We introduce CAScr, the first implementation
of Scribble (http://www.scribble.org, https://
nuscr.dev/) that relies on choreography automata,
for deadlock-free distributed programming. CAScr
supports the main theoretical results and construc-
tions in the related article. CAScr takes the popular
top-down approach to system development, based
on choreographic models, following the original
methodology of Scribble and multiparty session
types. The top-down approach enables correctness-
by-construction: a developer provides a global de-
scription for the whole communication protocol;
by projecting the global protocol, APIs are gen-
erated from local CFSMs, which ensure the safe
implementation of each participant. The theory
of choreography automata in the related article
guarantees deadlock freedom for the distributed
implementation of flexible global protocols. We
target web development, supporting in particular
the TypeScript programming language.