System prompt

A system prompt is a hidden instruction the company running AI search gives it before you ever type anything.

In a little more detail

It sets tone, rules and limits. You cannot see or change it, and it is one reason two AI search engines answer the same question differently.

Related terms

Prompt: A prompt is whatever you type to AI search: the question, the instruction, or both.
AI search: AI search is a program you ask questions in plain language, like ChatGPT, Claude, Gemini or Perplexity, which writes you an answer instead of handing you a list of links.

See it on your own site

The scan reads your site the way AI search does and reports where you stand on this and sixteen other checks.