macOS 26.5.1 x86_64: codex-cli 0.139.0 intermittently crashes with zsh trace trap / SIGTRAP after entering Working state

Summary

codex-cli 0.139.0 intermittently crashes on macOS with zsh: trace trap codex / SIGTRAP after entering the normal Working (...) phase.

This does not look like a pure MCP startup failure:

• short prompts can succeed
• Codex can render the TUI, accept input, and begin working
• the crash happens after that, during/after normal processing

Environment

• Codex CLI: 0.139.0
• Install method: global npm package (/usr/local/bin/codex -> @openai/codex/bin/codex.js)
• macOS: 26.5.1 (25F80)
• Kernel: Darwin 25.5.0 x86_64
• Machine class from crash report: MacBookPro16,2

What I observed

There seem to be two related symptoms on this machine:

1. codex itself has a macOS crash report with EXC_BREAKPOINT / SIGTRAP
2. some MCP sidecars also appear unstable on this machine (notably gitnexus via node crash reports), but the Codex crash still appears distinct from pure MCP startup failure

Existing local crash report for Codex:

• ~/Library/Logs/DiagnosticReports/codex-2026-06-07-172044.ips

Relevant crash signature from that report:

• exception type: EXC_BREAKPOINT
• signal: SIGTRAP

The vendor binary is code signed and includes com.apple.security.cs.allow-jit = true, so this is not obviously just an unsigned-binary case.

Failure mode

This kind of session can crash:

1. launch Codex normally
2. TUI renders correctly
3. optional MCP warnings appear (for example notion OAuth not logged in)
4. submit a non-trivial prompt
5. Codex shows Working (11s • esc to interrupt)
6. shell exits with:

zsh: trace trap  codex --dangerously-bypass-approvals-and-sandbox

I also see the same behavior outside YOLO mode, so this does not seem specific to --dangerously-bypass-approvals-and-sandbox.

Example transcript

⚠ MCP client for `notion` failed to start: ... Auth error: OAuth authorization required ...
⚠ MCP startup incomplete (failed: notion)

› [prompt omitted here for brevity; it was a real coding task]

• Working (11s • esc to interrupt)

› zsh: trace trap  codex --dangerously-bypass-approvals-and-sandbox

What does still work

This minimal command succeeded on the same machine:

codex --no-alt-screen "reply with exactly one word: ok"

So the failure appears to be intermittent or workload/state dependent, not a total startup failure.

Extra notes

• I tested with MCP servers temporarily disabled in config, and Codex could still complete a minimal request successfully.
• notion login failure appears to be noisy but likely not the root cause, because Codex continues past startup and only crashes later.
• There are existing open issues that look related:
• #27305 (0.138.0 trace trap during code review)
• #27358 (macOS SIGTRAP / entitlements path)

This report may be a duplicate/root-cause-adjacent to those, but I wanted to provide another concrete macOS 0.139.0 data point with local crash evidence.