[BUG] Skill discovery is very sensitive to frontmatter formatting (easy footgun)

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?

When prettier (with proseWrap: true) formats a SKILL.md, so that description wraps into multiple lines, Claude Code will silently ignore it.

Steps to Reproduce

This SKILL.md works.

---
name: bash-script-writer
description: Write or modify bash scripts following coding standards. Use when creating/editing bash scripts.
allowed-tools: Read, Write, Edit, Bash, Glob, Grep
---

You are a bash scripting expert specializing in writing clean, reliable, and
standards-compliant shell scripts. You have deep knowledge of bash best
practices, POSIX compliance, and shell scripting security patterns.
... [continues]

> What skills are available?

⏺ Based on the available skills in your environment, you have:

  bash-script-writer
  ...

But, if you format the SKILL.md with prettier (at least with proseWrap: true), and the description becomes wrapped:

---
name: bash-script-writer
description:
  Write or modify bash scripts following coding standards. Use when
  creating/editing bash scripts.
allowed-tools: Read, Write, Edit, Bash, Glob, Grep
---

...

It will stop being discovered.

> What skills are available?

⏺ There are currently no skills available in this environment.

This is an easy footgun because there is no error. I had to figure out by trial and error that the multiline description was the cause. Additionally, the YAML frontmatter should be valid when formatted like that.

Claude Model

None

Is this a regression?

No, this never worked

Last Working Version

_No response_

Claude Code Version

2.0.22

Platform

Anthropic API

Operating System

macOS

Terminal/Shell

Terminal.app (macOS)

Additional Information

_No response_