Hallucination

Overview

hallucination is a route-local plugin for fact-checking and response-quality screening after the decision already matched.

Key Advantages

• Adds route-local hallucination checks without changing global defaults.
• Makes response actions explicit when factual confidence is low.
• Works well for retrieval-heavy or grounded-answer routes.

What Problem Does It Solve?

Some routes need extra scrutiny after the model answers, especially when they promise factual precision. hallucination lets those routes add response-time verification without forcing every route to pay the cost.

When to Use

• a route should fact-check or annotate responses
• grounded or tool-backed routes need extra response screening
• the route should warn or annotate instead of silently passing low-confidence answers

Configuration

Add the plugin under routing.decisions[].plugins:

plugins:
  - type: hallucination
    configuration:
      enabled: true
      use_nli: true
      hallucination_action: header
      unverified_factual_action: header
      include_hallucination_details: true

header preserves the model response and adds warning metadata. body adds a warning to the response body, while none records the result without changing the response.

The plugin depends on global.model_catalog.modules.hallucination_mitigation; use_nli: true also uses the configured explainer/NLI model. Model responses and supplied grounding context are processed by those modules. Detection can identify unsupported text, but it cannot establish truth without authoritative evidence.

See a complete example: config/fragments/plugin/hallucination/fact-check.yaml.