What is dead-letter?
dead-letter is a MCP server by BigCactusLabs that convert .eml exports to Markdown with YAML front matter for RAG pipelines: thread splitting, signature stripping, attachment extraction and calendar parsing. It is listed under Communication and has 8 GitHub stars.
| Type | Mcp server |
|---|---|
| Author | BigCactusLabs |
| Repository | BigCactusLabs/dead-letter |
| Popularity | 8 GitHub stars |
| Category | Communication |
| Security | Low risk (96/100) |
| Rank | #1,853 of 4,418 MCP servers; #111 in Communication |
| Last commit | 2026-10-14 |
| Runs | Locally |
| Language | Python |
Is dead-letter safe to install?
dead-letter scores 96/100 on the MCPMods security check: Low risk. No checks raised a concern. It passed 5 of 6 checks.
MCP server results come from listing signals: who publishes it, where your data goes and what it can do. The code itself is not scanned yet.
| Check | Result |
|---|---|
| Community-built server | Note |
| Runs on your machine only | Pass |
| No credentials mentioned | Pass |
| Read-only by description | Pass |
| No code execution | Pass |
| Source on GitHub | Pass |
How do I install dead-letter?
- Find the launch command. The README says how the server starts (npx, uvx, docker or a remote URL) and which API keys it needs.
https://github.com/BigCactusLabs/dead-letter
- Add it to Claude Code. Replace the part after -- with the command from the README. Remote servers use --transport http with a URL.
claude mcp add dead-letter -- <command from README> claude mcp add --transport http dead-letter <server-url>
- Check it connected. This lists your MCP servers and their status.
claude mcp list
Or ask Claude to set it up
Paste this into Claude Code and it installs dead-letter for you:
Add the "dead-letter" MCP server from https://github.com/BigCactusLabs/dead-letter to Claude Code. Read its README for the launch command and any API keys I need, run claude mcp add, then check that it connects.