The best Claude Code agents are defined by what they refuse to do

TL;DR — When I write a Claude Code subagent, the most important part isn't the instructions for what it should do. It's the list of what it must refuse to do. This post explains why, and walks through a real ~50-line agent (free, MIT) that catches the embarrassing stuff in your diff before you merge. The agent that was too helpful The first useful-sounding Claude Code subagent I ever wrote was a "code reviewer." The prompt was the obvious thing: "You are a senior engineer. Review...