Support ephemeral execution for dotnet tool run similar to npx, docker, and uv

[JonDouglas]

Is your feature request related to a problem? Please describe.

In the AI-world, MCPs are becoming popular as a paradigm to share prompts, tools, and resources with a client. These are often run through package managers or docker environments in temporary fashion.

Describe the solution you'd like

Many ecosystems are using tools like npx, docker, uv, in various ways, but mostly in isolated, temporary environments where it downloads the dependency into an ephemeral environment, runs the thing, and then the environment is torn down

dotnet tool run could simply just support this by default if it isn't specified in the scope of a local environment where it would look for a local tool instead. Or a parameter to specify this is --ephermeral/temporary is fine too.

Additional context

https://github.com/modelcontextprotocol/servers

[Redth]

It's also worth contemplating a similar short-hand for this like node has with npx being a package runner.

dotnet tool run --temp could be simplified to dnx or dntx.

[richlander]

I think there are definitely some missing scenarios here. It would be good to see some documented, from other ecosystems and/or fake .NET ones.

Docker doesn't strike me as another ecosystem in the way npx is. I think the way to use both Node and .NET in Docker is well understood at this point and folks are successful using it in both weird and wonderful ways.

"temporary" is a good goal. "secure" is not. We're not in the business of providing secure environments, but relying on other systems to do that. We should avoid creating an experience that is as convenient and attractive as curl | sh.