Search for companies by name or company number
AI agents call search_companies to retrieve information from Companies House MCP Server without modifying anything — typically the context-gathering step in research, monitoring, and reporting workflows, before the agent takes action elsewhere.
This tool retrieves company information from a public database without creating, modifying, deleting, or executing any operations. It has no side effects and poses minimal risk even if misused by an AI agent—the worst outcome would be retrieving publicly available company information.
From the tool's definition Tool name 'search_companies' and description 'Search for companies by name or company number' indicate a query/search operation that retrieves data without modification.
Documented attack patterns abuse exactly the kind of access search_companies gives an agent:
PolicyLayer is an MCP gateway — it sits between your AI agents and Companies House MCP Server, and nothing reaches the server without passing your rules. This is the rule we recommend for search_companies:
{
"version": "1",
"default": "deny",
"tools": {
"search_companies": {}
}
}search_companies is read-only, so it stays allowed — but everything else on the server is denied unless you say otherwise.
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Search for companies by name or company number. It is categorised as a Read tool in the Companies House MCP Server MCP Server, which means it retrieves data without modifying state.
Register the Companies House MCP Server MCP server in PolicyLayer and add a rule for search_companies: allow, deny, rate-limit, or require approval. Point your MCP client at the PolicyLayer proxy URL and the rule is enforced on every call, before it reaches Companies House MCP Server. Nothing to install.
search_companies is a Read tool with low risk. Read-only tools are generally safe to allow by default.
Yes. Add a rate_limit block to the search_companies rule in your PolicyLayer policy. For example, setting max: 10 and window: 60 limits the tool to 10 calls per minute. Rate limits are tracked per agent session and reset automatically.
Set action: deny in the PolicyLayer policy for search_companies. The AI agent will receive a policy violation error and cannot call the tool. You can also include a reason field to explain why the tool is blocked.
search_companies is provided by the Companies House MCP Server MCP server (stefanoamorelli/companies-house-mcp). PolicyLayer sits as a proxy in front of this server to enforce policies before tool calls reach the server.
Start from Companies House MCP Server, add the rest of your stack, and see everything your agents can call. Then put policy on all of it.
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37 Companies House MCP Server tools catalogued and risk-classified — across an index of 43,000+ MCP servers.