Slash command autocomplete missing skills from certain plugin namespaces

Description

Some skill plugin namespaces don't appear in the slash command autocomplete picker, while others work fine. The skills themselves still load and can be invoked, but they don't surface in autocomplete when typing /.

Steps to Reproduce

1. Open Claude Code (desktop app, Opus 4.6 1M)
2. Type /anthro in the input — no results appear for anthropic-skills:* skills
3. Type /code-review — the engineering:code-review skill appears correctly
4. Type /feature — nothing appears for anthropic-skills:feature-request-parser

Affected Namespaces

These namespaces do not appear in slash command autocomplete:

• anthropic-skills: (feature-request-parser, skill-creator, pdf, docx, xlsx, pptx)
• data: (analyze, write-query, explore-data, create-viz, build-dashboard, etc.)
• enterprise-search: (search, digest, knowledge-synthesis)

Working Namespaces

These do appear correctly:

• engineering: (code-review, debug, architecture, system-design, etc.)
• Local custom skills in ~/.claude/commands/ and ~/.claude/skills/

Expected Behavior

All registered skill namespaces should appear in slash command autocomplete when the user types a matching prefix.

Environment

• Claude Code desktop app (macOS)
• Model: Opus 4.6 (1M context)
• Date: 2026-04-03