dead-letter

dead-letter runs locally from a Python package published to PyPI: dead-letter version 0.4.5. It speaks MCP over stdio, so the client starts it as a program and talks to it through standard input and output. It needs Python; clients usually start it with uvx (from uv) or after pip install — the usual command is uvx dead-letter.

dead-letter runs locally from an MCP Bundle: a single downloadable archive holding a local server and a manifest that describes it: https://github.com/BigCactusLabs/dead-letter/releases/download/v0.4.5/dead-letter-mcp-0.4.5.mcpb version 0.4.5. It speaks MCP over stdio, so the client starts it as a program and talks to it through standard input and output. It needs a client that installs MCP Bundles; the file is opened in, or added to, that client.

dead-letter runs locally from a container image in an OCI registry such as Docker Hub or GitHub Container Registry: ghcr.io/bigcactuslabs/dead-letter@sha256:18ff617fb594196e12e3574809caf8ff5b79bea8a831f801b8fc2ac6418a82a1. It speaks MCP over stdio, so the client starts it as a program and talks to it through standard input and output. It needs Docker or another OCI container runtime; started with docker run — the usual command is docker run -i --rm ghcr.io/bigcactuslabs/dead-letter@sha256:18ff617fb594196e12e3574809caf8ff5b79bea8a831f801b8fc2ac6418a82a1.

In the mcpServers JSON format that many desktop and editor MCP clients read, the entry looks like this (placeholders in angle brackets):

{
  "mcpServers": {
    "dead-letter": {
      "command": "uvx",
      "args": [
        "dead-letter"
      ]
    }
  }
}

Derived from the registry entry, not tested here. What the server does, and on what terms, is set by its publisher; check its repository or website before giving it access to your accounts or files. How to add an MCP server to an assistant · Before you connect