What problem does it solve? Building custom Claude Code Skills requires knowing the exact SKILL.md format, YAML frontmatter rules, and directory conventions, and mistakes in any of these prevent Claude from discovering or loading the skill. ## Core Features & Use Cases - Specification Reference: Documents the required name and description frontmatter fields, character limits, and formatting rules for valid SKILL.md files. - Progressive Disclosure Guidance: Explains the 3-level loading architecture (metadata, SKILL.md body, referenced files) so skills scale without context bloat. - Ready-to-Use Templates: Provides basic, intermediate, and advanced skill templates plus real-world examples for documentation and code generation skills. - Use Case: You want to build a custom skill that generates API documentation for your team. Use this Skill to scaffold the directory, write a compliant SKILL.md with proper frontmatter, and organize scripts and resources correctly. ## Quick Start Ask Claude to create a new skill called 'api-docs-generator' with proper frontmatter and directory structure using the skill-builder guidelines.