Stop Hooks as Hard Constraints: Enforcing Claude Code Behavior Outside the Model

1Key Takeaways

• Originally published on hexisteme notes .
• I run a fleet of Claude Code agents, and for a long time I tried to enforce behavioral rules the obvious way: write them into the system prompt and hope they hold.
• They mostly did — until pressure showed up.
• A plausible-sounding challenge from me, a long task, a shortcut that saves a turn, and the model would quietly drop a rule it had followed all session.