Codex macOS app renderer freezes at 100% CPU after auto-starting browser/node_repl runtime

Environment

• Codex desktop app: 26.609.71450
• Codex app build: 3965
• macOS: 15.6.1
• Architecture: Apple Silicon / arm64
• Install source: official DMG from https://persistent.oaistatic.com/codex-app-prod/Codex.dmg

Summary

Codex desktop on macOS freezes shortly after launch. The visible symptom is the Electron renderer process pegging one CPU core at ~100%.

Reinstalling /Applications/Codex.app from the official DMG does not fix it. The issue appears to be triggered by user-local Codex state under ~/.codex, specifically the app auto-starting the browser / node_repl runtime.

Observed behavior

After launch, Codex rewrites ~/.codex/config.toml and enables browser/runtime-related entries such as:

[plugins."browser@openai-bundled"]
enabled = true

[mcp_servers.node_repl]
command = "/Applications/Codex.app/Contents/Resources/cua_node/bin/node_repl"
startup_timeout_sec = 120

It also starts processes like:

/Applications/Codex.app/Contents/Resources/codex app-server --analytics-default-enabled
/Applications/Codex.app/Contents/Resources/cua_node/bin/node_repl
~/.codex/computer-use/Codex Computer Use.app/.../SkyComputerUseService

Shortly after node_repl appears, the renderer spins:

Codex (Renderer)  ~100% CPU

The app UI becomes unusable / appears frozen.

Reproduction notes

This was observed on an existing local Codex profile.

1. Launch Codex desktop app.
2. Wait roughly 1-2 minutes.
3. Observe node_repl being started.
4. Observe Codex (Renderer) jump to ~100% CPU.
5. App becomes effectively frozen.

The following did not permanently fix the issue:

• quitting/relaunching Codex
• reinstalling /Applications/Codex.app from the official DMG
• clearing some app cache directories
• disabling plugin entries in config.toml manually, because Codex rewrites parts of the config on launch

Why this does not look like a bad app install

The app bundle was replaced from the official DMG and verified as notarized:

/Applications/Codex.app: accepted
source=Notarized Developer ID

After reinstall, the same local profile still reproduced the freeze. This points to interaction between the current app version and persisted local state / plugin runtime setup under ~/.codex.

Related but likely different issue

This may be related to the broader desktop performance family, but the local trigger differs from #24510.

#24510 appears focused on high CPU from unbounded local thread metadata / sidebar history paths. In this case, the strongest correlation observed was the browser / node_repl runtime being auto-started and then the renderer immediately pegging CPU.

Expected behavior

Codex desktop should not freeze or spin the renderer at ~100% CPU when auto-starting browser / node_repl / computer-use runtime components.

If a local plugin/runtime state is incompatible, Codex should fail that runtime gracefully, avoid repeatedly starting it, and leave the main UI usable.

Actual behavior

Codex auto-starts the runtime chain and the renderer pegs ~100% CPU, making the desktop app unusable. Reinstalling the app bundle alone does not recover because the trigger appears to live in persisted user state.

Sanitization note

I have intentionally omitted full config.toml, logs, session files, and prompt history because they may contain local paths, private project data, or credentials. The snippets above are redacted to the relevant runtime entries only.