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 swan-gtm/gtm-skills --skill email-copy-optimizergit clone --depth 1 https://github.com/swan-gtm/gtm-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/swan-gtm/gtm-skills/email-copy-optimizer)<a href="https://agentmods.dev/skills/swan-gtm/gtm-skills/email-copy-optimizer"><img src="https://agentmods.dev/badge/skills/swan-gtm/gtm-skills/email-copy-optimizer/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/swan-gtm/gtm-skills/email-copy-optimizer"><img src="https://agentmods.dev/badge/skills/swan-gtm/gtm-skills/email-copy-optimizer.svg" alt="Reviewed on agentmods" width="80" height="20"></a>- NVIDIA SkillSpector pass
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 | $0.00167 | $0.01437 |
| Opus 5 | $0.00084 | $0.00718 |
| Sonnet 5 | $0.00033 | $0.00287 |
| Haiku 4.5 | $0.00017 | $0.00144 |
Grade A, and why
email-copy-optimizer 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 — 159 lines — stays where its author put it; the contents beside it link to each section on GitHub.
Email Copy Optimizer
Polish any email draft by applying 10 proven copywriting rules — from someone who writes for 7, 8, and 9-figure founders and has written/edited 1,000+ emails.
How to Use This Skill
When triggered, ask the user for:
To optimize your email, I need:
- Your email draft — Paste the full email
- Type of email — Newsletter, sales, nurture, launch, etc.
- Goal — What action should readers take?
- Target audience — Who's reading this?
The 10 Rules
Rule 1: Write at Least 10 Subject Line Variations
Your email doesn't matter if nobody opens it. Always brainstorm 10+ subject line variations using different psychological angles. Keep all subject lines under 42 characters (the cutoff for most mobile screens).
Action: Generate 10 subject line variations for the user's email.
Rule 2: Write the Intro Like a LinkedIn Hook
Skip the long greetings. Capture attention immediately. The first 1-2 lines should make someone want to keep reading — just like a social media hook.
Bad: "Hey there! Hope you're having a great week. I've been thinking a lot lately about..." Good: "I make a living writing emails for 7, 8, and 9 figure founders. Here are 10 tips..."
Action: Identify if the intro is weak and rewrite it as a hook.
Rule 3: Speak Directly to the Reader
The best emails feel like a 1:1 conversation. Look for instances of speaking to a crowd and fix them.
Checks:
- Replace "Hey everyone" → "Hey" or "Hey [name]"
- Aim for 80%+ second person ("you") vs. first person ("I") or third person ("they")
Action: Flag any crowd-speak and rewrite to direct address.
Rule 4: Edit for Mobile
Most readers are on mobile. Blocky paragraphs that look fine on desktop feel overwhelming on a phone.
Rule: Break any paragraph with 2-3 sentences into 1-sentence paragraphs with line breaks.
Action: Identify blocky paragraphs and suggest mobile-friendly formatting.
Rule 5: Do Copywork on the Greats
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 · 159 lines · 167 tokens per session scan A 435cb06ade03
email-copy-optimizer is a skill published in the GitHub repository swan-gtm/gtm-skills (150 stars, last pushed 2d ago), licensed MIT. It adds 167 tokens to every session and 1,437 once invoked, about $0.0008 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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