Codex app 100% CPU Usage even when only one agent is running

[beladiyaraj]

What version of the Codex App are you using (From “About Codex” dialog)?

Version 26.212.1823 (661)

What subscription do you have?

Plus

What platform is your computer?

Mac OS 26.3

What issue are you seeing?

I am experiencing this issue, only one agents are running right now and see the CPU Usage right now
https://image2url.com/r2/default/images/1771239005182-8a7708b9-5677-4d97-8956-86207364e2c8.png

I am on latest macos version : 26.3
I have Macbook M4 16GB varient

What steps can reproduce the bug?

Open the app and just give any task and the cpu usage will be at 100% right away

What is the expected behavior?

Even when i run many agents to do work it should not take this much cpu usage cause this is happening on cloud.

Additional information

No response

[github-actions]

Potential duplicates detected. Please review them and close your issue if it is a duplicate.

• macOS App: 100% CPU on Launch and ~60s UI Freeze on Any Interaction (M1 Pro, 32GB, Tahoe 26.1) #11596
• Codex desktop app high CPU and rapid memory growth on startup (macOS) #11161
• [Bug]: Massive CPU usage (100%+) and overheating (100°C) on M4 Mac Air - Version 260208.1016 #11124
• Massive CPU Usage in macOS app #10530
• Codex app on MacBook-pro (M4-max) - Massive CPU usage on startup for 55 seconds + Massive performance issues and lag + Response breaking #11584

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[etraut-openai]

@beladiyaraj, are you still seeing this with the latest version of the app? We've fixed a number of performance issues since then. If you're still seeing this, please provide additional details about how we might be able to repro the problem. You mentioned "this is happening in the cloud". Are you saying that you're using a cloud thread (where the tool calls are happening on Codex cloud), or is it a local thread? Are you seeing this with all threads or just some? For example, does it happen only with really long threads?

[lordsoffallen]

Having the same issue, syspolicyd spikes at 100 and i can't do anything. Even when i don't do anything, it's still happening.

[pllopis]

Observing the same thing that I mentioned in this other issue: #11179 (comment) it sems that Codex is doing posix_spawn on a directory(!) at root of my project (not a binary) repeatedly many times per second and triggering massive syspolicyd cpu spikes.

[whitemankpi]

same situation as in others, latest version

chip: Apple M1 Pro

[DigitarInt]

Adding a correlated data point from local diagnostics (Mar 5, 2026, macOS).

What looks wrong:

• CPU is mostly consumed by desktop client processes (Renderer/GPU), not a single backend call.
• Symptoms match a cluster of issues tied to:
  • long-session renderer growth (#11984, #12709)
  • large diff / generated-file tracking pressure (#11861, #11179, #12861)
  • heavy local file I/O (#12644)

Local measurements:

• Current snapshot: total Codex app CPU ~58%, RSS ~1.3 GB (Renderer + GPU processes dominate).
• Earlier today (09:17 session): WARN=6, ERROR=360, ENOENT=339.
• Later today (09:56 session): WARN=8, ERROR=14, ENOENT=8.

What improved usage-wise (correlation, not proof):

• Keeping active change set smaller,
• avoiding large generated/build artifacts in tracked diffs,
• restarting into a fresh session when UI starts lagging.

This looks like multiple client-side perf paths rather than one single bug.

[beladiyaraj]

@etraut-openai I have not encountered this issue after the update has been done

[etraut-openai]

@beladiyaraj, thanks for the confirmation. I'm going to leave this bug open a little longer to wait for confirmation from others who have posted here.

[DigitarInt]

Yes, problem solved and the new model is awesome (GPT-5.4)!

Edit: not solved. Perhaps worktrees cause the issue...after automations have been running...

[rob-balfre]

My mac is boiling running one prompt 🔥

[stanedgar6]

I have that issue when running codex on RustRover on Ubuntu