What an always-on Mac for AI agents actually needs

1. It must never sleep, and it must come back on its own

Set sleep to never, keep the disk awake, enable wake for network access, and turn on automatic restart after a power failure. Do not enable FileVault on a machine that has to reboot unattended. An encrypted disk stops at the unlock screen and waits for a person.

2. It must log itself in

Nearly everything an agent uses, the browser, the terminal tools, the Actions or agent services, runs as a per-user process inside a desktop session. After a reboot the Mac has to log straight into that user. Automatic login handles it. It only takes effect on the first login screen after boot. So any change to it needs one restart to prove it works.

A fresh account also shows a first-login setup assistant. It asks about iCloud, Siri and accessibility, and it sits on the screen until someone clicks through it. Suppress it, or the agent never reaches the desktop.

3. The agent process must be supervised

Processes crash, and a 24/7 agent is only as good as the thing that restarts it. A launch agent with keep-alive, or a small supervisor that checks the process every 30 seconds, turns an outage into a blip. Decide up front what "running" means and monitor that, not just whether the Mac is on.

4. You need a way in when it gets stuck

Agents stall on things only a person can do: a two-factor prompt, a captcha, a permission dialog, a login that expired. Screen Sharing on the Mac, reachable from wherever you are, is the difference between fixing that in a minute and driving home. Enable it before you need it, because on recent macOS it cannot be switched on from a script.

5. Wire it, and put it on a battery

Wi-Fi drops are the most common cause of a silently dead agent. Ethernet is not optional. Put the Mac and the router on a small UPS. A router that reboots takes the agent offline just as surely as the Mac losing power.

6. Give it only what it needs

• A dedicated user for the agent, not your own account.
• Accessibility and Screen Recording permissions granted once, by a person, for the tools that need them.
• No password-based SSH from the internet. Reach it over a private network or a tunnel.

The honest limits of a hosted or headless Mac

• iMessage and FaceTime are unreliable on Macs in data centers.
• A base 16 GB machine runs agents that call cloud models; it will not run large local models.
• Some websites challenge automation from a data-center address.

MacRun's agent plan sets up every item above for you on a dedicated M4 mini. The Mac's screen is one click away in your browser. If you would rather run your own, this page is the checklist.