No, a JSON schema provided via GuidedDecodingParams (e.g., using the json argument) is not automatically added to the prompt. The schema is only used to guide the model’s output structure, not to inform the model via the prompt text. The description field in a Pydantic schema (or JSON schema) is not injected into the prompt either; it is used for schema validation and documentation, not for prompt engineering or model guidance. You must manually include any schema details or descriptions you want the model to see in the prompt itself. See docs example and protocol source.
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