dns_lookup

Instructions

Implementation Reference

• src/dns/index.ts:71-125 (handler)

  The core implementation of dns_lookup. Uses Node.js built-in node:dns/promises to resolve DNS records. Supports A, AAAA, MX, TXT, NS, SOA, CNAME, and SRV record types. Returns an array of DnsRecord objects.

  export async function dnsLookup(domain: string, type: string): Promise<DnsRecord[]> {
    const records: DnsRecord[] = [];
  
    switch (type.toUpperCase()) {
      case "A": {
        const ips = await dns.resolve4(domain);
        for (const ip of ips) records.push({ type: "A", value: ip });
        break;
      }
      case "AAAA": {
        const ips = await dns.resolve6(domain);
        for (const ip of ips) records.push({ type: "AAAA", value: ip });
        break;
      }
      case "MX": {
        const mxs = await dns.resolveMx(domain);
        for (const mx of mxs) records.push({ type: "MX", value: mx.exchange, priority: mx.priority });
        break;
      }
      case "TXT": {
        const txts = await dns.resolveTxt(domain);
        for (const txt of txts) records.push({ type: "TXT", value: txt.join("") });
        break;
      }
      case "NS": {
        const nss = await dns.resolveNs(domain);
        for (const ns of nss) records.push({ type: "NS", value: ns });
        break;
      }
      case "SOA": {
        const soa = await dns.resolveSoa(domain);
        records.push({
          type: "SOA",
          value: `${soa.nsname} ${soa.hostmaster} ${soa.serial} ${soa.refresh} ${soa.retry} ${soa.expire} ${soa.minttl}`,
        });
        break;
      }
      case "CNAME": {
        const cname = await dns.resolveCname(domain);
        for (const c of cname) records.push({ type: "CNAME", value: c });
        break;
      }
      case "SRV": {
        const srvs = await dns.resolveSrv(domain);
        for (const s of srvs) {
          records.push({ type: "SRV", value: s.name, priority: s.priority, weight: s.weight, port: s.port });
        }
        break;
      }
      default:
        throw new Error(`Unsupported DNS record type: ${type}`);
    }
  
    return records;
  }

• src/protocol/tools.ts:27-35 (schema)

  Tool definition and schema for dns_lookup. Defines the tool name 'dns_lookup', description, Zod schema for 'domain' (string) and 'type' (enum of A/AAAA/MX/TXT/NS/SOA/CNAME/SRV), and the execute handler that calls dnsLookup().

  const dnsLookupTool: ToolDef = {
    name: "dns_lookup",
    description: "Resolve DNS records for a domain. Supports A, AAAA, MX, TXT, NS, SOA, CNAME, SRV record types.",
    schema: {
      domain: z.string().describe("Domain name to query"),
      type: z.enum(["A", "AAAA", "MX", "TXT", "NS", "SOA", "CNAME", "SRV"]).describe("DNS record type"),
    },
    execute: async (args) => json(await dnsLookup(args.domain as string, args.type as string)),
  };

• src/protocol/tools.ts:481-488 (registration)

  Registration of dns_lookup in the exported allTools array. The dnsLookupTool is included as the first entry in the DNS tools group (line 483).

  export const allTools: ToolDef[] = [
    // DNS (6)
    dnsLookupTool,
    dnsReverseTool,
    dnsEmailSecurityTool,
    dnsSpfChainTool,
    dnsSrvDiscoverTool,
    dnsWildcardCheckTool,

• src/protocol/tools.ts:8-8 (helper)

  Import of the dnsLookup function from src/dns/index.js into the tools registry module.

  import { dnsLookup, dnsReverse, dnsEmailSecurity, dnsSpfChain, dnsSrvDiscover, dnsWildcardCheck } from "../dns/index.js";

• src/index.ts:24-26 (registration)

  CLI category listing that includes 'dns_lookup' in the DNS tool group (no API key required). Also referenced in example usage on line 53.

  label: "DNS",
  env: null,
  tools: ["dns_lookup", "dns_reverse", "dns_email_security", "dns_spf_chain", "dns_srv_discover", "dns_wildcard_check"],