Anecdotally, my experience has been that the longer a conversation goes on in Cursor about a new feature or code change, the worse the output gets.
The best results seem to be from clear, explicit instructions and plan up front for a discrete change or feature, with the relevant files to edit dragged into the context prompt.
Yeah, that's why I often save context once there is enough information for work to be done. Then, once I notice regression in quality, I do a summary of work done (still could be a low quality) and add it on top of previous checkpoint.
The best results seem to be from clear, explicit instructions and plan up front for a discrete change or feature, with the relevant files to edit dragged into the context prompt.