Let me save you some frustration: Claude Code will misunderstand you. It will edit the wrong file. It will make a change that breaks something that was working fine. It will occasionally do exactly the opposite of what you asked.
This is normal. Not a sign that you're doing it wrong. Not a sign that the tool is broken. It's just what happens when you communicate complex ideas to an AI. Even humans misunderstand instructions.
The difference between a frustrated Claude Code user and an effective one isn't that the effective one never has problems. It's that they know how to recover.
Things went wrong. Your options, from simplest to most thorough:
Tell Claude to undo it