Ardour (https://ardour.org/) has an MCP server.

The most recent release of Logic Pro has an Intelligent Assistant and also Splice released a new DAW called Splice Create that is agent-native.

Yes. http://Tonos.music is the one I've been working on. Timber is a competitor that got $5m in funding from Adobe.

We seek to complement the user by giving them access to a mix and master engineer, not replacing them like with Suno. We've got a booth at MONO sf this weekend at the Midway in SF, come find us! if you're on the fence, email me for a promo code to the conference!