A newsletter-writing guide for recurring emails sent to a subscriber list, including subject lines, preview text, a full issue, and one engagement request.

Writing a weekly or regular newsletter, creating its format and publishing schedule, or refreshing one with falling opens or replies.

It helps keep each issue consistent, useful, and personal instead of treating a recurring relationship like a one-time advertisement.

newsletter — Skill for Claude Code and Codex by sanky369

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 sanky369/vibe-building-skills --skill newsletter

Clone the repo

git clone --depth 1 https://github.com/sanky369/vibe-building-skills

Made for: Claude Code, Codex.

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.

README.md

[![agentmods](https://agentmods.dev/badge/skills/sanky369/vibe-building-skills/newsletter/github.svg)](https://agentmods.dev/skills/sanky369/vibe-building-skills/newsletter)

Your own site

<a href="https://agentmods.dev/skills/sanky369/vibe-building-skills/newsletter"><img src="https://agentmods.dev/badge/skills/sanky369/vibe-building-skills/newsletter/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.

Your own site · 80×15

<a href="https://agentmods.dev/skills/sanky369/vibe-building-skills/newsletter"><img src="https://agentmods.dev/badge/skills/sanky369/vibe-building-skills/newsletter.svg" alt="Reviewed on agentmods" width="80" height="20"></a>

Per session 128 Skills are progressive disclosure: only the name and description are preloaded; the body loads when the skill is used.

When invoked 1,903 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.

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.

Model	Per session	Once invoked
Fable 5.1	$0.00128	$0.01903
Opus 5.5	$0.00051	$0.00761
Sonnet 5.5	$0.00026	$0.00381
Haiku 4.5	$0.00013	$0.00190

Measured 2mo ago against content hash 06be9750ef0c, method: parsed. Prices are Anthropic first-party input rates as of 2026-10-07, from the pricing page.

Security

Grade A, and why

newsletter 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 2mo 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.

skills/marketing/newsletter/SKILL.md · 124 lines

How it starts

The opening of the file, as written. The whole thing — 124 lines — stays where its author put it; the contents beside it link to each section on GitHub.

Write newsletter issues that subscribers open, read, and reply to. A newsletter is a recurring relationship, not a broadcast: it must be consistent (same format and cadence every time), valuable (useful before promotional), and personal (sounds like one human wrote it to one human). Prime directive: the reader must finish the issue glad they opened it — value first, promotion never more than a postscript.

When to use / when not to

Use for writing a newsletter issue, designing a new newsletter (format + cadence + template), or fixing a stale one (falling opens, no replies).
If the user wants automated emails triggered by behavior (welcome series, launch, sales sequence), use skills/marketing/email-sequences — a newsletter is a recurring broadcast, not an automation.
If the user has no list and no way to get subscribers, route to skills/marketing/lead-magnet first.
If the source material is a blog post being adapted for many channels at once, use skills/marketing/content-atomizer (it can hand the newsletter item back here).

Intake

Ask in one batch, only what's missing:

Audience and list — who subscribes, roughly how many, and what they signed up expecting.
This issue's raw material — a story, lesson, link roundup, data point, or recent piece of content. If nothing, ask for one recent professional observation or lesson; there is always one.
Voice — existing issues or a brand-voice guide to match (use skills/marketing/brand-voice output if it exists).
Goal — pure relationship-building, or is there something to softly promote?

If the user is starting a newsletter from scratch, also ask what they can sustain: writing capacity and how much source material their work naturally generates. Otherwise infer format and cadence from past issues. If enough is known, state assumptions and draft — don't stall.

Workflow

1. If new: lock the format and cadence (the Blueprint)

Pick one primary format by decision rule — the user can guest-star other formats occasionally, but the flagship format is what subscribers learn to expect:

Read the full file on GitHub · 124 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.

2mo ago First seen · 124 lines · 128 tokens per session scan A 06be9750ef0c

Subscribe to this mod's changes

newsletter is a skill published in the GitHub repository sanky369/vibe-building-skills (31 stars, last pushed 3mo ago), licensed MIT. It adds 128 tokens to every session and 1,903 once invoked, about $0.0005 per session on Opus 5.5. 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 2026-08-30.

Marketing and SEO Writing and docs ai-agents codex developer-tools frontend-design marketing-automation prompt-engineering

newsletter next to 6 skills from other repositories
Mod	Type	Stars	Last push	Licence	Scan	Tokens	Works with
newslettersanky369/vibe-building-skills	Skill	31	3mo ago	MIT	A	128	Claude Code, Codex
ads-youtubeAgriciDaniel/claude-ads	Skill	11k	5d ago	MIT	A	84	Claude Code
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aiwg-regenerate-copilotjmagly/aiwg	Skill	229	yesterday	MIT	A	25	Claude Code, Codex
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