System prompt advertises uninstallable Cowork skills as "available"

Summary

The Claude Code system prompt lists a large catalog of skills — small-business:*, finance:*, marketing:*, engineering:*, sales:*, legal:*, human-resources:*, productivity:*, product-management:*, design:*, operations:*, data:*, anthropic-skills:*, cowork-plugin-management:* — as "available for use with the Skill tool". None of these are present in the official marketplace (anthropics/claude-plugins-official) and none can be installed via claude plugin install. Invoking them with /<name> silently fails because there is nothing on disk to execute.

Repro

1. Open a fresh Claude Code session.
2. Look at the "Available skills" section the runtime injects into the system prompt — many Cowork-namespaced skills are listed.
3. claude plugin install small-business@claude-plugins-official → not found.
4. grep small-business ~/.claude/plugins/marketplaces/claude-plugins-official/.claude-plugin/marketplace.json → no results.
5. Try /small-business:invoice-chase (or any other) → nothing happens.

Expected

One of:

• Only list skills that are installed or installable from configured marketplaces, or
• Visually distinguish installed / installable / Cowork-only in the catalog and explain how to access Cowork-only ones, or
• Provide a user-level toggle to hide the Cowork promo catalog. The existing flags tengu_skills_dashboard_enabled and tengu_team_discovery are both already false in ~/.claude.json and have no effect on this listing.

Actual

A large promotional catalog of Cowork-only skills appears as "Available skills" with no way to install or disable it from the CLI, making it confusing which slash commands actually work. Users assume the listing reflects installable plugins.

Workaround

--bare mode silences the catalog but also disables hooks, auto-memory, CLAUDE.md auto-discovery and plugin sync — too aggressive for daily use.

Environment

• Claude Code 2.1.136
• Windows 11
• Marketplace: anthropics/claude-plugins-official
• Installed plugins: 9 (none of the listed Cowork skills among them)