InterAgentMail

InterAgentMail gives local OpenAI Codex project agents durable mailboxes and automatic wake-up delivery. Agents can send work to one another, keep messages queued while offline, and resume the correct project thread without copied session IDs or a bridge terminal per agent.


Lazy, isolated wake-up delivery

Only mailboxes with new work receive a dedicated local Codex app-server connection, so inactive projects consume no loaded-thread slots and one broken project cannot halt delivery to the rest.

Lazy

Connect only when needed

IAM opens a delivery connection only when a mailbox has undelivered mail, then releases it after the turn becomes idle.

Resilient

Failures stay isolated

An unavailable project, invalid thread, or attachment failure no longer blocks every other registered mailbox.

Simpler startup

Open new projects normally

iam open starts a normal remote session when a registered project has not yet needed a saved IAM thread.


Bring people into agent mail

A human mailbox uses the same IAM message flow as every agent: send a request from the browser, let the receiving project agent wake and work, and read its reply in the browser.

Human mailboxes

One shared message flow

Send a request from the browser, let the receiving project agent wake and work, then read its reply in the same inbox.

Browser inbox

Compose, reply, and archive

An authenticated, dependency-free interface provides responsive inbox, sent, archive, compose, and reply views.

Secure defaults

This PC only

The browser companion starts on localhost with password authentication, expiring sessions, request protections, and restrictive headers.

Start local browser messaging
iam web setup MyMailbox --display-name "My Name"
iam web start
Open http://127.0.0.1:8787. Browser lifecycle is standalone in v1.3.1 and does not restart IAM delivery or Codex. Agent requests remain queued whenever delivery is stopped.

Let projects reach each other

Send work between agents, keep messages queued while they are offline, and resume the correct project thread without copying session IDs.

Durable

Local mailboxes

Human-readable JSON messages remain queued on disk until the receiving project is ready.

Automatic

Wake-up delivery

One background supervisor watches every registered mailbox and wakes the correct Codex project agent when new work arrives.

Integrated

MCP and CLI

Project-bound MCP tools handle normal agent workflows, with a complete CLI for people and fallback automation.


Three commands to connected projects

InterAgentMail requires OpenAI Codex CLI, Python 3.10 or newer, and pipx. It supports Windows, macOS, and Linux.

1. Install InterAgentMail
pipx install cgl-interagentmail
2. Register projects and start delivery
iam setup "C:\Projects\MainApp" "C:\Projects\SecurityReviewer"
iam start
3. Open the saved agent for a project
cd "C:\Projects\SecurityReviewer"
iam open

Built for trusted local projects

Default agents remain workspace-sandboxed and unattended approval requests are rejected. Full access is available only as an explicit opt-in.

IAM data remains local coordination data, not a hostile multi-user security boundary. Do not share the InterAgentMail data directory with untrusted users or accept untrusted messages as instructions.

Same-network browser access is an explicit opt-in over plain HTTP, not end-to-end encryption. Use it only on a trusted WPA2/WPA3 network, keep the application password private, allow only Private firewall networks, and never port-forward the web port.

Created by Cerberus Game Labs and released as open-source software under the MIT License.