High CPU usage on macOS after updating Codex in VS Code extension to 26.325.31654

[Filly-MinghaoLUO]

What version of the IDE extension are you using?

26.325.31654

What subscription do you have?

High CPU usage and temperature on macOS after updating Codex

Which IDE are you using?

VS Code

What platform is your computer?

MacBook pro with Apple Silicon (M5 Pro) MacOS Tahoe 26.4

What issue are you seeing?

First of all, many thanks to Hlib Laskin. My comment here is intended as an update to his post, based on what I encountered with a newer version of the Codex extension.

For the full background and detailed explanation, I recommend reading his post, since he described the issue very clearly.
https://github.com/openai/codex/issues/7972?utm_source=chatgpt.com

I noticed this problem after my MacBook automatically updated to macOS 26.4. At first, I thought the overheating was caused by a compatibility issue between the latest macOS version and the VS Code extension. After checking both the hardware and software and finding no obvious problem, I came across their post. I then tried rolling back the Codex extension version, and that indeed solved the issue.

If anyone else is experiencing a similar problem, rolling back the Codex extension to a version that you remember being stable may help resolve it.

Model of Codex:

• GPT-5.4

The platform of my computer:

• MacBook pro with Apple Silicon (M5 Pro) MacOS Tahoe 26.4

How to install specific version?

• First, open VSCode "Extensions" and choose "Codex - OpenAI's coding agent"
• Click the downward arrow to the right of “Uninstall”, then select “Install Specific Version…”.
• Select a version that you remember as being stable. I chose the version from a week ago (26.318.11754). This step may vary from person to person. If you are not sure which one to choose, you can try one first and then check the CPU usage and temperature.

What steps can reproduce the bug?

View: https://github.com/openai/codex/issues/7972?utm_source=chatgpt.com

What is the expected behavior?

View: https://github.com/openai/codex/issues/7972?utm_source=chatgpt.com

Additional information

No response

[github-actions]

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

• VS Code and Cursor extension pins a core to 100% #16210
• VSCode Codex keeps 200% CPU and high power assumption on chat conversation page #16108
• Performance: Code Helper (Renderer) exceeds 100% when Codex applies a code patch in VS Code #15764
• MacBook Air M4 overheating running vs code codex extension #15706
• [Codex Extension][VS Code][macOS] Renderer CPU spikes after file-changing task completes #15958

Powered by Codex Action

[weathon]

+1

[rtpHarry]

Yeah I've been experiencing this several times. I've had this M4 over a year and I've only just started hearing the thermal fans after this bug has started cropping up. Not sure what I can say thats technical.

[kostiantyn-samkovskyi]

+1

[hermanekt]

I can confirm this on the same extension version (26.325.31654) and on macOS 26.4.

In my case the hot process is mainly the VS Code extension host, not the Codex backend:

• Code Helper (Plugin): about 36.4% CPU
• codex app-server: about 2.1% CPU

I also see repeated warnings in the Codex logs:

[warning] [IpcClient] Received broadcast but no handler is configured method=thread-stream-state-changed

Examples from one affected run:

• Codex.log:12
• Codex.1.log:1461
• Codex.3.log:255
• Codex.3.log:256
• Codex.3.log:265

The affected session also rotated logs quickly:

• Codex.1.log through Codex.6.log: 5.0 MB each
• Codex.log: 2.5 MB

This makes my case look very close to both:

• VS Code extension spams unsupported requests / thread-stream-state-changed broadcasts, causing high CPU/GPU usage on macOS #15397 for the exact thread-stream-state-changed warning loop
• this issue (High CPU usage on macOS after updating Codex in VS Code extension to 26.325.31654 #16231) for the regression on 26.325.31654

[neovirtual]

I am seeing a consistent high-CPU loop in the Codex VS Code extension that appears to be tied to a single conversation state, not prompt complexity.

Environment

• VS Code: 1.112.0
• Commit: 07ff9d6178ede9a1bd12ad3399074d726ebe6e43
• Electron: 39.8.0
• Chromium: 142.0.7444.265
• Node.js: 22.22.0
• V8: 14.2.231.22-electron.0
• OS: Fedora 43, Linux x64, kernel 6.19.10-200.fc43.x86_64
• Codex extension:
  • Identifier: openai.chatgpt
  • Version: 26.325.31654 (linux-x64)

Symptoms

• After several back-and-forth prompts in one Codex conversation, extension host CPU and renderer CPU ramp up and remain high.
• This is independent of prompt complexity (also happens with trivial prompts).
• Closing only that conversation immediately drops CPU back to normal.
• Starting a fresh conversation is fine initially, then the same high-CPU state returns after a few messages.
• The behavior is deterministic and reproducible.

Strong log signal

Logs show a tight repeated error loop:

• Error fetching: open-in-target not supported in extension
• URL involved: vscode://codex/open-in-targets
• Stack repeatedly includes extension request handling and then VS Code extension host message delivery pipeline.

In my case, this repeats at very high frequency (roughly dozens of log entries per second), and accumulates into many thousands of repeated entries across rotated logs in one session. That strongly suggests an immediate retry loop with no effective backoff once this state is reached.

Why this looks like an extension-side conversation-state loop

• The error indicates a capability mismatch: a request path is being issued that the installed extension build reports as unsupported.
• The loop is tied to a conversation lifecycle (close conversation, CPU drops immediately; reopen/start new, eventually re-enters loop).
• This does not look model-side or prompt-content-side; it looks like a per-conversation UI/extension state machine repeatedly issuing an unsupported action.

Repro steps

1. Open VS Code on Fedora 43 with extension version 26.325.31654 enabled.
2. Start a new Codex conversation.
3. Exchange 3-5 prompts/replies (content does not matter).
4. Observe extension host and/or renderer CPU rise and stay high.
5. Close that conversation (or panel): CPU drops quickly.
6. Start another conversation and repeat: same pattern.

The problem happens in two different Fedora 43 computers (so it's not tied to one environment).

Current workarounds

• Keep conversations short; close and restart when CPU climbs.
• Reset Codex NUX state from Command Palette, then reload window (sometimes helps clear stuck state).
• If available, install an older extension version (for example a Feb 2026 build) and disable auto-update for this extension as a temporary mitigation.

Regression check

• I reverted to Codex extension version 0.4.79, and this high-CPU loop does not occur with that version in the same environment.

[simon-verzity]

Can confirm that the issue disappears when reverting to 0.4.79. In my case using the Codex extension in Antigravity 1.21.9 (antigravity helper processes CPU usage to 100-200% until ending conversation.

[Yusuf007R]

yes its happening after 2 o 3 prompts, as soon as the codex panel its closed it goes back to normal even tho the agent it still running in the background