AI agent glossary
System prompt
The standing instructions given to a model before the conversation starts, setting its role, rules, tone, and how it should use its tools.
The system prompt is where you define who the agent is and how it should behave across every turn. It typically covers the agent's role and goal, the audience, important rules and boundaries, how to use the available tools, and what a good final answer looks like.
Strong system prompts explain the reasoning behind rules, not just the rules. A model that understands why it should escalate refunds above a certain amount will handle edge cases better than one that only knows the number.
Keep it as short as it can be while still being complete. Rarely needed knowledge can live in files or skills the agent loads on demand, which keeps every turn's context lean.
You are a support agent for an accounting app. Answer only from the help center articles provided by the search tool. If a customer reports a billing error, collect the invoice number and hand off to a human.
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