System Prompt
The hidden instructions sent to a language model before any user input, defining its role, rules and behaviour.
In detail
The system prompt is the instruction set the developer sends to the model to define its persona, constraints, output format and rules. It runs ahead of any user message and is treated as more authoritative than user input by most models. A typical system prompt for a customer service agent might cover the assistant's name, the tone, the products it knows about, what it must never do (give financial advice, share competitor info) and the structured output schema for handoffs.
Why it matters for Australian business
The system prompt is where most production AI deployments live or die. A weak system prompt produces inconsistent output, jailbreaks easily and leaks information. A strong system prompt is treated like a config file: versioned, reviewed, tested against adversarial inputs. For Australian businesses the system prompt is also where compliance language sits, for example reminding the model to recommend licensed advisors instead of giving direct legal or medical advice.