Policy-as-Code Gate

Problem

When the governance rules live inside the system prompt or are hard-coded in the agent, every policy change becomes a prompt edit followed by a redeploy, and the compliance officers responsible for the rules cannot read, audit, or change them without going through engineering. Natural-language rules embedded in the prompt also have no signed version, no machine-evaluable contract with the action that actually fired, and no independent audit trail an auditor can replay. Without an external, machine-readable policy surface, compliance and engineering are bound to the same release cycle and the rules become unauditable.

Solution

Maintain policies as code (OPA/Rego, Cedar, or equivalent) in a repository owned by compliance, optionally generated by a policy compiler that translates prose policy documents into the rule language. Before any tool dispatch, the agent emits a structured action proposal (tool, arguments, caller context, retrieved data fingerprints) to an external policy decision point. The engine returns allow, deny, or allow-with-obligations together with a policy hash and rule id. The agent dispatches the tool only on allow; on deny the agent surfaces the rule id to the user or escalates. Policies are versioned, signed, and ship through a separate pipeline from the agent. Evaluation results are logged with the policy hash so any decision can be re-checked against the exact rule version that fired.

When to use

• Governance rules are owned by a compliance, legal, or security function distinct from agent engineering.
• Policies change more often than the agent or model.
• Auditors require a signed, replayable rule version for each agent action.
• The action surface is non-trivial and contains operations that vary in risk.