[Feature Request] One-shot model override for single prompts without session switching

Bug Description
I work on a pay-per-token plan and use Sonnet as my default model. My typical workflow is to start a new task with a single complex prompt that benefits from Opus-level reasoning, then continue the rest of the session on Sonnet.

The problem is there's no way to use Opus for just one prompt and automatically revert back to Sonnet. My current options are:

• Manually /model opus before the prompt, then /model sonnet after — which I keep forgetting to do
• opusplan mode — doesn't suit me since I don't use plan mode
• Starting separate sessions per model — too much friction with resuming

What I'd love is a "one-shot model override" feature: something like a flag or prefix on a single prompt that uses a specified model for that turn only, then reverts to the session default. For example: /opus <my prompt> or a --model flag on an individual message.

This would be really valuable for pay-per-token users who want to be deliberate about Opus usage without the overhead of managing model switches manually.

Environment Info

• Platform: darwin
• Terminal: iTerm.app
• Version: 2.1.169
• Feedback ID: f113928d-90c4-4ff1-855a-96e536b0202d

Errors

[]