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
- Installs
- 256
- Last 24h
- —
- Trending rank
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- Security
- Not audited
Install
Works with every agent the skills CLI supports.
npx skills add https://github.com/guia-matthieu/clawfu-skills --skill deliverability-checker- 01
Install
Run the command in your project. The CLI asks which agents to install for.
- 02
Describe the task
Ask your agent for something this skill covers. It loads deliverability-checker automatically when relevant.
- 03
Review the result
The agent follows the SKILL.md steps, scripts and references bundled with the skill.
SKILL.md
The instructions your agent reads when the skill is triggered.
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
FAQ
What does the deliverability-checker skill do?
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
How do I install deliverability-checker?
Run npx skills add https://github.com/guia-matthieu/clawfu-skills --skill deliverability-checker in your project. The skills CLI detects the agents you use and copies the skill into the right folder. For Claude Code you can also place the skill folder at ~/.claude/skills/deliverability-checker/ (personal) or .claude/skills/deliverability-checker/ (project).
Which AI agents can use deliverability-checker?
Any agent that supports the open Agent Skills format (a folder with a SKILL.md file), including Claude Code, Codex, Cursor, GitHub Copilot, Gemini CLI, Windsurf, Cline, OpenCode and more.
Is deliverability-checker safe to install?
No partner security audit is available yet. Skills can run commands and scripts, so read the SKILL.md and any bundled files before installing.
Who maintains deliverability-checker?
It is published by guia-matthieu in guia-matthieu/clawfu-skills. It has 256 recorded installs.
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