無料GitHub で公開

subject-line-writer

Use this skill when you need cold email subject lines that get opened and do not look like marketing: "write subject lines for this email", "my open rates are low", "A/B test subject lines". Writes short, lowercase, internal-looking subject lines matched to the email's angle, explains the pattern behind each, flags spam and clickbait risks, and sets up a fair subject-line test. For cold outreach, follow-ups and re-engagement emails.

日本語の概要は準備中です。原文の説明を表示しています。

prosyo-ai/gtm-skillスター 11(GitHub 11 + cccskills 0)

実行スコア未検証

インストール方法を見る

含まれるファイル（1）

SKILL.md3.5 KB

SKILL.md（原文）

インストールする前に、エージェントに与えられる指示の中身を確認できます。

Use this after the email is written. The subject line's job is to get the email opened by the right person without promising something the body does not deliver.

Inputs

The email body (subject lines are written for a specific email, never in a vacuum).
The persona and seniority.
The trigger or angle the email uses.

The play

1. Write in the patterns that work for cold B2B

Pattern	Example	When
Topic, two to four words	"month-end close"	Default
Trigger reference	"new sdr team", "the series b"	Email leads with a trigger
Peer or customer	"contoso's close"	Strong, approved proof
Question	"manual reconciliations?"	Pain is very common
Their initiative	"europe expansion"	Announced plan
Mutual context (only if real)	"maria suggested i reach out"	Genuine referral

2. Follow the format rules

1 to 5 words; under 40 characters so it is not cut on phones.
Lowercase or sentence case; it should look like it came from a colleague.
No first-name merge field in the subject (it reads as automated), no emojis, no exclamation marks, no "quick question".
The subject must be true to the email. Clickbait wins opens and loses replies and trust.

3. Give options per pattern

Return 2-3 options for 3 patterns. Mark the recommended one.

4. Test fairly

Change only the subject; keep body, list and send time the same.
At least 200 sends per variant before judging.
Judge on reply rate, not opens. Open tracking is unreliable: privacy features pre-load images and inflate opens, and many teams disable tracking pixels to protect deliverability.

Output format

Recommended: <subject>
Topic: <3 options>
Trigger: <3 options>
Question: <3 options>
Avoid: <any risky phrasing found and why>
Test: A = <..>, B = <..>, judge on reply rate after 200+ sends each

What good looks like

Reads like a peer's email in a crowded inbox.
Connects directly to the first line of the email.
No spam-pattern words: "free", "guarantee", "act now", "limited time", percentages off.
The common mistake is clever or vague subjects ("thoughts?", "a crazy idea") that get opened out of curiosity and then deleted with irritation.

Rules

MUST keep subject lines under 40 characters.
MUST match the subject to the email's actual content.
NEVER use fake reply or forward prefixes ("Re:", "Fwd:") on a first email.
NEVER use a referral subject unless the referral is real.

Example prompts

"Write subject lines for this cold email to CFOs."
"Give me 10 subject lines for a follow-up that shares a case study."
"Set up a subject line test for our new campaign."

レビュー

まだレビューはありません。使ってみた感想をお寄せください。

ログインなしで書き込めます。使ってみた感想、質問、動かなかった環境などを気軽にどうぞ。

まだコメントはありません。最初のコメントを書いてみませんか。

同じリポジトリのスキル

abm-account-plan

無料

Use this skill when you run account-based marketing or sales on a short list of named accounts: "build an ABM plan", "account plan for our top 20", "how do we break into this enterprise account", "1:1 ABM program". Picks the accounts and the ABM tier (1:1, 1:few, 1:many), maps the buying group, writes the account insight and value hypothesis, plans coordinated sales and marketing plays by stage, and sets the metrics (engagement, meetings, pipeline) that show it is working.

日本語の概要は準備中です。原文の説明を表示しています。