AI Skills Marketplace / Email & Automation

Deliverability Health Diagnostic

The Deliverability Health Diagnostic is a free Claude Skill that parses raw SPF/DKIM/DMARC TXT records for real RFC-level syntax issues, not just presence booleans, plus a real linear-regression trend read on bounce/complaint history.

↗ View Source ⬇ Download Full Repo (.zip)
MIT
License
3 record parsers
Decision branches
RFC 7208 lookup limit
Escalation rules
Yes
Multi-tool support
Aug 14, 2026
Last updated
21/21 passing
Tests
README.md View raw ↗

What this is (and isn’t)

A parser and trend function over TXT record strings and rate history you supply, not a hosted service or a live DNS resolver.

Files

FilePurpose
diagnostic.jsparseSpf(), parseDkim(), parseDmarc(), trendSlope(), diagnose() — zero dependencies
test.js21-test suite covering real RFC-level syntax cases for all three record types
SKILL.mdFull skill definition, loadable in Claude Code/Desktop

Real gaps this catches

SPF exceeding RFC 7208’s 10-DNS-lookup limit, a permissive +all mechanism, an empty DKIM p= tag (explicitly revoked key, not just missing), and a DMARC policy of p=none (technically present but monitoring-only). Most "checker" tools only report presence, not these syntax-level issues.

FAQ

Is this skill free to use?

Yes. Free to download and run yourself. MV3 charges $175/hr only if you want it wired into your real DNS lookups and ESP rate history.

Does this look up DNS records for me?

No. You look up the SPF/DKIM/DMARC TXT records yourself (or pull them via a DNS API); this skill parses what you found.

What is the 10-lookup limit and why does it matter?

RFC 7208 caps SPF at 10 DNS-lookup mechanisms (include/a/mx/ptr/exists). Exceeding it can cause receiving servers to treat the whole record as a permanent failure, a real, common misconfiguration most checkers miss.

Does my DNS/rate data get sent to MV3?

No. Everything runs entirely in your own environment.

What does the trend analysis add over a snapshot rate?

A real linear-regression slope on your bounce/complaint history tells you whether deliverability is improving or worsening, not just where it stands today.

JR
Jordan Reeves
ABM & Outbound Pipeline, MV3 Marketing