Model changes to Medium uninstructed

[Redstar1337]

What version of Codex CLI is running?

0.98

What subscription do you have?

Pro

Which model were you using?

5.3 Codex

What platform is your computer?

PS7 Win10

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

PS7

What issue are you seeing?

Worked for 2m 59s ──────────────────────────────────────────────────────────────────────────────────────────────────────────────────────────────────────────────────────────────────────────────────────
• I found a potential regression risk in the patch and want to verify it empirically with a short replay: internal netting fills are now written to blotter, which may unintentionally affect turnover/fee
accounting. I’ll run a short-window smoke replay and inspect blotter plus turnover consistency.

/status

╭─────────────────────────────────────────────────────────────────────────────────╮
│ >_ OpenAI Codex (v0.98.0) │
│ │
│ Visit https://chatgpt.com/codex/settings/usage for up-to-date │
│ │
│ Model: gpt-5.3-codex (reasoning xhigh, summaries auto) │
│ Directory: E:\Python 3.12 │
│ Approval: never │
│ Sandbox: danger-full-access │
│ Agents.md: AGENTS.md │
│ Account: xxx (Pro) │
│ Collaboration mode: Default │
│ Session: 019c371b-daab-7ec3-9f22-10ba8c2c4738 │
│ Context window: 29% left (187K used / 258K) │
│ 5h limit: [███████████████████░] 95% left (resets 20:48) │
│ Weekly limit: [██████████░░░░░░░░░░] 49% left (resets 01:13 on 10 Feb) │
╰─────────────────────────────────────────────────────────────────────────────────╯

› Yes proceed

/status

╭─────────────────────────────────────────────────────────────────────────────────╮
│ >_ OpenAI Codex (v0.98.0) │
│ │
│ Visit https://chatgpt.com/codex/settings/usage for up-to-date │
│ information on rate limits and credits │
│ │
│ Model: gpt-5.3-codex (reasoning medium, summaries auto) │
│ Directory: E:\Python 3.12 │
│ Approval: never │
│ Sandbox: danger-full-access │
│ Agents.md: AGENTS.md │
│ Account: (Pro) │
│ Collaboration mode: Plan │
│ Session: 019c371b-daab-7ec3-9f22-10ba8c2c4738 │
│ │
│ Context window: 21% left (207K used / 258K) │
│ 5h limit: [███████████████████░] 94% left (resets 20:48) │
│ Weekly limit: [██████████░░░░░░░░░░] 48% left (resets 01:13 on 10 Feb) │
╰─────────────────────────────────────────────────────────────────────────────────╯

What steps can reproduce the bug?

I'm not sure yet, possibly turning on Plan mode causes it to happen but needs further testing to reproduce.

What is the expected behavior?

No response

Additional information

No response

[etraut-openai]

Thanks for the bug report. Let us know if you come up with reliable repro steps.

[Redstar1337]

I'm almost certain entering plan mode switches it to the default medium model, happened more than once now switching to plan mode.

[fullofcaffeine]

+1, having the same issue. I notice because it becomes too fast and then I realize it's a bit shallow on the replies. Annoying because plan mode is quite useful.

[fullofcaffeine]

Yep, switching to the plan mode does it. Codex 0.98.0, MacOS 15.4 (24E248).

1. Fire a new session, send the /model. command and make sure mode is something other then 'gpt5.3-codex-medium', i.e 'GPT5.3-codex-high';
2. Press shift+tab to switch to the plan mode;
3. Send the /model command again and you'll see gpt5.3-codex-medium selected again 😞

[guidedways]

Same: #11979