[BUG] [Cowork UI does not show plugins installed from "claude-for-legal" marketplace — claude- prefix conflict

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?

Preflight Checklist

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

Environment

• OS: macOS (Apple Silicon)
• Claude Desktop: 1.8555.2 (a476c3) — 2026-05-22
• Claude Code CLI: 2.1.150

What's wrong?

Plugins installed from the anthropics/claude-for-legal marketplace via claude plugin install --cowork show as enabled in the CLI (claude plugin list --cowork) but do not appear in the Cowork desktop app UI under Plugins.

Steps to reproduce

1. claude plugin marketplace add anthropics/claude-for-legal --cowork
2. claude plugin install commercial-legal@claude-for-legal --cowork
3. Confirm install: claude plugin list --cowork → shows Status: ✔ enabled
4. Quit and reopen Claude desktop app
5. Open Cowork tab → Plugins panel
6. Plugin does not appear

Expected behavior

Installed and enabled plugins should be visible in the Cowork Plugins panel.

Actual behavior

Plugins are not visible in Cowork UI despite being listed as enabled in the CLI. The marketplace name starts with claude- which may be triggering the reserved prefix validation bug (#56246).

Additional context

Related to #56246 ([BUG] Plugin names starting with "claude-" silently fail). In this case the issue is at the marketplace level, not the plugin name level — the marketplace itself is named claude-for-legal which may cause the same server-side rejection.

What Should Happen?

Installed and enabled plugins should be visible in the Cowork Plugins panel.

Error Messages/Logs

Steps to Reproduce

1. Run: claude plugin marketplace add anthropics/claude-for-legal --cowork
2. Run: claude plugin install commercial-legal@claude-for-legal --cowork
3. Confirm install: claude plugin list --cowork → shows Status: ✔ enabled
4. Quit Claude desktop app completely (Dock → right click → Quit)
5. Reopen Claude desktop app
6. Open Cowork tab → click Plugins panel
7. Plugin does not appear in the list

Claude Model

Sonnet (default)

Is this a regression?

No, this never worked

Last Working Version

Unknown — this is a fresh install, no previous version to compare.

Claude Code Version

Claude Desktop: 1.8555.2 (a476c3) — 2026-05-22 Claude Code CLI: 2.1.150 macOS (Apple Silicon)

Platform

Anthropic API

Operating System

macOS

Terminal/Shell

Terminal.app (macOS)

Additional Information

_No response_