OSINT MCP Server

Implementation Reference

• src/tools/securitytrails.ts:23-48 (handler)

  The getSubdomains method implementation in the SecurityTrailsApiClient class, which performs the actual API call to retrieve subdomains.

  async getSubdomains(domain: string): Promise<SecurityTrailsResult> {
    const apiKey = configManager.get("SECURITYTRAILS_API_KEY");
    if (!apiKey) {
      throw new McpError(
        ErrorCode.InvalidRequest,
        "SECURITYTRAILS_API_KEY is not configured"
      );
    }
  
    try {
      const data = await this.fetch<any>(`domain/${domain}/subdomains`, {
        method: "GET",
        headers: {
          APIKEY: apiKey,
        },
      });
  
      return SecurityTrailsResultSchema.parse(data);
    } catch (error) {
      if (error instanceof McpError) throw error;
      throw new McpError(
        ErrorCode.InternalError,
        `SecurityTrails error: ${(error as Error).message}`
      );
    }
  }

• src/index.ts:293-301 (registration)

  The MCP tool registration for 'securitytrails_subdomains' in src/index.ts.

  server.tool(
    "securitytrails_subdomains",
    { domain: z.string().describe("Domain to find subdomains in SecurityTrails") },
    async ({ domain }) => {
      const result = await stClient.getSubdomains(domain);
      return {
        content: [{ type: "text", text: JSON.stringify(result, null, 2) }],
      };
    }

• src/tools/securitytrails.ts:6-11 (schema)

  The Zod schema for validating the output of the SecurityTrails API request.

  export const SecurityTrailsResultSchema = z.object({
    endpoint: z.string().optional(),
    subdomains: z.array(z.string()).optional(),
    current_dns: z.any().optional(),
    history: z.any().optional(),
  });