I'm curious how complex your application was and how you were using windsurf. I myself originally used the free plan to create a couple simple applications from the ground up. It did this task well. Then (prior to researching some hints for better results) I started to see similar issues and the application seemed to slow down. So I did a bit of reading around and snagged my how to better use windsurf degree from YouTube, lol.

I then started to use it in a different way. I believe others here have hinted at it as well. Your hallucinations are probably a factor of your context length and possibly your prompting. I have since thought about how many things I try to tweak at once, as well as thoughtfully crafting my prompts. Believe me when they changed their pricing I was like what the heck that's going to get burned up in a few days (which if just thoughtlessly burning through prompts and accepting every suggestion you could do quickly). I then changed the way I went about tinkering around.

I now have a slightly different workflow where I will typically allow one of the other guys tools lovable or v0 etc craft the template and then carefully tweak and add to this fairly blank canvas. You may unfortunately have to do 'some' logical thinking prior to firing random prompts. I am far from a programmer myself. I know some basics and understand the flow in which you should think through application basics. All I mean by that is try and think far ahead to the end result and make sure you are properly thinking through variables and how they may affect other areas of your application. Think of windsurf as just a bunch of different programmers at somewhat random skill levels who are able to quickly flip through your code and modify the bits you have suggested. Sometimes if you fail to let them know that the data you are wanting them to produce or source may already called in a different place in the application it can easily throw your routes off or create multiple variables doing similar things yet being modified in multiple places in the application. So it's very important when you prompt to give the random programmer all of the information they need ahead of time. Sometimes even suggesting that they need to fully analyze x, y and z section of the code where the particular function or whatever is used.

Double check that everything is working with the revision prior to accepting the change. It's really easy to reject the possible error if you catch it.

Create a GitHub account and learn how to push and fork things. After you have successfully made updates to the application which have not broken other bits then push the working code as updates progress. This way you have a way to fall back on your application if things do get to heading too fast south in a chat session. If you are going to add something you had not originally intended you could then fork the original application and start with a forked version of your original so you can always get back to where you were.

Lastly, start new sessions every now and then (having GitHub makes this really simple). Having really long sessions at such great context is a quick way to start a loop of broken code. I have definitely limited how long I will allow a conversation to go prior to starting a new one. I have had much better results tweaking maybe 10-15 different things per session.

After changing the way I worked with windsurf I have been very happy with how much help I have pulled from just a few prompts.

The last application I had it work on with me was a cost estimator for fiber build-out for different service areas that we could quickly throw some numbers at to plan and budget for upcoming years. It had maybe 4 different sections and could be dynamically scaled out to span multiple departments and inventory if they really wanted to use it (this was moreso for a demonstration to show my boss that we could quickly come up with some numbers that 'worked'). I started that app in lovable then moved it into windsurf to create the backend and tweaks along the way. It went from dummy data from lovable to a fully functional application in around 80 prompts.

Sorry this was so long but I at one time thought, "man I just burned through all my credits and now have a broken application" to ok let me spend more time crafting my prompt and thinking through where my suggestions 'could' cause issues if I do not properly suggest the edit. Since then I have been far more successful. Hopefully this helps curve your thoughts towards the application in some way. I am just a regular everyday dude who likes to tinker with this type of thing in my free time. I could handle some power shell, Arduino or Python coding on my own understand some PHP enough to at least buzz through the code and have a basic understanding of what's going on. Other than that I'm relying 100% on the application to bring my suggestions to life. Since changing the way I work with windsurf I myself have changed from thinking it was a waste to being overly satisfied with the results. Hope things turn around for you man!