📝 add SKILL file

[ianardee]

Description

Types of changes

• Docs change / refactoring / dependency upgrade
• Bug fix (non-breaking change which fixes an issue)
• New feature (non-breaking change which adds functionality)
• Breaking change (fix or feature that would cause existing functionality to change)
• Requires a change to the official Guide documentation.

[sebastianMindee]

I'd add $ to class members, even though they are not written in most uses, because in my experience, LLMs tend to interpret them as the JSON return keys.