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 brainbytes-dev/everything-claude-marketing --skill email-deliverabilitygit clone --depth 1 https://github.com/brainbytes-dev/everything-claude-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/brainbytes-dev/everything-claude-marketing/email-deliverability)<a href="https://agentmods.dev/skills/brainbytes-dev/everything-claude-marketing/email-deliverability"><img src="https://agentmods.dev/badge/skills/brainbytes-dev/everything-claude-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/brainbytes-dev/everything-claude-marketing/email-deliverability"><img src="https://agentmods.dev/badge/skills/brainbytes-dev/everything-claude-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 | $0.00027 | $0.02749 |
| Opus 5.5 | $0.00011 | $0.01100 |
| Sonnet 5.5 | $0.00005 | $0.00550 |
| Haiku 4.5 | $0.00003 | $0.00275 |
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 2mo 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 — 283 lines — stays where its author put it; the contents beside it link to each section on GitHub.
Email Deliverability
When to Activate
Use this skill when:
- Setting up email infrastructure for a new domain or sender
- Diagnosing deliverability problems (emails going to spam)
- Warming a new IP or domain
- Cleaning an email list
- Setting up SPF, DKIM, and DMARC
- Improving inbox placement rates
- Planning a re-permission or re-engagement campaign
First Questions
Before optimizing deliverability, clarify:
- What email sending platform is being used? (ESP or self-hosted)
- Is this a shared IP or dedicated IP?
- What is the current sending volume? (Daily/weekly/monthly)
- What are current open rates and bounce rates?
- Has there been a recent deliverability drop? (When did it start?)
- Is the sending domain properly authenticated? (SPF, DKIM, DMARC)
- How was the email list built? (Organic, purchased, scraped — critical question)
- When was the last list cleaning?
Core Rules
- Deliverability is earned, not bought. No tool or trick replaces genuine engagement signals.
- Authentication is table stakes. SPF, DKIM, and DMARC must be configured correctly before anything else matters.
- List quality is deliverability quality. A clean, engaged list delivers. A dirty list destroys sender reputation.
- Never buy or rent email lists. This is the single fastest way to destroy deliverability.
- Engagement drives placement. ISPs watch how recipients interact with your email. High engagement = inbox. Low engagement = spam.
- Reputation is per domain AND per IP. Both matter, but domain reputation is increasingly dominant.
- Monitor proactively. Don't wait for problems — monitor deliverability metrics weekly.
Email Authentication Setup
SPF (Sender Policy Framework)
SPF tells receiving mail servers which IPs are authorized to send email on behalf of your domain.
Setup:
- Identify all services that send email from your domain (ESP, transactional email, CRM, etc.)
- Create a TXT record in your DNS:
v=spf1 include:_spf.google.com include:sendgrid.net include:mailchimp.com ~all - Include ALL authorized senders
- Use
~all(soft fail) or-all(hard fail — stricter) - Maximum 10 DNS lookups — consolidate if needed
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.
- 2mo ago First seen · 283 lines · 27 tokens per session scan A 05f95f446456
email-deliverability is a skill published in the GitHub repository brainbytes-dev/everything-claude-marketing (10 stars, last pushed 7mo ago), licensed MIT. It adds 27 tokens to every session and 2,749 once invoked, about $0.0001 per session on Opus 5.5. 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.
email-deliverability compared with skills from other repositories
| Mod | Type | Stars | Last push | Licence | Scan | Tokens | Works with |
|---|---|---|---|---|---|---|---|
| email-deliverabilitybrainbytes-dev/everything-claude-marketing | Skill | 10 | 7mo ago | MIT | A | 27 | Claude Code |
| imagegenopenai/codex | Skill | 133k | yesterday | Apache-2.0 | A | 113 | Codex |
| playwright-climicrosoft/playwright | Skill | 99k | yesterday | Apache-2.0 | A | 19 | Claude Code |
| local-ai-agentsmicrosoft/ai-agents-for-beginners | Skill | 79k | 4d ago | MIT | A | 200 | Claude Code, Codex |
| systematic-debuggingobra/superpowers | Skill | 313k | 3d ago | MIT | A | 21 | Claude Code |
| next-cache-components-adoptionvercel/next.js | Skill | 143k | yesterday | MIT | A | 95 | Claude Code |
| next-partial-prefetching-adoptionvercel/next.js | Skill | 143k | yesterday | MIT | A | 103 | Claude Code |