Here is a workaround method for anyone that wants to use the official DeepSeek API with Cursor:
Api: https://api.deepseek.com/v1
Model: deepseek-reasoner
Delete .cursorrules and make sure the Rules are empty in the cursor settings.
Switch to Chat mode and do not have your file attached as context
What you can do instead, is copy your entire file’s content and paste it in chat so it becomes like this:
Submit and it will work, not very intuitive but a good workaround so we don’t hop back and forth to the deepseek website, and still have the speed from the main API.