def _num_token_from_messages()

in aoai/token_count_utils.py [0:0]

• 32 lines of code
• 11 McCabe index (conditional complexity)

def _num_token_from_messages(messages: Union[List, Dict], model="gpt-3.5-turbo-0613"):
    """Return the number of tokens used by a list of messages.

    retrieved from https://github.com/openai/openai-cookbook/blob/main/examples/How_to_count_tokens_with_tiktoken.ipynb/
    """
    if isinstance(messages, dict):
        messages = [messages]

    if "gpt-4o" in model:
        encoding = tiktoken.get_encoding("o200k_base")      
    else:
        encoding = tiktoken.get_encoding("cl100k_base")

    if model == "gpt-3.5-turbo-0301":
        tokens_per_message = 4  # every message follows <|start|>{role/name}\n{content}<|end|>\n
        tokens_per_name = -1  # if there's a name, the role is omitted
    else:
        tokens_per_message = 3
        tokens_per_name = 1
        
    num_tokens = 0
    for message in messages:
        num_tokens += tokens_per_message
        for key, value in message.items():
            if value is None:
                continue

            # function calls
            if not isinstance(value, str):
                try:
                    value = json.dumps(value)
                except TypeError:
                    logger.warning(
                        f"Value {value} is not a string and cannot be converted to json. It is a type: {type(value)} Skipping."
                    )
                    continue

            num_tokens += len(encoding.encode(value))
            if key == "name":
                num_tokens += tokens_per_name
    num_tokens += 3  # every reply is primed with <|start|>assistant<|message|>
    return num_tokens