No, the problem is that when logging in, the provider's website can provide an authentication shell command that OpenCode will send to the shell sight unseen, e

No, the problem is that when logging in, the provider's website can provide an authentication shell command that OpenCode will send to the shell sight unseen, even if it is "rm -rf /home". This "feature" is completely unnecessary for the agent to function as an agent, or even for authentication. It's not about it being the default, it's about it being there at all and being designed that way.