extraKnownMarketplaces + enabledPlugins in project settings never prompts user to install

Summary

The docs for "Configure team marketplaces" state:

When team members trust the repository folder, Claude Code prompts them to install these marketplaces and plugins.

This does not happen. Configuring extraKnownMarketplaces and enabledPlugins in a project's .claude/settings.json does not trigger any prompt to install the marketplace or its plugins when a user opens the repository for the first time (or any subsequent time).

Reproduction

1. Create a project .claude/settings.json with:

``json
{
"extraKnownMarketplaces": {
"my-marketplace": {
"source": {
"source": "github",
"repo": "owner/plugin-repo"
}
}
},
"enabledPlugins": {
"my-plugin@my-marketplace": true
}
}
``

1. Commit and push this to a repository
2. Have a user (or yourself) clone the repo and run claude in it
3. Trust the project folder when prompted
4. Result: No prompt to install the marketplace or plugin. The plugin is not available. Skills do not load.

The marketplace does appear in ~/.claude/plugins/known_marketplaces.json and the plugin cache is populated, but installed_plugins.json is never updated and skills are not invocable.

Expected Behavior

After trusting the project folder, Claude Code should prompt the user to install the marketplace and the plugins listed in enabledPlugins, as documented.

Impact

This breaks the primary team distribution mechanism for plugins. The documented workflow for rolling out plugins across a team via project configuration does not function. Users must manually run /plugin marketplace add and /plugin install in every repo, which defeats the purpose of the project-level configuration.

Environment

• Claude Code CLI (latest)
• macOS
• Tested across 12+ repositories with identical configuration, none trigger the install prompt