F4 Hallucination from missing knowledge

The answer states facts that are false or unsupported, usually because the model did not know.

How counterfix finds it

Judge: lists the factual claims and marks false or unsupported ones; with a source (see counterfix.context) it checks the answer against that text. SamplingCheck can also re-ask the model and flag answers that change.

Fixes it tries

In this order (a model profile can reorder them). Each one is kept only if it passes 2 of 3 re-runs.

Intervention	Change
add_source	Put the source text in the prompt and answer only from it
allow_unknown	Let the model say it does not know instead of guessing

When no fix verifies

• Add retrieval (pass the source text)
• Use a larger model
• Abstain