Skills

Key Points

Skills extend an agent's "way of doing things" for you
Persist conventions/rules; AI auto-follows, killing re-teaching fatigue
One Markdown file; auto-activate or explicit call; share via Git
1 Skill = 1 concern, ~10/project, no confidential info

What Are Skills

Skills are a mechanism to extend an AI coding agent's "way of doing things" for yourself. Register project-specific conventions, repetitive tasks, and internal rules as a Skill, and the AI always follows them. Similar features exist in Claude Code, Codex, Cursor (this article centers on Claude Skills, organizing the common idea).

The Problem Skills Solve

Do you write the same preamble to AI every time?

"Commit messages in English, Conventional Commits format"
"Tests with Vitest, in a describe/it hierarchy"
"When refactoring, first list the impact range"

Persisting these as a Skill makes the AI auto-follow next time. "Re-teaching fatigue" disappears.

Skill Structure

A Skill can basically be defined in one Markdown file:

---
name: e2e-test-writer
description: |
  Style guide for writing E2E tests with Vitest + Playwright.
  File naming, describe hierarchy, data cleanup.
---

# Naming
- 1 feature 1 file
- File name: feature-name.e2e.ts

# describe hierarchy
- Top: feature name
- 2nd: user-operation sequence
...