Clawfu-skills deliverability-checker

Check email deliverability and DNS configuration. Use when: diagnosing email delivery issues; setting up new email domains; auditing email authentication; checking SPF/DKIM/DMARC; troubleshooting spam folder issues

install

source · Clone the upstream repo

git clone https://github.com/guia-matthieu/clawfu-skills

Claude Code · Install into ~/.claude/skills/

T=$(mktemp -d) && git clone --depth=1 https://github.com/guia-matthieu/clawfu-skills "$T" && mkdir -p ~/.claude/skills && cp -r "$T/skills/email-tools/deliverability-checker" ~/.claude/skills/guia-matthieu-clawfu-skills-deliverability-checker && rm -rf "$T"

manifest: skills/email-tools/deliverability-checker/SKILL.md

source content

Email Deliverability Checker

Diagnose email deliverability issues by checking SPF, DKIM, DMARC, and other DNS records - fix why your emails land in spam.

When to Use This Skill

Delivery troubleshooting - Emails landing in spam
New domain setup - Configure email authentication
Migration audit - Verify email config after domain change
Client onboarding - Check client email health
Compliance check - Ensure proper authentication

What Claude Does vs What You Decide

Claude Does	You Decide
Structures analysis frameworks	Metric definitions
Identifies patterns in data	Business interpretation
Creates visualization templates	Dashboard design
Suggests optimization areas	Action priorities
Calculates statistical measures	Decision thresholds

Dependencies

pip install dnspython click

Commands

Full Audit

python scripts/main.py audit example.com
python scripts/main.py audit example.com --output report.html

Check SPF

python scripts/main.py spf example.com

Check DKIM

python scripts/main.py dkim example.com --selector google
python scripts/main.py dkim example.com --selector default

Check DMARC

python scripts/main.py dmarc example.com

Check MX Records

python scripts/main.py mx example.com

Examples

Example 1: Full Email Audit

python scripts/main.py audit acme-corp.com

# Output:
# Email Deliverability Audit: acme-corp.com
# ──────────────────────────────────────────
# MX Records:      ✓ Found (Google Workspace)
# SPF:             ✓ Valid
# DKIM (google):   ✓ Valid
# DMARC:           ✗ Missing (CRITICAL)
#
# Score: 75/100
#
# Issues Found:
# 1. [CRITICAL] No DMARC record found
#    Fix: Add TXT record for _dmarc.acme-corp.com
#    Value: v=DMARC1; p=none; rua=mailto:dmarc@acme-corp.com

Example 2: Diagnose SPF Issues

python scripts/main.py spf newsletter-sender.com

# Output:
# SPF Analysis: newsletter-sender.com
# ────────────────────────────────────
# Record: v=spf1 include:_spf.google.com include:sendgrid.net ~all
#
# Status: ✓ Valid
#
# Authorized Senders:
# - Google Workspace (include:_spf.google.com)
# - SendGrid (include:sendgrid.net)
#
# Policy: ~all (soft fail)
# Warning: Consider changing to -all (hard fail) for better security

Email Authentication Records

Record	Purpose	Location
SPF	Authorize sending servers	`TXT` on root domain
DKIM	Cryptographic signature	`TXT` on `selector._domainkey`
DMARC	Policy and reporting	`TXT` on `_dmarc` subdomain
MX	Mail delivery servers	`MX` on root domain

Common SPF Includes

Provider	SPF Include
Google Workspace	`include:_spf.google.com`
Microsoft 365	`include:spf.protection.outlook.com`
SendGrid	`include:sendgrid.net`
Mailchimp	`include:servers.mcsv.net`
Amazon SES	`include:amazonses.com`

DKIM Selectors by Provider

Provider	Common Selector
Google Workspace	`google`
Microsoft 365	`selector1` , `selector2`
SendGrid	`s1` , `s2`
Mailchimp	`k1`

Deliverability Score Factors

Factor	Weight	Impact
Valid MX	20%	Can't receive replies
Valid SPF	25%	Server authorization
Valid DKIM	25%	Message integrity
Valid DMARC	30%	Policy enforcement

Skill Boundaries

What This Skill Does Well

Structuring data analysis
Identifying patterns and trends
Creating visualization frameworks
Calculating statistical measures

What This Skill Cannot Do

Access your actual data
Replace statistical expertise
Make business decisions
Guarantee prediction accuracy

Related Skills

dns-audit - Full DNS health check

Skill Metadata

Mode: centaur

category: email-tools
subcategory: deliverability
dependencies: [dnspython]
difficulty: beginner
time_saved: 2+ hours/week