@ai-sdk/provider/src/language-model/v2/language-model-v2-response-metadata.ts

export interface LanguageModelV2ResponseMetadata {
  /**
   * ID for the generated response, if the provider sends one.
   */
  id?: string;

  /**
   * Timestamp for the start of the generated response, if the provider sends one.
   */
  timestamp?: Date;

  /**
   * The ID of the response model that was used to generate the response, if the provider sends one.
   */
  modelId?: string;
}