Currently if you just write "lbryian tip 10", the bot doesn't reply or give any hints to the user about having to include the tip username. It should handle the error and reply back with the proper syntax for tipping.
The response in the twitter log is:
{"message":" ","stack":"TypeError: Cannot read property '0' of null\n at Parser. (/home/ubuntu/twitter-tipbot/bin/tipbot.js:142:34)\n at emitOne (events.js:116:13)\n at Parser.emit (events.js:211:7)\n at Parser.receive (/home/ubuntu/twitter-tipbot/node_modules/twitter/lib/parser.js:58:16)\n at IncomingMessage. (/home/ubuntu/twitter-tipbot/node_modules/twitter/lib/twitter.js:284:14)\n at emitOne (events.js:121:20)\n at IncomingMessage.emit (events.js:211:7)\n at addChunk (_stream_readable.js:263:12)\n at readableAddChunk (_stream_readable.js:250:11)\n at IncomingMessage.Readable.push (_stream_readable.js:208:10)","source":{"created_at":"Mon Apr 30 17:54:36 +0000 2018","id":991012959278288900,"id_str":"991012959278288898","text":"@ICTman1076 @lbryio @LBC_TipBot Let's try that again:\n\n@LBC_TipBot lbryian tip 10","display_text_range":[32,81],"source":"<a href="http://twitter.com\" rel="nofollow">Twitter Web Client","truncated":false,"in_reply_to_status_id":991011660776132600,"in_reply_to_status_id_str":"991011660776132608","in_reply_to_user_id":58914498,"in_reply_to_user_id_str":"58914498","in_reply_to_screen_name":"TomZarebczan","user":{"id":58914498,"id_str":"58914498","name":"Thomas Zarebczan 📚","screen_name":"TomZarebczan","location":"USA","url":"http://lbry.io/get","description":"Community and Quality Manager at LBRY, Cryptocurrency enthusiast, miner and overall tech geek","translator_type":"none","protected":false,"verified":false,"followers_count":1702,"friends_count":629,"listed_count":80,"favourites_count":13370,"statuses_count":7452,"created_at":"Tue Jul 21 20:42:08 +0000 2009","utc_offset":-14400,"time_zone":"Eastern Time (US & Canada)","geo_enabled":true,"lang":"en","contributors_enabled":false,"is_translator":false,"profile_background_color":"000000","profile_background_image_url":"http://abs.twimg.com/images/themes/theme1/bg.png","profile_background_image_url_https":"https://abs.twimg.com/images/themes/theme1/bg.png","profile_background_tile":false,"profile_link_color":"19CF86","profile_sidebar_border_color":"000000","profile_sidebar_fill_color":"000000","profile_text_color":"000000","profile_use_background_image":false,"profile_image_url":"http://pbs.twimg.com/profile_images/826278270085668864/0bkDxxJy_normal.jpg","profile_image_url_https":"https://pbs.twimg.com/profile_images/826278270085668864/0bkDxxJy_normal.jpg","profile_banner_url":"https://pbs.twimg.com/profile_banners/58914498/1520005836","default_profile":false,"default_profile_image":false,"following":null,"follow_request_sent":null,"notifications":null},"geo":null,"coordinates":null,"place":null,"contributors":null,"is_quote_status":false,"quote_count":0,"reply_count":0,"retweet_count":0,"favorite_count":0,"entities":{"hashtags":[],"urls":[],"user_mentions":[{"screen_name":"ICTman1076","name":"ICTman1076 🛡","id":2404934239,"id_str":"2404934239","indices":[0,11]},{"screen_name":"LBRYio","name":"LBRY","id":2863324024,"id_str":"2863324024","indices":[12,19]},{"screen_name":"LBC_TipBot","name":"LBC_TipBot","id":968503155465113600,"id_str":"968503155465113600","indices":[20,31]},{"screen_name":"LBC_TipBot","name":"LBC_TipBot","id":968503155465113600,"id_str":"968503155465113600","indices":[55,66]}],"symbols":[]},"favorited":false,"retweeted":false,"filter_level":"low","lang":"en","timestamp_ms":"1525110876279"},"level":"error","timestamp":"2018-04-30T17:54:36.574Z"}