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@guia-matthieuInstall SkillMarketing
Skill
/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
Claude Code
$ npx -y skills add guia-matthieu/clawfu-skills --skill deliverability-checker --agent claude-code
Codex
$ npx skills add guia-matthieu/clawfu-skills --skill deliverability-checker -a codex -y
Cursor
$ npx skills add guia-matthieu/clawfu-skills --skill deliverability-checker -a cursor -y
Gemini CLI
$ npx skills add guia-matthieu/clawfu-skills --skill deliverability-checker -a gemini-cli -y
GitHub Copilot
$ npx skills add guia-matthieu/clawfu-skills --skill deliverability-checker -a github-copilot -y
OpenCode
$ npx skills add guia-matthieu/clawfu-skills --skill deliverability-checker -a opencode -y
Windsurf
$ npx skills add guia-matthieu/clawfu-skills --skill deliverability-checker -a windsurf -y
SKILL.md
deliverability-checker.SKILL.mdname: deliverability-checker
description: "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"
license: MIT
metadata:
author: ClawFu
version: 1.0.0
mcp-server: "@clawfu/mcp-skills"
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](../dns-audit/) - Full DNS health check
Skill Metadata
- **Mode**: centaur
category: email-tools
subcategory: deliverability
dependencies: [dnspython]
difficulty: beginner
time_saved: 2+ hours/week
Read more
name: deliverability-checker description: "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" license: MIT metadata: author: ClawFu version: 1.0.0 mcp-server: "@clawfu/mcp-skills"
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](../dns-audit/) - Full DNS health check
Skill Metadata
- **Mode**: centaur
category: email-tools subcategory: deliverability dependencies: [dnspython] difficulty: beginner time_saved: 2+ hours/week
Ships withclawfu-skills
175 expert marketing methodologies for AI agents. Free. Open source. MIT licensed. Dunford on positioning. Schwartz on copywriting. Cialdini on persuasion. Ogilvy on advertising. Hormozi on offers. Voss on negotiation.
150175 skills
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@zubair-trabzadaInstall SkillQuestions about deliverability-checker.
- Which coding agents can use deliverability-checker?
- deliverability-checker installs in Claude Code, Codex, Cursor, Gemini CLI, GitHub Copilot, OpenCode and Windsurf with the skills CLI, using each agent's flag shown on this page. Flowy's auto-invocation, which fires a skill when your prompt matches, runs in Claude Code only.