Numeric skill name breaks slash command autocomplete

Description

A skill with a purely numeric name field (e.g., name: 3000) in its SKILL.md frontmatter breaks the slash command autocomplete dropdown. The autocomplete renders garbled text (skill names concatenated directly into descriptions with no separator) and can cause crashes under certain conditions.

Reproduction

1. Create a project skill with a numeric name:

mkdir -p .claude/skills/3000

.claude/skills/3000/SKILL.md:

---
name: 3000
description: Kill any process on port 3000 and start the Next.js dev server
---

Kill whatever is running on port 3000 and start the dev server fresh.

1. Restart Claude Code
2. Type / in the prompt

Expected: Clean autocomplete dropdown with skill names and descriptions properly separated
Actual: Garbled autocomplete — names and descriptions concatenated (e.g., /croEvaluate and develop pricing models... instead of /cro + "Evaluate and develop pricing models...")

Key findings

• Renaming the skill from 3000 to kill3k (non-numeric) immediately fixes the issue
• The bug affects ALL skills in the autocomplete, not just the numeric one
• Global skills (~/.claude/skills/) render correctly — only project-level skills are garbled
• Confirmed via binary search: with 19 project skills, isolating the single numeric-named skill as the cause
• Can also cause full crashes in some circumstances

Environment

• Claude Code version: 2.1.42
• OS: macOS (Darwin 25.3.0, Apple Silicon)
• Shell: zsh

Workaround

Rename the skill to use a non-numeric name (e.g., kill3k instead of 3000).