System Prompt
A hidden instruction layer that defines an AI's behavior before any user input arrives — its role, rules, tone, and boundaries. When a chatbot acts like a pirate or refuses certain requests, the system prompt is why. For creators using LLMs to draft image or video prompts, writing a good system prompt ('You are a cinematography-savvy prompt writer; always specify lens, lighting, and mood') turns a generic assistant into a specialized tool. In API workflows and AI agents, the system prompt is where you engineer consistent, on-brand behavior.