Skill tool fails to parse markdown with backticks and special characters

Bug Report: Skill Tool Parsing Error with Special Characters in Markdown

Summary

The Skill tool fails to parse skill files that contain certain markdown patterns with backticks and special characters, incorrectly attempting to execute extracted patterns as bash commands.

Environment

• Claude Code CLI
• macOS (Darwin 24.6.0)
• Multiple skills affected

Error Symptoms

When invoking skills using the Skill tool, it fails with errors like:

Bash command failed for pattern "!`, `": [stderr]
(eval):1: command not found: ,

or

Bash command failed for pattern "!` | `": [stderr]
(eval):1: parse error near `|'

Root Cause

The Skill tool's YAML/markdown parser appears to extract patterns from markdown content (not just YAML frontmatter) and incorrectly attempts to execute them as bash commands.

Affected Skills

1. branch-and-commit: Error pattern "!, "
2. commit-notation: Error pattern "! | "

Reproduction Steps

Test Case 1: branch-and-commit skill

# From Claude Code
/branch-and-commit
# or programmatically:
<invoke name="Skill">
<parameter name="skill">branch-and-commit