The issue is that "prompt-based guardrails" are insufficient to ensure safety. The article emphasizes that system prompts can prevent an agent from fabricating shipping rates, delivery times, or reasons for delays. However, prompts serve only as a layer of soft guidance. An agent can still: Misinterpret data from APIs. Invoke the wrong tool. Misjudge the severity of an incident. Send inappropriate notifications. Execute a sequence of actions that is syntactically correct but violates business logic. Be influenced by malicious or unreliable input data. In other words, prompts should not be viewed as the primary control mechanism. Critical actions require safeguards such as API permissions, schema validation, policy engines, transaction limits, audit logs, and rollback mechanisms.
