I setup an Avaliablity group and let the secondary as Read in Read Only Intent mode. I then wrote a small vbscript that should be sent to the secondary server but it did not. The query did run, but it was on the Primary server.
I did Select @@ServerName in the query as well as Profiler trace. Nothing touched the secondary. Direct access to it was turned off unless I changed it to Read Only for direct connections.
I expect the connection to be sent to the secondary server for the read. After that happens I would expect the Insert in my script to fail. I don't expect ApplicationIntent=ReadOnly to make my connection ReadOnly, but rather send me to the database that is readonly.