I want to submit a serious complaint about the Opus 4.5 model regarding HTML/CSS work in a .NET Core project.
I used this model for a very simple front-end task inside my .NET Core platform: placing date fields side by side in an HTML layout. This should have been a quick and basic UI fix. Instead, I had to spend a huge amount of usage just to get a usable result. My usage increased from 25% to 45% for this one small adjustment alone.
What makes this even more frustrating is that the model keeps making repeated mistakes. It does not reliably follow clear instructions, and it frequently breaks parts of the design that were already working correctly. Instead of applying a small targeted change, it often modifies unrelated sections, disrupts the layout, and creates new design issues.
This turned a very simple HTML/CSS edit in a .NET Core project into a long and exhausting process. I had to repeat myself multiple times, correct the output again and again, and still the results were unstable and inconsistent.
I am very dissatisfied with this experience. A premium model should not consume this much usage for such a basic task, especially while continuously making errors and damaging existing designs. This feels inefficient, unreliable, and far below the expected standard.
I hope this feedback is taken seriously and that the model is improved, especially for basic HTML/CSS tasks in .NET Core projects where precision and consistency are essential.