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 plugins/bigcactuslabs/dead-letter/plugin/plugin marketplace add BigCactusLabs/dead-lettergit clone --depth 1 https://github.com/BigCactusLabs/dead-letterGrade 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 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.
The source is not reproduced here
No licence file
A repository with no LICENSE is all rights reserved by default, so the body is not copied here. The metadata, the measurements and the link are.
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 First seen · 10 lines scan A af24ecc60e47
dead-letter is a plugin published in the GitHub repository BigCactusLabs/dead-letter (7 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
mcp-email-server
Email MCP tools with safe, non-secret setup and diagnostic guidance.
e2a
Open-source email API for applications and AI agents — transactional sending from any product, per-agent two-way inboxes, structured SPF/DKIM/DMARC evidence, and a queryable event log. 78 MCP tools over hosted streamable HTTP with OAuth.
apple-mail-mcp
Plugin marketplace listing 1 plugin: apple-mail.
apple-mail
Natural language interface for Apple Mail — search, compose, triage, organize, and analyze email with 24 MCP tools and an expert email management skill.
better-email-mcp
Email management via IMAP/SMTP — multi-account.
mail-muncher
mail-muncher — an email client for AI agents: filtered, read-only mail from any IMAP server or Gmail, delivered to disk and served over MCP.