Why your AI agent ignores the rules you wrote

You wrote the rule. The agent read it. It broke the rule anyway.

Here's one from a React Native project. My config said:

Never use pnpm add for native packages.

Clear enough. The agent ran pnpm add on a native package in the next session regardless. The build broke without an error message: pnpm resolved react-native@0.79 instead of the 0.76 the project was pinned to, the JS kept compiling, and the native module failed at runtime with a message that pointed nowhere useful. That cost me an hour.

The agent wasn't being disobedient. The rule was bad. It said what to avoid and nothing else, so the first time a situation didn't match the picture in my head, the agent treated it as a soft preference and grabbed the obvious tool.