completion_cost_details is the per-category USD breakdown of completion_cost.

Categories mirror completion_token_details. Returned only when the COMPLETION_COST_DETAILS field is requested.

completion_token_details is the per-category breakdown of completion_tokens.

Category names are model-specific (for example reasoning, audio). Returned only when the COMPLETION_TOKEN_DETAILS field is requested.

prompt_cost_details is the per-category USD breakdown of prompt_cost.

Categories mirror prompt_token_details. Returned only when the PROMPT_COST_DETAILS field is requested.

prompt_token_details is the per-category breakdown of prompt_tokens.

Category names are model-specific (for example cache_read, cache_write). Returned only when the PROMPT_TOKEN_DETAILS field is requested.