Function normalizeEngineError

src/utils/engineErrorHandler.ts:126–208

(
  error: unknown,
  provider: string,
  model: string
)

 * @returns A typed Error instance
 */
export function normalizeEngineError(
  error: unknown,
  provider: string,
  model: string
): Error {
  // If it's already one of our custom errors, return as-is
  if (
    error instanceof ModelNotFoundError ||
    error instanceof AuthenticationError ||
    error instanceof InsufficientCreditsError ||
    error instanceof RateLimitError ||
    error instanceof ServiceUnavailableError
  ) {
    return error;
  }

  const statusCode = getStatusCode(error);
  const message = extractErrorMessage(error);

  // Handle based on HTTP status codes
  switch (statusCode) {
    case 401:
      return new AuthenticationError(provider, message);

    case 402:
      return new InsufficientCreditsError(provider, message);

    case 404:
      // Could be model not found or endpoint not found
      if (isModelNotFoundMessage(message)) {
        return new ModelNotFoundError(model, provider, 404);
      }
      // Return generic error for other 404s
      return error instanceof Error ? error : new Error(message);

    case 429:
      const retryAfter = getRetryAfter(error);
      return new RateLimitError(provider, retryAfter, message);

    case 500:
    case 502:
    case 503:
    case 504:
      return new ServiceUnavailableError(provider, statusCode, message);
  }

  // Handle based on error message content
  if (statusCode === 400) {
    return error instanceof Error ? error : new Error(message);
  }

  if (isModelNotFoundMessage(message)) {
    return new ModelNotFoundError(model, provider, 404);
  }

  if (isInsufficientCreditsMessage(message)) {
    return new InsufficientCreditsError(provider, message);
  }