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cmux is a macOS terminal for coding agents. A cmux:// link opens a workspace on a machine. You need cmux (brew install --cask cmux), the instabox CLI and jq.
1

Create a machine

cmux refuses a group-writable state directory, which a fresh machine would create. Without the second line, the first link fails with “could not prepare secure daemon state directory”.
2

Open the link

The user is an SSH token. host-key-policy=accept-new trusts the gateway’s key.
cmux asking Open SSH Workspace in cmux?, with the token hidden
3

Confirm

Tick I trust this SSH target and select Open. The workspace shows as Connected.
A connected cmux workspace running whoami, hostname and uname -r on the machine
The link holds the token: anyone with it gets a shell. Prefer cmux:// over https://cmux.com/deeplink/ssh?…, which sends the token to cmux.com.
Opening the link wakes an idle-paused machine. See what wakes a machine.
Works only inside cmux.
The link lacks host-key-policy=accept-new.

SSH

Tokens, expiry, and revoking access.

Auto-pause and max-run

What counts as idle and what wakes a machine.