Standardize Your Work with Claude Skills
Summary — Key Takeaways from This Lesson
- Agent Skills are Claude extensions defined via a Markdown file called SKILL.md.
- Progressive Disclosure ensures that only the skills relevant to the current task are loaded on demand, keeping context consumption low.
- Each skill bundles together task knowledge, tool definitions, and scripts — allowing you to accumulate reusable templates.
- They are supported across Claude.ai, Claude Code, and the Claude Agent SDK, so you can use them regardless of environment.
- Once you template a repetitive task as a skill, the instruction cost for that task drops dramatically every time.
Contents (6)
What Are Agent Skills?
Agent Skills are extensions that allow Claude to load task-specific knowledge, tool definitions, and execution scripts all at once. If you write down "the tasks you always do in this project" as a skill, Claude will refer to that skill only when needed and act accordingly (Related article: How to Create Agent Skills).
Think of it as a way to turn a general-purpose Claude into a specialized agent with deep expertise in a specific domain.
Minimal Structure of a SKILL.md
Skills are defined in a Markdown file with a YAML frontmatter (SKILL.md).
---
name: api-conventions
description: 当社 REST API の設計規約
---
# API 規約
- URL パスは kebab-case
- JSON フィールドは camelCase
- エラーは { "error": { "code": "", "message": "" } } 形式
name: The identifier for the skill. description: The explanatory text Claude references when deciding which skill to use.
Write concrete instructions, rules, and code examples in the body.
What Is Progressive Disclosure?
The core design philosophy behind Agent Skills is Progressive Disclosure.
Even if you define 100 skills, Claude does not load all of them into the context window upfront.
It first references only each skill's name and description,
and then loads the full body of only the skills it determines are relevant to the current task.
This means that adding more skills does not inflate the context, minimizing the impact on processing cost and speed.
How to Create a Skill
- Set up a
.claude/skills/directory (or any skill folder of your choice) in your project. - Create a subfolder for each skill, and place a
SKILL.mdfile inside it. - Write the YAML frontmatter (
nameanddescription) and the body content inSKILL.md. - If needed, place scripts or configuration files in the same folder.
- Call the skill by specifying that skill folder from Claude Code or the API.
What Kinds of Work Is This Suited For?
- Applying coding conventions: No need to paste the same conventions on every code review.
- Unified writing style: Define tone and formatting rules as a skill.
- Internal process automation: Turn form submission procedures and templates into skills.
- Templatizing data analysis: Standardize "this data must always be preprocessed this way" as a skill.
Reference: Detailed Article
For real-world examples, step-by-step creation guides, and the common traits of well-designed skills, see "How to Create Agent Skills — The Basics and Templates in 5 Minutes".
