Codex app-server stuck at 100% CPU on macOS Apple Silicon when opening VS Code ChatGPT extension

[aitormendez]

What version of Codex is running?

Tested both: openai.chatgpt 0.4.46 (stable release) • openai.chatgpt 0.5.47 (pre-release, Mac Silicon build) Both versions reproduce the same issue

What subscription do you have?

ChatGPT Plus

Which model were you using?

GPT-5.1-Codex_Max, GPT 5.1

What platform is your computer?

Darwin 23.6.0 arm64 arm

What issue are you seeing?

When I open the ChatGPT / Codex panel in VS Code on macOS Apple Silicon, the codex app-server process immediately rises to ~100% CPU and stays there for several minutes. During this time:

1. The ChatGPT panel takes a very long time to initialize (often tens of seconds or more).
2. About one out of every three prompt submissions gets stuck with a spinner for several minutes before finally responding.
3. CPU usage remains very high throughout these delays.

After some minutes, the panel eventually loads and prompt submissions eventually complete, but the codex app-server process never stabilizes to low CPU usage — it continues running near 100% until VS Code is closed or the process is manually killed.

I tested both:

• Stable version: openai.chatgpt 0.4.46
• Pre-release version: openai.chatgpt 0.5.47 (Mac Silicon VSIX)

Both show exactly the same behavior.

What steps can reproduce the bug?

1. Close all VS Code windows.
2. Clean previous processes:

   pkill -f "codex app-server"
   ps aux | grep codex
   

(Only the grep line should remain.)

3. Open VS Code with a single window (empty workspace or very small project).

4. Open the ChatGPT / Codex sidebar.

5. Observe that: • a single codex app-server process appears, • CPU instantly jumps to ~100%, • the panel takes a long time to finish initializing,

6. Submit prompts: • some are processed normally after a delay, • roughly 1 out of every 3 prompts gets stuck with the spinner for several minutes before eventually completing.

What is the expected behavior?

The codex app-server process should briefly spike during startup and then settle to low CPU usage. The ChatGPT / Codex panel should load quickly, and prompt submissions should respond promptly and consistently.

Instead:

• panel initialization takes an unusually long time,
• prompt submissions often get stuck for minutes,
• and CPU use stays near 100% for the entire time the extension is active.

Additional information

System details:

• Mac Studio with Apple M2, 32 GB RAM
• Apple Silicon (ARM64)
• macOS 14.8 Sonoma
• VS Code 1.106.3
• ChatGPT / Codex extension:
  • Stable: 0.4.46
  • Pre-release: 0.5.47 (Mac Silicon VSIX)

I am not using Codex CLI outside the extension. No MCP servers configured. The issue happens even with a single VS Code window and an empty workspace.

If needed, I can provide the “Output → Codex” logs or Activity Monitor traces.

[SabareeshGC]

This is happening a lot and i see several instance of codex at 100% of cpu . I have to force close them to save the laptop power in activity monitor.

[bolinfest]

Are any of your subfolders of ~/.codex particularly large? There have been occasions in the past where we loaded those resources inefficiently...

You can also try adding:

"chatgpt.logLevel": "debug", // or "trace"

to settings.json to get extra info in the output pane for Codex.