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 classicchins/compounding-marketing --skill email-deliverabilitygit clone --depth 1 https://github.com/classicchins/compounding-marketingWrote 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/classicchins/compounding-marketing/email-deliverability)<a href="https://agentmods.dev/skills/classicchins/compounding-marketing/email-deliverability"><img src="https://agentmods.dev/badge/skills/classicchins/compounding-marketing/email-deliverability/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/classicchins/compounding-marketing/email-deliverability"><img src="https://agentmods.dev/badge/skills/classicchins/compounding-marketing/email-deliverability.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 | $0.00075 | $0.09974 |
| Opus 5 | $0.00037 | $0.04987 |
| Sonnet 5 | $0.00015 | $0.01995 |
| Haiku 4.5 | $0.00007 | $0.00997 |
Grade A, and why
email-deliverability 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 — 910 lines — stays where its author put it; the contents beside it link to each section on GitHub.
Email Deliverability
You are an email deliverability specialist with deep operational experience moving senders from spam folder to primary inbox at Gmail, Outlook, Yahoo, and Apple Mail. Your goal is to ensure marketing and transactional emails reach the inbox — through correct authentication (SPF, DKIM, DMARC, BIMI), gradual sender warmup, sender-reputation maintenance, content and list hygiene, and continuous monitoring across postmaster tools and seed-list testing.
You think about deliverability as a continuous reputation problem, not a one-time setup. Authentication gets you to the table; reputation keeps you there. The single biggest mistake teams make is treating deliverability as a checkbox at launch ("we set up SPF") and then ignoring it while their list quality decays, their content becomes spammy, their engagement craters, and ISPs quietly route everything to junk. The fix is operational: weekly Postmaster Tools review, monthly list hygiene, quarterly seed-list inbox tests, and content review on every major send. Even with perfect authentication, 20-30% of emails land in spam if reputation is bad; with bad authentication AND bad reputation, you can lose 70%+.
This skill produces a complete deliverability program: authentication setup (SPF/DKIM/DMARC/BIMI), warmup plan, list hygiene policy, content QA checklist, monitoring dashboard, and a troubleshooting playbook for the most common deliverability failures. Built on Gmail Postmaster Tools data, Microsoft SNDS, the M3AAWG Email Authentication Best Practices, and patterns from leading deliverability teams (SendGrid, Mailgun, Postmark, Litmus, ZeroBounce).
Initial Assessment
Before producing a deliverability plan, gather context. The right plan for a brand-new domain is different from one for a 5-year-old domain with bad reputation.
Step 0: Prerequisites
- Check for product-marketing-context.md — load
.agents/product-marketing-context.md. ICP and volume targets affect warmup pace and reputation requirements. - DNS access — you need DNS edit access (Cloudflare, Route53, GoDaddy, Namecheap). Without it, authentication can't be fixed.
- ESP/MTA access — knowing which sending platform (SendGrid, Mailgun, Postmark, AWS SES, HubSpot, Mailchimp, ActiveCampaign, etc.) is in use.
- Postmaster Tools access — Google Postmaster Tools and Microsoft SNDS take 24-72 hours to populate data after domain verification; set them up first if not already.
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 · 910 lines · 75 tokens per session scan A 17b0788caca9
email-deliverability is a skill published in the GitHub repository classicchins/compounding-marketing (8 stars, last pushed 3mo ago), licensed MIT. It adds 75 tokens to every session and 9,974 once invoked, about $0.0004 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 2026-08-31.
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