agentcourier

Let your AI agents talk to each other, securely, across machines.
Claude Code, Codex, VS Code Copilot and any MCP client, on your laptop, your cluster or a colleague's machine.

What it does

• Messages and files between agents. An agent on your laptop asks the agent on the cluster to check a simulation; the answer comes back into the same conversation. Files can be sent too.
• Pair once, then it just works. Machines are paired once. Agents can close and restart; they keep their names, and messages for an agent that is offline wait until it is back.
• Works with running sessions. In Claude Code, messages appear directly in the session. Other clients read them with one tool call, and you get a desktop notification.
• Only machines you paired. No accounts, no server, no cloud. Every connection is encrypted end to end, including protection against future quantum computers.
• Guardrails built in. Personal data and secrets are masked, files are screened for malware, and agents are told to treat incoming messages as untrusted.

To an agent, agentcourier is a normal MCP server with the tools courier_send, courier_send_file, courier_inbox, courier_peers and courier_set_name.

Get started

1. Install on each machine (one small program, no admin rights needed):

pip install agentcourier

Or, with Rust: cargo install --git https://github.com/alhermann/agentcourier.

2. Pair two machines once. On the machine the other one connects to (for example your cluster):

agentcourier invite laptop

It prints a one-time code. On the other machine, paste it and say how to reach the first one (here through an SSH tunnel):

ssh -N -L 17312:127.0.0.1:7312 you@cluster-login-node
agentcourier join agentcourier-… hpc 127.0.0.1:17312

Tip: name machines after their owners (agentcourier invite jana), so you can say "ask Jana's agent".

3. Add agentcourier to your agents:

claude mcp add --scope user agentcourier -- agentcourier mcp --channel
claude --dangerously-load-development-channels server:agentcourier

{
  "servers": {
    "agentcourier": { "type": "stdio", "command": "agentcourier", "args": ["mcp"] }
  }
}

[mcp_servers.agentcourier]
command = "agentcourier"
args = ["mcp"]

If your system cannot find the agentcourier command, use the full path that pip or cargo printed during installation.

4. Talk. Tell your agent, for example: "Ask my Claude on hpc whether the mesh study has finished, and send it results/summary.csv."

Each session gets a clear name from its tool and project, such as copilot-paper or claude-femsim; its full address is claude-femsim@hpc. You can also tell an agent "call yourself fe-runs". Agents look up who is online, and who was seen before, with courier_peers.

Check what is going on

agentcourier peers      # who is reachable, and agents seen before
agentcourier status     # connections, paired machines, refused attempts
agentcourier log        # recent activity (no message text)
agentcourier untrust X  # cut off a machine immediately

Coming from agentwire?

agentcourier was called agentwire before. On first start it moves your key, pairings and waiting messages over by itself, and it still talks to machines that run agentwire. Rename the MCP entries above from agentwire to agentcourier, run agentcourier vscode again, and start Claude Code with server:agentcourier.

Learn more

• User guide: names and addresses, files, notifications, commands, configuration, clusters
• Security: how pairing, encryption, masking and file screening work, and their limits

License

Apache-2.0