System Prompt
A hidden set of standing instructions that shapes how the AI behaves for an entire conversation: its role, tone, rules, and boundaries.
It is where an agent gets its identity and guardrails. Change it and the assistant becomes a different assistant.
System Prompt in practice
A system prompt is still a prompt, just one that runs before every message instead of once. The same structure from our prompting guide applies: role, context, task, format, examples, and constraints. For agents, a rich system prompt is often called a soul file, and our agent system prompt templates show six you can copy.
Frequently asked questions
What is a system prompt and where is it?
A system prompt is a hidden set of standing instructions that tells the AI its role, tone, rules, and boundaries for an entire conversation. You usually never see it, but it shapes every reply you get.
How is a system prompt different from what I type?
What you type is a one-time request, while the system prompt stays constant in the background and governs the assistant's whole personality and rules. Change the system prompt and you effectively get a different assistant.
Can a system prompt keep an AI on topic and safe?
Yes, it is where an agent gets much of its identity and its guardrails, like staying professional or refusing off-limits requests. It is one of the main places you set the boundaries a business wants.
New to all this? Start with what an AI agent really is, browse the full glossary, or explore the learning hub.
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