If you look at the commit history, they started work on this the Saturday before announcement, so about 2 days. There are references to design docs so it was in the works for some amount of time, but the implementation was from scratch (unless they falsified the timestamps for some reason).
That's what I didn't understand about the acquisitions/partnerships that came out of the various claws. It's a fairly simple concept, and people were doing it before this but it just wasn't a meme. With AI you can easily build a claw in a weekend with maybe a hundred bucks worth of tokens. How do I know?
Lol you think these github repos just materialize as is? They probably did all the iteration and development internally and then ported it over to a github repo and made it public afterwards