Codex hang using ~99% CPU after thinking for a few seconds on long conversation
What version of Codex is running?
0.1.2504172351
Which model were you using?
03
What platform is your computer?
Darwin 24.3.0 arm64 arm
What steps can reproduce the bug?
Not sure the exact steps as this has only happened once so far.
After using codex for a while (in full auto mode), when I sent a new prompt it "thought" for around 16s then the terminal stopped updating. Looking in Activity Monitor, the process was stuck using between 98 and 99% CPU. I waited for a few minutes but the terminal UI was still frozen and the process stuck at 99% CPU.
What is the expected behavior?
_No response_
What do you see instead?
_No response_
Additional information
This was running in an Apple Silicon macOS VM on macOS 15.3.2. I had been using it for around 15 minutes when the issue occurred. The working directory was a simple web app with less than 10 files and the largest file is 150 lines long.
Attached is a process sample taken at the time the process was in that state.
2 Comments
Happened to me once this morning as well on Ubuntu 25 at Vultr. But running it intensively since Fri AM and it was fine. Could have been bug in handling model responses.
Thank you for the feedback! Please try again on the latest version of Codex CLI. If the issue persists, we would appreciate any additional details you can provide.