What Are Claude Code Skills?

Claude Code skills are reusable instruction sets that extend Claude's capabilities within the CLI. Think of them as specialized playbooks — when a task matches a skill's trigger, Claude follows a proven workflow instead of improvising.

The skill system lives in .claude/skills/ and gets loaded into context when relevant. The best skills encode hard-won patterns that would otherwise require repeated explanation.

Debugging: superpowers:systematic-debugging

This is the single most valuable skill for daily development. Instead of letting Claude guess at fixes, it enforces the scientific method:

1. Observe the failure (exact error, reproduction steps)
2. Form a hypothesis
3. Test the hypothesis with minimal changes
4. Verify the fix doesn't break anything else

The difference is dramatic. Without this skill, Claude might suggest three different fixes in sequence. With it, Claude investigates root causes before proposing changes.

Test-Driven Development: superpowers:test-driven-development

Forces the red-green-refactor cycle. Write the test first, watch it fail, then implement. Claude naturally wants to write implementation code — this skill redirects that energy into test specifications.

Best used when adding new features or fixing bugs where the expected behavior is clear but the implementation path isn't.

Brainstorming: superpowers:brainstorming

Prevents Claude from jumping straight to code. When you say "add feature X," this skill triggers a structured exploration of requirements, edge cases, and design options before any implementation begins.

The output is a clear spec that both you and Claude can reference during implementation.

Verification Before Completion

The superpowers:verification-before-completion skill solves a common problem: Claude claiming work is done before actually running the tests. This skill requires evidence — run the command, show the output, confirm it passes — before making any success claims.

Building Your Own Skills

The best skills encode your team's specific patterns. A skill file is just markdown with frontmatter:

---
name: my-skill
description: When to trigger this skill
---

Instructions Claude should follow...

Start by documenting the corrections you make most often. If you keep saying "don't mock the database" or "always run the linter," those are skills waiting to be written.

Conclusion

Skills transform Claude Code from a capable assistant into a disciplined collaborator. The investment in writing good skills pays compound interest across every session.