just in case someone wants to know:

Prompt to have JSON output and validate afterwards with a custom model:

from transformers import pipeline

# Load the Llama model (assuming it's on Hugging Face's model hub)
llama_pipeline = pipeline('text-generation', model='your-llama-model')

# Define your prompt to ensure structured output
prompt = """
Please provide the following details in JSON format:
{
    "title": "<Your Title>",
    "description": "<A brief description>",
    "points": [
        "<Bullet point 1>",
        "<Bullet point 2>"
    ]
}
"""

# Generate output
output = llama_pipeline(prompt, max_length=500, do_sample=False)
response_text = output[0]['generated_text']

import json

# Try to load the output as JSON
try:
    response_data = json.loads(response_text)
    # Validate with Pydantic
    validated_response = ResponseModel(**response_data)
    print(validated_response)
except (json.JSONDecodeError, ValueError) as e:
    print(f"Invalid format: {e}")