Embassy

Embassy lets live Claude Code sessions and Codex CLI agents message one another by name, on one Mac or across user-owned Macs reached through SSH. The broker wakes the receiving agent through its native interface; agents do not poll. Claude→Claude, Claude→Codex, Codex→Claude, and Codex→Codex all use the same command and receipt model.

https://github.com/user-attachments/assets/b401d807-d208-4dbd-84b0-a27d6d1c9540

40 seconds, recorded live: a Claude Code session asks a Codex agent for a review and gets the reply natively. If the player does not render here, download the video.

If Embassy is useful to you, star the repository: GitHub notifies watchers about new releases, and the release notes are where changes are explained.

What it is

The core is deliberately small: one private ledger, one delivery coordinator, and three write adapters (Claude socket, Codex App Server operation, and SSH handoff). Aliases are lookup names. Opaque endpoint IDs are the routing identity, so a rename or replacement never silently retargets queued work.

Codex agents are discovered automatically from the running Codex daemon (the 20 most recent unarchived root agents; sub-agents are never endpoints). Claude sessions are recorded by exact native identity when they send. No helper or native advertisement process is installed. Every message returns a receipt; the receipt proves transport, not comprehension.

Requirements

• macOS and Node.js 22 or newer.
• Claude Code installed for the Claude sessions you use.
• To receive in Codex, its managed standalone installation with the App Server daemon already running under the same macOS login. Embassy does not install, start or update that daemon; merely having a codex executable on PATH is insufficient.
• Codex receiving requires a session attached to that managed App Server (CLI TUI or exec). Other hosts, including the ChatGPT desktop app's code-mode host, are send-only; a disk-listed thread is not proof that the daemon can resume it.
• Key-based, non-interactive SSH between configured machines when federating.

Quick start

1. Install and start the broker:

   npm install -g agent-embassy
   embassy service install
   embassy health
   

2. Give your agents the Embassy skill. embassy skills install installs or updates only embassy-peer for both providers, under ~/.claude/skills and ~/.codex/skills; Claude Code picks it up as /embassy-peer, Codex as $embassy-peer:

   embassy skills install
   

3. See who is there:

   embassy tui
   

4. Message an agent from inside a Claude Code or Codex session. The sender is inferred from the calling session; send takes exactly one of --to or --conversation and has no --from:

   printf '%s\n' 'Please review the change and reply' |
     embassy send --to codex-reviewer@studio
   

5. Reply with the exact command in the received hint. Ordinary Codex final output is not forwarded automatically, and conv_example is not a usable reference:

   printf '%s\n' 'Review complete.' |
     embassy send --conversation conv_example
   

@studio is the host name from nodes.json; first single-machine boot creates one from the short hostname. See Configuration.

Status

What works today, and is tested on every change:

• Claude→Codex, Codex→Claude, and same-provider messaging by name on one Mac.
• Automatic discovery of Codex agents; Claude sessions are recorded when they send.
• Messaging across your own Macs over SSH.
• Every release is exercised live on two Macs: discovery, waking a dormant agent over SSH, steering, retirement, broker restart. The automated suite runs on macOS and Ubuntu.

What Embassy deliberately does not promise:

• health and check tell you the broker works. They are not a provider readiness proof: they do not show that any agent can answer.
• A receipt proves the message was delivered, not that the agent read or understood it.
• Delivery to a busy Codex agent waits until it is idle. If something else starts a turn in that instant, Embassy cannot tell; the receipt still means the message was accepted.
• Between machines, your SSH login is the entire trust boundary.

How it works, briefly

Discovery. embassy tui and embassy status show every endpoint with its state, queue depth and each local route's last native operation. status --json prints one closed line, {"ok":true,"command":"status","result":{...}}, so route rows are at .result.routes. embassy refresh runs authorized live discovery. embassy register-codex is the fallback for a harness without native daemon integration.

embassy register-codex --alias codex-reviewer@your-host

Codex aliases must use codex-<name>@<host>: lowercase letters, digits, underscore and dash before @ (at most 32 characters including codex-); dots are allowed only in the host. Replace your-host with the host value from this broker's nodes.json, not the name of another machine. Never retire your own route to fix delivery; retirement cancels queued messages. To troubleshoot, run embassy refresh and read the safe code. If you already retired it, explicit register-codex can create a fresh endpoint after the managed App Server confirms the same thread is loaded and live (idle or busy); old messages and reply references do not follow it.

Conversations. A reply hint carries an identity-bound conversation reference. Conversation references are identity-bound, are not aliases, and may survive a broker restart while their retained ledger row and both exact endpoints remain valid. They stop resolving after retirement, replacement, expiry, eviction, or a state reset.

Delivery. One native wake can carry a bounded batch. The durable phases are queued, reserved, armed, accepted and terminal; an uncertain armed or accepted write is never replayed. An exact leading STEER: from Claude to Codex targets the active accepted Codex operation at its next safe tool-call boundary and never interrupts a generation; the kill switch is EMBASSY_STEERING_ENABLED=0. Inspect one delivery with embassy delivery-status --token dlv_example or block on it with embassy wait-delivery --token dlv_example. Contract: Delivery.

Other Macs. List peers in nodes.json; the broker reaches each over /usr/bin/ssh <node> embassy peer-stdio. The plain same-user SSH login is the trust boundary. status performs no provider or network I/O: it shows the last observed catalog rows, retains the last rows when a later refresh fails, and labels that node PEER_TUNNEL_UNAVAILABLE. Named and exact sends still ask the owner directly; the TUI shows one pane per host. Setup: Configuration.

The broker. embassy service install runs a per-user launchd agent with a crash-only keepalive: a verified SIGABRT crash relaunches it, while a clean exit, SIGTERM or kill -9 leaves it stopped, so inspect embassy service status and reinstall deliberately. embassy serve is the foreground alternative. embassy check is a broker-only loopback. Retire one endpoint with embassy retire --alias or --endpoint. Commands: Operations.

Safety

• One private Unix socket and mode-0600 state inside a mode-0700 directory; no TCP or HTTP listener.
• Native task/session IDs, socket paths, credentials, transcripts, and raw provider frames never appear in public output.
• Every native write is authorized against the exact current endpoint after preparation; names are never silently resolved again during an attempt.
• SSH is launched directly without a local shell, in batch mode with forwarding disabled.
• Embassy never changes a Codex approval or sandbox policy and never answers an approval.

Details: Security · Configuration · Operations · Delivery · Architecture · Contributing

Development

npm ci
TMPDIR=/tmp npm run check

Routine tests use test-owned directories and fake providers; no routine test connects a live provider or SSH host.

License

MIT