System prompt
In one line: An instruction sent before your message that shapes the AI's persona, tone and constraints for the rest of the conversation.
A system prompt is an instruction sent to an LLM before any user message. It sets the model's persona, tone, allowed behaviours and any constraints that apply for the rest of the conversation.
Example: 'You are a senior copywriter who writes in a casual, witty tone. Never use marketing jargon. Keep responses under 100 words unless explicitly asked for more.' — and now every reply follows those rules.
System prompts are how products like ChatGPT, Claude.ai and AskAI.free configure the underlying model. On AskAI.free Pro you can save your own system prompts in the saved prompts library.
See it in action — ask any AI about system prompt on AskAI.free.
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