40% of the code Claude writes for you is wasted. you're paying for the rewrite.
a 65-line markdown file fixes it. 120,000 developers have starred it.
the author tested it on "30 codebases over 6 weeks" and reported a mistake rate drop from 41% to either 11% or 3%
depending on whether you read the headline or the body.
the irony is that the article is right.
CLAUDE.md is the most under-leveraged file in your stack.
65 lines of behavioral rules outperform a 4,000-token preferences dump.
"be careful" is useless. testable imperatives are gold.
"be senior" doesn't work Claude already thinks it is.
the 4 rules that ship the most leverage:
/ state assumptions, never guess silently
/ minimum code, nothing speculative
/ surgical changes, don't refactor adjacent code
/ define success, loop until verified
compliance: ~80%. mistake rate: from ~40% to single digits.
no human caught the contradicting numbers in the title.
nobody had to.