A cap that cuts off, not an email. Alone at night, the agent retries a failing task: a hard limit stops the spending, an alert does not. Coding agent, overnight. a failing task. API key with no limit. handed to the agent. The AI provider. bills every attempt. A hard cap? Calls refused. the agent gets errors. Just an email alert. the loop goes on. At the provider : The AI provider, A hard cap? Coding agent, overnight → API key with no limit (calls with). API key with no limit → The AI provider (spends). The AI provider → A hard cap? (checks). A hard cap? → Calls refused (yes). A hard cap? → Just an email alert (no). Calls refused → Coding agent, overnight (stops the loop).