# Using agent-skills with GitHub Copilot

## Setup

### Copilot Instructions

Copilot supports creating agent skills using a `.github/skills`, `.claude/skills`, or `.agents/skills` directory in your repository.

```bash
mkdir -p .github

# Create files for essential skills
cat /path/to/agent-skills/skills/test-driven-development/SKILL.md > .github/skills/test-driven-development/SKILL.md
cat /path/to/agent-skills/skills/code-review-and-quality/SKILL.md > .github/skills/code-review-and-quality/SKILL.md
```

For more details, refer [Creating agent skills for GitHub Copilot](https://docs.github.com/en/copilot/how-tos/use-copilot-agents/coding-agent/create-skills).

### Agent Personas (agents.md)

Copilot supports specialized agent personas. Use the agent-skills agents:

```bash
# Copy agent definitions
cp /path/to/agent-skills/agents/code-reviewer.md .github/agents/code-reviewer.md
cp /path/to/agent-skills/agents/test-engineer.md .github/agents/test-engineer.md
cp /path/to/agent-skills/agents/security-auditor.md .github/agents/security-auditor.md
```

Invoke agents in Copilot Chat:

- `@code-reviewer Review this PR`
- `@test-engineer Analyze test coverage for this module`
- `@security-auditor Check this endpoint for vulnerabilities`

### Custom Instructions (User Level)

For skills you want across all repositories:

1. Open VS Code → Settings → GitHub Copilot → Custom Instructions
2. Add your most-used skill summaries

## Recommended Configuration

### .github/copilot-instructions.md

GitHub Copilot supports project-level instructions via `.github/copilot-instructions.md`.

```markdown
# Project Coding Standards

## Testing

- Write tests before code (TDD)
- For bugs: write a failing test first, then fix (Prove-It pattern)
- Test hierarchy: unit > integration > e2e (use the lowest level that captures the behavior)
- Run `npm test` after every change

## Code Quality

- Review across five axes: correctness, readability, architecture, security, performance
- Every PR must pass: lint, type check, tests, build
- No secrets in code or version control

## Implementation

- Build in small, verifiable increments
- Each increment: implement → test → verify → commit
- Never mix formatting changes with behavior changes

## Boundaries

- Always: Run tests before commits, validate user input
- Ask first: Database schema changes, new dependencies
- Never: Commit secrets, remove failing tests, skip verification
```

### Specialized Agents

Use the agents for targeted review workflows in Copilot Chat.

## Usage Tips

1. **Keep instructions concise** — Copilot instructions work best when focused. Summarize the key rules rather than including full skill files.
2. **Use agents for review** — The code-reviewer, test-engineer, and security-auditor agents are designed for Copilot's agent model.
3. **Reference in chat** — When working on a specific phase, paste the relevant skill content into Copilot Chat for context.
4. **Combine with PR reviews** — Set up Copilot to review PRs using the code-reviewer agent persona.
