What
When a plugin can't load because its marketplace source isn't known during this session (it's not in known_marketplaces.json, or it's listed under extraKnownMarketplaces but unusable), Claude Code now shows a specific diagnostic explaining why, and tells you to run claude plugin marketplace add <path-or-repo> to fix it. Previously this failed silently or with a generic marketplace-not-found error.
Why
This saves you from guessing why a plugin silently didn't load, and points directly at the fix.
Names in the bundleclaude plugin marketplace add
The entry above is what we published on the day. These lines were added later, as Anthropic's own pages caught up, and they sit beside the original rather than replacing it.
Confirmed since
Anthropic's documentation has since written up claude plugin marketplace add, on Error reference.
For an imitating name, the marketplace's own error reads `Claude Code refuses this marketplace's name: it looks like one of Anthropic's own` instead. `claude plugin marketplace add` refuses any impersonating name with `Marketplace name imp…errors see the edit
Added since
A small documentation edit on Discover and install prebuilt plugins through marketplaces touched a line naming claude plugin marketplace add after this was published.
To add a marketplace from that list in your shell instead, run `claude plugin marketplace add` with the `--claudeai` flag and the name the list shows:discover-plugins see the edit
One source agreesOne thing we can check says the same as this entry.
Anthropic's documentation agrees
A small documentation edit on Discover and install prebuilt plugins through marketplaces touched a line naming claude plugin marketplace add…