The article reports on an issue with Claude Code, a tool used for complex engineering tasks, which has become unusable due to a regression in its performance since the February updates. The issue is described as a decline in the model's ability to perform deep thinking, leading to incorrect and incomplete solutions. The author provides a detailed analysis of the problem, including data and metrics, and suggests possible solutions. The issue affects users who rely on Claude Code for complex tasks and has led to a significant increase in errors and corrections.