One-sentence description of what this skill does and when to use it (same as or concise version of frontmatter description). Required for Trae / simple-parser: first non-# line = skill description.

Skill Title

Constraint: Only use this skill when the user explicitly mentions "Pencil" (or the relevant context).

When to use this skill

• Use when the user asks to ...
• Use when ...
• Do NOT use when ...

Trigger phrases: "Pencil ...", "用 Pencil ...", ...

How to use this skill

1. Step one: ...
2. Step two: ...
3. Step three: ...