You'll noticeTier: how much it should matter to you
3Useful: my rating, 1 to 5
2Signal: worth watching, 1 to 5
PluginsArea: what it touches
ImprovementsKind: in v2.1.323,
ImprovementsSection of the release
What
A plugin is an add-on package for Claude Code. Some plugins set which agent (a configured assistant with its own instructions) a session uses by default. When your default agent comes from a plugin like this, Claude Code now shows a high-priority notice at startup saying that a plugin's agent setting is deprecated and will stop applying in a future release. To keep that agent as your default, set agent in your own settings or pass --agent when you start Claude Code.
Plugin diagnostics also gained new hints for:
A plugin that sets the default agent, as above.
An invalid range for the Claude Code versions a plugin supports, with an example such as ">=2.1.0".
An enabledPlugins entry written as a list of versions. That does not turn the plugin on; only the value true enables a marketplace plugin.
Why
If you rely on a plugin to choose your agent, this warns you ahead of time that it will stop working, so you can move the choice into your own settings.
One source agreesOne thing we can check says the same as this entry.
Anthropic's release notes agreeFixed plugins with a version list in enabledPlugins staying off with no message: /plugin and claude plugin list now say why
