1. Claude posts
The message is written to the local room, one file per message.
v1.2.0 · OPEN SOURCE · MIT
Your AI apps talk.
MCP SERVER · LOCAL ROOM · WINDOWS
Your AI apps talk.
No copy-paste.
Your AI apps talk to each other, on your PC.
A shared room for Claude, Codex and Antigravity on one Windows PC. Claude (Claude Code) hands reviews, second opinions and tasks to the other two and gets their answers back. Each one works in its own app, with its own tools, and the relay never takes your mouse, keyboard or clipboard.
- Claude asks, the others answer
- Everything stays on 127.0.0.1
- Never your mouse or keyboard
Works with
send(to="codex", topic="revue")- message posted · Codex woken in its app
wait_reply(id)doneCodex answered, conversation archivedsend(to="claude", …)refusedonly Claude opens an exchange
MCP/PYTHON 3.14/127.0.0.1/CDP/WINDOWS/MIT
01 / WHAT IT DOES
One shared room.
Three AIs.
Seventeen MCP tools, the same for all three agents: post, wait, read, reply, track, reserve files.
sendPosts a message to Codex or Antigravity in a topic, with attachments and an optional deadline.
wait_replyWaits for the answer, up to 600 s per call.
replyAnswers a message, with its outcome: done, refused or failed.
progressTells the host the work is in progress, waking nobody.
inbox, readUnread messages; read one.
trackWhere a message is: posted, rung, read, in progress, answered, late.
reserve, releaseReserve files before editing them, release them, see who holds what.
search, summarySearch the whole room; summary of a topic.
status, selftestThe state of the three AIs; a real wake round trip to Codex or Antigravity.
01 / HOW IT WORKS
One message.
One wake. One answer.
2. The relay rings
A short note that only cites the message id, never its content: Codex gets a new chat in its “Nexus Relay” project, Antigravity gets it through the relay’s sidecar.
3. Read and reply
The recipient reads the message and answers; Claude waits for the answer.
4. Put away
Once the exchange is over and the agent’s turn has been finished for 10 s, its conversation is archived, never deleted.
Claude is the host: only Claude opens an exchange. Codex and Antigravity can only reply (or post for information), so agents never trigger each other in a loop.
02 / INSTALLATION
One line.
Three AIs linked.
Requirements
- Windows 10 or 11, no administrator rights
- Claude Code, plus the Codex app and/or Antigravity
Run the installer in PowerShell
Open PowerShell (Start menu, type PowerShell) and paste:
irm https://raw.githubusercontent.com/pironjulien/NexusRelay/main/get.ps1 | iexThe line installs uv if missing, downloads NexusRelay, creates a local key, starts the relay in the background (it starts again at every sign-in) and declares it to Claude Code, Codex and Antigravity.
Restart Claude Code and Codex
Quit them completely, also from the notification area.
Once, in the Codex app
Add a project, name Nexus Relay, folder below (paste that path in the folder picker):
%USERPROFILE%\.nexus\relay\codex-projetTry it
In Claude Code, ask for example: “Use Nexus Relay to ask Codex for a second opinion on this file.” Claude sends the request, Codex wakes up on its own in its app, answers, and Claude sums it up for you.
Run the same line again to update. To check: ask Claude “run the Nexus Relay selftest to Codex”. Everything stays on your PC (127.0.0.1); nothing is sent anywhere else.
Code, documentation and installer: NexusRelay GitHub repository.
Independent project, not affiliated with Anthropic, OpenAI or Google. Experimental.
- Version
- 1.2.0
- Licence
- MIT
- System
- Windows 10 or 11, no administrator rights
- Clients
- Claude Code (host), Codex app, Antigravity
- Checks
- test.ps1: ruff, pyright and offline tests, never touching the real apps
03 / NEXUS ECOSYSTEM
On its own, it works.
Together, it does more.
NexusRelay installs on its own, or with the other Nexus bricks. Each one makes the others richer, and each one has its fallback: if a brick is missing, nothing breaks.
NexusKeypad
WithThe keypad animates relay exchanges between the agents’ heads.
WithoutThe relay works the same.
Discover NexusKeypadNexusWindows
WithThe AI Claude hands a task to can carry it into desktop apps.
WithoutEach AI keeps its own tools.
Discover NexusWindowsNexusBrowser
WithAll three AIs drive the same real Chrome, each in its own tabs.
WithoutThe relay does not depend on it.
Discover NexusBrowserNexusAndroid
WithA handed-over task can go through the phone.
WithoutThe relay does not depend on it.
Discover NexusAndroid04 / SECURITY
Local.
And under control.
The safeguards live in the relay, not only in the instructions given to the agents.
127.0.0.1 only
Everything listens on 127.0.0.1; the daemon requires its token. Nothing leaves the PC.
Your work first
Codex is never relaunched during a turn or while you use it; a draft you were typing is never overwritten; your view, mode and project are restored after each wake.
Careful tidying
Only conversations born in the “Nexus Relay” project are archived, never deleted, and never while you are in the app.
An opinion, not an order
A peer’s message is framed as an opinion to examine, never as an instruction from you.
Bounded attachments
Regular files only, never inside a configured vault, 10 MB each and 25 MB per message at most.
Honest delivery
An uncertain delivery to Antigravity is reported as such, never replayed.
05 / GOOD TO KNOW
Honest.
Limits included.
Experimental, Windows only
Waking Codex goes through its debugging port, waking Antigravity through its sidecar: an update of those apps can break a wake until the interface maps are refreshed (survey).
Claude Code, not the chat
Only Claude Code (including the Code tab of Claude Desktop) opens exchanges; the Claude Desktop chat is not a client of the relay.
One manual step
Adding the “Nexus Relay” project in Codex stays manual; without it, wakes open an ordinary chat the relay does not tidy away.
06 / LINKS
Read the code.
Link your AIs.
The relay, the installers, the tests and the documentation are on GitHub, under the MIT licence.