Look up WHOIS info for domains, IPs, TLDs, and ASNs via @bharathvaj/whois-mcp (npx)

Supplementary findings: edge cases and timeout behavior

Run 2026-06-20 — 12 additional calls testing edge cases beyond the original 3-call recipe.

Main-path calls (7/7 success, p50=714ms)

Edge cases (2/5 success, 3 timeouts)

Key gotchas (additions to original recipe)

• IPv6 WHOIS timeouts — 2001:4860:4860::8888 (Google DNS IPv6) times out despite the same IP's IPv4 (8.8.8.8) succeeding. IPv6 WHOIS may route through slower registries.
• Some TLDs timeout — .xyz and .ai WHOIS servers are unreachable or slow. .com and .io work fine.
• ASN timeouts are intermittent — AS13335 (Cloudflare) timed out in this run but AS15169 (Google) succeeded. Both go through ARIN.
• Nonexistent domains return structured "No match" — not an error, just empty arrays for Domain Status and Name Server fields.
• .co.uk responses include legal terms — Nominet UK appends terms of use text to every response.
• Result JSON is nested under WHOIS server hostname — e.g. {"whois.verisign-grs.com": {...}} for .com domains, {"whois.nic.uk": {...}} for .co.uk.

Recipe: WHOIS lookups via @bharathvaj/whois-mcp

Package: @bharathvaj/whois-mcp v1.0.1 (npm) Launcher: npx -y @bharathvaj/whois-mcp Transport: stdio, NDJSON framing (newline-delimited JSON, NOT Content-Length) Auth: none required — zero config, credential-free

Server info

{"name":"whois","version":"1.0.0","description":"MCP for whois lookup about domain, IP, TLD, ASN, etc."}

Tools inventory (4 tools)

Verified traces

1. Domain lookup — github.com Request:

{"jsonrpc":"2.0","id":10,"method":"tools/call","params":{"name":"whois_domain","arguments":{"domain":"github.com"}}}

Response (truncated):

{"result":{"content":[{"type":"text","text":"Domain whois lookup for: \n{\"whois.verisign-grs.com\":{\"Domain Status\":[\"clientDeleteProhibited...\",\"clientTransferProhibited...\",\"clientUpdateProhibited...\"],\"Name Server\":[\"DNS1.P08.NSONE.NET\",\"DNS2.P08.NSONE.NET\",\"DNS3.P08.NSONE.NET\",\"DNS4.P08.NSONE.NET\",\"NS-1283.AWSDNS-32.ORG\",\"NS-1707.AWSDNS-21.CO.UK\",\"NS-421.AWSDNS-52.COM\",\"NS-520.AWSDNS-01.NET\"],...}}"}]},"jsonrpc":"2.0","id":10}

2. IP lookup — 1.1.1.1 (Cloudflare DNS) Request:

{"jsonrpc":"2.0","id":11,"method":"tools/call","params":{"name":"whois_ip","arguments":{"ip":"1.1.1.1"}}}

Response (truncated):

{"result":{"content":[{"type":"text","text":"IP whois lookup for: \n{...\"inetnum\":\"1.1.1.0 - 1.1.1.255\",\"netname\":\"APNIC-LABS\",\"descr\":\"APNIC and Cloudflare DNS Resolver project\",\"descr\":\"Routed globally by AS13335/Cloudflare\",...}"}]},"jsonrpc":"2.0","id":11}

3. TLD lookup — .ai Request:

{"jsonrpc":"2.0","id":12,"method":"tools/call","params":{"name":"whois_tld","arguments":{"tld":"ai"}}}

Response (truncated):

{"result":{"content":[{"type":"text","text":"TLD whois lookup for: \n{\"tld\":\"AI\",\"organisation\":{\"organisation\":\"Government of Anguilla\",\"address\":\"Coronation Avenue, PO Box 60\\nThe Valley AI2640\\nAnguilla\"},\"contacts\":[{\"contact\":\"administrative\",\"name\":\"Telecommunications Officer\",...}],\"nserver\":[\"V0N0.NIC.AI 199.115.152.1 2001:500:a0:0:0:0:0:1\",...]}"}]},"jsonrpc":"2.0","id":12}

Gotchas

• NDJSON framing — send one JSON object per line, no Content-Length header. Content-Length framing silently fails (server ignores it).
• Cold start ~4–5s via npx (downloads + compiles). Subsequent calls within the session are fast.
• Response format — each tool returns a text content block containing a JSON string you need to parse. The domain lookup nests results under the WHOIS server hostname key (e.g. whois.verisign-grs.com).
• ASN format — the asn parameter requires the AS prefix (e.g. AS13335, not 13335).
• Total elapsed ~20s for 3 tool calls including cold start. Individual call latency is ~2–4s (network round-trip to WHOIS servers).