usageMetadata

Usage metadata for a message, such as token counts. This is a standard representation of token usage that is consistent across models. Example:

{
    "input_tokens": 350,
    "output_tokens": 240,
    "total_tokens": 590,
    "input_token_details": {
        "audio": 10,
        "cache_creation": 200,
        "cache_read": 100,
    },
    "output_token_details": {
        "audio": 10,
        "reasoning": 200,
    },
}

output_token_details.

• Throws LangChainInvalidDataException: if the JSON field has an unexpected type (e.g. if the server responded with an unexpected value).