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 boron-lettersgit 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/boron-letters)<a href="https://agentmods.dev/skills/guia-matthieu/clawfu-skills/boron-letters"><img src="https://agentmods.dev/badge/skills/guia-matthieu/clawfu-skills/boron-letters/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/boron-letters"><img src="https://agentmods.dev/badge/skills/guia-matthieu/clawfu-skills/boron-letters.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 | $0.00077 | $0.04891 |
| Opus 5 | $0.00039 | $0.02446 |
| Sonnet 5 | $0.00015 | $0.00978 |
| Haiku 4.5 | $0.00008 | $0.00489 |
Grade A, and why
boron-letters 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 12d 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 — 816 lines — stays where its author put it; the contents beside it link to each section on GitHub.
Boron Letters Copywriting
Master Gary Halbert's direct response copywriting principles from "The Boron Letters" (1984). The timeless fundamentals that separate pros from amateurs.
When to Use This Skill
- Writing direct response copy (sales letters, emails, ads)
- Creating headlines that demand attention
- Building mailing lists and segmentation
- Improving copy through the A-pile test
- Learning copywriting fundamentals from scratch
- Diagnosing why copy isn't converting
Methodology Foundation
Source: Gary Halbert - "The Boron Letters" (1984)
Core Principle: "Become a student of markets, not products." The list matters more than the copy. The A-pile beats the B-pile. Long copy outsells short. And the fundamentals of human psychology never change.
Why This Matters: These letters were written in the 1980s but remain the gold standard for direct response copywriting. Halbert's "coat of arms" letter mailed over 600 million times. The principles work because they're based on human psychology, not trends.
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 Skill Does
- Applies the A-pile test - Gets mail opened and read
- Identifies starving crowds - Finds markets hungry to buy
- Uses the AIDA formula - Structures persuasive copy
- Writes irresistible headlines - Stops readers cold
- Creates long-form sales copy - Converts readers to buyers
How to Use
Apply the A-Pile Test
Review this email/letter through Halbert's A-pile framework:
[paste copy]
Will it get opened? Will it get read? What's missing?
Write Sales Copy
Write a Halbert-style sales letter for:
Product: [description]
Target market: [who]
Main pain point: [problem]
Unique mechanism: [how it works]
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.
- 12d ago First seen · 816 lines · 77 tokens per session scan A 53f86930a702
boron-letters is a skill published in the GitHub repository guia-matthieu/clawfu-skills (149 stars, last pushed 5mo ago), licensed MIT. It adds 77 tokens to every session and 4,891 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 2026-08-30.
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