Output Policy

Status: DRAFT

1. Overview

Output policies are evaluated at the Output Interception point — after the LLM produces a response and before it is returned to the agent.

2. Evaluation Input

The policy engine receives an OutputContext (see Core Concepts §4.3).

3. Policy Scope

Output policies MAY inspect:

• The full response content
• Agent and session metadata

Output policies MUST NOT re-invoke the LLM. If a transformation requires generating new content, this must be handled by a configured fallback, not by the policy itself.

4. Supported Decisions

Decision	Permitted	Notes
allow	Yes
deny	Yes	Blocks the response from reaching the agent
redact	Yes	Applied to response content before delivery
transform	Yes	e.g. strip formatting, enforce tone
audit	Yes

5. Example: Rego Policy

Deny responses that contain content from a known blocked domain:

package aps.output

import future.keywords.if

blocked_domains := {"malicious-site.example", "phishing.example"}

default decision := "allow"

decision := "deny" if {
    some domain in blocked_domains
    contains(input.response.content, domain)
}

reason := "Response references a blocked domain."

6. Example: Runtime Rule (TypeScript)

Redact credit card numbers from model output:

import { OutputPolicy, OutputContext, PolicyDecision } from "@aps/core";

export class RedactCreditCardPolicy implements OutputPolicy {
  private readonly pattern = /\b(?:\d[ -]?){13,16}\b/;

  evaluate(context: OutputContext): PolicyDecision {
    if (!this.pattern.test(context.response.content)) {
      return { decision: "allow" };
    }
    return {
      decision: "redact",
      redactions: [
        {
          field: "response.content",
          strategy: "replace",
          replacement: "[REDACTED]",
          pattern: this.pattern.source,
        },
      ],
    };
  }
}