Function accumulateUsage

src/services/api/claude.ts:2993–3038

(
  totalUsage: Readonly<NonNullableUsage>,
  messageUsage: Readonly<NonNullableUsage>,
)

 * Used to track cumulative usage across multiple assistant turns.
 */
export function accumulateUsage(
  totalUsage: Readonly<NonNullableUsage>,
  messageUsage: Readonly<NonNullableUsage>,
): NonNullableUsage {
  return {
    input_tokens: totalUsage.input_tokens + messageUsage.input_tokens,
    cache_creation_input_tokens:
      totalUsage.cache_creation_input_tokens +
      messageUsage.cache_creation_input_tokens,
    cache_read_input_tokens:
      totalUsage.cache_read_input_tokens + messageUsage.cache_read_input_tokens,
    output_tokens: totalUsage.output_tokens + messageUsage.output_tokens,
    server_tool_use: {
      web_search_requests:
        totalUsage.server_tool_use.web_search_requests +
        messageUsage.server_tool_use.web_search_requests,
      web_fetch_requests:
        totalUsage.server_tool_use.web_fetch_requests +
        messageUsage.server_tool_use.web_fetch_requests,
    },
    service_tier: messageUsage.service_tier, // Use the most recent service tier
    cache_creation: {
      ephemeral_1h_input_tokens:
        totalUsage.cache_creation.ephemeral_1h_input_tokens +
        messageUsage.cache_creation.ephemeral_1h_input_tokens,
      ephemeral_5m_input_tokens:
        totalUsage.cache_creation.ephemeral_5m_input_tokens +
        messageUsage.cache_creation.ephemeral_5m_input_tokens,
    },
    // See comment in updateUsage — field is not on NonNullableUsage to keep
    // the string out of external builds.
    ...(feature('CACHED_MICROCOMPACT')
      ? {
          cache_deleted_input_tokens:
            ((totalUsage as unknown as { cache_deleted_input_tokens?: number })
              .cache_deleted_input_tokens ?? 0) +
            ((
              messageUsage as unknown as { cache_deleted_input_tokens?: number }
            ).cache_deleted_input_tokens ?? 0),
        }
      : {}),
    inference_geo: messageUsage.inference_geo, // Use the most recent
    iterations: messageUsage.iterations, // Use the most recent
    speed: messageUsage.speed, // Use the most recent
  }
}

function isToolResultBlock(
  block: unknown,