System Prompt
A system prompt is a high-priority instruction block sent to a language model before user messages, defining the assistant's role, tone, allowed topics, output format, and operational rules. It persists across the conversation and shapes how subsequent inputs are interpreted. Systems often use it to inject identity, safety policies, available tools, and domain context for an agent.
Definition
A system prompt is a high-priority instruction block sent to a language model before user messages, defining the assistant's role, tone, allowed topics, output format, and operational rules. It persists across the conversation and shapes how subsequent inputs are interpreted. Systems often use it to inject identity, safety policies, available tools, and domain context for an agent.
Examples
- 'You are a SQL assistant. Only output queries for the public schema.'
- Defining a refusal policy for medical advice before any user turn.
- Listing available function-calling tools and when to invoke each one.
Related terms
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Frequently asked
- What is System Prompt?
- A system prompt is a high-priority instruction block sent to a language model before user messages, defining the assistant's role, tone, allowed topics, output format, and operational rules. It persists across the conversation and shapes how subsequent inputs are interpreted. Systems often use it to inject identity, safety policies, available tools, and domain context for an agent.
- How is System Prompt used in practice?
- System Prompt is commonly used in scenarios such as: 'You are a SQL assistant. Only output queries for the public schema.'; Defining a refusal policy for medical advice before any user turn.; Listing available function-calling tools and when to invoke each one..
- How does yno.ai support System Prompt?
- yno.ai uses System Prompt to power its AI agents, which combine planning, tool use, and dynamic context to handle multi-step tasks.
- What other concepts are related to System Prompt?
- System Prompt relates to Prompt Engineering, System Instructions, Agentic AI, Dynamic Context. Each links to its own glossary page below.