[BUG] Skill autocomplete no longer filters by substring match (regression)

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?

Description

The slash command / skill autocomplete dropdown has regressed. Previously, typing /plan would filter the list to only skills whose names contain "plan". Now it shows unrelated skills that have no match with the typed query.

Expected Behavior (previous)

Typing /plan showed only matching skills:

• everything-claude-code:plan
• everything-claude-code:prp-plan
• everything-claude-code:multi-plan
• compose-multiplatform-patterns (matches "plat")

Actual Behavior (current)

Typing /plan shows a mix of matching and non-matching skills:

• plankton-code-quality (matches)
• seo ❌
• pptx ❌
• batch ❌
• blueprint ❌
• crosspost ❌
• agent-sort ❌
• golang-testing ❌ (highlighted/selected)
• claude-devfleet ❌
• golang-patterns ❌
• hipaa-compliance ❌
• product-capability ❌

Most items in the dropdown do not contain "plan" as a substring.

<img width="799" height="450" alt="Image" src="https://github.com/user-attachments/assets/9fa2755e-7cc2-42c0-9f48-f4df10f6fa45" />

What Should Happen?

1. Enable a plugin with many skills (e.g., everything-claude-code)
2. Type /plan in the prompt input
3. Observe the autocomplete dropdown

<img width="289" height="135" alt="Image" src="https://github.com/user-attachments/assets/21339def-6455-4872-a5a7-156cb2370bac" />

Error Messages/Logs

Steps to Reproduce

..

Claude Model

Sonnet (default)

Is this a regression?

Yes, this worked in a previous version

Last Working Version

_No response_

Claude Code Version

Claude 1.3883.0 (93ff6c) 2026-04-21T17:24:01.000Z

Platform

Anthropic API

Operating System

Windows

Terminal/Shell

Windows Terminal

Additional Information

_No response_