Email security

Full email auth posture: SPF, DMARC, DKIM, and composite deliverability score in one call.

When to use this pack

Diagnosing email authentication — can this domain be spoofed, and is its mail configuration complete.

Tools in this pack

• SPF check $0.003 POST /api/spf-check Fetch and validate a domain's SPF record (RFC 7208). Parses mechanisms (ip4/ip6/include/a/mx/all), counts DNS lookups against the famous 10-lookup limit, and flags the qualifier on `all` (-/fail, ~/softfail, ?/neutral). The first stop when an email is hitting the spam folder.
• DMARC check $0.003 POST /api/dmarc-check Fetch and validate a domain's DMARC policy at _dmarc.<domain> (RFC 7489). Surfaces the enforcement policy (none/quarantine/reject), reporting addresses, alignment modes, and common misconfigs (no rua, p=none stuck for months, percent <100). Pair with SPF and DKIM for full Feb-2024 sender-rule compliance.
• DKIM key lookup $0.003 POST /api/dkim-lookup Fetch and parse a DKIM public-key record at <selector>._domainkey.<domain> (RFC 6376). Returns the parsed key params (algorithm, length, flags) so you can verify rotation status or key strength. Caller must know the selector — use email-deliverability if you don't.
• Email deliverability check $0.005 POST /api/email-deliverability End-to-end email-auth report for a domain: SPF + DMARC + DKIM (probes common selectors automatically) + MX records + score 0–100. The one call to make when 'why is our mail going to spam?' lands in your inbox.

Workflow

1. Parse the SPF record — flag permissive +all, excessive lookups, or syntax errors.
2. Parse the DMARC policy — p=none means failures are ignored.
3. Probe common DKIM selectors and check key strength.
4. Run the composite deliverability score for an overall grade.

Run it in Claude

claude mcp add agent402 -s user -- npx -y agent402-mcp@latest

Then paste this prompt into Claude:

Check email security for stripe.com using Agent402's email-security skill pack. Get (1) SPF check, (2) DMARC policy, (3) DKIM probe, (4) deliverability score. Flag any missing or weak auth records.

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