Build a UK company research brief with AI and Companies House

To build a UK company register brief, give Company Lookup an explicit company number and request its profile and recent filings. Keep the returned facts, source links and retrieval date together. The two calls below produced a real Tesco PLC example through ToolRouter MCP and were repeated in Claude Code on 26 September 2026.

This brief answers a small research question: what does the register return for this company? It does not decide whether a business is trustworthy, solvent or suitable to hire. For source coverage and the other tools it powers, see Companies House on ToolRouter.

The result you can reproduce#

Download the recorded result and test boundary. Officer personal fields are omitted from the downloadable example. The records may have changed since this observation. Check the official company profile and filing history before relying on them.

The source links here are built from the explicit company number. They are not links returned by the tool. The collection timestamp is recorded by the test client, not an upstream freshness guarantee.

Connect your assistant#

For Claude chat, use the Claude remote connector guide, complete the sign-in flow and enable the connector in your conversation. Claude Code has its own setup guide.

Our successful client test used Claude Code with a ToolRouter API key, through https://api.toolrouter.com/mcp. A header-free test required sign-in and could not finish in the non-interactive test session. We have not verified Claude chat's UI flow in this example.

For the API-key route, create a key in ToolRouter API keys, then load it privately as TOOLROUTER_API_KEY and add the connection:

claude mcp add --transport http toolrouter https://api.toolrouter.com/mcp \
  --header "Authorization: Bearer $TOOLROUTER_API_KEY"

Keep the key out of shared configuration, recordings and prompts. If you already have a working ToolRouter connection, use it rather than adding a second one.

The upstream Companies House API requires authentication. Hosted service access supplied it in this test; no separate Companies House key was supplied by the caller. For your own source access, Company Lookup accepts companies_house_api_key. See Companies House API access.

Ask for a bounded brief#

Use ToolRouter Company Lookup to research UK company 00445790.
Call company_profile and filing_history (source uk, limit 3).
Request detailed responses. Report registered name, status, returned active-officer
count and the filing dates/types. Include the official company and filing-history
links and your retrieval time. Keep unknown fields unknown. Do not infer financial
health, competence or suitability from registration status. If a call fails, say so.

If you start with a name, run search_companies with country: UK and confirm the company number before continuing. Similar names are not the same company.

Exact MCP requests#

After discover with query: company-lookup, call use_tool:

{
  "tool": "company-lookup",
  "skill": "company_profile",
  "input": { "company_id": "00445790" },
  "response_format": "detailed"
}

{
  "tool": "company-lookup",
  "skill": "filing_history",
  "input": { "company_id": "00445790", "source": "uk", "limit": 3 },
  "response_format": "detailed"
}

Detailed output matters: the Claude Code test first received a concise profile without the registered name, then retrieved it with detailed output. Both skills are listed as free and completed with a zero-credit test account. Paid accounts extraction was not run. Your assistant's subscription or model usage is separate.

Reuse the example#

Download the tested HTTP recipe to repeat the two Tesco requests with your own ToolRouter API key. Inspect the script first, set TOOLROUTER_API_KEY privately in your terminal environment, then run sh requests.sh. The key stays out of the downloaded file. The recipe uses curl and prints both JSON responses; it does not schedule future calls.

Watch the short walkthrough to see the source page and recorded result. The video shows the dated example, not a new live assistant session.

Check the output before sharing it#

• Match the returned company number to the intended company.
• Keep register facts separate from any later website research or interpretation.
• Treat three filings as a bounded recent sample, not the entire filing history.
• Leave unknown or missing fields visible. In this test the company type was unknown.
• Use “returned active-officer count”; this example did not independently check all appointment records or pagination.
• Do not treat “active” as a credit assessment or a recommendation.

A test with company number 00000000 returned a not-found error. Recover by searching the registered name and confirming the identifier. For expired sign-in, reconnect the MCP server. For unavailable source access, check your provider settings or use the official register; do not silently replace the missing result with an AI guess.

When another route is simpler#

For a single manual lookup, the official register may be all you need. If you only need this source and are comfortable configuring it, a dedicated Companies House connector may suit you. ToolRouter's useful difference is having the same assistant connection available for the next research task as well; this example does not claim a speed or cost win over those alternatives.

For a wider company investigation, research competitors in Claude and label website observations separately from register records. Re-run the register brief when a new research question or review requires it. This two-call recipe does not monitor companies or send alerts automatically.