Prefix every prompt with the active model version (e.g. 5.3)

What variant of Codex are you using?

codex-cli 0.98.0

What feature would you like to see?

<h1>Feature Request: Codex CLI always show the active model in the prompt</h1>

<h2>Variant</h2>
<p>Codex CLI (Windows)</p>

<h2>Summary</h2>
<p>
Please add an option so the Codex CLI prompt always displays the currently active model (or model version),
so I never have to manually check which model I’m using mid-session.
</p>

<h2>Problem</h2>
<p>
I constantly switch models depending on the task. For basic HTML edits, 5.1 is fine. For complex spatial engine work, I use 5.3.
Right now I have to keep checking what model is active, which breaks flow.
</p>

<h2>Requested change</h2>
<p>When interactive mode is running, the CLI prompt should always include the active model.</p>

<h3>Example behaviour</h3>
<ul>
<li>If active model is 5.3, prompt shows: <code>[5.3] &gt;</code></li>
<li>If active model is 5.1, prompt shows: <code>[5.1] &gt;</code></li>
</ul>

<p>If the model changes during the session, the prompt must update immediately for the next input.</p>

<h2>Acceptance criteria</h2>
<ul>
<li>Active model/version is always visible in the prompt while typing.</li>
<li>Prompt updates immediately after switching models.</li>
</ul>

Additional information

_No response_