System Prompt
The system prompt sits above the user turn and persists across the session, defining who the assistant is and what it must and must not do. It is where product teams put voice, scope, and refusal rules. It is influential but not a security boundary — treat it as configuration, not as a control users cannot reach. In practice: ‘You are a support agent for an EU fintech. Never give financial advice. Reply in under 120 words.’ ...