VS Code extension host Code Helper (Plugin) high CPU with repeated thread-stream-state-changed warnings on macOS

Summary

When I open the Codex VS Code extension and start using it in a single VS Code window, CPU usage rises significantly and the machine heats up.

The dominant process is the VS Code extension host (Code Helper (Plugin)), not the Codex backend itself. This looks related to #3022 and possibly adjacent to #7456 / #7473, but my main symptom is extension-host CPU plus repeated warning spam in the Codex logs.

Environment

• macOS 26.4 (25E246)
• Apple Silicon
• OpenAI VS Code extension openai.chatgpt 26.325.31654
• Single VS Code window

Observed behavior

At the time of capture:

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

The issue appears specifically when the Codex extension is active.

Reproduction

1. Open VS Code.
2. Open the OpenAI / Codex extension.
3. Start or resume a chat session.
4. CPU usage rises and the machine heats up.

Logs

The logs repeatedly contain:

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

Examples from one affected session:

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

The session log directory also rotated quickly and produced multiple large files:

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

Local log path:

~/Library/Application Support/Code/logs/20260402T162242/window3/exthost/openai.chatgpt/

Expected behavior

The extension should not drive sustained high CPU usage in the VS Code extension host during normal chat usage.

Related issues

• #3022
• #7456
• #7473

I can provide full logs if needed.