For official documentation, see the Anthropic Claude Code docs. MCP specifications are available at modelcontextprotocol.io.
Claude Code custom skills let you execute complex workflows with a single command. They work like macros, but with a critical difference — the AI understands the procedure and adapts flexibly to different situations.
For instance, saying “Buy this on Amazon,” “Send a LINE message,” or “Reserve a restaurant” triggers a fully automated workflow. In this article, I explain how Claude Code custom skills work and showcase the skills I use daily.
How Claude Code Custom Skills Work
Each skill is a SKILL.md Markdown file placed under .claude/skills/. The file contains step-by-step instructions for the AI — essentially a procedure document written in natural language.
Therefore, you do not need programming knowledge to create Claude Code custom skills. Just describe the steps in plain English (or any language), and Claude Code reads the instructions, combines MCP tools, and executes the task. Moreover, since these are not rigid scripts, the AI can handle errors and skip unnecessary steps automatically.
📊 Skill Execution Flow
SKILL.md Structure
# Skill Name
## Triggers
Natural language phrases that activate this skill
## Prerequisites
Required MCP servers, login states, etc.
## Procedure
1. Step 1
2. Step 2
3. ...
## Precautions
Things to avoid, confirmation requirements, etc.Real-World Claude Code Custom Skills
Amazon Purchase Skill
Trigger: “Buy on Amazon” / “Order from Amazon”
Uses k-chrome MCP to operate Amazon.co.jp — from product search to cart addition and order confirmation. Since it uses the existing browser session, no login is needed. However, it always pauses for user confirmation before placing the order to prevent unintended purchases.
LINE Message Skill
Trigger: “Send a LINE message” / “Message [name] on LINE”
Operates the LINE PC desktop app via Windows MCP. The workflow involves screenshot capture, coordinate detection, clicking the search bar, typing the recipient’s name, opening the chat, and entering the message. Confirmation is always required before sending.
Restaurant Reservation Skill
Trigger: “Find a restaurant” / “Make a reservation”
Searches restaurants on review sites and Google Maps, evaluates reviews, ratings, and availability, then proposes candidates. Furthermore, it can complete the reservation through the booking site. The skill improves over time by referencing user preferences stored in memory.
Travel Booking Skill
Trigger: “Book a flight” / “Should I take the train or fly?”
Searches flights via Kiwi.com MCP and operates airline websites through the browser. It handles round-trip search, comparison, booking, and check-in. Additionally, it can compare flight versus train options on time and cost to recommend the optimal choice.
Invoice Skill
Trigger: “Submit the invoice” / “Do this month’s invoice”
Automates the entire invoice workflow: Excel template editing, PDF conversion, B2B platform upload, and email notification. What used to take 30 minutes of monthly routine work now completes in 5 minutes, thanks to Claude Code custom skills.
Four Tips for Skill Design
- Use natural language triggers — Register multiple conversational phrases, not command-style syntax
- Include confirmation checkpoints — Always require approval before irreversible actions like purchases or messages
- Document fallback procedures — Describe alternative approaches when the primary MCP is unavailable
- Prioritize security — Manual password entry and read-only financial access are non-negotiable rules
Following these principles ensures your Claude Code custom skills are both safe and reliable. As a result, you can confidently automate everyday tasks that previously required manual attention.
Next Up
The next article covers Memory. You will learn how Claude Code’s memory system retains context across conversations and how to use it effectively.
