OpenAI GPT Model Selection and API Guide

from openai import OpenAI

client = OpenAI()  # reads OPENAI_API_KEY

completion = client.chat.completions.create(
    model="gpt-5",
    messages=[
        {"role": "system", "content": "You are a helpful assistant"},
        {"role": "user", "content": "Write a quicksort in Python"}
    ],
    temperature=0.7
)
print(completion.choices[0].message.content)

# Streaming
stream = client.chat.completions.create(
    model="gpt-5",
    messages=[{"role": "user", "content": "Write an article about AI"}],
    stream=True
)
for chunk in stream:
    if chunk.choices[0].delta.content:
        print(chunk.choices[0].delta.content, end="")