Codex CLI 0.154.0 hangs on startup on macOS after Homebrew upgrade

What version of Codex CLI is running?

0.154.0

What subscription do you have?

Business Premium seat

Which model were you using?

N/A — CLI hangs before startup

What platform is your computer?

Darwin 25.6.0 arm64 arm

What terminal emulator and version are you using (if applicable)?

SSH session into macOS, zsh, tmux also in use

Codex doctor report

not available — `codex doctor --json` also cannot run because every Codex invocation hangs

What issue are you seeing?

Codex CLI 0.154.0 hangs indefinitely immediately on startup after upgrading from 0.153.4 via Homebrew Cask.

There is no stdout/stderr output and the process has to be interrupted manually.

All of these hang:

codex
codex doctor --json
codex --version
codex --help
/opt/homebrew/Caskroom/codex/0.154.0/bin/codex completion bash

This also causes:

brew reinstall --cask codex

to appear to hang at:

==> Linking Binary 'codex' to '/opt/homebrew/bin/codex'

Process inspection shows that Homebrew successfully gets past the actual binary-link step and then launches:

/opt/homebrew/Caskroom/codex/0.154.0/bin/codex completion bash

That Codex process hangs indefinitely.

The issue started immediately after upgrading from 0.153.4 to 0.154.0.

What steps can reproduce the bug?

1. Upgrade Codex CLI installed through Homebrew Cask to 0.154.0.

2. Run:

codex --version

Observe that the process hangs indefinitely with no output.

The same happens with codex --help and normal codex startup.

I also reproduced it while bypassing my normal Codex configuration:

tmp="$(mktemp -d)"
CODEX_HOME="$tmp" /opt/homebrew/Caskroom/codex/0.154.0/bin/codex --version

This still hangs.

I also tested a copied and ad-hoc signed binary:

cp /opt/homebrew/Caskroom/codex/0.154.0/bin/codex /tmp/codex-0.154.0
codesign --force --sign - /tmp/codex-0.154.0
/tmp/codex-0.154.0 --version

codesign succeeds, but the resulting binary still hangs.

What is the expected behavior?

codex --version and codex --help should return immediately, and normal codex startup should launch the CLI.

Additional information

An existing Codex 0.153.4 process that was already running continued to work after the upgrade, but new 0.154.0 processes cannot start.

I initially suspected MCP configuration, but reproducing the issue with a fresh temporary CODEX_HOME appears to rule out my normal Codex configuration.

Homebrew itself does not appear to be the root cause: during reinstall, the child process that hangs is codex completion bash.

No source files or tests are named. First reproduce the hang with CODEX_HOME set to a temporary directory using codex --version, codex --help, and codex completion bash, then trace the 0.154.0 startup path on macOS. Done means these commands return promptly and normal Codex startup launches successfully after the Homebrew upgrade.