system
A chat on subreddit /r/wallstreetbets
human
Algos are overfitting to 'trade talks are going well' since there is a positive reaction each time. So they long the market milliseconds after the tweet is out.  
 There are probably dozens of sentiment and key word detection bots eyeing trumps acc.

gpt
So basically Trump has figured out the phrase 'trade talks going well' sends algos buying. 
  
 He's beat the system!  Algos hate him!