Yes, on the hosted side (agents platform): full sessions come with VAD and turn-taking handled - we set them up and tune them for your use case, so that is the closest thing to conversation in a box. If you run your own orchestration, the gateway is just the routing layer and turn-taking stays in your framework - in our own stack we run Pipecat's Smart Turn in-process and tune the commit threshold on real calls. We also share our benchmarks here: https://benchmarks.speko.ai/turntaking

On fast dumb models answering while a smarter one takes over: we are experimenting with exactly that split - a small fast model holds the conversation while a larger one works behind it. Today it runs as two pinned routes, not one packaged API. Most turns in a phone call do not need a frontier model, and the fastest models on our LLM board are all small, so this is where routing earns its keep. We publish benchmarks on LLMs here: https://benchmarks.speko.ai/llm