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.
git clone --depth 1 https://github.com/BigCactusLabs/dead-letterWrote 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/plugins/bigcactuslabs/dead-letter/plugin)<a href="https://agentmods.dev/plugins/bigcactuslabs/dead-letter/plugin"><img src="https://agentmods.dev/badge/plugins/bigcactuslabs/dead-letter/plugin/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/plugins/bigcactuslabs/dead-letter/plugin"><img src="https://agentmods.dev/badge/plugins/bigcactuslabs/dead-letter/plugin.svg" alt="Reviewed on agentmods" width="80" height="20"></a>Grade A, and why
dead-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 6d 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.
The source is not reproduced here
A licence we could not identify
The repository carries a LICENSE file, but it is custom or dual enough that GitHub cannot name it and neither can this catalogue. Unknown terms are not permission, so the body is not copied here. Read the licence at the source and decide for yourself.
What it installs
The manifest is a name and a version. 1 skill, 5 commands, 1 MCP server travel with it, and installing the plugin installs all of them — 169 tokens a session between them. Each is measured on its own page, and each can be installed alone.
What ships with it
1 file beside plugin.json in the same directory: the scripts, references and assets a skill reads on demand. Not counted in the per-session cost; read them before you install if any of them is executable.
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.
- 6d ago Changed · +6 lines d9d65368a312
- 7d ago Changed · +6 lines cd454b4b78c9
- 9d ago Changed · +1 lines b3879ba6fcc9
- 17d ago Changed 9f40a4f4b4ff
- 26d ago Changed e57b5f16b39f
- 1mo ago First seen · 10 lines scan A af24ecc60e47
dead-letter is a plugin published in the GitHub repository BigCactusLabs/dead-letter (8 stars, last pushed yesterday), with no licence file. Its token cost is not measured: this kind of file is read by the harness, not the model. 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 2026-08-31.
Other plugins, from other repositories
obsidian
Create and edit Obsidian vault files including Markdown, Bases, and Canvas. Use when working with .md, .base, or .canvas files in an Obsidian vault.
kordoc marketplace
Single-plugin marketplace shipping kordoc — Korean official-document toolkit (.hwp/.hwpx/.hml + PDF/DOCX/XLS/XLSX) for Claude.
kordoc
A document tool for reading, creating, filling, patching, comparing, checking, and rendering Korean official files such as HWP, HWPX, PDF, DOCX, and spreadsheets.
deckprobe
Inspect PDF, Microsoft Office, and Apple iWork documents with bounded, deterministic probes.
geml
Block-addressed docs: read or replace one section of an existing Markdown file instead of loading the whole thing. Adds per-block history and a code-graph navigator.
xlsx-for-ai
Recalculate spreadsheet formulas, check a sheet for errors, and write real .xlsx files from Claude. Use it when the answer depends on formula results, on whether saved values are current, or on handing back a working spreadsheet file. Your spreadsheet files are sent to the hosted xlsx-for-ai server for processing.