Linux Codex CLI cannot use GPT-5.6 models while macOS works with the same Codex version (0.144.0)

What version of Codex CLI is running?

0.144.0

What subscription do you have?

ChatGPT authentication

Which model were you using?

gpt-5.6

What platform is your computer?

Ubuntu 24.04 LTS

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

_No response_

Codex doctor report

What issue are you seeing?

Summary

I'm seeing a platform-specific issue where GPT-5.6 models work on macOS but consistently fail on Linux, despite using:

• the same OpenAI account
• the same ChatGPT authentication
• the same reported Codex CLI version (0.144.0)

macOS can use GPT-5.6 Sol/Terra/Luna normally.

Linux consistently returns:

Model metadata for 'gpt-5.6-sol' not found.
Defaulting to fallback metadata; this can degrade performance and cause issues.

followed by:

{
  "type": "error",
  "status": 400,
  "error": {
    "type": "invalid_request_error",
    "message": "The 'gpt-5.6-sol' model requires a newer version of Codex. Please upgrade to the latest app or CLI and try again."
  }
}

However, codex doctor reports that Linux is already running the latest available version.

---

Environment

Linux

• Ubuntu 24.04 LTS
• Codex CLI 0.144.0
• ChatGPT authentication
• Same OpenAI account as macOS

codex --version

Output:

codex-cli 0.144.0

which codex

Output:

/home/user/.local/bin/codex

---

macOS

• macOS 15
• Codex CLI 0.144.0
• Same OpenAI account

codex --version

Output:

codex-cli 0.144.0

GPT-5.6 works correctly on macOS.

---

Steps to reproduce

codex -m gpt-5.6-sol

(or gpt-5.6-terra / gpt-5.6-luna)

---

Expected behavior

The GPT-5.6 model should start normally, as it does on macOS.

---

Actual behavior

Linux reports:

Model metadata for 'gpt-5.6-sol' not found.

then immediately returns:

400 invalid_request_error

The 'gpt-5.6-sol' model requires a newer version of Codex.
Please upgrade to the latest app or CLI and try again.

---

Troubleshooting already performed

Verified:

• Same OpenAI account
• Same ChatGPT authentication
• Same Codex CLI version (0.144.0)
• Fresh login (codex logout / codex login)
• Reinstalled Codex
• Reinstalled via npm
• kernel.unprivileged_userns_clone=1
• Bubblewrap installed and working
• Network connectivity OK
• codex doctor reports the CLI is already up to date

Nothing above changes the behavior.

---

Interesting observation

One noticeable difference is the rollout information reported by codex doctor.

Linux

active rollouts: 1664

Linux also reports:

rollout files are missing from the state DB;
state DB rows point at missing or unusable rollout files

macOS

active rollouts: 67846

The macOS doctor reports a different rollout warning:

rollout scan was incomplete or found bad files

I don't know whether the rollout counts are expected to differ across platforms, but the difference is significant, and the Linux client is also the only one that cannot find GPT-5.6 model metadata.

This may or may not be related, but it seemed worth mentioning.

---

Additional information

I'm happy to provide:

• Full codex doctor output
• Linux/macOS comparison
• Screenshots
• Any additional logs if helpful

Thanks!

What steps can reproduce the bug?

Reproduction steps

1. Install the latest available Codex CLI on Linux (Ubuntu 24.04).

codex --version
# codex-cli 0.144.0

1. Authenticate with ChatGPT.

codex login

1. Launch any GPT-5.6 model.

codex -m gpt-5.6-sol

(Also reproducible with gpt-5.6-terra and gpt-5.6-luna.)

1. Enter any prompt, for example:

hello

1. The request immediately fails with:

Model metadata for 'gpt-5.6-sol' not found.
Defaulting to fallback metadata; this can degrade performance and cause issues.

followed by:

400 invalid_request_error

The 'gpt-5.6-sol' model requires a newer version of Codex.
Please upgrade to the latest app or CLI and try again.

Expected behavior

The model should start normally, as it does on macOS using the same OpenAI account and the same reported Codex CLI version (0.144.0).

Notes

• This reproduces consistently on Ubuntu 24.04.
• The same account can successfully use gpt-5.6-sol on macOS with Codex CLI 0.144.0.
• codex doctor reports that the Linux installation is already up to date.

What is the expected behavior?

_No response_

Additional information

_No response_