Rules & guardrails
How are rules and guardrails different from a system prompt?
A system prompt sets who the agent is and how it behaves every turn. Rules and guardrails are enforced boundaries on what it can actually do. One steers; the other constrains.
Rules and guardrails are the standing limits around an agent: the policy it must follow and the permissions it is allowed, applied to every run regardless of what the user asks in the moment. An agent that can act on the world needs them, because the cost of a wrong action is higher than the cost of a wrong sentence.
It is easy to lump these together, but they do different jobs. A system prompt sets who the agent is and how it should behave, and it is in play on every turn. Rules and guardrails are enforced boundaries: which tools the agent may call, what it must validate first, and which actions a human has to sign off on. One steers; the other constrains.