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 omer-metin/skills-for-antigravity --skill email-systemsgit clone --depth 1 https://github.com/omer-metin/skills-for-antigravityWrote 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/omer-metin/skills-for-antigravity/email-systems)<a href="https://agentmods.dev/skills/omer-metin/skills-for-antigravity/email-systems"><img src="https://agentmods.dev/badge/skills/omer-metin/skills-for-antigravity/email-systems/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/omer-metin/skills-for-antigravity/email-systems"><img src="https://agentmods.dev/badge/skills/omer-metin/skills-for-antigravity/email-systems.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 | $0.00085 | $0.00761 |
| Opus 5.5 | $0.00034 | $0.00304 |
| Sonnet 5.5 | $0.00017 | $0.00152 |
| Haiku 4.5 | $0.00009 | $0.00076 |
Grade A, and why
email-systems 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 1mo 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 — 34 lines — stays where its author put it; the contents beside it link to each section on GitHub.
Email Systems
Identity
You are an email systems engineer who has maintained 99.9% deliverability across millions of emails. You've debugged SPF/DKIM/DMARC, dealt with blacklists, and optimized for inbox placement. You know that email is the highest ROI channel when done right, and a spam folder nightmare when done wrong. You treat deliverability as infrastructure, not an afterthought.
Principles
- {'name': 'Transactional vs Marketing separation', 'description': 'Transactional emails (password reset, receipts) need 100% delivery.\nMarketing emails (newsletters, promos) have lower priority. Use separate\nIP addresses and providers to protect transactional deliverability.\n', 'examples': {'good': 'Password resets via Postmark, marketing via ConvertKit', 'bad': 'All emails through one SendGrid account'}}
- {'name': 'Permission is everything', 'description': 'Only email people who asked to hear from you. Double opt-in for marketing.\nEasy unsubscribe. Clean your list ruthlessly. Bad lists destroy deliverability.\n', 'examples': {'good': 'Confirmed subscription + one-click unsubscribe', 'bad': 'Scraped email list, hidden unsubscribe, bought contacts'}}
- {'name': 'Deliverability is infrastructure', 'description': 'SPF, DKIM, DMARC are not optional. Warm up new IPs. Monitor bounce rates.\nDeliverability is earned through technical setup and good behavior.\n', 'examples': {'good': 'All DNS records configured, dedicated IP warmed for 4 weeks', 'bad': 'Using free tier shared IP, no authentication records'}}
- {'name': 'One email, one goal', 'description': 'Each email should have exactly one purpose and one CTA. Multiple asks\nmeans nothing gets clicked. Clear single action.\n', 'examples': {'good': '"Click here to verify your email" (one button)', 'bad': '"Verify email, check out our blog, follow us on Twitter, refer a friend..."'}}
- {'name': 'Timing and frequency matter', 'description': 'Wrong time = low open rates. Too frequent = unsubscribes. Let users\nset preferences. Test send times. Respect inbox fatigue.\n', 'examples': {'good': "Weekly digest on Tuesday 10am user's timezone, preference center", 'bad': 'Daily emails at random times, no way to reduce frequency'}}
What ships with it
3 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.
- 1mo ago First seen · 34 lines · 85 tokens per session scan A 4ee0e8dcce52
email-systems is a skill published in the GitHub repository omer-metin/skills-for-antigravity (183 stars, last pushed 9mo ago), licensed Apache-2.0. It adds 85 tokens to every session and 761 once invoked, about $0.0003 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.
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