# Agent Instructions

These instructions apply to AI coding agents working in this repository.

## Project context

This is an educational full-stack project focused on backend development. The expected stack is Node.js, React, and a local PostgreSQL database on Ubuntu.

The repository may start with only documentation and gradually grow into a structured application. Prefer small, understandable changes that are suitable for students learning backend engineering.

## Communication

- Reply to the user in Czech unless the user explicitly asks for another language.
- Write documentation, code comments, commit messages, and generated project text in English.
- Keep explanations practical and tied to the current codebase.

## Engineering guidelines

- Read the existing files before making assumptions about project structure.
- Follow existing conventions once code is added.
- Keep changes scoped to the requested task.
- Prefer clear, boring solutions over clever abstractions.
- Add comments only when they clarify non-obvious behavior.
- Do not commit local secrets, `.env` files, database dumps, or generated dependency directories.

## Expected local tools

- Node.js 22 or newer
- PostgreSQL installed locally
- Git
- npm unless the repository later standardizes on another package manager

## Suggested application conventions

When application code is introduced, prefer this layout unless the project chooses another structure:

```text
apps/backend
apps/web
packages/shared
docs
```

For backend work, include:

- Explicit environment variable validation.
- Database migrations instead of manual schema changes.
- Focused automated tests for controllers, services, and database behavior.
- Clear separation between HTTP handlers, business logic, and persistence.

For frontend work, include:

- React components with clear responsibilities.
- Typed API contracts shared with or generated from the backend when practical.
- Accessible forms, loading states, and error states.

## Database guidance

- Use a dedicated local database user for the application.
- Do not use the `postgres` superuser as the application user.
- Store local connection strings in `.env`.
- Keep schema changes in migrations once a migration tool is selected.

Recommended local development database URL:

```bash
DATABASE_URL="postgresql://rg_academy:rg_academy@localhost:5432/rg_academy_dev"
```

## Verification

Before finishing code changes, run the relevant checks when they exist:

```bash
npm run lint
npm run test
npm run build
```

If a command is missing because the project has not been scaffolded yet, state that clearly in the final response.