I could experiment, of course, but the point of documentation is to avoid the need for reverse-engineering.
withDefaultArgs is described as
Configures default arguments for future commands.
If it were likeCMD, I would expect something more like "configures default arguments for the container's entrypoint, for use when the container is executed without explicit parameters".
Docker's own documentation describes CMD as "provide defaults for an executing container". Defaults for the container != defaults for commands.
the example
["-v", "--no-cache"]
seems more like something that would be added to aRUNdirective than to aCMDdirective.
So... is Dagger missing an equivalent for Dockerfile's CMD, or have I misinterpreted the documentation?