
- 2
In your terminal, run codex mcp add arlet --url https://mcp.arlet.dev/mcp/ to add Arlet as an MCP server.
- 3
Codex detects OAuth support and opens your browser. Sign in with Google and click Allow on the consent screen.
- 4
Once connected, both the CLI and the IDE extension can call Arlet tools (the configuration is shared).
If the browser does not open, run codex mcp login arlet to redo the authentication.