"Use Codex from another machine" sounds like one problem. It is actually four different workflows, and choosing the wrong one can create duplicated state or a broken destination.
Use Codex Remote when Codex should keep running on the original computer and you want to supervise it from another authorized device. The host must remain awake, online, and running Codex. OpenAI's current documentation: Remote connections and Work with Codex from anywhere.
Use Remote SSH when your laptop should operate against a project and execution environment that remain on a different Mac. The remote Mac still owns the files, tools, and runtime. This is remote access, not a copy and not synchronization.
This is a migration. Signing into the same ChatGPT account does not turn all local Codex state and workspace files into ordinary cloud history.
A complete move may need to preserve:
.git, branches, worktrees, stashes, uncommitted files, and untracked files;
Avoid blindly copying all of ~/.codex. Authentication, installation identity, runtime locks, caches, and other machine-specific data should not be cloned onto the destination.
I built Codex Migrate for this Mac-to-Mac case. It inventories the selected scope, transfers directly over SSH, stages and validates the incoming data, verifies a destination rollback backup before replacement, and preserves the new Mac's existing Codex login and installation identity.
The CLI and source are MIT licensed. The signed and Apple-notarized Apple-silicon beta is $50 once, with best-effort support and a 30-day refund policy.
That is synchronization, not migration. It requires conflict handling for Git state, uncommitted files, sessions, paths, and machine-local configuration. Repeatedly mirroring all of ~/.codex is not a safe substitute.
| What you want | Use |
|---|---|
| Check the running host from your phone | Codex Remote |
| Keep the project on another computer | Remote SSH |
| Retire the old Mac and continue on the new one | One-time migration |
| Work on the same state from two active computers | A real synchronization system |
I wrote a longer, source-linked comparison here: Access Codex from another machine. Disclosure: I maintain Codex Migrate. It is an independent project and is not affiliated with or endorsed by OpenAI.