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Claude with Skills

Exercise 01: Build Your First Skill

Goal

Create a skill named explain-code that asks Claude to explain a piece of code in plain language, as if talking to someone who does not know the programming language.

Requirements

Your skill must:

  1. Have a valid name field: explain-code (lowercase, hyphens only, matches the directory name)
  2. Have a description field that includes at least two or three trigger keywords so Claude auto-invokes it reliably
  3. Have a body with clear steps telling Claude what to do

What to put in the body

Think through what Claude needs to do this well:

  • What code? Claude needs to know which code to explain. The body should tell Claude to read the file or code currently being discussed, or the last file mentioned in the conversation.
  • For what audience? The skill is for someone unfamiliar with the language. The body should say that explicitly.
  • What depth? The body should specify: overall purpose, main data flow, any non-obvious logic. It should also say what to skip — do not over-explain parts that are obvious from naming.

Hints

  • The description drives auto-invocation. A user typing “explain this code to me” or “walk me through this” should trigger the skill. Include those phrases as guidance in the description.
  • The body should guide Claude to check what language the code is written in — the explanation style differs between a bash script and a React component.
  • Use an analogy only if it genuinely helps. Do not force one.

Validation

  1. Create the skill file at: ~/.claude/skills/explain-code/SKILL.md
  2. Open Claude Code in any project that has code you want to understand
  3. Test auto-invocation: type “explain this code to me” or “walk me through this function” and check that the skill activates
  4. Test direct invocation: type /explain-code and verify it works
  5. Check the output quality: is it in plain language? Does it cover the three required areas (purpose, data flow, non-obvious logic)?

Solution

A reference solution is in solutions/01-explain-code/SKILL.md. Try writing your own version first — there is no single correct answer, and your description keywords should reflect how you naturally ask for explanations.