Auto() in agent mode not routing on too large context

Thanks for reporting a bug you have found in Cursor!
Please add the following info to help us diagnose your issue:

:white_check_mark: Check the forum to ensure the issue hasn’t been reported already
:lady_beetle: Attachments are too long and auto fails, except it wouldn’t if the auto logic pushed the request to Gemini 2.5… auto should route appropriately in that scenario.
:counterclockwise_arrows_button: Attach a few thousand lines of text and the other models fall over apparently.
:laptop: Windows Desktop, latest
:prohibited: Tell us if the issue stops you from using Cursor. Nope.