Codex Computer Use helper can keep macOS replayd/ReplayKit active and spike CPU while idle

Summary

On macOS, the Codex app's Computer Use helper appeared to keep Apple's ReplayKit daemon (/usr/libexec/replayd) active and caused a noticeable CPU spike even though I was not actively using desktop control.

This was observable as replayd repeatedly reappearing in Activity Monitor / process listings and accumulating CPU. Restarting replayd alone did not resolve it because it immediately respawned due to IPC clients. Stopping the Codex Computer Use helper caused the CPU usage to settle.

Environment

• macOS: 14.8.3 (23J220)
• Codex.app: 26.623.42026, bundle version 4514
• Codex bundle id: com.openai.codex
• Architecture: arm64
• Chrome was also running, including a video_capture.mojom.VideoCaptureService, but the CPU spike dropped after stopping the Codex Computer Use helper.

What I observed

replayd was the legitimate Apple binary:

/usr/libexec/replayd
Identifier=com.apple.replayd

launchctl showed it being launched by Mach IPC:

gui/501/com.apple.replayd
state = running
program = /usr/libexec/replayd
immediate reason = ipc (mach)
runs = 22
last terminating signal = Killed: 9

Unified logs showed replayd repeatedly accepting connections from these clients:

accepted client connection PID: <ControlCenter>
accepted client connection PID: <Google Chrome>
accepted client connection PID: <Codex.app>
accepted client connection PID: <Codex Computer Use / SkyComputerUseService>

At the moment of the spike, the relevant process snapshot looked like this:

Codex.app                         ~24% CPU
SkyComputerUseService             ~19% CPU
/usr/libexec/replayd                0% CPU immediately after respawn
Google Chrome video_capture helper  0% CPU

After terminating only SkyComputerUseService, the machine settled:

/usr/libexec/replayd     0.0% CPU
Codex.app                ~0.4% CPU
SkyComputerUseService    no longer active

Expected behavior

The Computer Use helper should not keep ReplayKit/replayd active or repeatedly connected when no desktop-control or screen-capture workflow is active. If it needs to start ReplayKit, it should release the session promptly when idle.

Actual behavior

replayd kept respawning because ReplayKit clients were still attached. The Codex Computer Use helper was one of those clients and was consuming significant CPU. Stopping that helper cleared the issue.

Impact

This can show up to users as replayd repeatedly appearing in Activity Monitor and consuming CPU/battery. It is confusing because the visible high-CPU process may be Apple's replayd, while the triggering client appears to be the Codex Computer Use helper.

Notes

I could not read the macOS TCC database due to privacy protections, so I could not list screen-recording permissions from the terminal. The evidence above comes from ps, launchctl print, codesign, and unified logs.