If you are talking about Aigents Language, then service discovery and versioning are not defined at language level — but in can be extended on top of the language. See example of existing interaction logs: http://aigents.com/test/aigents_turing_test.html

If you are talking about SingularityNET, there should be JSON-RPC protocol with Service discovery and versioning provided as well — later this summer, stay tuned for news: https://blog.singularitynet.io/