Infinite response loop in Codex VS Code extension (chat & agent, all models)

What version of Codex is running?

0.4.51

What subscription do you have?

ChatGPT Plus

Which model were you using?

gpt-5 to gpt-5.2 - All available models affected

What platform is your computer?

Debian 12 Testing - Linux 6.17.9+deb14-amd64 x86_64 unknown - VS Code: Linux Codex VS Code extension (current stable)

What issue are you seeing?

Codex enters an infinite response loop even for trivial prompts.
The same output is generated repeatedly ("OK", "Thinking", "OK", …) until the user manually aborts.
This happens in both Chat and Agent modes and is independent of the selected model.

What steps can reproduce the bug?

1. Open VS Code
2. Open an empty workspace
3. Start Codex (Chat or Agent)
4. Select any model
5. Prompt: "Answer exactly once. No variations. No suggestions. Just the word: OK."

What is the expected behavior?

Single response:
OK

Additional information

Clearing ~/.config/Code/User/globalStorage and workspaceStorage does not help.
Appears to be a server-side execution/termination bug.