System Prompt
A hidden text that sets the behavior, role, and rules of an AI model before the conversation with the user begins.
What is a system prompt?
A system prompt is an instruction passed to the AI model before the user writes their first message. It acts as a "job description" or briefing for the AI: it defines what role it should play, how it should communicate, and what it may or may not do.
What a system prompt typically contains
- Role and persona: "You are a customer assistant for company XY"
- Behavior rules: "Always respond in English, be concise"
- Restrictions: "Do not provide legal or medical advice"
- Context: Product information, FAQs, or company processes
Relationship to security
The system prompt is the target of prompt injection attacks - the attacker tries to make the model ignore it. This is why it is important to write system prompts robustly.