Plugin installation now checks if a plugin is already installed before attempting reinstallation. If a plugin with the same name and scope already exists, a clear message is shown: Plugin '<name>' is already installed (scope: <scope>).
Evidence
Plugin duplicate check (search for "is already installed") — CLK at line ~229155
Strings lifted out of the shipped bundle, so the claim above can be checked against them.
How sure we are
One source agreesOne thing we can check says the same as this entry.
Anthropic's release notes agreeplugin install on an already-installed plugin now installs any missing dependencies instead of stopping at "already installed"
