creating-copilot-packages

Creating GitHub Copilot Packages

Overview

GitHub Copilot uses natural language markdown instructions. Repository-wide instructions use plain markdown with NO frontmatter. Path-specific instructions use YAML frontmatter with applyTo field.

Package Types

Type	File Location	Frontmatter
Repository-wide	.github/copilot-instructions.md	None (plain markdown)
Path-specific	.github/instructions/*.instructions.md	Required (applyTo field)

Quick Reference

Repository-Wide (No Frontmatter)

# API Development Guidelines

Follow REST best practices when developing API endpoints.

## Principles

- Use semantic HTTP methods (GET, POST, PUT, DELETE)
- Return appropriate status codes
- Include error messages in response body

Path-Specific (With Frontmatter)

---
applyTo: "src/api/**/*.ts"  # REQUIRED
excludeAgent: "code-review"  # Optional
---

Creating Repository-Wide Instructions

File: .github/copilot-instructions.md

Plain markdown with NO frontmatter:

# TaskManager Development Guidelines

## Architecture

### Frontend
- React 18 with TypeScript
- Vite for build tooling
- Zustand for state management
- Tailwind CSS for styling

### Backend
- Node.js with Express
- PostgreSQL with Prisma ORM
- JWT for authentication

## Coding Conventions

- Use TypeScript strict mode
- Functional components with hooks
- Colocate tests with source files
- Use Zod for runtime validation

## Testing

- Use Vitest for unit tests
- Aim for 80% coverage on new code
- Mock external dependencies

## Examples

\`\`\`typescript
// Good: RESTful endpoint
app.get('/api/users', async (req, res) => {
  try {
    const users = await db.users.findAll();
    res.json({ users });
  } catch (error) {
    res.status(500).json({ error: 'Failed to fetch users' });
  }
});
\`\`\`

Creating Path-Specific Instructions

File: .github/instructions/api-endpoints.instructions.md