Can you use JSON RPC error codes to implement retries?

Yes, absolutely. JSON RPC error codes can be used to implement retry logic. When a client receives an error code, it can check the code to determine whether a retry is appropriate. For example, a 'timeout' error might warrant a retry after a short delay, while a 'permission_denied' error might require the client to re-authenticate. Implementing exponential backoff is a good practice to avoid overwhelming the server during retries.