Anthropic says "double-check your work" is now an anti-pattern. I counted 125 of those lines in my own config and cannot tell which ones matter.

Anthropic recently published guidance indicating that instructions like "double-check your work" are now counterproductive, leading to increased costs and reduced performance. These directives can cause models to perform unnecessary tasks, such as redundant knowledge-base searches or redoing already completed work. The issue extends to contradictory rules within configurations, which can prevent desired outcomes. Developers are now questioning how to audit their existing configurations to identify and remove these anti-patterns effectively.

Unlike previous advice to add thoroughness instructions, Anthropic now advises against them, citing concrete examples where they increased costs and reduced performance.