Glossary
What is system prompt?
The standing instruction an assistant follows before it sees your message.
Every assistant runs with a hidden instruction that sets its role, tone and limits. Your message is appended to it rather than replacing it.
This is why the same question can get different answers from two products built on the same model: the system prompt differs.
It also consumes context. A long system prompt leaves less room for the documents you send.
In practice
An assistant that keeps refusing to give a direct recommendation is usually following a system prompt, not being cautious about your question.
Common questions
- What does system prompt mean in one sentence?
- The standing instruction an assistant follows before it sees your message.
- Why does system prompt matter when you use Claude or ChatGPT?
- It also consumes context. A long system prompt leaves less room for the documents you send.
- Can you give an example of system prompt?
- An assistant that keeps refusing to give a direct recommendation is usually following a system prompt, not being cautious about your question.
Related terms
- Prompt engineeringWriting the instruction so the model does what you meant.
- Context windowThe amount of text an AI assistant can hold in mind during a single conversation.
- Prompt injectionText inside a document that tries to give the AI instructions instead of information.
- Glossary indexEvery AI context term, defined in plain language.
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