Click on "Deploy Server".
Wait a few minutes for the server to deploy. Once ready, it will show a "Started" state.
In the chat, type @ followed by the MCP server name and your instructions, e.g., "@Deliverability Doctor Check spoofing risk for acme.com"
That's it! The server will respond to your query, and you can continue using it as needed.
Here is a step-by-step guide with screenshots.
Remote MCP server: "Can my domain be email-spoofed?" answered from public DNS, graded, with concrete fixes. Connectable to Claude (custom connector) and ChatGPT (Apps SDK / MCP connector) — both speak MCP, one server serves both.
check_email_security(domain) — SPF (incl. RFC 7208 multiple-record permerror
and redirect= handling), DMARC (policy, rua, pct), MX, DKIM at 7 common
selectors. Graded A–F report, fixes per finding, upsell line only when problems
exist. Accepts bare domain, URL, or email address.
compare_email_security(domains[2..5]) — comparison table with grades.
Related MCP server: Blackveil DNS
Authless: reads public DNS only, stores nothing, takes nothing but a domain. Lowest possible connect friction; nothing sensitive to protect.
DNS-over-HTTPS (Cloudflare → Google fallback): identical code runs on local
Node and on Cloudflare Workers — no dns module dependency.
Stateless streamable HTTP: fresh transport per request, no sessions; safe to scale, trivial for clients.
NXDOMAIN is refused, not graded — "domain doesn't exist" ≠ "spoofable".
Verified against known postures before first run: gmail.com (redirect= must
not be flagged), n8n.io (must grade A on p=reject), missing-everything domain
(must grade F), NXDOMAIN (must refuse).
npm install
node server.js # :8787/mcpQuick public demo: cloudflared tunnel --url http://localhost:8787 → use
https://<random>.trycloudflare.com/mcp as the connector URL.
Local: end-to-end MCP verified (initialize / tools/list / tools/call).
Public: live via quick tunnel, initialize verified from the public URL.
Durable hosting: pending — Cloudflare Workers deploy needs Kacper's account (~5 min). Tunnel URL dies with the process/PC.
Directory submissions (Anthropic connector directory, ChatGPT apps): need the durable URL first, then Kacper's developer accounts.
Free tool = distribution. Report links the $99 written audit (niekonieczny.gumroad.com/l/vscjt) only when problems are found. NOTE: Gumroad payouts currently frozen on Stripe KYC — unfreeze before promoting.
This server cannot be deployed
Email posture for any domain: can it receive mail, can it be spoofed? MX, SPF and DMARC.
Monitor and manage email authentication (SPF, DKIM, DMARC, MTA-STS, BIMI) for your domains.
Free SPF, DKIM, DMARC, MX deliverability check with graded shareable reports, plus referral terms
Check email deliverability for a domain: MX, SPF, DKIM, DMARC, blacklists. Graded, no key.
