How to Configure Agents and Instructions in GitHub Copilot

---
name: Backend Agents(TypeScript)
description: This custom agent implements backend features using TypeScript.
model: GPT-5.2
---

---
applyTo: "src/**/*.ts" # e.g. targeting ts files under src
---

---
name: Backend Developer Agent
description: Expert in backend development using NestJS
---

# Role

You are an expert in backend development using NestJS and TypeScript.

# Tech Stack

- **Framework**: NestJS 11.x
- **Language**: TypeScript 5.x
- **Database**: PostgreSQL
- **ORM**: TypeORM
- **Testing**: Jest

# Coding Conventions

- Adhere to the hexagonal architecture.
- Always add validation decorators to DTOs.
- Use custom exceptions that return appropriate HTTP status codes for exception handling.

# Testing Policy

- Write unit tests for all Service classes.
- Aim for a test coverage of over 80%.
``` ````

### Overall Instructions: Project-wide Conventions

```md: .github/copilot-instructions.md
# Coding Conventions

## Common Rules

- **Language**: Write comments and documentation in Japanese
- **Naming Convention**: 
  - Class names: PascalCase
  - Function and variable names: camelCase
  - Constants: UPPER_SNAKE_CASE
- **Indentation**: 2 spaces
- **Strings**: Use single quotes

## Prohibited Items

- Use of `any` type is generally prohibited (define types appropriately)
- Committing `console.log` statements is prohibited (use a logger)
- Hardcoding sensitive information is strictly forbidden

## Security

- Always validate external input
- Implement measures against SQL injection
- Apply guards to endpoints that require authentication and authorization
```

### Domain-specific Instructions: TypeScript-specific Rules

````md: .github/instructions/typescript.instructions.md
---
applyTo: "**/*.ts"
---

# TypeScript-specific Rules

## Naming Convention

- File names: kebab-case

## Type Definitions

- Prefer explicit type annotations
- Utilize Utility Types (`Partial`, `Pick`, `Omit`, etc.)
- Define complex types using `type` aliases

```typescript
// Good
type UserProfile = {
  id: string;
  name: string;
  email: string;
};

type UserProfileUpdate = Partial<Pick<UserProfile, 'name' | 'email'>>;

// Bad
const updateUser = (data: any) => { ... };
```

## Asynchronous Processing

- Use `async/await` (avoid Promise chains)
- Handle errors using `try-catch`

## Import Order

1. External libraries
2. Internal modules (absolute paths)
3. Relative paths

```typescript
// External libraries
import { Injectable } from '@nestjs/common';
import { Repository } from 'typeorm';

// Internal modules
import { UserEntity } from '@/entities/user.entity';
import { CreateUserDto } from '@/dto/create-user.dto';

// Relative paths
import { UserService } from './user.service';
```