[BUG] Cowork Customize panel has no "+" button to add marketplace or create plugin on Pro plan (macOS 1.3109.0)

Filed on behalf of a Claude Pro ($20/month) user — I am on a higher tier and cannot reproduce from my own account.

Preflight Checklist

• [x] I have searched existing issues and this hasn't been reported
• [x] This is a single bug report
• [x] I am using the latest version of Claude Code

What's Wrong?

On Cowork Desktop 1.3109.0 on macOS, a Claude Pro ($20/month) account has no UI affordance to add a third-party plugin marketplace or create/upload a personal plugin. Clicking Customize navigates directly to the Anthropic plugin directory. There is no "+" button, no "Add marketplace" action, and no "Create plugin" entry point anywhere in the Customize panel.

First-party Anthropic plugins (e.g. Finance) install without issue, so the plugin runtime itself is healthy. The gap is specifically in the UI surface for user-contributed content.

Related issues (#41653, #40475, #40600, #47347) describe backend failures after attempting to add a marketplace. This report is upstream of those: the user cannot reach the code path that would trigger those errors, because the entry-point UI is missing.

What Should Happen?

One of the following should be true, and clearly communicated to the user:

1. If adding marketplaces / creating plugins is a paid-tier feature, the Customize panel should show a locked/upsell state explaining the tier requirement. Today it gives no indication either way.
2. If it is available on Pro, the "+" button or equivalent action should be present.

Steps to Reproduce

1. Sign into Cowork Desktop with a Claude Pro ($20/month) account
2. Open Customize
3. Observe: lands on Anthropic plugin directory with no option to add a marketplace or create a personal plugin
4. Compare to documentation at code.claude.com/docs/en/plugin-marketplaces, which describes adding personal marketplaces as a supported workflow without mentioning a subscription requirement

Environment

• App: Cowork 1.3109.0 (35cbf6)
• Platform: macOS (MacBook Air, Apple Silicon)
• Plan: Claude Pro ($20/month)
• Works: Installing first-party Anthropic plugins (Finance confirmed)
• Fails: No UI affordance to add a marketplace or create a plugin

Question for the Team

Is the absence of these UI affordances on Pro:

• (a) intentional tier gating — in which case please document it on the pricing page and surface a clear upsell in the UI, or
• (b) a bug / incomplete rollout — in which case, is there a workaround or ETA?