GitHub Copilot Instructions - Ruler

Apply consistent development rules across all coding agents for the Ruler project.

What This Does

This skill configures GitHub Copilot to follow strict TDD (Test-Driven Development) practices, code formatting standards, and pull request workflows for the Ruler repository. It ensures all changes are properly tested, formatted, and reviewed before merging.

Instructions

Follow Test-Driven Development (TDD)

1. **Always write tests first** before implementing features

2. **Verify tests fail** before writing implementation code

3. **Make minimal changes** to pass the tests

4. **Ensure comprehensive test coverage** including:

- Unit tests for individual functions and modules

- Integration tests for component interactions

- End-to-end tests for full user workflows

Maintain Code Quality

1. **Run Prettier before every commit** to ensure consistent formatting

2. **Never commit unformatted code** - formatting is mandatory, not optional

3. **Follow existing code patterns** in the repository

Use Proper Git Workflow

1. **Create feature branches** for all changes (unless explicitly told otherwise)

2. **Submit pull requests** instead of committing directly to main

3. **Write descriptive PR descriptions** that include:

- Rationale behind the change

- Functional changes being made

- Specific files and modules affected

4. **Ensure all CI tests pass** before marking PR as ready:

- `npm ci` - Clean install dependencies

- `npm run lint` - Lint all code

- `npm test` - Run all tests

- `npm run build` - Verify build succeeds

Identify AI Commits

When committing code yourself using `git commit`, **always** include the AI author flag:

```bash

git commit --author="AI <[email protected]>" -m "Your commit message"

```

This allows AI-generated commits to be easily identified and tracked.

Workflow Example

1. Create a feature branch:

```bash

git checkout -b feature/your-feature-name

```

2. Write failing tests first:

- Add test cases that define the expected behavior

- Run tests to verify they fail: `npm test`

3. Implement minimal code to pass tests:

- Write only the code needed to make tests pass

- Run tests again to verify: `npm test`

4. Format code with Prettier:

```bash

npx prettier --write .

```

5. Run full CI suite locally:

```bash

npm ci && npm run lint && npm test && npm run build

```

6. Commit with AI author attribution:

```bash

git commit --author="AI <[email protected]>" -m "Add feature X with tests"

```

7. Push and create pull request:

```bash

git push origin feature/your-feature-name

```

8. Write comprehensive PR description covering rationale, changes, and affected files

Constraints

Key Files