End-of-Article CTA Designer
samber/cc-skills
Interviews you about objective, audience and context, then designs an end-of-article call to action with copy, placement, A/B test plan and accessibility check.
A/B test subject line variations using proven copywriting frameworks.
Install Email Subject Line Optimizer
$ npx skills add OneWave-AI/claude-skills --skill email-subject-line-optimizer -a claude-codeProject install by default; add -g for ~/.claude/skills/.
$ gh skill install OneWave-AI/claude-skills email-subject-line-optimizer --agent claude-codeProject scope by default; add --scope user for a personal install. Needs GitHub CLI 2.90.0 or later (public preview).
$ git clone --depth 1 https://github.com/OneWave-AI/claude-skills.git skills-src && mkdir -p .claude/skills && cp -r skills-src/email-subject-line-optimizer .claude/skills/email-subject-line-optimizer && rm -rf skills-srcUse ~/.claude/skills/ instead of .claude/skills for a personal install. The folder must contain SKILL.md.
Claude Code skills documentation · loads skills from .claude/skills/
Install the "email-subject-line-optimizer" agent skill from https://github.com/OneWave-AI/claude-skills/tree/main/email-subject-line-optimizer into .claude/skills/email-subject-line-optimizer/ in this project. Copy the whole folder (SKILL.md and every file beside it), keep the folder name "email-subject-line-optimizer", then confirm the skill loads.Claude Code copies the folder itself, the same result as the manual copy. Check what it changed before you commit it.
$skill-installer install https://github.com/OneWave-AI/claude-skills/tree/main/email-subject-line-optimizerType this inside Codex. $skill-installer <name> installs a curated skill from openai/skills. The installer writes to $CODEX_HOME/skills (default ~/.codex/skills). Restart Codex if the skill does not show up.
$ npx skills add OneWave-AI/claude-skills --skill email-subject-line-optimizer -a codexProject install goes to .agents/skills/; add -g for ~/.codex/skills/.
$ gh skill install OneWave-AI/claude-skills email-subject-line-optimizer --agent codexProject scope by default (.agents/skills/); add --scope user for a personal install.
$ git clone --depth 1 https://github.com/OneWave-AI/claude-skills.git skills-src && mkdir -p .agents/skills && cp -r skills-src/email-subject-line-optimizer .agents/skills/email-subject-line-optimizer && rm -rf skills-srcUse ~/.agents/skills/ instead of .agents/skills for a personal install.
Codex skills documentation · loads skills from .agents/skills/
Install the "email-subject-line-optimizer" agent skill from https://github.com/OneWave-AI/claude-skills/tree/main/email-subject-line-optimizer into .agents/skills/email-subject-line-optimizer/ in this project. Copy the whole folder (SKILL.md and every file beside it), keep the folder name "email-subject-line-optimizer", then confirm the skill loads.Codex copies the folder itself, the same result as the manual copy. Check what it changed before you commit it.
$ npx skills add OneWave-AI/claude-skills --skill email-subject-line-optimizer -a cursorProject install goes to .agents/skills/; add -g for ~/.cursor/skills/.
$ gh skill install OneWave-AI/claude-skills email-subject-line-optimizer --agent cursorProject scope by default (.agents/skills/); add --scope user for a personal install.
$ git clone --depth 1 https://github.com/OneWave-AI/claude-skills.git skills-src && mkdir -p .cursor/skills && cp -r skills-src/email-subject-line-optimizer .cursor/skills/email-subject-line-optimizer && rm -rf skills-srcUse ~/.cursor/skills/ instead of .cursor/skills for a personal install.
Cursor skills documentation · loads skills from .cursor/skills/, .agents/skills/, .claude/skills/, .codex/skills/
Install the "email-subject-line-optimizer" agent skill from https://github.com/OneWave-AI/claude-skills/tree/main/email-subject-line-optimizer into .cursor/skills/email-subject-line-optimizer/ in this project. Copy the whole folder (SKILL.md and every file beside it), keep the folder name "email-subject-line-optimizer", then confirm the skill loads.Cursor copies the folder itself, the same result as the manual copy. Check what it changed before you commit it.
$ gemini skills install https://github.com/OneWave-AI/claude-skills.git --path email-subject-line-optimizer--scope user (default) or --scope workspace; --path is the subfolder of the repo that holds the skill; --consent skips the security confirmation prompt.
$ npx skills add OneWave-AI/claude-skills --skill email-subject-line-optimizer -a gemini-cliProject install goes to .agents/skills/; add -g for ~/.gemini/skills/.
$ gh skill install OneWave-AI/claude-skills email-subject-line-optimizer --agent gemini-cliProject scope by default (.agents/skills/); add --scope user for a personal install.
$ git clone --depth 1 https://github.com/OneWave-AI/claude-skills.git skills-src && mkdir -p .gemini/skills && cp -r skills-src/email-subject-line-optimizer .gemini/skills/email-subject-line-optimizer && rm -rf skills-srcUse ~/.gemini/skills/ instead of .gemini/skills for a personal install, then run /skills reload.
Gemini CLI skills documentation · loads skills from .gemini/skills/, .agents/skills/
Install the "email-subject-line-optimizer" agent skill from https://github.com/OneWave-AI/claude-skills/tree/main/email-subject-line-optimizer into .gemini/skills/email-subject-line-optimizer/ in this project. Copy the whole folder (SKILL.md and every file beside it), keep the folder name "email-subject-line-optimizer", then confirm the skill loads.Gemini CLI copies the folder itself, the same result as the manual copy. Check what it changed before you commit it.
$ gh skill install OneWave-AI/claude-skills email-subject-line-optimizerInstalls for Copilot at project scope by default; add --scope user for a personal install. Preview a skill first with gh skill preview. Needs GitHub CLI 2.90.0 or later (public preview).
$ npx skills add OneWave-AI/claude-skills --skill email-subject-line-optimizer -a github-copilotProject install goes to .agents/skills/; add -g for ~/.copilot/skills/.
$ git clone --depth 1 https://github.com/OneWave-AI/claude-skills.git skills-src && mkdir -p .github/skills && cp -r skills-src/email-subject-line-optimizer .github/skills/email-subject-line-optimizer && rm -rf skills-srcUse ~/.copilot/skills/ instead of .github/skills for a personal install. Commit .github/skills so cloud agent and code review can use it.
GitHub Copilot skills documentation · loads skills from .github/skills/, .claude/skills/, .agents/skills/
Install the "email-subject-line-optimizer" agent skill from https://github.com/OneWave-AI/claude-skills/tree/main/email-subject-line-optimizer into .github/skills/email-subject-line-optimizer/ in this project. Copy the whole folder (SKILL.md and every file beside it), keep the folder name "email-subject-line-optimizer", then confirm the skill loads.GitHub Copilot copies the folder itself, the same result as the manual copy. Check what it changed before you commit it.
$ npx skills add OneWave-AI/claude-skills --skill email-subject-line-optimizer -a opencodeOpenCode documents no install command of its own. Project install goes to .agents/skills/; add -g for ~/.config/opencode/skills/.
$ gh skill install OneWave-AI/claude-skills email-subject-line-optimizer --agent opencodeProject scope by default (.agents/skills/); add --scope user for a personal install.
$ git clone --depth 1 https://github.com/OneWave-AI/claude-skills.git skills-src && mkdir -p .opencode/skills && cp -r skills-src/email-subject-line-optimizer .opencode/skills/email-subject-line-optimizer && rm -rf skills-srcUse ~/.config/opencode/skills/ instead of .opencode/skills for a personal install.
OpenCode skills documentation · loads skills from .opencode/skills/, .claude/skills/, .agents/skills/
Install the "email-subject-line-optimizer" agent skill from https://github.com/OneWave-AI/claude-skills/tree/main/email-subject-line-optimizer into .opencode/skills/email-subject-line-optimizer/ in this project. Copy the whole folder (SKILL.md and every file beside it), keep the folder name "email-subject-line-optimizer", then confirm the skill loads.OpenCode copies the folder itself, the same result as the manual copy. Check what it changed before you commit it.
Facts
- Skill name
email-subject-line-optimizer- GitHub stars
- 336
- Used in
- 1 other repo
- Token cost
- ~357 tokens
- SKILL.md length
- 137 words
- Files
- 1
- Skills in repo
- 69
- Repo updated
- First seen
- Licence
- MIT
At a glance
A/B test subject line variations using proven copywriting frameworks.
- Works in 5 steps: Be Specific: Focus on concrete,… → Use Templates: Provide copy-paste ready… → Include Examples: Show real-world usage → …
- Tasks that involve A/B testing
- Instructions only: no scripts, shell commands, URLs or credentials in SKILL.md
- Tasks that involve Copywriting
What it does
Email Subject Line Optimizer is an agent skill from OneWave-AI/claude-skills. A/B test subject line variations using proven copywriting frameworks. Predict open rates based on historical performance.
Its SKILL.md is about 360 tokens, which your agent loads only when the skill is triggered. It is a single SKILL.md file with no bundled scripts.
It sits in Writing & Content, covering A/B testing and Copywriting. The repository describes itself as: 200+ production-ready Claude Code skills for sales, marketing, design, engineering, and AI agent architecture. Built and maintained by OneWave AI. The licence is MIT.
When your agent uses it
- Tasks that involve A/B testing
- Tasks that involve Copywriting
Example prompts
- “/email-subject-line-optimizer”
Workflow steps
5 steps, taken from the first numbered list in SKILL.md.
- Be Specific: Focus on concrete, actionable outputs
- Use Templates: Provide copy-paste ready formats
- Include Examples: Show real-world usage
- Add Context: Explain why recommendations matter
- Stay Current: Use latest best practices for marketing
What it can do on your machine
Read from SKILL.md and the folder at commit fc5b785. It shows what the files ask for, not the result of running them.
Tool permissions
Pre-approves nothing: there is no allowed-tools line, so your agent's usual permission prompts apply.
From allowed-tools in the SKILL.md frontmatter.
Runs code
No scripts in the folder and no shell commands in SKILL.md (its code samples are markdown).
From the folder's file list and the shell code blocks in SKILL.md.
Network
No URLs in SKILL.md.
From URLs in SKILL.md, links to its own repository left out.
Credentials
Names no API keys, tokens, secrets or passwords.
From names ending in _API_KEY, _TOKEN, _SECRET, _KEY or _PASSWORD in SKILL.md.
Context cost
Email Subject Line Optimizer loads about 357 tokens when it runs. Until then it costs about 38 tokens; SKILL.md has 137 words of instructions outside code blocks.
Estimates: characters ÷ 4, the usual rule of thumb; real counts depend on the model's tokenizer. Scripts and assets cost tokens only if the agent reads them.
Safety
Auto-check passed
The automated check found no risky patterns in SKILL.md.
Automated static check — not a guarantee. Review scripts before installing. It scans the text of SKILL.md for risky patterns (piping downloads into a shell, reading credential files, hidden Unicode, destructive commands); files beside SKILL.md are not scanned.
SKILL.md
The full file from OneWave-AI/claude-skills at commit fc5b785, republished under its MIT licence (© OneWave-AI). 137 words, ~357 tokens.
Download SKILL.mdSave it as
.claude/skills/email-subject-line-optimizer/SKILL.md (or your agent's skills folder).- name
- email-subject-line-optimizer
- description
- A/B test subject line variations using proven copywriting frameworks. Predict open rates based on historical performance.
Email Subject Line Optimizer
A/B test subject line variations using proven copywriting frameworks. Predict open rates based on historical performance.
Instructions
You are an expert at email marketing and copywriting. Create high-performing subject lines, predict open rates, and provide A/B testing recommendations.
Output Format
# Email Subject Line Optimizer Output
**Generated**: {timestamp}
---
## Results
[Your formatted output here]
---
## Recommendations
[Actionable next steps]
Best Practices
- Be Specific: Focus on concrete, actionable outputs
- Use Templates: Provide copy-paste ready formats
- Include Examples: Show real-world usage
- Add Context: Explain why recommendations matter
- Stay Current: Use latest best practices for marketing
Common Use Cases
Trigger Phrases:
- "Help me with [use case]"
- "Generate [output type]"
- "Create [deliverable]"
Example Request:
"[Sample user request here]"
Response Approach:
- Understand user's context and goals
- Generate comprehensive output
- Provide actionable recommendations
- Include examples and templates
- Suggest next steps
Remember: Focus on delivering value quickly and clearly!
© OneWave-AI, MIT. Rendered from Markdown: HTML in the file is shown as text, images as links, and headings moved down two levels. Raw file
Files
Just SKILL.md in email-subject-line-optimizer of OneWave-AI/claude-skills.
Open the folder on GitHubat commit fc5b785
Used in 1 other repository
We found 1 copy of this SKILL.md (exact, near-identical or edited) in other folders, from 1 other GitHub owner. This page covers the copy in OneWave-AI/claude-skills, which our catalogue first saw on October 7, 2026.
Compare with similar skills
Email Subject Line Optimizer next to the 5 skills that share the most tags, products or categories with it. Stars are the repository's; “used in” counts other GitHub owners with a copy.
| Skill | Stars | Used in | Tokens | Auto-check | Licence | Repo updated |
|---|---|---|---|---|---|---|
| Email Subject Line Optimizer this skillOneWave-AI/claude-skills | 336 | 1 repos | ~357 | Automated safety check: Pass | MIT | |
| End-of-Article CTA Designersamber/cc-skills | 227 | — | ~3.1k | Automated safety check: Pass | MIT | |
| Ads Copywriterclaude-office-skills/skills | 505 | — | ~2.1k | Automated safety check: Pass | MIT | |
| Memstack Marketing Facebook Adcwinvestments/memstack | 423 | — | ~2.6k | Automated safety check: Pass | Proprietary | |
| Hormozi Ad Factorypedronauck/skills | 634 | — | ~2.1k | Automated safety check: Pass | None | |
| Map Your MarketVarnan-Tech/opendirectory | 674 | — | ~4.3k | Automated safety check: Pass | MIT |
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Related
Categories
Questions about Email Subject Line Optimizer
What does Email Subject Line Optimizer do?
A/B test subject line variations using proven copywriting frameworks. Email Subject Line Optimizer is an agent skill from OneWave-AI/claude-skills. A/B test subject line variations using proven copywriting frameworks.
When should I use Email Subject Line Optimizer?
Email Subject Line Optimizer fits situations like: tasks that involve A/B testing; tasks that involve Copywriting.
How do I install Email Subject Line Optimizer in Claude Code?
Run `npx skills add OneWave-AI/claude-skills --skill email-subject-line-optimizer -a claude-code`. Or copy the skill folder (email-subject-line-optimizer in OneWave-AI/claude-skills) into .claude/skills/email-subject-line-optimizer in your project. Claude Code loads it when a task matches its description.
How do I install Email Subject Line Optimizer in Codex?
Run `npx skills add OneWave-AI/claude-skills --skill email-subject-line-optimizer -a codex`. Or copy the skill folder (email-subject-line-optimizer in OneWave-AI/claude-skills) into .agents/skills/email-subject-line-optimizer in your project. Codex loads it when a task matches its description.
Can I use Email Subject Line Optimizer in Cursor, Gemini CLI or GitHub Copilot?
Cursor, Gemini CLI, GitHub Copilot and OpenCode also load SKILL.md folders. With the skills CLI, run `npx skills add OneWave-AI/claude-skills --skill email-subject-line-optimizer -a cursor` (or -a gemini-cli, github-copilot or opencode for the others). To copy it by hand, put the folder in .cursor/skills/email-subject-line-optimizer, .gemini/skills/email-subject-line-optimizer, .github/skills/email-subject-line-optimizer and .opencode/skills/email-subject-line-optimizer in your project.
What does Email Subject Line Optimizer need to run?
SKILL.md names no scripts, command-line tools or credentials: Email Subject Line Optimizer is instructions for the agent only.
Does Email Subject Line Optimizer access the network?
SKILL.md contains no URLs. Any network use would come from the scripts or tools the agent runs. This is read from the text; nothing was executed.
Is Email Subject Line Optimizer safe to install?
Our automated static check of SKILL.md found no risky patterns, such as piping downloads into a shell, reading credential files or hidden Unicode. It is not a guarantee. Review the folder before installing.
What licence does Email Subject Line Optimizer use?
Email Subject Line Optimizer is published under the MIT licence (the repository's licence). It allows redistribution, so the full SKILL.md is shown on this page.
How many tokens does Email Subject Line Optimizer use?
About 357 tokens (SKILL.md is roughly 1.4k characters). Agents keep only the skill's name and description in context until a task matches; then they load SKILL.md in full.
What are the alternatives to Email Subject Line Optimizer?
Skills that share tags, products or a category with Email Subject Line Optimizer: End-of-Article CTA Designer (samber/cc-skills, 227 stars), Ads Copywriter (claude-office-skills/skills, 505 stars), Memstack Marketing Facebook Ad (cwinvestments/memstack, 423 stars) and Hormozi Ad Factory (pedronauck/skills, 634 stars). The comparison table on this page puts their stars, adoption, token cost, safety result and licence side by side.
Who maintains Email Subject Line Optimizer?
OneWave-AI (a GitHub organization) maintains it in OneWave-AI/claude-skills, which has 336 GitHub stars. The repository holds 69 skills in this directory. The repository was last updated on October 2, 2026.
Source: OneWave-AI/claude-skills on GitHub. Facts on this page come from the repository at the commit we read; the author's words are quoted as theirs.