[BUG] Plugins not loading

Preflight Checklist

• [x] I have searched existing issues and this hasn't been reported yet
• [x] This is a single bug report (please file separate reports for different bugs)
• [x] I am using the latest version of Claude Code

What's Wrong?

The Cowork plugin marketplace UI fails to load on Windows — all tabs (By Anthropic & Partners, Personal) remain stuck on skeleton/placeholder tiles indefinitely and never display plugin content.

Root cause confirmed via DNS lookup: plugins.claude.ai does not resolve.

nslookup plugins.claude.ai
Server: UnKnown
Address: 192.168.101.1
*** UnKnown can't find plugins.claude.ai: Non-existent domain

While claude.ai and api.anthropic.com both resolve correctly, plugins.claude.ai returns Non-existent domain, preventing the marketplace from loading.

Plugins installed via CLI (claude plugin install sales@knowledge-work-plugins) report successful installation (scope: user), but slash commands do not appear in Cowork conversations, suggesting the VM cannot reach plugins.claude.ai to activate installed plugins either.

Steps to reproduce:

1. Open Claude Desktop on Windows
2. Open Cowork and click Browse Plugins
3. Observe all tabs stuck on skeleton loaders
4. Run nslookup plugins.claude.ai — returns Non-existent domain

Expected behavior: Marketplace loads and displays available plugins. Installed plugins activate slash commands in Cowork conversations.

Actual behavior: Marketplace never loads. Slash commands do not appear even after successful CLI installation.

Environment:

• OS: Windows
• Claude Desktop with Cowork
• Related open issues: #26951, #26450

What Should Happen?

Here's the expected behavior section:

---

The Cowork plugin marketplace should load successfully and display available plugins in all tabs (By Anthropic & Partners, Personal, Your Organization).

Specifically:

• plugins.claude.ai should resolve via DNS so the marketplace UI can fetch and display plugin content
• Plugins installed via CLI (claude plugin install sales@knowledge-work-plugins) should appear in the Personal tab and be active in Cowork conversations
• Slash commands (e.g. /sales:call-prep) should be available after successful plugin installation
• The marketplace should not remain stuck on skeleton/placeholder tiles indefinitely

Error Messages/Logs

Steps to Reproduce

Here's the steps to reproduce section:

---

1. Install Claude Desktop on Windows and open Cowork
2. Click Browse Plugins — observe all tabs stuck on skeleton/placeholder tiles indefinitely
3. Run the following DNS lookup in PowerShell to confirm root cause:

nslookup plugins.claude.ai

Result:

Server:  UnKnown
Address:  192.168.101.1
*** UnKnown can't find plugins.claude.ai: Non-existent domain

1. Confirm other Anthropic domains resolve correctly:

nslookup claude.ai
nslookup api.anthropic.com

Both return valid IP addresses (e.g. 160.79.104.10), confirming the issue is specific to plugins.claude.ai

1. Install a plugin via CLI to confirm installation succeeds but plugins remain inactive:

& "C:\Users\<username>\AppData\Roaming\Claude\claude-code\2.1.51\claude.exe" plugin marketplace add anthropics/knowledge-work-plugins
& "C:\Users\<username>\AppData\Roaming\Claude\claude-code\2.1.51\claude.exe" plugin install sales@knowledge-work-plugins

1. Open a Cowork conversation and type / — slash commands (e.g. /sales:call-prep) do not appear despite successful installation

Claude Model

Sonnet (default)

Is this a regression?

I don't know

Last Working Version

_No response_

Claude Code Version

2.1.51 (Claude Code)

Platform

Anthropic API

Operating System

Windows

Terminal/Shell

PowerShell

Additional Information

_No response_