Skill tool: tab-completed short skill name fails with 'Unknown skill' when invoked mid-message

Summary

When a user tab-completes a skill name in the prompt bar (e.g. /skill-validation-workflow), Claude Code inserts the short name without the plugin namespace. If that skill reference appears mid-message (rather than as a standalone slash command at the start of a new prompt), Claude invokes Skill("skill-validation-workflow") - which fails with Unknown skill: skill-validation-workflow because the namespace prefix is required.

Steps to reproduce

1. In a message, type /skill-va
2. Tab-complete to /skill-validation-workflow (or any namespaced plugin skill)
3. The prompt bar shows: ...up /skill-validation-workflow
4. Submit the message
5. Claude attempts Skill("skill-validation-workflow") - fails with Unknown skill

Expected behaviour

One of:

• Tab-complete inserts the fully-qualified name: /toast-skills-toolkit:skill-validation-workflow
• OR: the Skill tool resolves short names to their namespaced form using the available skills list

Actual behaviour

Unknown skill: skill-validation-workflow error. The skill works fine when invoked as a standalone slash command at the start of a new prompt (e.g. /toast-skills-toolkit:skill-validation-workflow), because that path does namespace resolution. Mid-message tab-complete does not.

Environment

• Claude Code CLI
• Plugin: toast-skills-toolkit (private marketplace)
• Skill: skill-validation-workflow
• The short name skill-validation-workflow is unambiguous in the installed plugin set

Workaround

Type the full namespaced form manually: /toast-skills-toolkit:skill-validation-workflow. This works but defeats the purpose of tab-complete for plugin skills with long namespace prefixes.

Impact

Every tab-completed plugin skill invoked mid-message silently fails. The user has done the right thing (used tab-complete), but the resulting Skill() call is missing its namespace.