Domain Signal

Overview

domain classifies the request topic family. Define domain rules under routing.signals.domains.

The detector uses the classifier configured under global.model_catalog.modules.classifier and its model bindings under global.model_catalog.system.

Key Advantages

• Routes by topic without hard-coding every phrase into keyword lists.
• Keeps domain policy reusable across multiple decisions.
• Supports stable category families that are easy to audit.
• Works well as the first learned signal in a routing graph.

What Problem Does It Solve?

Keyword routing breaks down once prompts are paraphrased or when domain boundaries are broader than a handful of phrases.

domain solves that by mapping topic classification into named routing signals that decisions can compose with complexity, safety, or plugin logic.

When to Use

Use domain when:

• routes are organized around topic families
• lexical matching is too brittle
• the same topic boundary should feed several decisions
• you want a stable learned classifier before adding more specialized signals

Configuration

routing:
  signals:
    domains:
      - name: business
        description: Business and management related queries.
        mmlu_categories: [business]
      - name: law
        description: Legal questions and law-related topics.
        mmlu_categories: [law]
      - name: psychology
        description: Psychology and mental health topics.
        mmlu_categories: [psychology]
      - name: health
        description: Health and medical information queries.
        mmlu_categories: [health]
      - name: other
        description: General fallback traffic.
        mmlu_categories: [other]

Keep domain names stable because decisions reference those names directly.

Dependencies and Limitations

Domain classification uses the configured classifier module and processes the request text. Treat other as a fallback, and re-evaluate labels and thresholds when the classifier changes. See a complete example: config/fragments/signal/domain/mmlu.yaml.