Plugin skills discoverable but not invocable via Skill tool

Description

Skills defined in skills/*/SKILL.md within a custom org plugin appear correctly in the Cowork slash command menu (under a "Plugin name" section). However, invoking them — either by clicking in the menu or typing /skill-name — returns:

Unknown skill: plugin-name:skill-name

The Skill tool cannot resolve plugin skills. Only anthropic-skills:* skills work via the Skill tool.

Reproduction

1. Create an org plugin with skills in skills/*/SKILL.md (standard structure, valid YAML frontmatter)
2. Deploy via Claude Team Plan admin as an org plugin
3. Open Cowork — skills appear in the / slash command menu under the plugin name
4. Click any skill or type /skill-name
5. Result: "Unknown skill: plugin-name:skill-name"

Expected behavior

Plugin skills that appear in the slash command menu should be invocable via the Skill tool, the same way anthropic-skills:* skills work.

Workaround

Add a skills table to the plugin's CLAUDE.md that maps trigger phrases to file paths. Claude reads the SKILL.md file directly via the Read tool when the Skill tool fails. This works but adds an unnecessary failure/retry step to every skill invocation.

Environment

• Cowork (claude.ai)
• Custom org plugin deployed via Claude Team Plan admin
• GitHub-hosted plugin repo
• Skills use standard skills/*/SKILL.md structure with YAML frontmatter

🤖 Generated with Claude Code