Function buildResponsesUsage

packages/openai-base/src/usage.ts:87–118

(
  usage: OpenAI.Responses.ResponseUsage | undefined | null,
)

 * zeroed totals.
 */
export function buildResponsesUsage(
  usage: OpenAI.Responses.ResponseUsage | undefined | null,
): TokenUsage | undefined {
  if (!usage) return undefined

  const result = buildBaseUsage({
    promptTokens: usage.input_tokens || 0,
    completionTokens: usage.output_tokens || 0,
    totalTokens: usage.total_tokens || 0,
  })

  // Despite the SDK types marking these required, they can be undefined at runtime.
  // eslint-disable-next-line @typescript-eslint/no-unnecessary-condition
  const cachedTokens = usage.input_tokens_details?.cached_tokens
  if (cachedTokens && cachedTokens > 0) {
    result.promptTokensDetails = {
      ...result.promptTokensDetails,
      cachedTokens,
    }
  }

  // eslint-disable-next-line @typescript-eslint/no-unnecessary-condition
  const reasoningTokens = usage.output_tokens_details?.reasoning_tokens
  if (reasoningTokens && reasoningTokens > 0) {
    result.completionTokensDetails = {
      ...result.completionTokensDetails,
      reasoningTokens,
    }
  }

  return result
}

/**
 * Build normalized {@link TokenUsage} from an OpenAI Images API `usage` object.