Here it is https://docs.vapi.ai/calls/call-features#call-control-feature and there is more messages type to it which you can check out from here named as

ClientInboundMessgaes

https://api.vapi.ai/api-json# https://cdn.discordapp.com/attachments/1211484481848873020/1326987673226969161/Screenshot_2025-01-10_at_00.24.39.png?ex=67816d13&is=67801b93&hm=4ce361345c07cf43edd2eca2e2533a879942fa9501433dbc79576949c03e96ba&