Asd Ste100
danyuchn/asd-ste100-skill
A skill your agent uses when English text must be parsed without a human to resolve ambiguity — tool descriptions, error messages, inter-agent instructions, system prompts, status reports — and…
Agent skill
Email Subject Line Optimizer
by aiskilloftheweek in aiskilloftheweek/claude-ai-skill-of-the-week
Analyzes a subject line against proven best practices and generates 5 optimized alternative versions.
Install Email Subject Line Optimizer
$ npx skills add aiskilloftheweek/claude-ai-skill-of-the-week --skill email-subject-line-optimizer -a claude-codeProject install by default; add -g for ~/.claude/skills/.
$ gh skill install aiskilloftheweek/claude-ai-skill-of-the-week 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/aiskilloftheweek/claude-ai-skill-of-the-week.git skills-src && mkdir -p .claude/skills && cp -r skills-src/skills/001-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/aiskilloftheweek/claude-ai-skill-of-the-week/tree/main/skills/001-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/aiskilloftheweek/claude-ai-skill-of-the-week/tree/main/skills/001-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 aiskilloftheweek/claude-ai-skill-of-the-week --skill email-subject-line-optimizer -a codexProject install goes to .agents/skills/; add -g for ~/.codex/skills/.
$ gh skill install aiskilloftheweek/claude-ai-skill-of-the-week 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/aiskilloftheweek/claude-ai-skill-of-the-week.git skills-src && mkdir -p .agents/skills && cp -r skills-src/skills/001-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/aiskilloftheweek/claude-ai-skill-of-the-week/tree/main/skills/001-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 aiskilloftheweek/claude-ai-skill-of-the-week --skill email-subject-line-optimizer -a cursorProject install goes to .agents/skills/; add -g for ~/.cursor/skills/.
$ gh skill install aiskilloftheweek/claude-ai-skill-of-the-week 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/aiskilloftheweek/claude-ai-skill-of-the-week.git skills-src && mkdir -p .cursor/skills && cp -r skills-src/skills/001-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/aiskilloftheweek/claude-ai-skill-of-the-week/tree/main/skills/001-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/aiskilloftheweek/claude-ai-skill-of-the-week.git --path skills/001-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 aiskilloftheweek/claude-ai-skill-of-the-week --skill email-subject-line-optimizer -a gemini-cliProject install goes to .agents/skills/; add -g for ~/.gemini/skills/.
$ gh skill install aiskilloftheweek/claude-ai-skill-of-the-week 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/aiskilloftheweek/claude-ai-skill-of-the-week.git skills-src && mkdir -p .gemini/skills && cp -r skills-src/skills/001-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/aiskilloftheweek/claude-ai-skill-of-the-week/tree/main/skills/001-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 aiskilloftheweek/claude-ai-skill-of-the-week 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 aiskilloftheweek/claude-ai-skill-of-the-week --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/aiskilloftheweek/claude-ai-skill-of-the-week.git skills-src && mkdir -p .github/skills && cp -r skills-src/skills/001-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/aiskilloftheweek/claude-ai-skill-of-the-week/tree/main/skills/001-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 aiskilloftheweek/claude-ai-skill-of-the-week --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 aiskilloftheweek/claude-ai-skill-of-the-week 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/aiskilloftheweek/claude-ai-skill-of-the-week.git skills-src && mkdir -p .opencode/skills && cp -r skills-src/skills/001-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/aiskilloftheweek/claude-ai-skill-of-the-week/tree/main/skills/001-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
- 148
- Token cost
- ~2.1k tokens
- SKILL.md length
- 1,046 words
- Files
- 1
- Skills in repo
- 13
- Repo updated
- First seen
- Licence
- None found
At a glance
Analyzes a subject line against proven best practices and generates 5 optimized alternative versions.
- Works in 2 steps: Silent analysis → Output
- The user wants to improve
- SKILL.md covers Process, 🔍 Subject Line Audit, ✏️ 5 Optimized Alternatives and 💡 Recommendation, plus 2 more sections
- Instructions only: no scripts, shell commands, URLs or credentials in SKILL.md
What it does
Email Subject Line Optimizer is an agent skill from aiskilloftheweek/claude-ai-skill-of-the-week. Analyzes a subject line against proven best practices and generates 5 optimized alternative versions. Use this skill whenever the user wants to improve, test, or rewrite an email subject line. Trigger on phrases like "improve this subject line", "optimize the subject", "write a better subject line", "suggest subject line alternatives", "this subject line isn't converting", "help me with the subject line", "rewrites for the subject", or when the user pastes an email and asks specifically about the subject line…
Its SKILL.md is about 2.1k 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 Copywriting. The repository describes itself as: Curating the greatest Claude Skills that actually change how you work.
When your agent uses it
- The user wants to improve
- Rewrite an email subject line
- Phrases like improve this subject line
- Optimize the subject
Example prompts
- “improve this subject line”
- “optimize the subject”
- “write a better subject line”
- “/email-subject-line-optimizer”
Workflow steps
2 steps, taken from the step headings in SKILL.md.
- Silent analysis
- Output
What it can do on your machine
Read from SKILL.md and the folder at commit f3b155c. 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.
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 2.1k tokens when it runs. Until then it costs about 192 tokens; SKILL.md has 1,046 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
Without a licence we can't republish the file, so here is its outline and opening line. It has 1,046 words (~2,065 tokens).
“You receive an email subject line (and optionally the email body for context) as input.”
- name
- email-subject-line-optimizer
Files
Just SKILL.md in skills/001-email-subject-line-optimizer of aiskilloftheweek/claude-ai-skill-of-the-week.
Open the folder on GitHubat commit f3b155c
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 skillaiskilloftheweek/claude-ai-skill-of-the-week | 148 | — | ~2.1k | Automated safety check: Pass | None | |
| Asd Ste100danyuchn/asd-ste100-skill | 4.2k | — | ~4.1k | Automated safety check: Pass | MIT | |
| AI Copywritermikiarlo3/ai-copywriter | 1.2k | — | ~12k | Automated safety check: Pass | MIT | |
| Brand Voice Guideluongnv89/claude-howto | 42k | — | ~609 | Automated safety check: Pass | MIT | |
| Ralph Copywritermuratcankoylan/ralph-wiggum-marketer | 777 | — | ~2.4k | Automated safety check: Pass | None | |
| Humanities Writing Companiontizzy916/humanities-writing-companion | 435 | — | ~3.4k | Automated safety check: Pass | CC-BY-NC-4.0 |
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Related
Categories
Questions about Email Subject Line Optimizer
What does Email Subject Line Optimizer do?
Analyzes a subject line against proven best practices and generates 5 optimized alternative versions. Email Subject Line Optimizer is an agent skill from aiskilloftheweek/claude-ai-skill-of-the-week. Analyzes a subject line against proven best practices and generates 5 optimized alternative versions.
When should I use Email Subject Line Optimizer?
Email Subject Line Optimizer fits situations like: the user wants to improve; rewrite an email subject line; phrases like improve this subject line; optimize the subject.
How do I install Email Subject Line Optimizer in Claude Code?
Run `npx skills add aiskilloftheweek/claude-ai-skill-of-the-week --skill email-subject-line-optimizer -a claude-code`. Or copy the skill folder (skills/001-email-subject-line-optimizer in aiskilloftheweek/claude-ai-skill-of-the-week) 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 aiskilloftheweek/claude-ai-skill-of-the-week --skill email-subject-line-optimizer -a codex`. Or copy the skill folder (skills/001-email-subject-line-optimizer in aiskilloftheweek/claude-ai-skill-of-the-week) 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 aiskilloftheweek/claude-ai-skill-of-the-week --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?
No licence was found for Email Subject Line Optimizer or its repository. Without one, default copyright applies: ask the author before reusing or redistributing it.
How many tokens does Email Subject Line Optimizer use?
About 2.1k tokens (SKILL.md is roughly 8.3k 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: Asd Ste100 (danyuchn/asd-ste100-skill, 4.2k stars), AI Copywriter (mikiarlo3/ai-copywriter, 1.2k stars), Brand Voice Guide (luongnv89/claude-howto, 42k stars) and Ralph Copywriter (muratcankoylan/ralph-wiggum-marketer, 777 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?
aiskilloftheweek (a GitHub user) maintains it in aiskilloftheweek/claude-ai-skill-of-the-week, which has 148 GitHub stars. The repository holds 13 skills in this directory. The repository was last updated on June 5, 2026.
Source: aiskilloftheweek/claude-ai-skill-of-the-week on GitHub. Facts on this page come from the repository at the commit we read; the author's words are quoted as theirs.