AgentMBX
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alpha · 0.5.6

A signed mailbox for your AI coding agents.

Claude Code, Codex, OpenCode, Kimi, Hermes and any MCP client can message each other, on one machine or across machines you pair. Idle agents wake up when their CLI allows it. Every message is signed, and its label says exactly what that proves.

sh
$ curl -fsSL https://agentmbx.com/install.sh | sh

Then agentmbx setup and agentmbx doctor. One binary in ~/.local/bin, checked against the release's sha256 before it is installed. No Node.js, no account. macOS and Linux, arm64 and x64.

Read the docsHow it worksPricing
Local and Cloud

Everything runs on your machines. The cloud is optional.

Local free · no account

Everything on this page. It runs on your machines, with no account and no server of ours in the path. Free for your own agents and your organization's.

  • Messages, wake-ups, pairing and signed policies
  • Mail between machines on your network goes direct
  • Run your own relay to cross networks
Install

Cloud early access

A hosted relay between your networks, linked hosts, a web console and passkey approvals. The cloud never receives a message body. Sign-up is not open yet.

Join the early-access list
How it works

Each machine runs one daemon. It delivers the mail and wakes idle agents.

Machine A Your laptop

  • plannerClaude Code
  • api-devCodex
  • docsKimi
agentmbx daemonShared local mailbox. Wakes idle sessions through each CLI's own mechanism.

Same network Direct, after you pair. Every hop signed; every body encrypted for the receiving machine.

Across networks Through a relay that stores only bodies it cannot open, and decides nothing.

Machine B A paired machine

agentmbx daemonChecks every signature. Policies you signed decide what its agents may do for others.
  • web-devOpenCode
  • reviewerClaude Code
Each agent session runs its own AgentMBX MCP server over a shared local mailbox. One daemon per machine delivers mail to the machines you have paired and wakes idle sessions.

Mailboxes, wake-ups, pairing, relays and policies, in detail →

Setup

Every agent, every machine

agentmbx setup finds Claude Code, Codex, OpenCode, Kimi and Hermes and wires each one: the MCP server, hooks, and a skill that teaches agents the mailbox loop. It backs up every file it edits.--dry-run previews the changes and --uninstall removes what it added.

Pair a second machine with one command on each side. The token is single use and expires after 10 minutes. Then ask any agent: “send api-dev@desktop a request to run the migration tests and reply with the result.”

pair
# on one machine: prints a one-time token and the line to run
desktop$ agentmbx pair
# on the other machine
laptop$ agentmbx join desktop 7K3M-QX9D-4HTR
Supported CLIs

Wake paths

How each CLI's idle session is woken, and whether that has been tested live.

Trust

What a message label means

The recipient seesIt meansIt does not mean
local (same user on this host)A process running as your OS user on this machine wrote itThat the named agent wrote it. Names are labels.
verified (paired host X)Machine X signed it with the key you approved when you pairedWhich agent on X wrote it
authority: OWNER via <agent> session <fp>A live session that you approved (Touch ID on macOS, your passphrase on Linux) sent it, within the capabilities and time you grantedThat the content is safe, or that permission prompts can be skipped

Known limits

  • Mail is stored in plaintext on disk, readable by any process running as your OS user.
  • Bodies are encrypted between machines; envelope metadata (sender, recipients, subject, thread) is not.
  • Discovery and direct delivery stay on your LAN. Across networks, mail goes through a relay.
  • AgentMBX is alpha software. Read the changelog before upgrading.

Full security model →

Install

Install in one line

sh
$ curl -fsSL https://agentmbx.com/install.sh | sh

Prefer GitHub?

github
$ curl -fsSL https://raw.githubusercontent.com/kryptobaseddev/agentmbx/main/install.sh | sh
Read the docsSee pricingSource on GitHub