NOT Decisions

Overview

Use config/decision/not/ when a route should match only if a risky or disallowed signal is absent.

NOT is the simplest exclusion rule in the decision catalog.

Key Advantages

• Makes negative policy explicit.
• Works well for safety gates and premium-route exclusions.
• Keeps exclusion logic in the route graph instead of hidden downstream.
• Makes audits easier because the denied signal is named directly.

What Problem Does It Solve?

Some routes should only run when a known risk signal is absent. If that exclusion is implicit, reviewers have to infer it from downstream behavior.

NOT solves that by putting the exclusion directly in the route definition.

When to Use

Use not/ when:

• known jailbreak or PII-bearing traffic must be excluded
• premium routes should stay away from unsafe inputs
• a conflicting signal must be absent before escalation

Configuration

Source fragment: config/decision/not/exclude-jailbreak.yaml

routing:
  decisions:
    - name: safe_only_route
      description: Match only when the known prompt-injection signal is absent.
      priority: 70
      rules:
        operator: NOT
        conditions:
          - type: jailbreak
            name: prompt_injection
      modelRefs:
        - model: qwen2.5:3b
          use_reasoning: false

Use NOT sparingly and keep the excluded signal explicit, otherwise the decision becomes hard to audit.