newsletter-writer

newsletter-writer is a skill for Claude Code from cbrock84/headcount. It costs 84 tokens per session (881 once invoked), scanned A, original, MIT.

A guide to writing newsletters and marketing emails, from subject lines and openings to structure and calls to action. A newsletter is a recurring email sent to subscribers.

In plain words
What is it for?
Use it to draft or edit newsletters, improve subject lines, plan email sequences, set a publishing rhythm, or reuse an issue in another format.
Why use it?
It helps emails earn attention without misleading promises or unnecessary introductions. It also keeps each issue focused on one job, such as teaching, arguing, or selling.

Skill for Claude Code

Written for Claude Code: shipped in a Claude Code plugin.

Part of the marketing plugin — 19 skills shipped together

Good fit Use it to draft or edit newsletters, improve subject lines, plan email sequences, set a publishing rhythm, or reuse an issue in another format.

Compare 6 skills from other repositories ↓
Install with agentmods
npx agentmods add skills/cbrock84/headcount/newsletter-writer
About the project

headcount is an organization of independently installable Claude Code plugins, each grouping skills for a department such as finance, security, or demand generation. Claude Code users install the departments they need and invoke their skills for specialized work; the catalogue entries are skills and related agent tooling from that organization.

cbrock84/headcount · 1,351 stars · on GitHub · cbrock84.github.io

Install

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.

Any agent
npx skills add cbrock84/headcount --skill newsletter-writer
Clone the repo
git clone --depth 1 https://github.com/cbrock84/headcount

Made for: Claude Code.

Or install marketing, the plugin that ships this one along with the rest of its 19 skills.

Wrote 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.

agentmods badge for newsletter-writer

README.md
[![agentmods](https://agentmods.dev/badge/skills/cbrock84/headcount/newsletter-writer/github.svg)](https://agentmods.dev/skills/cbrock84/headcount/newsletter-writer)
Your own site
<a href="https://agentmods.dev/skills/cbrock84/headcount/newsletter-writer"><img src="https://agentmods.dev/badge/skills/cbrock84/headcount/newsletter-writer/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.

agentmods 80×15 button for newsletter-writer

Your own site · 80×15
<a href="https://agentmods.dev/skills/cbrock84/headcount/newsletter-writer"><img src="https://agentmods.dev/badge/skills/cbrock84/headcount/newsletter-writer.svg" alt="Reviewed on agentmods" width="80" height="20"></a>
Per session 84 Skills are progressive disclosure: only the name and description are preloaded; the body loads when the skill is used.
When invoked 881 The whole file, excluding the scripts and references it only reads on demand.
Security scan A 0 findings. A grade says what 26 rules found in the file — not that it is safe. Third-party audits
  • NVIDIA SkillSpector pass 7 Sept 2026
How audits are shown
Origin original No closer match found in the catalogue.
Token cost

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.

ModelPer sessionOnce invoked
Fable 5.1 $0.00084 $0.00881
Opus 5 $0.00042 $0.00441
Sonnet 5 $0.00017 $0.00176
Haiku 4.5 $0.00008 $0.00088

Measured 7d ago against content hash c42b010268a2, method: parsed. Prices are Anthropic first-party input rates as of 2026-09-10, from the pricing page.

Security

Grade A, and why

newsletter-writer 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 7d 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.

plugins/marketing/skills/newsletter-writer/SKILL.md · 90 lines

How it starts

The opening of the file, as written. The whole thing — 90 lines — stays where its author put it; the contents beside it link to each section on GitHub.

Newsletter writer

A newsletter is a standing invitation that can be withdrawn at any time. Every issue either renews it or spends it.

Decide the job before writing

One issue, one job: teach something, argue something, or sell something. Issues attempting all three achieve the first two badly and the third not at all.

Subject line and preview

They are read together and should not repeat each other — the preview extends the subject rather than echoing it. Never leave the preview to default to the first line of the body, which is usually "View in browser."

What works: specific over clever, a claim over a topic, curiosity that the issue actually resolves. What does not: questions the reader can answer "no" to, manufactured urgency, and anything that overpromises relative to the body. Overpromising buys one open and costs the next five.

Opening

The first sentence decides whether the rest is read. Start inside the story or with the claim — no throat-clearing, no "hope you're well," no explaining what the newsletter is about.

Cut your first paragraph after drafting. It is almost always warm-up you needed to write and the reader does not need to read.

Structure

Short paragraphs. One idea each. Enough white space that the issue looks readable before it is read — people decide whether to read from the shape of the thing.

Signpost where the issue turns, so someone skimming still gets the argument. Most readers skim.

Voice

The thing that makes a newsletter worth opening is that it sounds like a person. Specifically:

  • First-hand detail. What you actually did, saw, or got wrong. This is the part nobody else can write, and the part most drafts leave out.
  • Opinions with a stance. Balanced surveys of both sides are forgettable.
  • Varied rhythm. Uniform sentence length reads as generated, because it is what generated text does.
  • Concrete nouns and real numbers in place of abstractions.

Avoid the register tells: "In today's fast-paced world," "it's no secret that," "let's dive in," tricolon everywhere, and every paragraph the same length.

Read the full file on GitHub · 90 lines

Changes

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.

  1. 7d ago First seen · 90 lines · 84 tokens per session scan A c42b010268a2

Subscribe to this mod's changes

newsletter-writer is a skill published in the GitHub repository cbrock84/headcount (1,351 stars, last pushed 8d ago), licensed MIT. It adds 84 tokens to every session and 881 once invoked, about $0.0004 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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