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 skills add guia-matthieu/clawfu-skills --skill sales-letter-writergit clone --depth 1 https://github.com/guia-matthieu/clawfu-skillsWrote 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/guia-matthieu/clawfu-skills/sales-letter-writer)<a href="https://agentmods.dev/skills/guia-matthieu/clawfu-skills/sales-letter-writer"><img src="https://agentmods.dev/badge/skills/guia-matthieu/clawfu-skills/sales-letter-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.
<a href="https://agentmods.dev/skills/guia-matthieu/clawfu-skills/sales-letter-writer"><img src="https://agentmods.dev/badge/skills/guia-matthieu/clawfu-skills/sales-letter-writer.svg" alt="Reviewed on agentmods" width="80" 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 5.1 | $0.00105 | $0.05322 |
| Opus 5 | $0.00053 | $0.02661 |
| Sonnet 5 | $0.00021 | $0.01064 |
| Haiku 4.5 | $0.00011 | $0.00532 |
Grade A, and why
sales-letter-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 9d 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.
How it starts
The opening of the file, as written. The whole thing — 821 lines — stays where its author put it; the contents beside it link to each section on GitHub.
Sales Letter Writer
Write high-converting direct response sales letters using the proven methodologies of Gary Halbert (The Boron Letters) and Dan Kennedy (The Ultimate Sales Letter)—master the art of persuasive long-form copy that turns readers into buyers.
When to Use This Skill
Use this skill when you need to:
- Write a long-form sales letter for a product or service
- Create direct mail pieces that generate response
- Write landing page copy in sales letter format
- Craft email sequences with direct response principles
- Develop VSL scripts (video sales letters)
- Write advertorials that sell through story
- Create launch emails that drive conversions
- Improve existing copy that isn't converting
This skill is particularly valuable for:
- Direct response copywriters
- Course and info product creators
- Coaches and consultants selling services
- E-commerce brands with high-ticket items
- Anyone selling through written persuasion
- Marketers needing to write their own sales copy
Methodology Foundation
Sources:
- Gary Halbert - "The Boron Letters" (1984)
- Dan Kennedy - "The Ultimate Sales Letter" (1981, revised editions)
Core Principle: The success of a sales letter depends first on the market (a "starving crowd"), second on the offer, and third on the copy. Master all three to create letters that consistently convert.
"The best thing you can do to improve your copywriting is to copy, by hand, great advertisements and sales letters." — Gary Halbert
"The ability to write a compelling sales letter is the most valuable skill you could ever acquire." — Dan Kennedy
What Claude Does vs What You Decide
| Claude Does | You Decide |
|---|---|
| Structures production workflow | Final creative direction |
| Suggests technical approaches | Equipment and tool choices |
| Creates templates and checklists | Quality standards |
| Identifies best practices | Brand/voice decisions |
| Generates script outlines | Final script approval |
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.
- 9d ago First seen · 821 lines · 105 tokens per session scan A 5edaec82990b
sales-letter-writer is a skill published in the GitHub repository guia-matthieu/clawfu-skills (149 stars, last pushed 5mo ago), licensed MIT. It adds 105 tokens to every session and 5,322 once invoked, about $0.0005 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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