Verified80% confidenceSolutionExact time
Setting additionalProperties: false in a JSON Schema rejects any extra fields not explicitly declared in the schema, eliminating the possibility of the model inventing additional fields.
4
Sources
80%
Confidence
Long-term
Relevance
7/20/2026
First Seen
Sources
Related Claims
UnverifiedSome APIs enable constrained decoding to force the model to output JSON conforming to the Schema, while others only use the Schema as a hint, so enums can greatly reduce but not completely eliminate the probability of the model fabricating values.79% similarUnverifiedStructured output (JSON schema constraints) can only eliminate the single error of malformed output; other types of errors (such as semantic classification errors) are unaffected.75% similarUnverifiedThis patch ensures that the additionalProperties: false field in JSON Schema is correctly preserved when passing tool definitions to xAI models.75% similarUnverifiedOpenAI's Structured Outputs require additionalProperties: false in the JSON Schema and that all fields be listed in required, with optional fields expressed as nullable.75% similarUnverifiedWhen the string content sent by the model is unambiguous, valid JSON, parsing it directly carries no risk and is a low-cost fix for the schema validation degradation problem.74% similar
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