StructuredOutputs Schema Missing in Prompt [Unlike OpenAI API Default Behavior]

When using StructuredOutputs, I noticed that the model's outputs were nonsensical and didn't align with expectations. After debugging, I discovered that the output schema isn't included in the prompt, leaving the model unaware of its options and what it should generate. While developers could manually add the schema to the prompt, this isn't a common practice. For instance, OpenAI's API automatically includes the schema (easily verified by counting input prompt tokens), and I believe this behavior should be standard for all inference engines. I tested Ollama in three different ways, and all of them exhibited the same behavior. Below is the code to reproduce the issue: ```python import aiohttp from pydantic import BaseModel, Field from typing import Union, List, Literal from typing import Annotated class Action1(BaseModel): type: Literal["action1"] __doc__: str = "store in memory" class Action2(BaseModel): type: Literal["action2"] __doc__: str = "call someone" class Action3(BaseModel): type: Literal["action3"] __doc__: str = "move to a location" class Response(BaseModel): steps: Annotated[ List[Union[Action1, Action2, Action3]], Field(..., description='Sequence of steps to perform', discriminator='type') ] messages = [ {"role": "system", "content": "Decompose input request into sequence of steps. Possible steps are listed in the response schema."}, {"role": "user", "content": "I want to go to the park."}, ] payload = { "model": 'qwen2.5-coder:7b', "messages": messages, "stream": False, "options": {"temperature" : 0.0}, "format": Response.model_json_schema() } async def get_response(payload): async with aiohttp.ClientSession() as session: async with session.post('http://localhost:11434/api/chat', json=payload) as response: json_response = await response.json() raw_string = json_response['message']['content'] res = Response.model_validate_json(r…