Mastering Claude Code Skills: From Basics to Real‑World PPT Generation

Introduction

When using AI‑assisted programming, developers often repeat project specifications, lack guided processes for tasks such as PPT or Excel generation, and find it hard to standardize AI behavior across a team.

Repeatedly describing project standards and coding style.

AI lacks specialized workflow guidance for tasks like PPT or Excel.

Difficulty standardizing AI behavior in team collaboration.

Claude Code Skills encapsulate expert knowledge, standard operating procedures, and project conventions into reusable skill packages that Claude can load and execute automatically.

What is a Claude Code Skill?

Core definition

A Skill is a folder containing a SKILL.md file written in Markdown. The file holds structured instructions that tell Claude how to perform a specific class of tasks (e.g., writing Spring Boot code, generating PPT, analyzing data).

Key features

On‑demand loading : Claude first reads only the Skill’s name and description (about 30–50 tokens). If the context matches, the full instructions are loaded, avoiding token waste.

Cross‑platform reuse : The same Skill works in Claude Code CLI, the Claude.ai web UI, and the API.

Version control & team sharing : Store Skill folders under .claude/skills/ and manage them with Git.

Automatic triggering : Claude automatically matches conversation context and loads the appropriate Skill without manual specification.

Difference from related concepts

CLAUDE.md – project‑level global rules (background, coding standards) that are auto‑loaded each conversation.

Slash Commands – manual shortcuts like /deploy that users invoke explicitly.

Skills – domain‑specific expert knowledge and workflows, auto‑loaded by AI based on context.

Built‑in and community Skills

Official built‑in Skills

docx – create, edit, and analyze Word documents (.docx).

pptx – create, edit, and analyze PowerPoint presentations (.pptx).

xlsx – create, edit, and analyze Excel spreadsheets (supports formulas).

pdf – extract, merge, and fill PDF forms.

These skills use zero‑shot generation: Claude needs no extra training data to perform complex document operations.

Community contributions

canvas-design – generate posters, illustrations (PNG/PDF) based on design principles.

theme-factory – produce professional themes for slides, documents, or web apps.

spring-boot-review – conduct expert review of Spring Boot code.

jpa-patterns – provide JPA best‑practice patterns.

Installing and using Skills

Installation locations

Project level : <project root>/.claude/skills/ – available only to the current project, suitable for team‑specific standards.

User level : ~/.claude/skills/ – available to all projects, ideal for personal reusable skills.

Example:

# Copy the spring‑boot‑review skill folder into the project‑level directory
cp -r ./spring-boot-review /your-project/.claude/skills/

Repository: https://github.com/anthropics/skills

Usage modes

Automatic triggering (recommended)

During a normal conversation Claude detects intent and loads the matching Skill. Example: asking to analyze an Excel sales sheet loads the xlsx Skill.

User: “Help me analyze this Excel sales data.” Claude automatically loads xlsx Skill and performs the analysis.

Manual invocation

Enter /skill-name to force a specific Skill, e.g.:

User: /canvas-design generate a tech‑style poster

Listing loaded Skills

Enter /skills in the Claude Code session to see all currently loaded Skill names.

Creating a custom Skill

A custom Skill is defined by a SKILL.md file with two sections.

YAML metadata (required)

---
name: skill-name
description: A concise one‑sentence description used for automatic matching.
---

Markdown instruction body

Provide detailed steps, checklists, and output format requirements. The more specific, the better.

Example: Spring Boot code review Skill

---
name: spring-boot-review
description: Review Spring Boot code, focusing on controllers, services, and security practices.
---
# Spring Boot Code Review Skill

When asked to review Spring Boot code, follow this process:

1. **Architecture review**
   - Verify layered architecture (Controller → Service → Repository).
   - Prefer constructor injection over field injection.

2. **Controller review**
   - Ensure REST endpoint naming (e.g., /api/users).
   - Use DTOs instead of exposing entities.
   - Validate parameters (e.g., @Valid).

3. **Service review**
   - Keep business logic clear, avoid deep nesting.
   - Reasonable @Transactional scope.
   - Proper custom exception handling.

4. **Security review**
   - Check for SQL injection, XSS risks.
   - Mask sensitive data such as passwords.

5. **Report format**
   - **Overall rating**: Excellent / Good / Needs improvement
   - **Key issues**: List of high‑risk problems
   - **Improvement suggestions**
   - **Best practices**: Highlight good code

Hands‑on demo: generating a project PPT with the pptx Skill

Prerequisites

Claude Code installed (the pptx Skill is built‑in, no extra install needed).

Project directory initialized, preferably under Git.

Step 1 – Issue the request

Start a Claude Code session and type a natural‑language request, for example:

Please generate a PPT for the “User Management System” project progress, covering background, current status, issues, and next‑week plan, in a professional concise style.

If the pptx Skill folder is not yet in the project, copy it into .claude/skills/ as shown.

Step 2 – Automatic loading

Claude detects the “generate PPT” intent, loads the pptx Skill, and produces the presentation.

Best practices and cautions

Precise description : The description field drives automatic matching; keep it clear and scoped.

Layered instruction : Break complex workflows into sub‑steps with explicit checks.

Combine with global config : Use CLAUDE.md for project‑wide settings and Skills for task‑specific logic.

Version control : Store .claude/skills/ in Git for traceability and team sharing.

Chat before writing : Discuss complex requirements with Claude first to refine the design, reducing rework.

Conclusion

Claude Code Skills provide a lightweight, extensible way to customize AI capabilities. Built‑in document‑processing Skills and custom Skills for code review or architecture design capture expert knowledge and align the AI with specific business needs.

The pptx example demonstrates the “describe intent, not implementation details” workflow and serves as a template for creating additional Skills.

References Claude Code official documentation Awesome Claude Skills community repository