diff --git a/telegram/Command.cs b/telegram/Command.cs
index 9909933..08fe97d 100644
--- a/telegram/Command.cs
+++ b/telegram/Command.cs
@@ -1,7 +1,6 @@
 using System;
 using System.Collections.Generic;
 using System.Linq;
-using NeoSmart.Unicode;
 using TdLib;
 using static telegram.tgcli;
 using static telegram.Util;
@@ -10,26 +9,26 @@ namespace telegram
 {
     public abstract class Command
     {
-        public string Trigger;
-        public string Shortcut;
-        public string Description;
-        public string Syntax;
-        public int ParamCount;
+        public string trigger;
+        public string shortcut;
+        public string description;
+        public string syntax;
+        public int paramCount;
         public abstract void Handler(List<string> inputParams);
 
         protected Command(string trigger, string shortcut, string description, string syntax, int paramCount)
         {
-            Trigger = trigger;
-            Shortcut = shortcut;
-            Description = description;
-            ParamCount = paramCount;
-            Syntax = syntax;
+            this.trigger = trigger;
+            this.shortcut = shortcut;
+            this.description = description;
+            this.paramCount = paramCount;
+            this.syntax = syntax;
         }
     }
 
     public static class CommandManager
     {
-        public static List<Command> Commands = new List<Command>
+        public static readonly List<Command> Commands = new List<Command>
         {
             new ClearCommand(),
             new CloseCommand(),
@@ -57,25 +56,27 @@ namespace telegram
         {
             var split = input.Split(" ").ToList();
             var trigger = split.First();
-            var command = Commands.Find(p => p.Trigger == trigger || p.Shortcut == trigger);
+            var command = Commands.Find(p => p.trigger == trigger || p.shortcut == trigger);
             if (command == null)
             {
-                //TODO Console.WriteLine("do something");
+                lock(@lock)
+                    messageQueue.Add($"{Ansi.Red}[tgcli] Invalid command. Check /help for all available commands.");
                 return;
             }
 
             split.RemoveAt(0);
-            if (command.ParamCount == -1)
+            if (command.paramCount == -1)
             {
                 command.Handler(split);
             }
-            else if (split.Count == command.ParamCount)
+            else if (split.Count == command.paramCount)
             {
                 command.Handler(split);
             }
             else
             {
-                //TODO Console.WriteLine("do something");
+                lock(@lock)
+                    messageQueue.Add($"{Ansi.Red}[tgcli] Invalid command syntax. Check /help for more information.");
             }
         }
     }
@@ -88,8 +89,11 @@ namespace telegram
 
         public override void Handler(List<string> inputParams)
         {
-            if (inputParams.Count == 0)
-                return; //TODO do something
+            if (inputParams.Count == 0){
+                lock(@lock)
+                    messageQueue.Add($"{Ansi.Red}[tgcli] Invalid command syntax. Check /help for more information.");
+                return;
+            }
             var query = inputParams.Aggregate((current, param) => current + " " + param).Trim();
             var chatId = SearchChatId(query);
             if (chatId == 0) return;
@@ -162,7 +166,12 @@ namespace telegram
         public override void Handler(List<string> inputParams)
         {
             var chat = GetChatByUsernameGlobal(inputParams[0]);
-            if (chat == null) return; //TODO do something
+            if (chat == null)
+            {
+                lock(@lock)
+                    messageQueue.Add($"{Ansi.Red}[tgcli] User not found. Try /s <query> to find valid usernames.");
+                return;
+            }
 
             currentChatId = 0;
             currentChatUserId = 0;
@@ -230,9 +239,7 @@ namespace telegram
 
         public override void Handler(List<string> _)
         {
-            if (currentChatId == 0)
-                return; //TODO do something
-            if (GetChat(currentChatId).Type is TdApi.ChatType.ChatTypeSecret type)
+            if (currentChatId != 0 && GetChat(currentChatId).Type is TdApi.ChatType.ChatTypeSecret type)
             {
                 CloseSecretChat(type.SecretChatId);
                 DeleteChatHistory(currentChatId);
@@ -240,7 +247,8 @@ namespace telegram
             }
             else
             {
-                //TODO do something
+                lock(@lock)
+                    messageQueue.Add($"{Ansi.Red}[tgcli] No secret chat selected, cannot continue.");
             }
         }
     }
@@ -256,9 +264,18 @@ namespace telegram
             var userId = GetUserIdByUsername(inputParams[0]);
 
             if (userId == 0)
-                return; //TODO do something
+            {
+                lock(@lock)
+                    messageQueue.Add($"{Ansi.Red}[tgcli] User not found. Try /s <query> to find valid usernames.");
+                return;
+            }
+
             if (GetSecretChats().Count(p => ((TdApi.ChatType.ChatTypeSecret) p.Type).UserId == userId) > 0)
-                return; //TODO do something
+            {
+                lock (@lock)
+                    messageQueue.Add($"{Ansi.Red}[tgcli] You already have a secret chat with the specified user.");
+                return;
+            }
 
             var chat = CreateSecretChat(userId);
             CommandManager.HandleCommand("osd " + chat.Id);
@@ -276,12 +293,18 @@ namespace telegram
             var id = inputParams[0];
             if (!long.TryParse(id, out var chatId))
             {
-                return; //todo do something
+                lock (@lock)
+                    messageQueue.Add($"{Ansi.Red}[tgcli] Invalid chat id.");
+                return;
             }
 
             var chat = GetChat(chatId);
             if (chat == null)
-                return; //TODO do something
+            {
+                lock (@lock)
+                    messageQueue.Add($"{Ansi.Red}[tgcli] Invalid chat id.");
+                return;
+            }
 
             TdApi.SecretChat secChat;
             if (chat.Type is TdApi.ChatType.ChatTypeSecret secretChat)
@@ -293,7 +316,9 @@ namespace telegram
             }
             else
             {
-                return; //TODO do something
+                lock (@lock)
+                    messageQueue.Add($"{Ansi.Red}[tgcli] The specified chat isn't a secret chat.");
+                return;
             }
 
             chat.Title = TruncateString(chat.Title, 20);
@@ -361,11 +386,17 @@ namespace telegram
             var query = inputParams.Aggregate((current, param) => current + " " + param).Trim();
             var userId = SearchUserInChats(query);
             if (userId == 0 || query.Length == 0)
-                return; //TODO do something;
+            {
+                lock (@lock)
+                    messageQueue.Add($"{Ansi.Red}[tgcli] No matching chat found.");
+                return;
+            }
             var chat = GetSecretChats().Find(p => ((TdApi.ChatType.ChatTypeSecret) p.Type).UserId == userId);
             if (chat == null)
             {
-                return; //TODO do something
+                lock (@lock)
+                    messageQueue.Add($"{Ansi.Red}[tgcli] No matching secret chat found.");
+                return;
             }
 
             TdApi.SecretChat secChat;
@@ -378,7 +409,9 @@ namespace telegram
             }
             else
             {
-                return; //TODO do something
+                lock (@lock)
+                    messageQueue.Add($"{Ansi.Red}[tgcli] No matching secret chat found. (this error should be impossible to produce)");
+                return;
             }
 
             chat.Title = TruncateString(chat.Title, 20);
@@ -443,7 +476,12 @@ namespace telegram
 
         public override void Handler(List<string> inputParams)
         {
-            if (currentChatId == 0) return; //TODO: do something
+            if (currentChatId == 0)
+            {
+                lock (@lock)
+                    messageQueue.Add($"{Ansi.Red}[tgcli] No open chat, cannot continue.");
+                return;
+            }
             MarkUnread(currentChatId);
             CommandManager.HandleCommand("c");
         }
@@ -457,7 +495,12 @@ namespace telegram
 
         public override void Handler(List<string> inputParams)
         {
-            if (currentChatId == 0) return; //TODO: do something
+            if (currentChatId == 0)
+            {
+                lock (@lock)
+                    messageQueue.Add($"{Ansi.Red}[tgcli] No open chat, cannot continue.");
+                return;
+            }
 
             currentChatId = 0;
             currentChatUserId = 0;
@@ -486,7 +529,12 @@ namespace telegram
 
         public override void Handler(List<string> inputParams)
         {
-            if (currentChatId == 0) return; //TODO: do something
+            if (currentChatId == 0)
+            {
+                lock (@lock)
+                    messageQueue.Add($"{Ansi.Red}[tgcli] No open chat, cannot continue.");
+                return;
+            }
 
             var history = inputParams.Count == 1 && int.TryParse(inputParams[0], out var limit)
                 ? GetHistory(currentChatId, limit)
@@ -589,7 +637,11 @@ namespace telegram
         public override void Handler(List<string> inputParams)
         {
             if (inputParams.Count == 0)
-                return; //TODO do something
+            {
+                lock (@lock)
+                    messageQueue.Add($"{Ansi.Red}[tgcli] Invalid syntax, check /help for more information.");
+                return;
+            }
 
             var query = inputParams.Aggregate((current, param) => current + " " + param).Trim();
 
@@ -619,6 +671,7 @@ namespace telegram
 
         public override void Handler(List<string> inputParams)
         {
+            /*
             var query = inputParams[0];
 
             var chat = GetChatByUsernameGlobal(query);
@@ -628,7 +681,11 @@ namespace telegram
                 //TODO implement when TDLib 1.6 is released
             }
             else
-                return; //TODO do something
+            {
+                lock (@lock)
+                    messageQueue.Add($"{Ansi.Red}[tgcli] Username does not refer to a user.");
+            }
+            */
         }
     }
 
@@ -665,12 +722,12 @@ namespace telegram
                 messageQueue.Add($"{Ansi.Yellow}[tgcli] Listing {CommandManager.Commands.Count} commands:");
                 CommandManager.Commands.ForEach(command =>
                 {
-                    var commandText = $"/{command.Trigger}";
-                    if (!string.IsNullOrWhiteSpace(command.Syntax))
-                        commandText += $" {command.Syntax}";
-                    commandText += $": {command.Description}";
-                    if (!string.IsNullOrWhiteSpace(command.Shortcut))
-                        commandText += $" ({command.Shortcut})";
+                    var commandText = $"/{command.trigger}";
+                    if (!string.IsNullOrWhiteSpace(command.syntax))
+                        commandText += $" {command.syntax}";
+                    commandText += $": {command.description}";
+                    if (!string.IsNullOrWhiteSpace(command.shortcut))
+                        commandText += $" ({command.shortcut})";
 
                     messageQueue.Add($"{Ansi.Yellow}{commandText}");
                 });
@@ -710,24 +767,39 @@ namespace telegram
 
                 var message = inputParams.Aggregate((current, param) => current + " " + param).Trim();
 
-                if (currentChatId == 0) return; //TODO do something
+                if (currentChatId == 0)
+                {
+                    lock (@lock)
+                        messageQueue.Add($"{Ansi.Red}[tgcli] No open chat, cannot continue.");
+                    return;
+                }
 
                 if (lastMessage == null)
                 {
                     //try to find last message
                     var history = GetHistory(currentChatId, 50);
                     var last = history.LastOrDefault(p => p.IsOutgoing);
-                    if (last == null) return; //TODO do something
+                    if (last == null)
+                    {
+                        lock (@lock)
+                            messageQueue.Add($"{Ansi.Red}[tgcli] No message to edit found, cannot continue.");
+                        return;
+                    }
                     lastMessage = last;
                 }
 
                 if (string.IsNullOrWhiteSpace(message))
+                {
+                    lock (@lock)
+                        messageQueue.Add($"{Ansi.Red}[tgcli] No message specified, cannot continue.");
                     return;
+                }
                 EditMessage(message, lastMessage);
             }
             catch
             {
-                //TODO do something
+                lock (@lock)
+                    messageQueue.Add($"{Ansi.Red}[tgcli] Unknown error editing message.");
             }
         }
     }
@@ -744,7 +816,9 @@ namespace telegram
             {
                 if (inputParams.Count < 2)
                 {
-                    return; //TODO do something
+                    lock (@lock)
+                        messageQueue.Add($"{Ansi.Red}[tgcli] Invalid syntax, check /help for more information.");
+                    return;
                 }
 
                 var history = GetHistory(currentChatId, 50);
@@ -755,18 +829,26 @@ namespace telegram
 
                 if (!parsed || string.IsNullOrWhiteSpace(message) || history.Count < offset)
                 {
-                    return; //TODO do something
+                    lock (@lock)
+                        messageQueue.Add($"{Ansi.Red}Invalid syntax, check /help for more information.");
+                    return;
                 }
 
                 var replyMessage = history[offset - 1];
 
-                if (currentChatId == 0) return; //TODO do something
+                if (currentChatId == 0)
+                {
+                    lock (@lock)
+                        messageQueue.Add($"{Ansi.Red}[tgcli] No open chat, cannot continue.");
+                    return;
+                }
 
                 SendMessage(message, currentChatId, replyMessage.Id);
             }
             catch
             {
-                //TODO do something
+                lock (@lock)
+                    messageQueue.Add($"{Ansi.Red}[tgcli] Unknown error sending message.");
             }
         }
     }
diff --git a/telegram/Util.cs b/telegram/Util.cs
index 84f30c0..ea7745c 100644
--- a/telegram/Util.cs
+++ b/telegram/Util.cs
@@ -269,7 +269,6 @@ namespace telegram
         public static void ClearCurrentConsoleLine()
         {
             Console.Write("\u001b[2K\r");
-            //TODO is there a better solution?
 
             //Console.SetCursorPosition(0, Console.WindowHeight);
             //Console.Write(new string(' ', Console.WindowWidth));
diff --git a/telegram/tgcli.cs b/telegram/tgcli.cs
index 7c6f7e9..b663353 100644
--- a/telegram/tgcli.cs
+++ b/telegram/tgcli.cs
@@ -14,7 +14,6 @@ namespace telegram
 {
     /*
      * TODO:
-     * waaay more error messages instead of just doing nothing or crashing (search for TODOs and "do something")
      * mute,unmute chats
      * photo & document download & show externally
      * publish AUR package
@@ -22,6 +21,8 @@ namespace telegram
      * ref: http://www.lihaoyi.com/post/BuildyourownCommandLinewithANSIescapecodes.html#cursor-navigation
      * ref: https://en.wikipedia.org/wiki/ANSI_escape_code#Escape_sequences
      * refactor everything
+     * re-evaluate ClearCurrentConsoleLine function
+     * When TDLib 1.6 is released: implement contacts
      */
 
     // ReSharper disable once InconsistentNaming
@@ -175,7 +176,6 @@ namespace telegram
                     var chat = update.SecretChat;
                     switch (chat.State)
                     {
-                        //TODO: send notifs here!
                         case Td.TdApi.SecretChatState.SecretChatStateClosed _:
                             lock (@lock)
                                 messageQueue.Add($"{Ansi.Red}[tgcli] Secret chat with {chat.Id} was closed.");