AI engineering glossary · Prompt context engineering
What is system prompt?
System prompt (also called System message): A message placed at the start of a conversation that sets the model's role, rules, tone and limits for every later turn. Developers write it once, and end users usually never see it. It is the main place to say what the assistant should and should not do.
System prompt: an example
A bank app's system prompt says: 'You are a support assistant for a savings bank in India. Answer only about accounts and cards. Never give investment advice.'
Related terms
More Prompt context engineering terms
- Task decomposition
- Template variable
- Thinking budget
- Token budget
- Token counting
- Token pricing
- Tool choice
- Tool description
Where you learn it
System prompt is part of the AI Engineering Program, which teaches it with notes, a hands-on lab and an exam. The first lesson is free.