The --plugin-dir flag has been updated from accepting a single paths argument to being individually repeatable.
What changed:
Old: --plugin-dir <paths...> (space-separated paths in one argument)
New: --plugin-dir <path> (repeat the flag: --plugin-dir A --plugin-dir B)
Session-only plugins are now labeled as "Session-only plugins (--plugin-dir):" in the UI
The reserved marketplace name "inline" is used internally for --plugin-dir session plugins
Evidence
Repeatable plugin-dir flag (search for "Load plugins from a directory for this session only (repeatable: --plugin-dir A --plugin-dir B)")
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 agreeUpdated --plugin-dir to only accept one path to support subcommands — use repeated --plugin-dir for multiple directories
