An old Mac as a machine

An old Mac mini on a shelf, or a MacBook you replaced, is a good machine to code on: it is already paid for, it is fast enough for a few workspaces, and it sits on your own network. devmachine sets it up the same way it sets up a VPS. Intel and Apple Silicon both work; the CLI reads which one it is and finds Homebrew or MacPorts in the right place.

You need: a Mac you can reach over SSH, an admin account on it, and a Mac or Linux computer to run the CLI. Tested on macOS 15 on Intel and macOS 27 on Apple Silicon. Older versions are not tested.

What a Mac does not get: caddy, docker, firewall, tailscale and the other Linux-only packages. A site with HTTPS at your own domain, or Docker, needs a Linux machine. See what works on each.

Before you start: on the Mac

Do these once, sitting at the Mac.

1. Turn on Remote Login. System Settings > General > Sharing > Remote Login. With “Only these users”, leave your admin account in the list; sync adds each workspace account to it later.

2. Give the admin account passwordless sudo. A Mac has no root login, so the CLI works through sudo -n. In Terminal, with your own account name in place of alice:

   echo 'alice ALL=(ALL) NOPASSWD:ALL' | sudo tee /etc/sudoers.d/devmachine-alice

3. Keep it awake. A Mac that sleeps drops every session. On a Mac mini, System Settings > Energy: turn on “Prevent automatic sleeping when the display is off” and “Start up automatically after a power failure”. On a MacBook, keep it on power; with the lid closed it sleeps unless an external display is connected, so leave the lid open.

4. Find its address. System Settings > General > Sharing shows a name such as studio.local under Local hostname. That works from any computer on the same network.

An old Intel Mac stuck on an old macOS? Pick MacPorts in the next step. Homebrew supports only recent macOS versions and builds everything from source on older ones; MacPorts supports much older releases.

By hand

1. Add the Mac

From your own computer. On your first machine, run devmachine setup; next to a machine you already have, run:

devmachine machines add

Give it the address (studio.local), the admin login (alice) and its password, once. Check the fingerprint it shows against the Mac’s. Then it:

• installs a key and proves it;
• asks which accounts keep SSH password login. On a Mac that is every account on it, so name the people who still SSH in with a password. The login window, sudo and Screen Sharing keep their passwords either way. See password login, account by account;
• asks Homebrew or MacPorts, then asks before it installs the Xcode Command Line Tools (5 to 10 minutes), the package manager and Ansible;
• starts the machine with base and devmachine-app in place of essentials, which runs only on Linux.

Name it studio when it asks. Why each step needs its own yes is in what a machine needs.

2. Make a workspace

devmachine workspaces new acme --machine studio
devmachine packages add claude-code --workspace acme
devmachine sync --machine studio
devmachine ssh acme

Each workspace is its own macOS account on the Mac, with its own tools and logins. --machine studio is needed only when you have more than one machine.

3. Reach it away from home

studio.local works only on your own network. To reach the Mac from anywhere, put it on Tailscale. The tailscale package is Linux only, so on a Mac you install Tailscale yourself:

• On a Mac someone logs in to, the Tailscale app is enough.
• On a Mac that sits at the login window, the app does not start. Use the open-source tailscaled, which starts at boot: brew install tailscale, then sudo brew services start tailscale and sudo tailscale up. See Tailscale’s macOS variants.

Then put its Tailscale name first in its addresses. Open config.yml (devmachine config path prints where it is):

machines:
  - name: studio
    hosts:
      - tailscale:studio
      - studio.local

<name> after tailscale: is what tailscale status lists for the Mac. Your computer needs Tailscale too, on the same account. devmachine tries the addresses in order; see reaching your server.

4. After a restart

With FileVault on, a Mac that restarts waits at its screen for a password before Remote Login starts. For a restart you plan, run sudo fdesetup authrestart on the Mac: it unlocks the disk once, by itself. After a power cut, somebody has to type the password at the Mac.

With your agent

Open a session on your own computer (devmachine skills add taught it the CLI) and say:

Add my Mac at studio.local as a devmachine machine called studio. Log in as
alice; it has Remote Login on and passwordless sudo. Use MacPorts. Then
create a workspace acme on it with claude-code.

The agent shows you the fingerprint to check and asks before it installs the Command Line Tools. It never answers that question for you: --yes does not install prerequisites. The steps it follows are in set up devmachine with a coding agent.

Check it: devmachine doctor --machine studio passes every line, and devmachine machines show studio says Darwin with the Mac’s architecture.