Adrafinil is free and open source, holds sleep only while agents work, and needs macOS 26 and a root helper. Clamshell costs $9.99, needs no admin rights, and runs on macOS 14 or later.
Clamshell for Mac keeps the Mac awake with the lid closed while armed. No sudo, no monitor. Free for 7 days, then $9.99 once.
Download free trialpmset disablesleep through a small root helper while an agent is working. Clamshell uses an unprivileged control while you have it armed, with no helper or admin rights.Adrafinil is a free, MIT-licensed app that keeps a Mac awake only while AI agents are working: hooks in Claude Code, Codex, Cursor and others acquire and release a hold, and the Mac sleeps when the last session ends. Overriding lid sleep its way needs root, so it uses a small privileged helper that toggles pmset disablesleep. Clamshell for Mac is a paid menu bar app for Apple Silicon MacBooks that you arm yourself; it uses an unprivileged system control, needs no admin rights, and runs on macOS 14 or later.
Side-by-side comparison
Every Adrafinil cell comes from its own pages, checked October 2, 2026. "Not stated" means we could not find it on their official pages; it does not mean the feature is missing.
| Adrafinil | Clamshell | |
|---|---|---|
| Price | Free. Open source under the MIT license. | 7-day free trial, then $9.99 once for 1 Mac or $19.99 for 3 Macs. 14-day money-back guarantee. |
| Closed-lid support | Yes, with the lid fully closed. | Yes, with no external display. |
| How closed-lid works | A privileged helper sets pmset disablesleep while a hold is live, per its README. It also suppresses idle sleep while held. |
Unprivileged IOKit clamshell sleep-state control plus an idle-sleep assertion while armed. Not pmset. |
| Admin or helper | Admin rights once at first launch to register the root helper. A non-admin install path covers the CLI only. | None. No sudo, admin rights, kernel extension, driver, or privileged helper. |
| Agent auto-detection | Yes. One-click hooks for Claude Code, Codex, Cursor, Gemini CLI, Aider, Hermes, OpenCode, Cline and Pi, plus optional process sniffing. | No. Arm from scripts with clamshell://arm and clamshell://disarm, or Shortcuts actions. |
| Thermal safeguard | A thermal cutout force-releases the hold. | Always on. Serious or critical thermal pressure disarms toward normal lid sleep and blocks arming until cooled. |
| Battery safeguard | Not stated. | Optional low-battery disarm at a level you choose, off by default. Re-applies on every plug or unplug. |
| Restore behavior | Sleeps normally once the last agent session releases. Locks on lid close. The helper resets disablesleep to 0 on respawn so a crash does not leave it on; manual fallback is sudo pmset -a disablesleep 0. |
Option-close session ends on lid open and the Mac locks. Menu or URL arming stays until disarmed. Never persists across a restart. |
| Availability | Signed, notarized DMG from GitHub releases and an official Homebrew cask. | clamshell.dev and Setapp. |
| Platform | macOS 26 or later. A community fork backports to macOS 15. Chip support not stated. | Apple Silicon MacBooks, macOS 14 or later. |
| Source code | Open source, MIT. | Closed source. |
Where Adrafinil is stronger
- Free and open source. No price and an MIT license you can read and build yourself.
- Agent-aware holds. Hooks in nine agents acquire and release automatically, so the Mac sleeps the moment work ends. Clamshell does not detect agents.
- Feedback in the dark. A chime confirms the hold when you close the lid, and a morning summary reports what ran and how hot it got.
- Official Homebrew cask. Install with
brew install --cask adrafinil.
Where Clamshell is stronger
- No admin rights or root helper. Clamshell overrides lid sleep with an unprivileged IOKit control. Adrafinil needs an administrator once to register a root helper, which rules it out on many work Macs.
- Not
pmset disablesleep. Clamshell never changes the system-wide sleep setting, and its state never survives a restart. - Older macOS. Clamshell runs on macOS 14 or later. Adrafinil requires macOS 26, or a community backport for macOS 15.
- Works for any job. Downloads, renders or SSH sessions stay up as long as you keep it armed, with no agent hooks required.
- Battery and thermal safeguards. An optional low-battery disarm, and thermal safety that acts at serious pressure, not only critical.
What Clamshell does not do: detect agents, run on Intel, offer a free tier past the trial, or act as a general keep-awake app. It also pauses while an external display is connected.
Try the narrow option. Clamshell is free for 7 days with no payment details, then $9.99 once for one Mac.
Download free trialWhich should you pick
You want free and agent-aware, and have admin rights
Adrafinil. It costs nothing and releases the Mac as soon as your agents finish.
A work Mac without admin rights
Clamshell, since it needs no administrator access or helper.
macOS 14 or 15
Clamshell runs on macOS 14 or later. Adrafinil needs macOS 26 or a community backport.
Long jobs that are not agents
Clamshell keeps the Mac awake for whatever is running, as long as it is armed.
For agent runs, the Clamshell wrapper calls open "clamshell://arm" before the run and open "clamshell://disarm" after. The Claude Code lid-closed guide has a complete script.
Frequently asked questions
What is the difference between Adrafinil and Clamshell?
Adrafinil is a free, open-source app that holds sleep only while AI agents are working, using a root helper that sets pmset disablesleep. Clamshell for Mac is a paid menu bar app that keeps an Apple Silicon MacBook awake with the lid closed while armed, with no admin rights or helper.
Is Adrafinil free?
Yes. It is free and open source under the MIT license. Clamshell is $9.99 once for one Mac after a 7-day free trial.
Does Adrafinil need admin rights?
Yes for the standard install: the first launch asks for admin rights once to register its privileged helper. Clamshell needs no admin rights.
Which macOS versions do they support?
Adrafinil requires macOS 26 or later, with a community backport for macOS 15. Clamshell runs on macOS 14 or later on Apple Silicon MacBooks.
Is there an Adrafinil alternative that needs no root helper?
Clamshell for Mac. It uses an unprivileged system control instead of pmset disablesleep, so there is no helper, sudo or admin prompt.
Related guides
- LidRun vs Amphetamine vs Clamshell
- Hold My Lid vs Clamshell
- Best apps to keep a MacBook awake with the lid closed
- What sudo pmset disablesleep 1 does and how to undo it
- Keep Claude Code running with the lid closed
Sources checked October 2, 2026: Adrafinil's homepage and GitHub README. Clamshell details come from its own documentation and changelog. Clamshell is the publisher of this comparison. Product names belong to their respective owners.