That seems very Ruby to me: sig { params(x: Integer).returns(String) } I can read it outloud: Signature is defined as: one parameter called x of type Inte

That seems very Ruby to me: sig { params(x: Integer).returns(String) } I can read it outloud: Signature is defined as: one parameter called x of type Integer and will return a String. Sorbet may have some warts, but the example you show is simple and easy to understand. The `sig` is as Ruby as you get IMO: class MyTest extend T::Sig end MyTest.method(:sig).source_location => ["...gem/ruby/3.3.4/gems/sorbet-runtime-0.5.11495/lib/types/sig.rb", 27] And when opening that file we can get something like: def sig(arg0=nil, &blk) T::Private::Methods.declare_sig(self, Kernel.caller_locations(1, 1)&.first, arg0, &blk) end I do agree about RBS being separate files that is something that can stop a coding flow.