[DOCS] Add example for allowing only the official marketplace in `strictKnownMarketplaces`

Documentation Type

Unclear/confusing documentation

Documentation Location

https://code.claude.com/docs/en/settings and https://code.claude.com/docs/en/plugin-marketplaces

Section/Topic

settings#strictknownmarketplaces or plugin-marketplaces#common-configurations

Current Documentation

_No response_

What's Wrong or Missing?

The strictKnownMarketplaces documentation (plugin-marketplaces and settings reference) does not include an example for what is likely the most common enterprise use case: allowing only the official Anthropic marketplace while blocking everything else.

The "Common configurations" section shows:

• Empty array [] (complete lockdown)
• Custom org repos (acme-corp/approved-plugins)
• hostPattern for internal git servers

But it doesn't show how to reference the official marketplace (claude-plugins-official). The official marketplace repo name appears in the Reserved Names list, but there is no example connecting it to strictKnownMarketplaces.

Suggested Improvement

1. Add the below code as a "Common configuration" example in the plugin-marketplaces page, under the "Managed marketplace restrictions" section
2. Clarify in the empty array [] description that it blocks all marketplaces including the official Anthropic marketplace
3. Optionally, add a note that the official marketplace is not implicitly allowed — it must be explicitly listed if strictKnownMarketplaces is set

{
  "strictKnownMarketplaces": [
    {
      "source": "github",
      "repo": "anthropics/claude-plugins-official"
    }
  ]
}

Impact

Low - Minor confusion or inconvenience

Additional Context

Related:

• #34873 — strictKnownMarketplaces: [] blocks official marketplace
• #77709 — Add settings example: official marketplace only