I share I did write up an algorithm for it at some point I think it is lost in a git comment someplace. I’ll put together a pseudo/go code this week.

Super simple:

Making a reply:

1. If yarn has one use that. (Maybe do collision check?)
   
2. Make hash of twt raw no truncation.
   
3. Check local cache for shortest without collision
   
   • in SQL: select len(subject) where head_full_hash like subject || '%'
     

Threading:

1. Get full hash of head twt
   
2. Search for twts
   
   • in SQL: head_full_hash like subject || '%' and created_on > head_timestamp
     

The assumption being replies will be for the most recent head. If replying to an older one it will use a longer hash.