Why does setting the seed parameter not yield reproducible responses with OpenAI models?

Hello,

I followed the documentation to craft a script that uses the seed parameter in hopes of generating reproducible outputs. However, even with identical inputs and a set seed, both the "gpt-4-1106-preview" and "gpt-3.5-turbo" models are returning different results.

Am I misunderstanding how the seed parameter is supposed to work? Below is my code for reference:

PYTHONCopied
from openai import OpenAI
import difflib

# GPT_MODEL = "gpt-4-1106-preview"
GPT_MODEL = "gpt-3.5-turbo"
client = OpenAI(api_key='■■■■■■■■■■■■■■■■■■■■■■■■■■■■■■■■■■■■■■■■■■■U47cWLiN')

def get_chat_response(system_message: str, user_request: str, seed: int = None):
    messages = [
        {"role": "system", "content": system_message},
        {"role": "user", "content": user_request},
    ]

    response = client.chat.completions.create(
        model=GPT_MODEL,
        messages=messages,
        seed=seed,
        temperature=0.7
    )

    # print(response)

    response_content = response.choices[0].message.content
    system_fingerprint = response.system_fingerprint
    prompt_tokens = response.usage.prompt_tokens
    completion_tokens = (
            response.usage.total_tokens - response.usage.prompt_tokens
    )

    print(response_content+"\n")
    print(f"system_fingerprint:{system_fingerprint}\n")
    print(f"prompt_tokens:{prompt_tokens}\n")
    print(f"completion_tokens:{completion_tokens}\n")
    print("---------\n")
    return response_content

def compare_responses(previous_response: str, response: str):
    diff = difflib.Differ().compare(previous_response.splitlines(), response.splitlines())
    print('\n'.join(diff), end="")

def main():
    topic = "a happy journey to Mars"
    system_message = "You are a helpful assistant that generates short stories."
    user_request = f"Generate a short story about {topic}."

    seed = 12345

    response1 = get_chat_response(
        system_message=system_message, user_request=user_request, seed=seed,
    )

    response2 = get_chat_response(
        system_message=system_message, user_request=user_request, seed=seed,
    )

    compare_responses(response1, response2)

main()

I appreciate any insights or suggestions on achieving reproducibility with the seed parameter. Thanks!