Discover website-serving subdomains for a single domain.
AI agents call lookup_subdomains to retrieve information from Wappalyzer MCP without modifying anything — typically the context-gathering step in research, monitoring, and reporting workflows, before the agent takes action elsewhere.
This tool retrieves information about subdomains associated with a domain—a read-only query operation. It has no side effects, does not modify data, execute code, or trigger financial transactions. The blast radius of misuse is limited to information disclosure, making it low severity.
From the tool's definition Tool name is 'lookup_subdomains' and description states it 'Discover website-serving subdomains for a single domain.' The verb 'discover' and 'lookup' indicate data retrieval with no modification or execution of external operations.
Attacks that exploit this kind of access
Discover website-serving subdomains for a single domain. It is categorised as a Read tool in the Wappalyzer MCP MCP Server, which means it retrieves data without modifying state.
Register the Wappalyzer MCP server in PolicyLayer and add a rule for lookup_subdomains: 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 Wappalyzer MCP. Nothing to install.
lookup_subdomains 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 lookup_subdomains 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 lookup_subdomains. 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.
lookup_subdomains is provided by the Wappalyzer MCP server (wappalyzer/mcp). PolicyLayer sits as a proxy in front of this server to enforce policies before tool calls reach the server.
Every MCP server has a record like this.
Type a name, get the same breakdown: verified identity, auth posture, risk grade, capabilities, recommended policy.
Teams ship this data inside their own products. See what a licence covers →