A JSON schema enforces that an action field must be one of [approve, reject, escalate]. The schema enforcement passes (the model returns a valid action value), but the model is escalating too many cases that should be rejected. What is this failure category?
Answer: A semantic failure — the schema enforces structure, not semantic correctness of values
Schema enforcement guarantees structure — the response has the right keys and values within the allowed enum. It does not guarantee semantic correctness — the model may choose 'escalate' when 'reject' was correct, and the schema has no way to catch this. This is a semantic failure: the values are structurally valid but semantically wrong. It requires better criteria in the prompt (D is partially correct, but A and B are both wrong for different reasons). Schema weights (A) are not a valid JSON Schema concept. The enum constraint is being honored (B is wrong).