response = client.chat.completions.create(
    model='gpt-4o',
    messages=[
        {'role': 'system', 'content': 'Extract information as JSON.'},
        {'role': 'user', 'content': 'Alice bought 3 items for $45.'}
    ],
    response_format={'type': 'json_object'}
)

tools = [{
    'type': 'function',
    'function': {
        'name': 'get_weather',
        'description': 'Get weather for a location',
        'parameters': {
            'type': 'object',
            'properties': {
                'location': {'type': 'string'},
                'units': {'type': 'string', 'enum': ['celsius', 'fahrenheit']}
            },
            'required': ['location']
        }
    }
}]

import json
try:
    data = json.loads(response.choices[0].message.content)
except json.JSONDecodeError:
    print("Invalid JSON — retry or fall back")

tool = {
    'type': 'function',
    'function': {
        'name': 'search_products',
        'description': 'Search products by keyword and price range',
        'parameters': {
            'type': 'object',
            'properties': {
                'query': {'type': 'string'},
                'max_price': {'type': 'number'}
            },
            'required': ['query']
        }
    }
}