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 matthewdigiuseppe/MStack --skill cover-lettergit clone --depth 1 https://github.com/matthewdigiuseppe/MStackWrote 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/matthewdigiuseppe/mstack/cover-letter)<a href="https://agentmods.dev/skills/matthewdigiuseppe/mstack/cover-letter"><img src="https://agentmods.dev/badge/skills/matthewdigiuseppe/mstack/cover-letter.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 5.1 | $0.00049 | $0.00684 |
| Opus 5 | $0.00024 | $0.00342 |
| Sonnet 5 | $0.00010 | $0.00137 |
| Haiku 4.5 | $0.00005 | $0.00068 |
Grade A, and why
cover-letter 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.
How it starts
The opening of the file, as written. The whole thing — 68 lines — stays where its author put it; the contents beside it link to each section on GitHub.
/mstack:cover-letter
Stage: submit Voice: editor (calibrated as the author addressing the editor)
When to invoke
After /mstack:journal-fit settles a target journal. The cover letter is read in 30 seconds; precision and specificity matter more than warmth.
Procedure
-
Load.
.mstack/config.yaml(target journal — top tier), abstract frompaper/sections/abstract.tex, contribution sentence from.mstack/research-question.md. -
Identify the editor. Ask the user for the current editor name and salutation if not in
.mstack/config.yaml. Don't guess from training data — editors change. -
Draft three paragraphs, ≤ 400 words total:
¶1: Fit
What the paper does, in one sentence, and why it fits this journal. Reference one or two recent papers from the journal it's in conversation with — concrete, not "this builds on the journal's strong tradition in X."
¶2: Contribution
What the paper adds. Use the contribution sentence from
/mstack:research-question. State the headline finding and the design that delivers it. Resist hedge language.¶3: Declarations
- Preregistration status + URL (from
.mstack/config.yaml). - Data and code availability (link or commitment).
- Not under review elsewhere.
- Conflicts of interest.
- IRB approval if applicable.
- Word count.
- Acknowledgement of past presentations / earlier versions if any.
- Preregistration status + URL (from
-
Sign-off. Author name(s) and affiliation(s). One line.
-
Save to
submission/cover-letter.md. Format as Markdown — convert to whatever the journal accepts at submission time. -
Cross-check before declaring done:
- Editor name correct and current.
- Journal name spelled correctly throughout.
- Word count within journal limit.
- Declarations cover everything the journal's submission portal will ask.
Outputs
submission/cover-letter.md.- Summary block: word count, editor addressed, declarations covered — plus a reminder to set
paper.status: "submitted"in.mstack/config.yamlonce the portal confirms.
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.
- 7d ago First seen · 68 lines · 49 tokens per session scan A 913cea46edf2
cover-letter is a skill published in the GitHub repository matthewdigiuseppe/MStack (14 stars, last pushed 11d ago), licensed MIT. It adds 49 tokens to every session and 684 once invoked, about $0.0002 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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