AgentForceTest/AGENT_SKILLS_GUIDE.md

VS Code Agent Skills: Complete Guide

Summary

Agent Skills are reusable folders containing instructions, scripts, and resources that GitHub Copilot can automatically load when relevant to perform specialized tasks. They form an open standard working across multiple AI agents including GitHub Copilot in VS Code, CLI, and coding agent.

---

Key Points

1. What Are Agent Skills?

• Folders of instructions, scripts, and resources that Copilot loads on-demand
• Open standard (agentskills.io) enabling portability across different AI tools
• Automatically activated based on your prompt—no manual selection needed

2. Key Benefits

• Specialize Copilot: Tailor capabilities for domain-specific tasks
• Reduce repetition: Create once, use automatically across all conversations
• Compose capabilities: Combine multiple skills to build complex workflows
• Efficient loading: Progressive disclosure—only relevant content loads into context

3. Agent Skills vs Custom Instructions

Aspect	Agent Skills	Custom Instructions
Purpose	Teach specialized capabilities and workflows	Define coding standards and guidelines
Portability	Works across VS Code, Copilot CLI, and coding agent	VS Code and GitHub.com only
Content	Instructions, scripts, examples, and resources	Instructions only
Scope	Task-specific, loaded on-demand	Always applied (or via glob patterns)
Standard	Open standard (agentskills.io)	VS Code-specific

4. When to Use Agent Skills

• Create reusable capabilities across different AI tools
• Include scripts, examples, or resources alongside instructions
• Share capabilities with the wider AI community
• Define specialized workflows (testing, debugging, deployment)

5. Skill Storage Locations

• Project skills: .github/skills/ (recommended) or .claude/skills/ (legacy)
• Personal skills: ~/.copilot/skills/ (recommended) or ~/.claude/skills/ (legacy)

---

Creating a Skill: Step-by-Step

Directory Structure

.github/skills/
└── your-skill-name/
    ├── SKILL.md              (required)
    ├── script-template.js    (optional)
    ├── examples/             (optional)
    └── other-resources/      (optional)

SKILL.md File Format

Header (YAML Frontmatter - Required):

---
name: skill-name # Lowercase with hyphens (max 64 chars)
description: Brief description... # What and when to use (max 1024 chars)
---

Body (Content):

• Clear, specific instructions
• What the skill accomplishes
• When to use it
• Step-by-step procedures
• Examples of input and output
• References to included resources using relative paths: [reference](./filename)

Example Structure

A testing skill might include:

• SKILL.md - Testing instructions
• test-template.js - Template test file
• examples/ - Example test scenarios

---

How Copilot Uses Skills: Three-Level Loading System

Level 1: Skill Discovery

• Copilot reads name and description from YAML frontmatter
• Lightweight metadata determines skill relevance
• No context overhead

Level 2: Instructions Loading

• When request matches skill description
• Full SKILL.md body loads into context
• Detailed instructions become available

Level 3: Resource Access

• Copilot accesses scripts, examples, documentation as needed
• Resources don't load until referenced
• Keeps context efficient

Result: Install many skills with minimal context consumption—only what's needed loads.

---

Using Shared Skills

Finding Shared Skills

• Browse github/awesome-copilot repository
• Check anthropics/skills for reference skills

Implementation Steps

1. Browse available skills in repository
2. Copy skill directory to your .github/skills/ folder
3. Review and customize SKILL.md for your needs
4. Optionally modify or add resources

Security Considerations

• Always review shared skills before using
• Ensure compliance with your standards
• VS Code terminal tool provides controls for script execution
• Configure auto-approve options with allow-lists

---

Portability Across AI Agents

Agent Skills work with:

• GitHub Copilot in VS Code: Available in chat and agent mode
• GitHub Copilot CLI: Accessible in terminal
• GitHub Copilot Coding Agent: Used during automated coding tasks

Open standard enables skills to work across multiple AI ecosystems.

---

Current Status & Enablement

• Status: Currently in preview
• Enablement: Set chat.useAgentSkills setting to use Agent Skills

---

Related Resources

• Customize AI responses overview
• Create custom instructions
• Create reusable prompt files
• Create custom agents
• Agent Skills specification
• Reference skills repository

---

Quick Reference Checklist

When creating a skill, ensure you have:

• Unique, lowercase skill name with hyphens (max 64 chars)
• Clear description of capabilities and use cases (max 1024 chars)
• Comprehensive SKILL.md with header and body
• Step-by-step procedures and examples
• Optional: supporting scripts, templates, examples
• Optional: resource documentation with relative paths
• Placed in .github/skills/ or ~/.copilot/skills/
• Tested with chat.useAgentSkills enabled