Hey, thanks for the report. This is expected behavior right now, not an issue with your account. On mobile screen widths, the web app uses an older simplified model list that doesn’t include the reasoning effort controls or the Fast / non-Fast toggle. The full parameterized picker is currently only available at desktop widths.
You already found the workaround. Turn on Request Desktop Site in your mobile browser, and you’ll get the full model picker with parameters.
Upgrading the mobile picker is on our radar, but I can’t share an exact timeline yet. The same case is discussed here: Unable to remove fast mode on cursor mobile web. I’ll merge the threads so everything’s in one place, and I’ll follow up if there’s an update.