How to Build a Claude Code Skill from Scratch

Skills enable Claude to retain expertise across sessions via slash commands, eliminating repetitive explanations of workflows and preferences. A skill is a directory containing SKILL.md file with structured instructions that activate on command, stored in ~/.claude/skills/. SKILL.md requires Trigger, Description, and Instructions sections; Examples and Constraints are optional but improve task accuracy significantly. Building a skill involves creating a directory, writing SKILL.md with clear exp