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.
npx agentmods add skills/cwinvestments/memstack/newsletternpx skills add cwinvestments/memstack --skill newslettergit clone --depth 1 https://github.com/cwinvestments/memstackWrote 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.
[](https://agentmods.dev/skills/cwinvestments/memstack/newsletter)<a href="https://agentmods.dev/skills/cwinvestments/memstack/newsletter"><img src="https://agentmods.dev/badge/skills/cwinvestments/memstack/newsletter.svg" alt="Measured on agentmods" height="20"></a>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 | $0.00060 | $0.02407 |
| Opus 5 | $0.00030 | $0.01203 |
| Sonnet 5 | $0.00012 | $0.00481 |
| Haiku 4.5 | $0.00006 | $0.00241 |
Grade A, and why
memstack-content-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 yesterday.
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.
How it starts
The opening of the file, as written. The whole thing — 253 lines — stays where its author put it; the contents beside it link to each section on GitHub.
Newsletter: Writing email newsletter edition...
Produces an email newsletter edition with subject line formulas, section structure, personalization, link placement strategy, growth tactics, and engagement optimization.
Activation
When this skill activates, output:
Newsletter: Writing email newsletter edition...
Then execute the protocol below.
Context Guard
| Context | Status |
|---|---|
| User says "newsletter", "email newsletter", "weekly digest" | ACTIVE |
| User says "subscriber growth" or "open rates" | ACTIVE |
| User wants to write a newsletter edition or start a newsletter | ACTIVE |
| User wants a lead magnet with email capture | DORMANT: use Lead Magnet |
| User wants a full content automation pipeline | DORMANT: use Content Pipeline |
Common Mistakes
| Mistake | Why It's Wrong |
|---|---|
| "Newsletter = company updates" | Nobody cares about your company news. Deliver value: insights, tips, curated content. |
| "Generic subject line" | "[Company] Monthly Newsletter" gets 10% opens. Curiosity-driven subjects get 35%+. |
| "No consistent format" | Readers want predictable value. A consistent structure builds habit and trust. |
| "Too many links" | More than 3-5 links per section dilutes clicks. Feature one primary link prominently. |
| "No growth strategy" | "Build it and they will come" doesn't work. Actively promote every issue. |
Protocol
Step 1: Gather Newsletter Requirements
If the user hasn't provided details, ask:
- Topic/niche: what's the newsletter about?
- Audience: who reads it? (role, industry, experience level)
- Frequency: weekly, biweekly, or monthly?
- Type: curated links, original essays, tips, industry news, or mixed?
- Current state: new or existing? (subscriber count, open rates)
- Monetization: free, paid, or sponsored?
Step 2: Write the Subject Line
Subject line formulas:
| Formula | Template | Example |
|---|---|---|
| Curiosity gap | [Topic]: The [thing] nobody talks about | "Pricing: The metric nobody tracks" |
| Numbered value | [X] [things] to [outcome] this week | "5 tools to ship faster this week" |
| Question | Why [common practice] [doesn't work / is wrong]? | "Why your landing page isn't converting?" |
| Personal | I [did thing], here's what happened | "I quit meetings for a month" |
| Direct value | How to [outcome] (in [constraint]) | "How to write copy that converts (in 20 min)" |
| Current event | [Event/trend]: What it means for [audience] | "GPT-5: What it means for developers" |
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.
- yesterday Changed 0569a210c612
- 5d ago First seen · 253 lines · 60 tokens per session scan A ec43fb189bb5
memstack-content-newsletter is a skill published in the GitHub repository cwinvestments/memstack (419 stars, last pushed today), licensed MIT. It adds 60 tokens to every session and 2,407 once invoked, about $0.0003 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 2026-08-30.
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