Getting it into your agent
One page per mod, every tool's command on it. A separate URL per tool would split the same page into five that compete with each other.
npx skills add guia-matthieu/clawfu-skills --skill deliverability-checkergit clone --depth 1 https://github.com/guia-matthieu/clawfu-skillsWrote this? Show the measurements
A badge with what this costs and how it scanned, read live from this page, so it follows the numbers instead of freezing them. Markdown for a README, HTML for a documentation site or a project page.
[](https://agentmods.dev/skills/guia-matthieu/clawfu-skills/deliverability-checker)<a href="https://agentmods.dev/skills/guia-matthieu/clawfu-skills/deliverability-checker"><img src="https://agentmods.dev/badge/skills/guia-matthieu/clawfu-skills/deliverability-checker/github.svg" alt="Measured on agentmods" height="20"></a>Or the 80×15 button, for a site that already has a row of RSS and ATOM ones. Only the verdict fits; the numbers stay here.
<a href="https://agentmods.dev/skills/guia-matthieu/clawfu-skills/deliverability-checker"><img src="https://agentmods.dev/badge/skills/guia-matthieu/clawfu-skills/deliverability-checker.svg" alt="Reviewed on agentmods" width="80" height="20"></a>What it costs to keep this loaded
Counted locally with the o200k_base tokenizer, which is exact for GPT models; Claude uses its own tokenizer and its counts differ. Treat this as one consistent yardstick across the catalogue rather than a bill. Prices are per million input tokens.
| Model | Per session | Once invoked |
|---|---|---|
| Fable 5.1 | $0.00044 | $0.01119 |
| Opus 5 | $0.00022 | $0.00560 |
| Sonnet 5 | $0.00009 | $0.00224 |
| Haiku 4.5 | $0.00004 | $0.00112 |
Grade A, and why
deliverability-checker scanned grade A with 0 findings against 26 rules in 11 categories — prompt injection, anti-refusal, data exfiltration, privilege escalation, supply chain, agent snooping, system-prompt leakage, SSRF and excessive agency — measured 9d ago.
A static scan of the body, not an audit. Every finding is printed with the line that produced it so you can judge whether it matters here. A mod is markdown that instructs an agent; that is exactly why what it instructs is worth reading.
Nothing flagged
None of the 26 patterns this scan looks for appear in this file: no shell pipes, no recursive deletes, no credential paths, no hidden text, no instruction-override or anti-refusal phrasing, no agent-config snooping. That is not a guarantee, it is the absence of the things that are checkable.
How it starts
The opening of the file, as written. The whole thing — 176 lines — stays where its author put it; the contents beside it link to each section on GitHub.
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:[email protected]
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
What ships with it
2 files beside SKILL.md in the same directory: the scripts, references and assets a skill reads on demand. Not counted in the per-session cost; read them before you install if any of them is executable.
What this file has done since we first saw it
Hashed on every crawl. A supply-chain change to an agent config is a question of when, not whether, so the history is kept rather than the latest state alone.
- 9d ago First seen · 176 lines · 44 tokens per session scan A 8c7436103824
deliverability-checker is a skill published in the GitHub repository guia-matthieu/clawfu-skills (149 stars, last pushed 5mo ago), licensed MIT. It adds 44 tokens to every session and 1,119 once invoked, about $0.0002 per session on Opus 5. A static security scan graded it A with 0 findings. No closer match exists in the catalogue, so it is treated as the original; first seen 2026-09-03.
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