Three Things Almost Everyone Gets Wrong About Claude Code
From the person who built Claude Code. A short, practical guide.
The three fixes below came from one talk by Boris Cherny, who built Claude Code. None of them are settings. All three are about how you set the job up before the model ever runs.
1. Delete most of your instructions
He deleted roughly 80% of Claude Code's system prompt, and the tool got better. Long instruction files are usually a museum of old problems. Most lines were written to babysit a weaker model, and that model is gone.
What to do this week:
- Open your CLAUDE.md and read it as if you wrote it for a new hire who is already excellent.
- Delete every line that exists to stop a mistake you have not actually seen in the last month.
- Delete every line that explains something the model can read from the code itself.
- Keep only what is true, specific and impossible to infer: your stack, your conventions, your hard rules.
If a line would embarrass you to say out loud to a senior engineer, cut it
A good target is a single screen. If yours is longer, you are probably describing the model instead of your project.
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