I told my agent not to work around a refusal. It obeyed forever.

Last week I spent forty minutes debugging an agent that refused to do something it was fully allowed to do.

The fix was one sentence. The lesson took longer.

The setup

My agent has capability levels. At the lowest level it can't write source files at all. I wanted that refusal to be visible, not just an absence — so instead of leaving the tool unregistered, I registered a stub that always fails:

@agent.tool(name="write_project_file")

I told my agent not to work around a refusal. It obeyed forever.

Related reading

Your agent stops obeying your rules halfway through the session. Here's the…

Your agent's memory needs the word 'no' — and a way to prove nobody edited it

I denied 7 dangerous commands. My agent deleted the files anyway

The agent edited the rule that made its change wrong

Your agent's failed traces are wasted fine-tuning data

I stopped writing rules for coding agents that CI could not enforce